1 2 Louisiana Rice Production Handbook Foreword Clayton A. Hollier Introduction...... 4 Steven D. Linscombe General Agronomic Guidelines...... 4 Steven D. Linscombe, John K. Saichuk, K. Paul Seilhan, Patrick K. Bollich and Eddie R. Funderburg Growth and Development of the Rice Plant...... 12 Richard T. Dunand DD-50 Rice Management Program...... 20 John K. Saichuk, Steven D. Linscombe and Patrick K. Bollich Rice Varieties...... 23 Kent S. McKenzie, Steven D. Linscombe, Farman L. Jodari, James H. Oard and Lawrence M. White III Soils, Plant Nutrition and Fertilization...... 32 Patrick K. Bollich, John K. Saichuk and Eddie R. Funderburg Pest Management...... 37 Weed Management David Jordan and Dearl E. Sanders Disease Management Donald E. Groth, Milton C. Rush and Clayton A. Hollier Insect Management Dennis R. Ring, James Barbour, William C. Rice, Michael Stout and Mark Muegge Blackbird Management James F. Fowler and Joseph A. Musick Harvest and Storage...... 95 Harvesting Rice William A. Hadden Rice Drying and Storage Douglas L. Deason Rice Economics...... 100 L. Eugene Johnson, G. Grant Giesler and Michael E. Salassi Farm Management Marketing U. S. Farm Policy for Rice Glossary...... 110

3 Foreword Clayton A. Hollier Rice has been produced in Louisiana since the early 1700s. Not only have the methods of growing rice changed dramatically in the last 300 years, but also the systems by which we share information about rice production. Although there are other methods of disseminating information, for years extension and research publications have addressed specific aspects of rice production in the state. In the 1980s several faculty members in the Louisiana State University Agricultural Center recognized that a comprehensive, one-volume publication was needed to advise extension agents, agribusiness dealers, consultants and any other rice industry representatives about rice production in Louisiana. That Rice Production Handbook, published in 1987, was not intended to replace other LSU Agricultural Center publications, but to enhance existing and future rice publications written by the LSU Agricultural Center faculty. The current volume, in many ways, is not a revision of the 1987 publication although some portions of the original version have been revised. The Louisiana Rice Production Handbook is, in reality, a new publication encompassing the technology and knowledge of today that will help the rice industry of Louisiana flourish in the next millennium. I thank all of those who supported this effort, especially the authors of the various sections and the reviewers of the entire publication. Their many hours of dedication, advice and encouragement are appreciated more than can be expressed here. Also, thank you to all who provided the slides for the photographs. Photographs express in many ways what words cannot.

Introduction Steven D. Linscombe French explorers led by Bienville first introduced rice into Louisiana in 1718. The production of rice was limited for the next 150 years. It was grown mainly in small plots along the Mississippi River as food for laborers and low income farmers. Production increased rapidly after the Civil War. The total crop increased from 1.6 million pounds in 1864 to 9.5 million pounds four years later. Production reached 22 million pounds by 1874 and doubled in the next three years. In 1884, a visiting farmer from Iowa discovered that rice could be produced on the broad flat prairie lands of southwest Louisiana by using mechanized methods then used to produce wheat in the upper Mississippi Valley. This led to a major expansion of rice production. Production has expanded to other areas of Louisiana, especially the northeastern portion. Rice continues to be an important agronomic crop in southwestern Louisiana also. Rice acreage has fluctuated in Louisiana in recent years from a high of 620,000 acres in 1994 to a low of 518,000 acres in 1991. Much of this fluctuation has been caused by farm policy programs and world market economics. Rice will continue to be important to Louisiana agriculture. With this in mind, LSU Agricultural Center scientists who work in various aspects of rice production and economics in Louisiana have written this publication to help Louisiana producers increase yields while holding down costs and thus increase their profits. The information incorporates the latest findings from extensive rice research and extension programs conducted in Louisiana by the LSU Agricultural Center. Much of this work is funded at least partially by the state’s rice producers through check-off funds administered by the Louisiana Rice Research Board. 4 GeneralGeneral AgronomicAgronomic GuidelinesGuidelines Steven D. Linscombe, John K. Saichuk, K. Paul Seilhan, Patrick K. Bollich and Eddie R. Funderburg

Site Selection soils are usually not suitable for rice Because rice is grown under flooded production. An important factor, regardless conditions, it is best produced on land that of soil texture, is the presence of an is nearly level, minimizing the number of impervious subsoil layer in the form of a water retaining barriers or levees required. fragipan, claypan or massive clay horizon Some slope is required to facilitate that minimizes the percolation of irrigation adequate drainage. Generally, slopes of water, making it possible to hold water in less than 1 percent are necessary for rice paddies which are, in essence, adequate water management. Most of shallow ponds. Louisiana’s rice-growing areas are well suited for rice production with a minimum Water Requirements of land forming. Recent innovations using The ability to achieve optimum water laser systems have made precision leveled management is essential in attempting to or graded fields physically and maximize rice yields. In general, pumping economically feasible. capabilities are adequate if a field can be Precision grading of fields to a slope of flushed in two to four days, flooded in 0.2 foot or less change in elevation four to five days, and drained, dried and between levees is important in rice reflooded in two weeks. This is much production for the following reasons: (1) easier on fields that have been uniformly permits uniform flood depth, (2) may leveled to a slope of no more than 0.2 eliminate a large number of levees, (3) foot fall between levees. facilitates rapid irrigation and drainage, (4) can lead to the use of straight, parallel Planting Dates levees which will increase machine The optimum seeding dates will vary efficiency, (5) eliminates knolls and by location as well as from year to year potholes which may cause delay of flood because of variation in environmental or less than optimum weed control and (6) conditions. Rice yields may be reduced by reduces the total amount of water planting too early or too late. Average necessary for irrigation. daily temperature at seeding is important Previous cropping history is important in stand establishment. At or below 50 when selecting fields. Some herbicides degrees F, little or no rice seed used on rotation crops may persist in the germination occurs. From 50 degrees to soil and injure rice planted the next year. 55 degrees F, germination increases but Some herbicide labels may preclude not to any great extent until above 60 growing rice the year after that herbicide degrees F. Plant survival is not satisfactory is used. until the average daily temperature is above 65 degrees F. Soils Based on this information and seeding Rice can be grown successfully on date research, the following dates of many different soil textures throughout seeding recommendations are made: Louisiana. Most rice is grown on the silt Southwest Louisiana - March 20 - April loam soils derived from either loess or old 30 alluvium, which predominate the North Louisiana - April 10 - May 15 southwestern region, and, to a lesser Extremely early seeding can lead to a extent, the Macon Ridge area of northeast number of problems including (1) slow Louisiana. The clay soils in the emergence and poor growth under colder northeastern and central areas derived conditions because of the inherent lack of from more recent alluvial deposits are also seedling vigor and cold tolerance in many well adapted to rice culture. Deep sandy varieties, (2) increased damage from 5 seedling diseases (predominantly water disease pressure and spindly plants that mold) under cool conditions, (3) increased may be more susceptible to lodging. damage from birds (blackbirds, ducks and Experimental results and commercial geese) which are more numerous in the experience have shown that higher early spring and (4) decreased activity of seeding rates are required when broadcast some herbicides. seeding than drilling rice. Water seeding or While later seeding may avoid some dry broadcasting requires 120-150 pounds problems associated with very early of seed per acre. Drill seeding requires planting, delays much beyond the 90-110 pounds of seed per acre. Within optimum planting dates usually result in each category is a range of planting rates other problems. In general, excessively to allow for some adjustment. The higher late planting results in lower yields, seeding rates should be used when increased disease and insect pressure, and planting under less than optimum poorer grain quality at harvest. conditions. Examples of circumstances when the higher seeding rate should be Seeding Rates used include: The establishment of a satisfactory plant (a) Use higher recommended seeding population is an essential first step in rates when planting early in the season successful rice production. When when there is potential for unfavorably compared to other crops such as corn and cool growing conditions. Cool conditions soybeans, the emergence rate of rice is will favor water mold (seedling disease) in quite low, ranging from 50 percent to 60 water-seeded rice. This can reduce stands. percent. This is especially true in water Varieties also differ in tolerance to cool seeding and reduced tillage systems. growing conditions in the seedling stage. Seeding rates have been determined by (b) Varieties differ considerably in researchers with these factors taken into average seed weight. Thus, a variety with consideration. a lower average seed weight will have Rice in Louisiana is planted using three more seed per pound. Table 1 shows seed basic methods: water seeding (dry or weight per pound and the average number presprouted seed dropped into a flooded of seed per square foot at several seeding field), drill seeding (planting with a drill rates for most of the varieties. Producers on 7- to 10-inch drill spacing) and dry may want to adjust seeding rates for this broadcasting (dry seed applied to a factor. drained or dry field by either ground (c) Where seed depredation by equipment or airplane). blackbirds is potentially high, use a higher Regardless of the seeding system used, seeding rate. the desired plant stand is constant. The (d) Where seedbed preparation is optimum stand is 15-20 plants per square difficult and a less than optimum seedbed foot; the minimum stand is eight plants per is prepared, use a higher seeding rate. square foot and the maximum stand is (e) If it is necessary to use seed of low about 30 plants per square foot. Like most germination percentage, compensate with grasses, rice has the ability to tiller or stool seeding rates. Always use high and produce several panicle-bearing stems germination, certified seed if possible. from one plant. This ability to compensate (f) When water seeding into stale or accounts for successful grain production no-till seedbeds with excessive vegetation, from as few as eight seedlings per square use higher seeding rates. foot, provided proper cultural practices are (g) If any other factor exists which may used and growing conditions are good. cause stand establishment problems (such Stands also can be too dense. Excessive as slow flushing capability or saltwater plant populations can often lead to problems), consider it when selecting a reduced tiller production, more severe seeding rate.

6 Dry Seeding, Fertilization Timing and recommended. Avoid large amounts of Water Management preplant nitrogen in a dry-seeded system Dry seeding is the predominant method since wetting and drying cycles before the of seeding used in the north Louisiana permanent flood can lead to loss of much rice-growing areas. Dry seeding normally of this nitrogen. Most of the nitrogen works best on those soils where a well- should be applied to a dry soil surface prepared seedbed is practical and where within five days of permanently flooding red rice is not a severe problem. Rice can the field. If the precise nitrogen be dry-seeded using either a grain drill or requirement is known, if the permanent by broadcasting. flood will be maintained, and if the field When rice is to be drill seeded, a well- will not be allowed to dry until maturity, prepared, weed-free seedbed is desirable. all of the nitrogen can be applied ahead of A well-prepared seedbed will facilitate the permanent flood. uniform seeding depth. This is important When the required nitrogen rate is not in establishing a uniform stand. Depth of known, or the field will be drained before seeding is important with all varieties, but harvest for any reason, apply about 70 is critical with semidwarf varieties. The percent of the estimated requirement at semidwarfs are inherently slower in this time. Additional nitrogen should be development during the seedling stage, applied at mid season. Large amounts of and the mesocotyl length is shorter than in nitrogen should not be applied into the taller varieties. Therefore, semidwarfs flood on seedling rice because it is subject should be seeded no deeper than 1 inch to to loss. With this system, the permanent maximize uniform stand establishment. flood should be applied as soon as The taller varieties may be planted possible without submerging the rice somewhat deeper, but avoid seeding plants. This will normally be at the 4 to 5 depths of more than 2 inches with any leaf stage in fairly level fields. Delaying variety. permanent flood with the intention of Where soil moisture is adequate, a flush reducing irrigation costs may increase may not be necessary. But, when soil other production costs, reduce yields and moisture is insufficient and rainfall is not decrease profits. Additional information imminent, the field should be flushed on fertilizer timing in relation to water within four days after seeding to assure management can be found in the Rice uniform emergence. This necessitates Soils, Plant Nutrition and Fertilization having levees constructed and butted at or section. soon after seeding. Rice can be broadcast on a dry seedbed Water Seeding, Fertilizer Timing and using either ground or aerial equipment. Water Management Seed should be covered using a harrow or Water seeding is the predominant similar implement. Uniformity of seeding method of rice seeding used in Louisiana. depth is much more difficult using this It is widely used in southwest Louisiana system. As with drill seeding, an and, to a lesser extent, in the northern immediate flush may facilitate uniform portion of the state. stand establishment. The use of a water seeding system can Fertilization timing and water provide an excellent cultural method of management are similar for both drill- red rice suppression and is the primary seeded and broadcast dry rice. reason for the popularity of this system in Phosphorus, potassium and micronutrient south Louisiana. Rice farmers who raise fertilizers should be preplant incorporated crawfish in rice fields use water seeding based on soil test results. The addition of because it is easily adapted to the 15 to 20 pounds of preplant nitrogen will situation. Other farmers have adopted ensure against nitrogen deficiency in water planting as a matter of custom, seedling rice and is generally convenience or both. Water seeding is

7 sometimes an alternative planting loss during the initial drain is increased by operation when excessive rainfall prevents dragging. dry planting methods. Water planting may be accomplished Seedbed preparation is somewhat with dry or presprouted seed. Using different when water seeding is used. The presprouted seed when water planting seedbed should be left in rougher offers the advantages of higher seed weight condition than for dry seeding. This can be and initiation of germination. Presprouting is accomplished by preparing a seedbed accomplished by soaking seed for 24-36 consisting primarily of large clods hours and draining for 24-36 hours prior to (approximately baseball-sized). This seeding. Under cool conditions, these method may be easier to accomplish with periods may need to be extended heavy textured soil. Then begin flooding somewhat. A disadvantage is that seed must as soon as possible. The rice should then be planted shortly after presprouting or be seeded within three to four days. This deterioration will occur. will reduce potential weed problems and Water management of water-seeded rice provide a more favorable oxygen after seeding may be categorized as relationship at the soil/water interface. prolonged drainage, pinpoint flood or Low oxygen levels are often a problem continuous flood. where flood water is held for a long time before seeding. Delayed Flood A preferable alternative is to prepare a When a delayed flood system is used, smooth seedbed similar to that for drill fields are drained after water seeding for an seeding then firm with a grooving extended period (usually three to four implement. The result is a seedbed with weeks) before the permanent flood is grooves (1 ½ - 2 inches deep) on 7- to 10- applied. This system is normally used inch centers. In some cases a field where red rice is not a problem because it cultivator can do an acceptable job. Some gives no red rice suppression. With this producers are constructing tools solely for system, fertilization timing and water this purpose. They are based on similar management after the initial drainage are tools used in California and on Louisiana similar to dry-seeded systems. ingenuity. The rough seedbeds minimize seed Pinpoint Flood drift and facilitate seedling anchorage and The most common water seeding system rapid seedling development. Seed and is the pinpoint flood. After seeding with seedling drift can often be quite severe, presprouted seed, the field is drained especially in large cuts which are briefly. This drainage period is only long becoming more common as a result of enough to allow the radicle to penetrate the precision leveling. The large clods or soil (peg down) and anchor the seedling. shallow grooves provide a niche for the Under normal conditions, a three- to five- seed to fall into and give some protection day drainage period is sufficient. The field from wave action. is then permanently flooded until the rice Avoid dragging a field in the water nears maturity. (An exception is when before seeding because: (1) Dragging midseason drainage is necessary to alleviate leaves a seedbed in an extremely slick straighthead.) Rice plants emerge through condition, which will often lead to severe the flood. The plant must be above the seed drift, (2) crusting and curling of the water surface by at least the fourth leaf surface after draining is normally more stage. Before this stage, the plant normally severe where a field has been dragged, has sufficient stored food and available (3) when the drag is pulled to an oxygen to survive. Atmospheric oxygen excessive depth, incorporated fertilizers and other gases are then necessary for the and herbicides are displaced and unevenly plant to grow and develop. This system is distributed and (4) the potential for soil an excellent means of suppressing red rice

8 from seeds in the soil. Since the field is Fertilization timing is the same for both maintained in a flooded (or saturated) the pinpoint and continuous flood systems. condition, oxygen necessary for red rice Phosphorus, potassium, sulfur and zinc germination is not available. should be preplant incorporated as in the dry-seeded system. Once the flood is Continuous Flood applied, the soil should not be allowed to A continuous flood system is used on a dry. limited basis in Louisiana. This system is If the nitrogen requirement is known, all similar to the pinpoint system, except that nitrogen should be incorporated preflood- after seeding, the field is never drained. Of preplant. Otherwise, incorporate 70 per- the three water management systems, cent of the estimated requirement, then continuous flood is normally best for red apply the additional nitrogen as a topdress rice suppression, but stand establishment is at midseason. More information on fertilizer most difficult. Even the most vigorous timing in relation to water management is variety may have problems becoming in the Soils, Plant Nutrition and Fertilization established under this system. section. Second Crop Table 1. Seed per pound and average number of Production in Rice seed per square foot for important rice varieties. The climatic ______conditions of Average number of seed/ft2 at southwest Louisiana, various seeding rates along with the 80 100 120 140 earliness of Variety Seed/lb lb/A lb/A lb/A lb/A commonly grown rice ______varieties, combine to create an opportunity Akitakomachi 17579 32 40 48 56 for second crop Alan 20731 38 48 58 67 production. Second Bengal 15442 28 35 42 49 crop rice, also known Cypress 19156 35 44 53 62 as stubble or ratoon Della 21429 39 49 59 69 crop rice, is Dellrose 18564 34 43 52 60 produced from Dixiebelle 21919 40 50 60 70 regrowth on the Drew 20938 38 48 58 67 stubble after the first Gulfmont 16099 30 37 44 52 crop has been Jackson 18607 34 43 52 60 harvested. Jasmine-85 18088 34 42 50 59 Weather during Jefferson 15133 28 35 42 49 the fall will normally Jodon 18160 34 42 50 59 dictate how Katy 21827 40 50 60 70 successful a farmer Kaybonnet 21826 40 50 60 70 can be at producing a Lacassine 18306 34 42 50 59 second crop. Mild Lafitte 17734 33 41 49 57 temperatures will LaGrue 18088 34 42 50 59 speed second crop Lemont 17322 32 40 48 56 maturity and can Litton 17597 32 40 48 56 prevent excessive Mars 17832 33 41 49 57 sterility (or blanking) Maybelle 18996 35 44 53 62 Millie 17004 31 39 47 55 associated with low Priscilla 16449 30 38 45 52 temperatures at Rico 1 17024 31 39 47 55 flowering. Remember Saturn 21120 38 48 58 67 that average daily Toro-2 17869 33 41 49 57 high and low temperatures used in 9 DD-50 based predictions are just as apply the nitrogen to a dry soil surface important in the development of second and establish a shallow flood immediately crops. Later than normal first frost dates after harvest. This will facilitate rapid will help to produce second crops, regrowth and efficient use of applied especially when the first crop was nitrogen. harvested later than August 10. It is Consult the annual publication Rice recommended that the first crop be Varieties and Management Tips (Publication harvested at least by the middle of August 2270) when selecting varieties with the to assure adequate time for the second intention of producing ratoon or second crop to develop. In years with an crop rice. abnormally mild fall and a late first frost, second crops can be produced when the Conservation Tillage Management first crop is harvested as late as the first The following information is based in week of September, but this is the part on specific research results obtained exception rather than the rule. from studies conducted at the Rice While cooperation from the weather is Research Station since 1987. Some has essential for second crop production, been generalized based on observations cultural practices can play an extremely from these studies and not necessarily critical part in maximizing stubble crop scientific measurements. The knowledge yields. It must be emphasized that cultural base on conservation tillage in rice is still practices used in the first crop can have a limited, and additional research needs to major impact on second crop production. be conducted. Basic components of these Excessive rates of nitrogen applied to the alternative production practices will be first crop can often delay the regrowth of summarized emphasizing advantages and the second crop. Therefore, excessive disadvantages. This information is rates of nitrogen should be avoided even adequate for use as a general guideline with a variety with high levels of but may not be applicable to every resistance to lodging. Disease pressure in situation. Three alternative seedbeds have the first crop can have an effect on the been compared with conventionally second crop. Severe disease pressure in prepared seedbeds in both water- and the first crop can actually cause death of drill-seeded cultural systems. The practices tillers and prevent regrowth from these are defined as follows: plants. Use of a foliar fungicide in the first crop can be beneficial to the second crop. Spring Stale Seedbed Conditions at harvest will influence Land is prepared three to six weeks whether a second crop should be before planting. Depending on attempted. If it’s necessary to harvest temperature and rainfall, vegetation that under muddy conditions and the field is establishes before planting is usually small, excessively rutted, second cropping will sparse and easy to control. Most farmers be difficult and probably should not be see little advantage to this option when attempted. Excessive amounts of red rice compared with spring seedbed preparation in the first crop will also limit yield and at the normal time. But, this option does reduce quality in the second. It may be offer one important benefit. During dry beneficial to avoid second crop production springs, seedbeds can be worked early and concentrate on encouraging and readied for planting. If excessive germination of red rice seed followed by rainfall occurs before planting, time, destroying the seedlings by fall plowing. money and labor can be saved by This may decrease the red rice problem in controlling preplant vegetation with a succeeding crops. burndown herbicide rather than waiting for An application of nitrogen fertilizer will the seedbed to dry enough to prepare be necessary when striving for high mechanically. This system improves the second crop yields. It is normally best to chance of timely planting.

10 Fall Stale Seedbed in the planted rice crop. There are also Seedbeds are completely prepared in preplant intervals for Harmony Extra (45- the fall. Vegetation that establishes over day) and 2,4-D (15-day) applied alone or the winter in this practice is usually tankmixed with burndown herbicides. A uniform in cover, 8 to 10 inches in height, disadvantage is the extended preplant time and consists of winter annual grasses, intervals, especially with Harmony Extra. clovers, vetches and other broadleaves. All of these herbicides must be applied This practice is probably the most popular according to label directions. in the southwest area. Better drying Planting practices - Use presprouted conditions and more favorable weather in seed when water seeding. This will help the fall allow more opportunity for field establish stand more rapidly and minimize preparation. germination problems associated with poor floodwater quality, low oxygen, seedling No-till diseases and potential seed midge Rice is planted directly into previous damage. Seed-to-soil contact is important crop residue or native vegetation. In the and is a function of the amount of southwest area, soybeans would be the vegetation and, to some extent, the type typical rotation crop. Cotton and soybeans of vegetation. When drill seeding, it is are options in northeast Louisiana. Preplant important to use planting equipment that vegetation is usually not uniform in size places seed at a uniform depth and closes and is usually comprised of much larger, the seed slit to conserve moisture. On woody winter weeds that pose problems some soils, it may not be necessary to use when controlling preplant vegetation. Rice no-till equipment. establishment practices used in Good quality conventional planters conservation tillage systems are described perform well on mellow seedbeds. Heavy, below. no-till equipment is desirable where Preplant vegetation control - vegetation is excessive and seedbeds are Roundup and Gramoxone are labeled for compacted. burndown in rice. Consult the herbicide Water management - Reduced stand label for rate of application and weed has been a common problem in water- control spectrum. Rate depends on type seeded, no-till rice, especially when and size of weed, and herbicides should pinpoint flooding. Delaying permanent be applied according to label directions. flood establishment for two to three weeks Some rice is no-tilled without termination after water seeding and draining will of preplant vegetation. This is possible if improve stands in some situations. It is weed growth is minimal and the important, however, that adequate vegetation is winter annuals that will moisture be provided by rainfall or eventually die out or be killed by flooding. irrigation in delayed flood systems. Significant yield reductions have occurred Excessive drying of the seedbed during in studies where preplant vegetation was rooting can also cause stand reduction. excessive and a herbicide was not used Delayed flooding is not a desirable for burndown. Opting not to use a management practice when red rice is a burndown chemical can be risky, and problem, and control or suppression of red weed identification is extremely important. rice will be significantly reduced when Time of application in relation to this type of water management is planting - Best results in most of the practiced. Red rice control using research have occurred with a seven- to conservation tillage has been less 10-day preplant application. This is consistent than conventional water seeding especially true when the residual practices. herbicides are tankmixed with the Stand establishment difficulties burndown herbicides. Longer intervals encountered when drill seeding have often between burndown and planting reduce been associated with lack of moisture. If the effectiveness of residual weed control moisture is inadequate at planting, flush 11 the field to encourage uniform emergence Fertilizer management - Plant and stand establishment. Gibberellic acid nutrients can be surface applied in a no-till seed treatment may also enhance system. In stale seedbeds, phosphorus (P) emergence of some varieties. In water- and potassium (K) can be incorporated at seeded systems, seed to soil contact is the time of land preparation. This is often poor. As a consequence, frequent becoming a popular practice with fall flushing in delayed flood systems may be prepared seedbeds. Nitrogen management required. In a pinpoint flood system, it in the spring rice crop is much easier may be necessary to drain more than once when P and K have already been applied. to encourage rooting. In areas where scumming may be a Variety selection - Variety selection in problem, P and K should be applied in a a no-till system is important. Good no-till system after rice stand has been seedling vigor, tillering ability and yield established but by the fifth leaf stage. potential are important characteristics. These nutrients can be applied into Under ideal conditions, any commercial standing floodwater or before permanently variety being grown could be considered. flooding. Research supports the fact that no-till and When not to no-till - Excessive stale seedbeds are not ideal situations, and vegetation, hard to control weeds, rutted varieties that possess all of the above fields, unlevel land and red rice problem characteristics have shown the most fields are all candidates to consider for consistency. Some semidwarf varieties, more conventional planting practices. such as Lemont, struggle to establish stand Heavy vegetation reduces seed-to-soil in no-till seedbeds, especially when water contact and increases problems seeded. Yields have generally been establishing adequate stand. Weeds not reduced. Varieties that are taller or possess controlled before planting will cause good seedling vigor have performed well. significant problems with expensive Cypress is a semidwarf but has solutions after planting. Rutted fields and excellent seedling vigor and has shown unlevel land affect both flooding and consistency and good yielding ability. Tall draining of rice fields. Water management varieties, such as Mars and Jackson, are problems can be detrimental to successful also good candidates. Maybelle has been rice production. Control of red rice in no- somewhat inconsistent. Any of these till fields is still being evaluated. Severely varieties has potential in a no-till system infested fields should be managed by under ideal conditions; however, there is more conventional means. merit to choosing one over another based on the above general criteria.

GrowthGrowth andand DevelopmentDevelopment ofof thethe RiceRice PlantPlant Richard T. Dunand Introduction Growth and development of the rice The changes that occur in the rice plant plant involve continuous change. This as it grows and develops occur inside as means important growth events are well as outside and underground as well occurring in the rice plant at all times. as above ground. These changes can be Therefore, the overall daily health of the grouped into two phases of growth, each rice plant is important. If the plant is of which has several identifiable growth unhealthy during any state of growth, the stages based on development of the shoot. overall growth, development and grain The ability to identify growth stages is yield of the plant are limited. It is important for proper management of the important to understand the growth and rice crop. As more becomes known about development of the plant. factors affecting rice growth and 12 development, management practices Imbibition of water activates the embryo, designed to increase rice production will and the endosperm can serve as a source emerge. These management practices, just of nutrients for the growing embryo for as some of those in present use, will be about three weeks. In the embryo, two tied to the growth and development of the primary structures grow and elongate: the rice plant. An understanding of the growth radicle (first root) and coleoptile of rice is essential for management of a (protective covering enveloping the first healthy crop and for the proper use of the leaf). As the radicle and coleoptile grow, DD-50 rice management program. they apply pressure to the inside of the hull. Eventually the hull weakens under Phases of Growth the pressure, and the pointed, slender The growth and development of rice radicle and coleoptile emerge. When the begin with the germination of the seed radicle and coleoptile emerge from the and end with the formation of grain. hull, the stage of growth of the plant is During that period, the growth and germination (Fig. 1). development of the rice plant can be After germination, the radicle and divided into two phases: vegetative and coleoptile continue to grow and develop reproductive. These two phases deal with primarily by elongation (or lengthening) the growth and development of different (Fig 2). The coleoptile elongates until it plant parts, and they overlap. encounters light. To help the coleoptile to The vegetative phase deals primarily reach light, sometimes a second elongating with the growth and development of the structure, the mesocotyl, develops (Fig. 3). plant from germination to the beginning of The mesocotyl originates from the embryo panicle development inside the main stem. area and is attached to the base of the The reproductive phase deals mainly with coleoptile. The mesocotyl and coleoptile the growth and development of the plant can elongate at the same time. They are from the end of the vegetative phase to sometimes difficult to tell apart. Usually grain maturity. Both phases are important the mesocotyl is white, and the coleoptile in the life of the rice plant. They is off-white, slightly yellowish. Shortly complement each other to produce a plant after the coleoptile is exposed to light, which can absorb sunlight and convert that usually at the soil surface, it stops energy into food in the form of grain. elongation. At this time the stage of The vegetative and reproductive growth of the plant is emergence. phases of growth are subdivided into groups of growth stages. In the vegetative Seedling Stages phase of growth, there are four groups: (1) The seedling stages of growth begin emergence stages (2) seedling stages (3) when the primary leaf appears shortly tillering stages and (4) internode formation after the coleoptile is exposed to light and stages. Similarly, the reproductive phase splits open at the end (Fig. 4). The of growth is subdivided into five groups: primary leaf elongates through and above (1) prebooting stages (2) booting stages (3) the coleoptile (Fig. 5). It has no typical heading stages (4) grain filling stages and leaf blade and is usually an inch or less in (5) maturity stages. These growth stages length. The primary leaf acts as a are easily identified. protective covering for the next developing leaf. As the seedling grows, Growth Stages in the Vegetative Phase the next leaf elongates through and past the tip of the primary leaf. Continuing to Emergence Stages grow and develop, the leaf differentiates There are two emergence stages, into three distinct parts: the sheath, collar germination and emergence. Germination and blade (Fig. 6). A leaf that is is the first event in the life of a rice plant. differentiated into a sheath, a collar and a When exposed to the proper conditions, blade is complete; thus the first leaf to the seed swells as moisture is absorbed. develop after primary leaf is the first 13 complete leaf. This stage of growth is first on the first complete leaf. This trend is leaf (Fig. 7). noted for each subsequent leaf until about All subsequent leaves after first leaf are the ninth complete leaf, after which leaf complete leaves. The sheath is normally size decreases. Although a rice plant can the bottom-most part of a complete leaf produce many leaves, as new leaves are and is an elongated structure which grows produced, older leaves senesce, resulting upright and surrounds the stem. During the in a somewhat constant four to five leaves seedling stages, leaf sheaths originate at per plant at any given time. The second the base of the stem. In rice, the collar is a complete leaf develops on the side of the small area at the top of a leaf sheath and is culm from the first complete leaf. the point of origin of the blade. The Subsequent leaves develop in this sheath and collar are the most rigid alternate fashion so the third complete portions of the leaf. The blade is flexible. leaf is higher on the stem than the second The blade angles away from the sheath complete leaf and develops on the same and is flat with a pronounced, rigid midrib side of the stem as the first leaf, producing on its underside. The midrib runs the a pattern referred to as two-ranked and in length of the blade and provides support a single plane. Seedling growth continues for the blade. in this manner through third to fourth leaf, The blade is the part of the leaf where clearly denoting plant establishment. most photosynthesis occurs. It contains The root system begins to develop more chlorophyll than any other part of more fully during the seedling stages. In the leaf. Chlorophyll is the compound in addition to the radicle, other fibrous roots leaves which absorbs sunlight and converts develop from the seed area and, with the it to energy for growth. Chlorophyll is radicle, form the primary root system. The green, causing the blade to be the primary root system grows into a shallow, greenest part of the plant. The blade is the highly branched mass limited in its growth first part of a complete leaf to appear as a to the immediate environment of the seed. leaf grows and develops. It is then The primary root system is temporary, followed in order by the appearance of serving mainly to provide nutrients and the collar at the base of the blade and then moisture to the emerging plant and young the sheath below the collar. During the seedling. In contrast, the secondary root vegetative phase of growth, only the collar system originates from the base of the and blade of each complete leaf become coleoptile. During the seedling stages, the fully visible. Only the upper portion of the secondary root system is not highly sheath is visible, since the sheath remains developed and appears primarily as covered in part by sheaths of leaves several nonbranched roots spreading in all whose development preceded it. directions from the base of the coleoptile Since growth and development are in a plane roughly parallel to the soil continuous, at first leaf the tip of the blade surface. The secondary root system is of the second complete leaf usually is more permanent. It provides the bulk of already protruding through the top of the the water and nutrient requirements of the sheath of the first complete leaf. The plant after the seedling stages. second complete leaf grows and develops During the seedling stages, the plant in the same manner as the first complete has clearly defined shoot and root parts leaf, and when the collar is visible above (Fig. 9). Above the soil surface, the shoot the collar of the first complete leaf, the is composed of one or more completely stage of growth is second leaf (Fig. 8). developed leaves at the base of which are Subsequent leaves develop in the same the primary leaf and upper portions of the manner, and the stages of growth are coleoptile. Below the soil surface, the root classified accordingly as third leaf, etc. system is composed of the primary root When the second complete leaf system originating from the seed and the matures, the sheath and blade are each secondary root system originating from the longer and wider than their counterparts base of the coleoptile. Plants originating 14 from seed placed deep below the soil Tillers grow and develop in much the surface will have extensive mesocotyl and same manner as the main shoot, but they coleoptile elongation compared to plants lag behind the main shoot in their originating from seed placed near the soil development. This lag is directly related to surface. Seed placement on the soil surface the time a tiller first appears. It usually usually results in no mesocotyl results in tillers producing fewer leaves development and little coleoptile and having less height and slightly later elongation. In general, the presence of maturities than the main shoot. primary and secondary roots and a shoot During the tillering (stooling) stages, at which consists of leaf parts from several the base of the main shoot, crown leaves is the basic structure of the rice development becomes noticeable. The plant during the seedling stages of growth. crown is the region of a plant where a shoot and secondary roots join. Inside a Tiller Stages crown, nodes form at the same time as the Tillers (stools) first appear as the tips of development of each leaf. The nodes leaf blades emerging from the tops of appear as white bands about 1/16 inch sheaths of completely developed leaves on thick and running across the crown, usually the main shoot. This gives the appearance parallel with the soil surface. With time the of a complete leaf that is producing more nodes become separate and distinct, with than one blade. This occurs because tillers spaces (internodes) about 1/4 inch or less originate inside the sheath of a leaf just in length between them (Fig. 12). Initially above the point where the sheath attaches the plant tissue between nodes is solid, but at the base of the plant. If the leaf sheath with age the tissue disintegrates, leaving a is removed, the bud of a beginning tiller hollow stem between nodes. will appear as a small green triangular In addition to crown development, leaf growth at the base of the leaf. Tillers and root development continue on the which originate on the main shoot in this main shoot. An additional five to six manner are primary tillers. When the first complete leaves form with as many complete leaf of the first primary tiller is additional nodes forming above the older visually fully differentiated (blade, collar nodes in the main shoot crown. On the and sheath apparent), the stage of growth main shoot, some of the older leaves turn of the plant is first primary tiller (Fig. 10). yellow and brown. The changes in color The first primary tiller usually emerges begin at the tip of a leaf blade and from the sheath of the first complete leaf gradually move to the base. From this point before fifth leaf. If a second tiller appears, on, there is continuous aging of older it usually emerges from the sheath of the leaves and production of new leaves. The second complete leaf and so on. result is that there are never more than Consequently, tillers develop on the main four or five functioning leaves on a shoot shoot in an alternate fashion like the at one time. leaves. When the second primary tiller In addition to changes in leaves, the appears, the stage of growth of the plant is main shoot crown area expands. Some of second primary tiller (Fig. 11). The the older internodes at the base of the appearance of tillers in this manner usually crown crowd together and become continues through about fourth or fifth indiscernible by the unaided eye. Usually primary tiller. If plant populations are very no more than seven or eight crown low (fewer than 10 plants per square foot), internodes are clearly observable in a tillers may originate from primary tillers dissected crown. Sometimes the uppermost much in the same manner as primary tillers internode in a crown elongates ½ - 1 inch. originate from the main shoot. Tillers This can occur if depth of planting, depth originating from primary tillers are of flood, plant population, nitrogen fertility secondary tillers, and, when this occurs, and other factors which tend to promote the stage of growth of the plant is elongation in rice are excessive. Also secondary tillering. during the tiller stages, tiller crowns 15 develop. Along with growth of the main an internode, and it is also the first stem in shoot and tiller shoot crowns, more which internode formation ends. In the secondary roots form, arising from the tillers, internode formation lags behind the expanding surface of the crowns. These main stem and usually begins in the older roots grow larger than those which formed tillers first. during the seedling stages. They are wider During the internode formation stages, and longer at maturity. As the tiller stages each newly formed internode on a stem is end, the rice plant has actively tillered and longer and slenderer than the preceding has some dead and yellowing leaves, a one. The first internode formed is the basal completely developed main stem crown, most internode. It is the shortest and developing tiller crowns and an actively thickest internode of a stem. The basal developing secondary root system. internode is located directly above the crown. Sometimes, if the uppermost crown Internode Formation Stages internode is elongated, it can be confused The formation of internodes (joints) with the first internode of the main stem. above a crown is the process that produces One difference between these two a stem and determines stem length. internodes is the presence of roots. Internode formation above a crown begins Sometimes, especially late in the with the formation of a stem node similar development of the plant, the node at the to that of the crown nodes. The stem node top of the uppermost crown internode will forms above the uppermost crown node, have secondary roots associated with it. and a stem internode begins to form The upper node of the first stem internode between the two nodes. As the stem will usually have no roots. If roots are internode begins to form, chlorophyll present, they will be short and fibrous. The accumulates in the tissue below the stem last or uppermost internode which forms is node. This produces green color in that the longest and slenderest internode and is tissue. If the stem is properly dissected at directly connected to the base of the this time, green color encircling the stem panicle. The elongation of the uppermost (the green ring) may be apparent. This can internodes causes the panicle to be thrust be common for all internodes formed out in the heading stages during the above the crown. When the stem node and reproductive phase of growth. the uppermost node of the crown of the Internode length varies, depending on main shoot are clearly separated, internode variety and management practices. In elongation has begun and the stage of general, internode lengths vary from 1 inch growth of the plant is first internode or (basal internode) to 10 (uppermost green ring (Fig. 13). internode) inches in semidwarf varieties Before the first internode above the and from 2 inches to 15 inches in tall crown completes elongation, a second varieties. These values, as well as stem node forms above it. A second internode elongation in general, can be internode then begins to form below the influenced by planting date, plant second stem node and develops in a population, soil fertility, depth of flood, manner similar to that of the first internode weed competition, etc. (Fig. 14). This sequence recurs until the The number of internodes which forms last internode elongates completely. As the in the main stem is relatively constant for a newly formed nodes on the main stem variety. Varieties now being grown have become clearly separated by internodes, five to six internodes form above the the stages of growth of the plant progress crown in the main stem. In tillers, fewer from first internode to second to third, etc. internodes form than in the main stem. The With the formation and elongation of each number is highly variable and depends on stem internode, the length of the stem and how much the tiller lags behind the main the height of the plant increase. stem in growth and development. Internode elongation occurs in all stems. The time between seeding and The main stem is usually the first to form internode formation depends primarily on 16 the maturity of the variety, which is become highly branched. Newly formed normally controlled by heat unit exposure roots are white; older roots are brown and (see DD-50 Rice Management Program black. A matted root system forms in section). It can also be influenced by addition to the secondary root system. It is planting date, plant population, soil composed of fibrous roots, which fertility, flood depth and weed interweave and form a mat of roots near competition. In general, varieties classified the soil surface. In general, the root as very early season maturity reach first system has developed horizontally to a internode six weeks after emergence. greater degree than vertically. Varieties classified as early season maturity Tiller formation usually ceases and tiller reach first internode seven weeks after senescence (die off) begins during the emergence, and varieties classified as internode formation stages. More tillers are midseason maturity reach first internode produced during the tiller stages than will eight weeks after emergence. survive to maturity. In those tillers which The appearance of nodes above the will not survive, tiller senescence begins crown marks a change in the role of the as the crown becomes fully differentiated node as the point of origin of several plant and continues until the last internode forms parts. Before internode formation begins above the crown. A tiller which does not above the crown, all leaves, tillers and survive until maturity begins to lag behind secondary roots formed during that time in its development. Tiller senescence can originate from crown nodes. But after be recognized by the smaller size of a internode formation begins above the tiller in comparison to other tillers on a crown, the nodes serve mainly as the plant. It appears significantly shorter than point of origin of all subsequent leaves. other tillers, has fewer complete leaves Although possible, significant formation and fails to have significant internode of tillers and roots from nodes above the development above the crown of the tiller. crown is rare. Since the nodes become Eventually most leaves on an aging tiller separated significantly by internodes, the lose coloration while most leaves on other leaves which originate at these nodes are tillers are still green. Finally, the leaves more separate and distinct than leaves and stems of senescing tillers turn brown formed before internode formation. The and gray and, in most instances, disappear separation of these leaves increases as the before the plant reaches maturity. length of the internodes increases. The internode formation stages signal Eventually, more complete leaf structure the end of the vegetative stages of growth becomes apparent until the last two leaves as markers for determining the stage of to form have all or most of all three parts growth of the plant. As stem internodes (sheath, collar and blade) completely begin to form, the reproductive phase of visible. Since the last leaves formed growth is beginning. originate primarily from nodes above the crown, this means that, in varieties now in Growth Stages During the use, no more than six new complete Reproductive Phase leaves are produced on the main shoot after stem internode formation begins. The Prebooting Stages last of these leaves to form is the flag leaf. The prebooting stages of growth are It is the uppermost leaf on a mature shoot, the only stages during the reproductive and the sheath of the flag leaf encloses the phase that occur before leaf formation panicle during the elongation of the last ceases. During the prebooting stages, the two internodes. remaining leaves of the plant develop, Root growth approaches a maximum as internode elongation and stem formation internode formation above the crown continue, and panicle formation begins. begins. At this time, the secondary root The prebooting stages are identified by system has developed extensively in all the development of the panicle inside the directions below the crown and has main stem before the appearance of the 17 sheath (boot) of the flag leaf, the last leaf panicle branches which branch off the produced. The prebooting stages follow main trunk of the panicle (panicle axis) internode formation and, like internode and bear the florets. During the formation, involve the movement of the prebooting stages of growth, the panicle growing point inside the main stem away branches and florets first become visible from the crown. Within the growing point at the tip of the panicle. With time, is a specialized group of cells which panicle branches and florets appear becomes active during the prebooting below the tip. stages. The specialized group of cells While these developmental changes begins actively dividing and differentiates are occurring, the panicle continues to into a small panicle. elongate. As the panicle grows and When the cells first begin actively develops in this manner and reaches 2 dividing in the main stem, the stage of inches, the stage of growth is 2-inch growth of the plant is panicle initiation panicle. The identification of the (PI). Panicle initiation occurs during the prebooting stages of growth continues in fifth week before heading. Although this manner in 1-inch increments until the panicle initiation can be positively flag leaf has differentiated on the main identified only by microscopic stem. At that time the panicle inside the techniques, it is closely associated with main stem has elongated about 4 inches. the vegetative phase of growth. The The florets at the tip of the panicle are growth stages that coincide closely with clearly differentiated, while those near panicle initiation differ, depending on the the bottom are still in the developmental maturity of a variety. In very early season stages. varieties, panicle initiation and first internode (green ring) occur at about the Booting Stages same time. In early season varieties, The booting stages include a period panicle initiation and second internode during which the preflowering growth occur almost simultaneously, and, in and development of a panicle and its midseason varieties, panicle initiation and constituent parts are completed inside the third internode are closely concurrent. sheath of the flag leaf. The sheath of the The specialized group of cells that first flag leaf is the boot, and the booting begins actively dividing at panicle stages are classified according to its initiation continues to divide actively. development. Booting is divided into Eventually, a small panicle about 1/8 inch three stages: early, middle and late. Early in length and 1/16 inch in diameter boot (Fig. 16) occurs when the sheath of forms. At this point, the panicle can be the flag leaf first appears above the collar seen inside the stem, looking like a small of the penultimate leaf (leaf below the tuft of fuzz. When this occurs in the main flag leaf) on the main stem and lasts until stem, the stage of growth is panicle the sheath of the flag leaf is about 2 differentiation (PD) or panicle 2-mm (Fig. inches out of the sheath. Middle boot 15). The panicle, although small, has occurs when the sheath of the flag leaf is already begun to differentiate into distinct 2 to 5 inches out of the sheath, and late parts. Under a microscope, the boot (Fig. 17) when the sheath of the flag beginnings of panicle branches and leaf is 5 or more inches out of the sheath florets are recognizable. The panicle of the penultimate leaf. continues to grow during the prebooting During the booting stages, the growth stages. When the panicle is 1 inch long, and development of the panicle result in the stage of growth is 1-inch panicle. At a fully elongated panicle with a complete this stage, the panicle is a very compact, complement of panicle branches bearing elongated, slender structure covered with mature florets. In the florets, the many small knobs. As it grows, the production of mature pollen begins with knobby structures differentiate into the formation of pollen mother cells. This

18 begins in the uppermost florets on a identified by the appearance of small, panicle and progresses down the panicle. usually white or yellow anthers external The production of mature pollen reaches to the florets. Sometimes pollination a maximum during early boot. begins shortly after first heading, and Of the panicle parts which become sometimes it begins after full heading. apparent during the booting stages, the Most of the time, the first florets to panicle branches and florets are the most emerge are the first florets in which distinct and contribute greatly to the pollination occurs. Pollination then increase in panicle size. This is apparent continues down the panicle. The panicle in the outward appearance of a stem. As in most varieties is green, erect and the panicle branches and the florets grow relatively compact. and develop during the booting stages, the sheath of the penultimate leaf and the Grain Filling Stages flag leaf swell. This creates a noticeable During the grain filling stages, the bulge in the upper portion of a stem. As florets on the main stem change to the booting stages end, the panicle inside immature grains of rice. The formation of the boot has grown to its final length and grain results mainly from the is fully differentiated into a main axis accumulation of carbohydrate in the with panicle branches bearing fully florets. The source of the carbohydrate is developed florets. Also leaf development the uppermost three to four leaves and has been completed and only the two the stem. The carbohydrate which internodes directly below the panicle accumulates in the florets is stored in the remain to elongate significantly. form of starch, and the starchy portion of the grain is the endosperm. The Heading Stages carbohydrate which is translocated from The heading stages are associated with the leaves and stem is white and milky in the emergence of the panicle through the consistency as it initially accumulates. The sheath of the flag leaf on the main stem. first florets which have this accumulation (The heading stages are critical for timing are the first florets pollinated. When this of foliar fungicides; see the Disease milky accumulation is first noticeable Management section for more detail.) This inside florets on the main stem, the stage process is brought about mainly by the is milk stage (Fig. 20). gradual and continuous elongation of the During milk stage, the accumulation of uppermost internodes. As the elongation carbohydrate increases floret weight. of the uppermost internodes of the main Since the florets which accumulate stem pushes the panicle out of the sheath carbohydrate first are located near the tip of the flag leaf and the tip of the panicle of the panicle, the panicle begins to lean becomes visible, the stage is first heading and eventually will turn down. After the (Fig. 18). The uppermost internodes first florets which pollinated fill, the continue to elongate after first heading, carbohydrate begins to solidify. When the revealing more of the panicle above the texture of the carbohydrate of the first sheath of the flag leaf. After the florets pollinated on the main stem is like uppermost internode completes bread dough or firmer, the stage of elongation, the full length of the panicle growth is dough stage (Fig. 21). As the and a portion of the uppermost internode carbohydrate in these florets continues to are exposed above the collar of the flag solidify during the dough stage, the leaf. When this has occurred on the main endosperm becomes firm and has a stem, the stage is full heading (Fig. 19). chalky texture (Fig. 22). During the heading stages, pollination During the grain filling stages, the begins (Fig. 19). Pollination is the process florets develop and mature unevenly in which pollen is released, leading to because pollination and subsequently fertilization and grain development. It is grain filling occur unevenly. In the dough

19 stage, only the florets on the main stem Maturity Stages which pollinated first have an endosperm The maturity stages occur when with the texture of bread dough. At the carbohydrate is no longer translocated to same time, the florets which pollinated the panicle. The moisture content of the later, including those on the tillers, have grain is high after grain filling, and the endosperms less mature. These are the primary process which occurs in the last florets to accumulate carbohydrate. panicle during the maturity stages is the As more and more florets fill with loss of moisture from the grain. The carbohydrate during dough stage, the moisture content of the grain is easily translocation of carbohydrate to the determined. It is used as the basis for the panicle starts to decline, and the final maturity stages of growth. When the phases of grain filling occur. physiological processes associated with The panicle changes in color and form grain filling cease, and the collective as the florets develop and mature. For moisture content of the grain on the main most varieties of rice, the panicle stem is 25 percent to 30 percent, the changes from a uniform light green at plant has reached physiological maturity. milk stage to a mixture of shades of At this time, the endosperm of all brown and green during dough stage. As grains on the panicle of a main stem is the color changes, the shape changes firm. Most grains are some shade of also because of the accumulation of brown, and the grains in the lower carbohydrate in the florets. The weight of quarter of the panicle are the only ones the carbohydrate causes the panicle to with a greenish tint. As the maturity bend over and the panicle branches to be stages of growth progress and moisture less compact around the panicle axis. At loss continues, the greenish tint fades and the end of the grain filling stages, the the endosperm of all grains becomes panicle on the main culm has a bent and uniformly hard and translucent. When this slightly open shape and is various shades occurs, and the average moisture content of brown and green. The bent and of the grains on the main stem is 15 slightly open configuration of the panicle percent to 18 percent (crop grain remains unchanged from dough stage to moisture, 18 percent to 21 percent), the maturity. stage of growth of the plant is harvest maturity (Fig. 23).

DD-50DD-50 RiceRice ManagementManagement ProgramProgram JohnJohn K. Saichuk,Saichuk, StevenSteven D. Linscombe and Patrick K.K. Bollich

The Louisiana DD-50 Rice Management low temperatures in degrees Fahrenheit Program helps rice producers manage their and subtracting 50. crops better. Many cultural practices For example, if the high temperature depend on specific stages in the growth for a given day is 85 degrees and the low and development of the rice plant. The is 60 degrees, then the average term DD-50 is derived from degree-day temperature (72.5) minus 50 equals 12.5 50, a term referring to a temperature-time heat units or DD-50 units for that day. value called a heat unit. Because virtually Threshold values of accumulated heat units all growth and development processes in for various growth stages of rice have rice stop at temperatures at or below 50 been established through research. By degrees F, the term DD-50 is used. No adding the heat units from a given stage of heat units accumulate at temperatures growth (emergence is the best), future below 50 F, but no negative values are growth stages can be predicted. used in the calculations. It is calculated by Weather information is obtained from averaging the maximum daily high and locations around the state and compiled by

20 computer. Knowing the date of emergence date is reached for a particular field, return on a field of a particular variety of rice in the completed DD-50 card to the county a particular area of the state enables the agent’s office. program to provide a producer with A printout (Fig. 25) will then be predictions on when plants in that field will provided showing growth stage predictions reach certain growth stages. The initial and recommended cultural practices based prediction is based on average on these growth stages. Again, updated temperatures and their corresponding heat predictions are provided when necessary. units in the area over the previous years. Remember these are just predictions. Updated predictions are provided as often Fields must still be monitored closely to as needed to compensate for specific determine precise stages of development. conditions in a particular growing season. With the aid of these predictions, critical The program, provided to Louisiana growth stages can be forecast. The field producers by the LSU Agricultural Center, is should be monitored for a particular growth coordinated by the county agent in each stage about four to five days prior to the rice-producing parish. To participate, a predicted date for its occurrence to avoid producer may fill out a DD-50 card (Fig. missing the stage in the event of errors. 24) for each field or contact a county agent. Anything which stresses a field of rice Accuracy is essential, especially in will interfere with the accuracy of these determining date of emergence. If this predictions. Stresses may include insect information is incorrect, corresponding pressure, delay of permanent flood, lack of predictions will be wrong. nutrients, disease pressure or many other The date of emergence depends on the factors. For maximum yields, avoid these seeding system. If rice is water-seeded stress factors. (using prolonged drainage, pinpoint The varieties available with this program flooding or continuous flooding water will change from year to year as new management), the date of emergence is varieties are released and older varieties when the seedlings (shoot) are about 1/2 to are deleted from recommended lists. A 3/4 inches long. With dry-seeded rice personal computer version of the DD-50 (whether drilled or broadcast), the date of program is also available. More information emergence is when an average of 10 is available from Louisiana Cooperative seedlings are visible (just breaking the soil Extension Service agents. surface) per square foot. As soon as this

LOUISIANA DD - 50 RICE GROWTH STAGE PREDICTION PROGRAM

PRODUCER COUNTY AGENT NAME______NAME______ADDRESS______PARISH______FIELD NUMBER______PHONE______VARIETY______#OF ACRES______DATE OF EMERGENCE______SEEDING METHOD: WATER______DRY (SOIL)______

PLEASE RETURN TO YOUR COUNTY AGENT

Figure 24. D-D50 Rice Management Program Enrollment Card 21 Louisiana DD-50 Rice Management Program MID-SOUTH Agricultural Weather Service Center, Stoneville, Miss. National Weather Service and Louisiana Cooperative Extension Service, cooperating

Rice Farmer Acadia 123 Able Crowley 1998 Crowley, LA 70527

FIELD-NO FIELD-NAME ACRES VARIETY SEEDED 1 Cypress 125 Cypress Water 2 Maybelle 110 Maybelle Water 3 Bengal 100 Bengal Dry 4 Mars 75 Mars Water

FLD 1 FLD 2 FLD 3 FLD 4 1 Effective Planting Date 0/0 0/0 0/0 0/0 2 Date of Emergence 4/20 4/22 4/23 4/25 3 First Tiller 5/4 5/9 5/12 5/12 4 Drain for Straighthead 5/19 5/17 5/23 5/23 5 Begin Checking Internodes 5/29 5/27 6/2 6/2 6 Check for pH 6/5 6/3 6/11 6/11 7 Early Boot 6/21 6/13 6/25 6/25 8 Heading 6/30 6/22 7/6 7/6 9 Harvest 8/4 7/27 8/20 8/20

NOTE: These are just predictions. Fields must be closely monitored to assure proper growth stages.

Louisiana DD-50 Rice Management Program

LSU Ag Center Recommendations - Numbers in the margin correspond to the growth stages listed on the prediction printout. 2 Emergence equals 8-10 seedlings visible per square foot for drill-seeded rice and seedlings around 3/4 inch (average) for water-seeded rice. Pinpoint flood may be started at this time. If Karate is to be used for water weevil control, begin scouting as soon as the field has been flooded or flushed. Treat when adults are present. Continue to scout at least weekly. Two or more applications may be required. 3 Majority of plants displaying first tiller. Under normal conditions, nitrogen should be applied and a field permanently flooded by this time (dry-seeded or prolonged seeded drained fields). Research has shown that 70% to 100% of nitrogen should be applied to a dry (if possible) soil surface within 7 days before the permanent flood is applied. If propanil is used, begin flooding within 24 hours of application. In cold, cloudy weather, delay flood 4-5 days to enhance propanil activity. 4 Where straighthead is a potential problem, fields should be drained, dried and reflooded before the green ring stage. 5 Begin checking for internode elongation (green ring) stage. This is normally the best time for a mid- season nitrogen application (if needed). Begin scouting for foliar diseases. Apply phenoxy herbicides at the first green ring. Do not apply after the second green ring stage. This is the earliest recommended timing for application of any fungicide. If Moncut fungicide is to be used, the first application at 0.7 to 1.0 lb. per acre should be made now with a second application at the same rate to follow in 10 to 14 days. 6 Panicle differentiation (panicle 2mm), mid-season nitrogen should be applied at least by this time. If Tilt fungicide is to be used and two (6 ozs. per acre) applications are intended, apply the first at or shortly after this stage. If Quadris is to be used for sheath blight control ONLY, a single application at 12.3 ozs. per acre should be made 5 to 10 days AFTER panicle differentiation is reached. 7 Early boot is when there is a 1- to 2-inch panicle in the boot. First application of Benlate (1 lb. per acre) or Rovral ( 1 pt. per acre) should be made at this stage. If Quadris is to used for blast control, the first 12.3 ozs. per acre application should be made at this time. A second 6 ozs. per acre (or one 10 oz. per acre) Tilt application should be made at this stage, but must be made before heading. 8 Heading is when 50% of the stems are showing heads. The second Benlate (1 lb. per acre) or Rovral (1 pt. per acre) or Quadris (12.3 ozs. per acre for blast control) application should be made. Begin scouting for rice stink bugs. Treatment thresholds are 30 or more per 100 sweeps during the first 14 days after heading and 100 per 100 sweeps from 15 days after heading until hard dough stage is reached. 9 Harvest is when a grain sample is around 20% moisture. Normally, fields should be drained two weeks before harvest on silt loams and three weeks before on heavier (clay) soils. 22 Figure 25. D-D50 printout RiceRice VarietiesVarieties Kent S. McKenzie, Steven D. Linscombe, Farman L. Jodari, James H. Oard and Lawrence M. White III

Development of rice varieties has been Rice Varietal Improvement Program an important tool for improving rice In the early days, Louisiana rice production in Louisiana and in the United production depended on varietal States. Release of improved varieties by introductions by individuals. In 1909, the public breeding programs in Louisiana, first rice breeding program in the United Texas, Arkansas, Mississippi and California, States was initiated when the Rice in conjunction with advancements in rice Research (Experiment) Station was production technology, has provided a established at Crowley. The rice breeding continuous increase in rice production and activities there were under the direction of quality. Considerable genetic potential USDA scientists from the inception of the exists to improve on current rice varieties, program until the Louisiana Agricultural and rice breeding efforts should continue Experiment Station (LAES) assumed to help improve production in Louisiana. responsibility for the program in 1981.

23 Since its inception, the program has Florida, Mississippi and Texas. Cooperative formally released 26 improved rice evaluations of advanced materials are also varieties (Table 2). conducted with breeders and plant To develop a new rice variety, a pathologists in Argentina, Columbia, Italy breeder must first create new genetic and Uruguay. combinations. Artificial hybridization is the Typically, eight to 10 years are most common method used to achieve this necessary from the artificial hybridization goal. Old varieties, breeding lines, foreign until seed of a new variety is made introductions and mutations compose the available to rice producers. A typical pool of genetic materials known as sequence of steps in the development of a germplasm. From this germplasm, the new variety is illustrated in Table 3 using breeder selects materials with desirable the new variety Lafitte as an example. characteristics to use as parents in the The breeding project uses a winter hybridization program. The second nursery facility in Lajas, Puerto Rico, to generation of offspring from hybridization facilitate varietal development. The will contain thousands of different nursery typically turns over early combinations of the parents’ characteristics. generation material to speed the interval This is the result of the transfer and from artificial hybridization to early yield recombination of the genes from the testing. The nursery is also often used to parents, and such material is said to show increase and purify seed of potential genetic variability. The breeder begins releases. The breeding project, in selecting desirable plants in this cooperation with biotechnologists at the genetically variable material. The Rice Research Station, also uses anther selections are grown and re-selected for culture to expedite development of many generations until the selected lines homozygous (pure) lines, which can begin to breed true. Thousands of lines decrease the time from hybridization to will be grown and discarded annually. The initial yield evaluation. very best lines which survive the selection The rice breeding project depends process are increased and tested for yield, heavily on many cooperating projects for quality and pest resistance in the advanced assistance in the development and testing phase. evaluation of experimental lines. The testing program includes on-station, Cooperators include agronomists, off-station and by cooperating programs. entomologists, pathologists, The off-station testing program includes biotechnologists, geneticists, weed research at several locations in commercial scientists, food scientists and physiologists. growers’ fields throughout the Louisiana This cooperation is essential for the rice production area. In addition to success of varietal improvement efforts providing performance data in additional aimed at numerous characteristics, environments, each of these off-station including but not limited to yield, milling locations is used for local field days in quality, cooking quality, insect resistance, cooperation with county agents and disease resistance, herbicide tolerance, specialists with the Louisiana Cooperative seedling vigor, lodging resistance, fertilizer Extension Service. These field days responsiveness, stress tolerance, earliness provide excellent opportunities for and ratooning. producers to evaluate potential new The Rice Breeding and cooperating varieties under conditions similar to their projects also evaluate potential varietal production environment. In addition, releases from other breeding projects (both advanced testing is conducted at the private and public) to determine their Northeast Research Station near St. Joseph. adaptability under Louisiana growing The breeding project also conducts conditions. Many rice varieties from out-of- cooperative advanced testing with public state breeding programs are well adapted rice breeders in Arkansas, California, to Louisiana and are widely grown.

24 Rice Varieties: Characteristics and The following information is included: Performance Days to 50% heading: Average number of The two primary grain types grown in days from emergence to 50 percent Louisiana are long grain and medium grain. heading. Most varieties will reach Long grains are characterized by a grain harvest maturity (20 percent grain length:width ratio of more than 3:1 and moisture) within 30 to 40 days after typically cook dry and fluffy because of a heading under normal conditions. high to intermediate gelatinization Seedling vigor: Visual estimate. temperature characteristic and a relatively Plant height: Height at maturity in inches high amylose content. Medium grains from soil line to extended panicle. typically have a length:width ratio of Lodging: Comparative estimate of resis- between 2:1 and 3:1 (usually closer to 3:1) tance to lodging. Most varieties rated as and cook soft and sticky because of a low resistant to lodging can lodge, especially gelatinization temperature characteristic under excessive levels of applied and a relatively low amylose content. nitrogen. Abbreviations are: HR = highly Southwestern Louisiana producers have resistant, R = resistant, MR = moderately historically planted from 20 percent to 50 resistant, MS = moderately susceptible, S percent of rice acreage in medium grains, = susceptible, HS = highly susceptible. and those in northeastern Louisiana grow Resistance to lodging is generally almost exclusively long-grain varieties. In influenced by both plant height and recent years, the percentage of the state straw strength. rice acreage planted to medium grains has Grain yield: Dry weight (converted to 12 continually decreased. Interest in special percent moisture), lb/A. purpose varieties has gained in popularity. Milling: a) Head = % of whole kernels These varieties have distinctly different after milling; b) Total = % of all kernels cooking quality attributes, such as aroma, (whole and broken) after milling. elongation or a unique cooking characteristic that may be favored by many Recommended Varieties ethnic populations living in the United The following section provides specific States as well as other consumers information about each recommended interested in gourmet or premium rice. variety. The location in parentheses The major specialty types include soft indicates origin of the variety. cooking aromatic Jasmine, flaky cooking Jodon (Louisiana): Jodon is a elongating and aromatic Basmati, Kokuhoe, semidwarf, long-grain variety that is a waxy, standard long-grain aromatic Della, sister line to Cypress. It has displayed soft cooking non-aromatic Toro and other good levels of resistance to lodging but less known gourmet types. Most specialty may lodge more readily than Lemont-type rice marketed in the United States is semidwarfs. This variety has very good imported from Thailand, India and seedling vigor and excellent first and Pakistan. Efforts are under way at the Rice second crop yield potential. Milling yields Research Station to develop adapted are generally fair to good. Jodon is varieties that can be used in the domestic susceptible to sheath blight and blast and production of imported specialty types. A to straighthead. Jodon has amylographic number of specialty varieties from the characteristics similar to L-202, which may Della, Toro and Jasmine groups are under make it cook slightly softer than other long limited production in the southern United grains and, thus, be unsuitable for canning States. processes. Table 4 displays agronomic, yield and Jackson (Texas): Jackson is a sister quality characteristics of those line to Maybelle (developed from the recommended for Louisiana production in same cross), but it is seven to 10 days later 1998. Data were generated in the in maturity and 2 to 3 inches taller than commercial variety tests from various Maybelle. Jackson typically is superior to locations throughout Louisiana. Maybelle in first crop yield potential. The 25 variety is susceptible to sheath blight and Lemont (Texas): Lemont is a blast diseases; second crop potential is semidwarf that has displayed very high very good. yield potential, as well as excellent milling Alan (Arkansas): Alan is taller and characteristics. It has poor seedling vigor, somewhat more susceptible to lodging and shallow seeding depth is essential. than the other varieties in this group. First Because of the short plant height and good and second crop yield potential is good. straw strength, Lemont is highly resistant to Milling yields are generally fair to good. It lodging. Lemont is very susceptible to has excellent seedling vigor. Alan is sheath blight and susceptible to blast. It susceptible to sheath blight and blast. has shown very good ability to tiller (stool) Maybelle (Texas): Maybelle is the and good second crop potential. earliest maturing variety recommended for Rico 1 (Texas): This variety has Louisiana. Although Maybelle is not a excellent yield potential and good milling semidwarf, it displays fairly good performance. It has typically yielded resistance to lodging. It displays excellent higher than other recommended medium- seedling vigor and has good first crop and grain varieties in yield trials. It is a tall excellent second crop yield potential. It is variety and is susceptible to lodging, susceptible to blast and sheath blight. especially if nitrogen fertilization rates are Drew (Arkansas): Drew is a too high. Seedling vigor is fair. It ripens conventional height, early long-grain very slowly, maturing about one week variety very similar in appearance to later than Mars. It is moderately resistant to Kaybonnet. It has excellent resistance to straighthead, moderately susceptible to predominant blast races. Yield potential of sheath blight and susceptible to sheath rot the variety is excellent and milling yields and blast. Rico 1 is characterized by short, are typically good. It is moderately plump grains, making it more difficult to susceptible to lodging and will stand dry under certain conditions. It also tends somewhat better than Kaybonnet. to produce chalky grains, especially under Kaybonnet (Arkansas): This high nitrogen fertilization. As a result, conventional height, early long-grain some mills may be reluctant to accept it. variety has displayed excellent yield Bengal (Louisiana): Bengal is a potential and good milling characteristics. semidwarf variety that has displayed very The variety has very high levels of good yield potential and excellent milling resistance to most races of blast common quality. The milled grains are plumper to Louisiana. Kaybonnet is rated as than other commonly grown medium susceptible to sheath blight disease and grains in the South, a characteristic favored moderately susceptible to lodging. It has for some processing uses. Seedling vigor displayed second crop potential. is good, and Bengal has displayed good Cypress (Louisiana): Cypress is an second crop yield potential. It is early semidwarf long grain that is susceptible to blast and straighthead and moderately resistant to lodging. It is moderately susceptible to sheath blight. It somewhat more susceptible to lodging has displayed susceptibility to panicle than Lemont, and this is especially a blight. potential problem under excessive rates of Lafitte (Louisiana): Lafitte is a short- nitrogen fertilizer. Cypress has displayed statured medium grain that is five to six excellent first crop and good second crop days earlier in maturity than Bengal. It is 2 yield potential. It has very good seedling to 3 inches taller than Bengal and is more vigor. Milling yields are very good and susceptible to lodging. It has displayed may not be as adversely affected by sub- good stable yields and consistently had optimum harvest moistures as other long- higher head rice yields in testing. Lafitte is grain varieties. This is primarily associated resistant to the predominant blast races. with superior resistance to fissuring. Seedling vigor is good, and the variety has Cypress is susceptible to sheath blight and displayed good second crop potential in blast diseases. limited testing. It is moderately susceptible 26 to sheath blight and susceptible to LaGrue (Arkansas): LaGrue is a 1993 straighthead. very early, long grain release. This variety is about 43 inches tall and moderately Other Varieties susceptible to lodging. LaGrue has This section provides information on excellent yield potential. Milling yields are varieties that are not generally variable, generally averaging less than recommended but may be grown on recommended varieties in this maturity limited acreage. group. LaGrue is susceptible to blast and Dixiebelle (Texas): The variety has a sheath blight. Newrex-type cooking quality Litton (Mississippi): Litton is a short- characterized by 2 percent to 3 percent statured long grain that has had only higher amylose content than conventional limited testing in Louisiana. It has averaged U.S. long grains. This cooking quality type 1 to 2 inches taller than Cypress but is favored by the rice canning industry and appears to have fairly good resistance to should be grown on a contract basis. It has lodging. Litton is two to three days later in fair yield potential and milling quality. It is maturity than Cypress. a semidwarf and has good resistance to Mars (Arkansas): This variety has lodging. This variety has very poor high yield potential and generally good seedling vigor. milling characteristics. Mars is a stiff- Gulfmont (Texas): This semidwarf strawed variety moderately susceptible to variety is very similar to Lemont. Gulfmont lodging. It is susceptible to blast. has normally been somewhat earlier in Straighthead may also be a problem. maturity than Lemont. It has very good Seedling vigor is generally quite good. second crop potential. Milling yields have Millie (Arkansas): Millie is a very been good. Disease reactions are similar to early, long-grain variety that is fairly Lemont. resistant to lodging. It has moderate yield Jefferson (Texas): Jefferson is a potential and excellent milling semidwarf long grain that is about the characteristics. It is susceptible to blast and same maturity as Jodon, Jackson and Alan. moderately susceptible to sheath blight. About the same height as Lemont, it is Millie has exhibited substantial injury highly resistant to lodging. Milling yields from several widely used rice are good, but seedling vigor is poor. herbicides. Jefferson is susceptible to sheath blight Priscilla (Mississippi): Priscilla is a and moderately susceptible to blast. semidwarf early long grain variety that has Katy (Arkansas): Katy has a high level shown good yield potential. It is slightly of resistance to blast disease. It is tall, taller and slightly earlier than Lemont. moderately susceptible to lodging and has Milling yields are fair. good seedling vigor. The variety has Saturn (Louisiana): Saturn is an old shown more resistance to sheath blight (released in 1964) medium-grain variety than other varieties in this maturity group. still grown in southwest Louisiana. The It is moderately susceptible to variety has good seedling vigor but is tall straighthead. Katy has moderate yield and extremely susceptible to lodging. potential. Saturn has moderate yield potential and Lacassine (Louisiana): Lacassine is excellent milling characteristics. less leafy than Lemont or Gulfmont, and the panicle is more prominently displayed. Special Purpose Varieties Lacassine, like Lemont and Gulfmont, is These varieties have special cooking or highly susceptible to sheath blight and processing characteristics. They are susceptible to blast. It has good first and generally grown on a limited acreage. second crop yield potential. Lacassine also Because of their unique cooking has somewhat poor seedling vigor in a characteristics, they should not be co- dry-seeded system, and shallow seeding mingled with standard U.S. long-grain depth is important. varieties. 27 Jasmine 85 (Texas): Jasmine 85 is an blast and moderately resistant to aromatic, soft-cooking rice. Because of low straighthead. amylose content, its grains tend to stick Akitakomachi (Japan): This variety is together when cooked. Agronomically, it is grown on a very limited acreage for the a true semidwarf but is somewhat taller premium quality market. It is a true short than Lemont. It is susceptible to lodging, grain with limited yield potential and is very resistant to blast, moderately resistant very susceptible to lodging. It should not to sheath blight, very susceptible to be grown unless a market has been straighthead and moderately susceptible to identified. panicle blight. Its yielding ability is good to excellent, but milling yields are inferior Summary to current varieties. Because of the Variety selection is a critical early step noticeable differences in the specialty in a successful program. No rice variety is qualities of Jasmine 85 and imported ideal, and relative strengths and Jasmine, this variety has not been widely weaknesses must be weighed in selecting accepted by the traditional consumers of varieties for each operation. It is generally Jasmine rice. Markets should be identified recommended to plant several varieties to for this cultivar before it is planted. minimize potential problems with adverse Toro-2 (Louisiana): Toro-2 is a weather and disease epidemics. With this nonaromatic, low amylose (sticky cooking) in mind, it is beneficial to plant varieties long-grain special purpose variety. In taste with differential relative strengths and tests, Toro-2 was judged to have weaknesses, especially relative to disease acceptable Toro-type cooking and taste susceptibility. characteristics. A true semidwarf variety, it For additional updated varietal is resistant to the predominant blast races information, check the Extension Service’s and moderately susceptible to sheath publication 2270, Rice Varieties and blight. It is very susceptible to Management Tips, revised each year. straighthead. Della (Louisiana): Della is an aromatic standard long-grain rice favored for its Seed Certification unique popcorn aroma and taste Once a new variety has been characteristics. It is grown on limited developed, a mechanism is needed to acreage in Louisiana. Della is a midseason purify, maintain and distribute high quality, variety and displays low yield potential genetically pure seed to the rice industry. compared to other varieties. Disease Seed certification accomplishes this and susceptibility is often a problem because provides an operating procedure to Della is susceptible to most major rice achieve high quality seed and to guarantee diseases. It is tall and very susceptible to it to the user. lodging, even under conditions of low The foundation seed rice program of yield potential. the Rice Research Station is the first phase Dellrose (Louisiana): Dellrose is a in the seed certification process. A small Della-type aromatic long-grain variety amount of seed of a new variety is recently released by the LAES. Taste panel supplied by the breeder to the foundation evaluations indicate similar aroma and seed project. Single rice panicles are flavor ratings between Della and Dellrose. grown in individual rows (one panicle per Chemical analysis of rice aroma compound row) called headrows. This allows the shows the aroma intensity of Dellrose to breeder and foundation seed personnel to be higher than Dellmont and lower than purify and discard mixtures, off types or Della. Dellrose is a semidwarf variety with outcrosses. Acceptable headrows are high grain yield, high milling yield and combined in bulk to produce breeder seed, high ratoon yield potential. It is susceptible which is maintained by the foundation to sheath blight, moderately susceptible to seed project and used to plant the next

28 Table 2. Principal rice varieties released from the Rice Research Station in Crowley. ______

Grain Year Variety C.I./P.I. No. type released Breeders Involved ______Colusa 1600 short 1917 Chambliss, Jenkins Fortuna 1344 long 1918 Chambliss, Jenkins Acadia 1988 short 1918 Chambliss, Jenkins Delitus - long (A) 1918 Chambliss, Jenkins Tokalon - long 1918 Chambliss, Jenkins Evangeline 1162 long 1918 Chambliss, Jenkins Rexora 1779 long 1928 Chambliss, Jenkins Nira 2702 long 1932 Chambliss, Jenkins Magnolia 8318 medium 1945 Jodon Lacrosse 8985 medium 1949 Jodon Sunbonnet 8989 long 1953 Jodon Toro 9013 long 1955 Jodon Nato 8998 medium 1956 Jodon Saturn 1415 medium 1964 Jodon Della 9483 long (A) 1973 Jodon Vista 9628 medium 1973 Jodon, McIlrath LA 110 9962 medium 1979 McIlrath, Jodon Leah 9979 long 1982 Trahan, Jodon Toro-2 483070 long 1984 McKenzie, Jodon Mercury 506428 medium 1987 McKenzie Lacassine 548772 long 1991 Linscombe, Jodari Bengal 561735 medium 1992 Linscombe, Jodari Cypress 561734 long 1992 Linscombe, Jodari Jodon 583831 long 1994 Linscombe, Jodari Dellrose 593241 long (A) 1995 Jodari, Linscombe Lafitte 593690 medium 1996 Linscombe, Jodari

(A) = Aromatic.

stage in the seed certification process. The provided by the Rice Research Station. foundation seed project uses this small Registered seed is used to produce the last amount of breeder seed to plant and generation, certified seed, in the produce foundation seed. It is distributed certification process. In some instances, from the Rice Research Station to certified seed may be produced directly commercial seed growers who have from foundation seed. Certified seed is applied through a county agent for an used by farmers to plant rice crops for allotment of foundation seed of a particular milling and cannot be used to produce variety. Allocation of the foundation seed seed in the seed certification process. rice in Louisiana is directed by the The official seed certifying agency in Louisiana Seed Rice Growers Association. Louisiana is the Louisiana Department of The next generation in the seed Agriculture and Forestry. This agency certification process is registered seed, establishes the guides for all aspects of the which is grown by commercial seed rice certification process. All levels of the growers from the foundation seed certification process from breeder seed to

29 Table 3. Sequence of events in the development of the rice variety Lafitte.

Step Year ID Number Stage of Development

1 1988 88CR018 (winter cross) Artificial hybridization Mercury & x Mercury/Koshihikari

2 1988 88T1020 F1 - Space plant nursery 3 1989 89F7034 F2 - Bulk - segregation 4 1990 9010848 F3 - Headrow - segregation 5 1991 9120071 F4 - Headrow - segregation 6 1992 9205777 F5 - Preliminary yield test - Purification 7 1993 9302008 F6 - Uniform Regional Nursery (URN) (Arkansas, Louisiana, Texas, Mississippi, California, Florida)

- Advanced yield test (AY) (Five locations in Louisiana) - Purification 8 1994 9302008 F7 - URN - AY Commercial variety test (CV) (Five locations in Louisiana) - Purification 9 1994 9302008 (Puerto Rico) F8 - Headrow increase 10 1995 9302008 F9 - URN - AY - CV Breeder-Foundation seed field 11 1996 Lafitte F10 - Release to seed growers

Table 5. Isolation Requirements strip a minimum No. of Feet From Same Variety/ No. of Feet from Other Varieties/ of 10 Different Class Planted By All Classes Planted By feet if the Ground Air Ground Air adjoining Drill Broadcast Right Parallel Drill Broadcast Right Parallel crop is Angle Angle the same variety 10 10 1,320 10 20 100 1,320 100 and class. In addition, certified seed are monitored, inspected the following isolation distances will and tested by the Louisiana Department of pertain if the adjoining crop is a different Agriculture and Forestry. Below are the class or different variety (Table 5). Rice Seed Certification standards. Any part of the applicant’s field or fields closer than these distances must be Isolation Requirements harvested before the final inspection or Fields offered for certification must be plowed up. Failure to comply with this clearly separated from other fields by a requirement will disqualify the entire field ditch, levee, roadway, fence or barren (Table 6). 30 Table 4. Agronomic, yield and milling characteristics of recommended rice varieties, 1998.

Maturity and Days to grain type Yield Milling % Seedling 50% Height group (lb/A) (head-total) vigor heading (in) Lodging

Very Early Long Grain

Jodon 7271 60 - 69 Good 90 38 MR Alan 7173 59 - 69 Good 90 42 MS Jackson 7047 59 - 70 Good 91 41 MR Maybelle 6074 60 - 70 Very good 85 38 MR

Early Long Grain

Drew 7831 64 - 70 Very good 95 46 S Kaybonnet 7729 63 - 70 Very good 95 45 S Cypress 7259 66 - 70 Very good 95 40 MR Lemont 6750 61 - 70 Fair 97 38 HR

Medium Grain

Rico 1 8373 60 - 69 Fair 97 44 S Bengal 7896 65 - 70 Good 96 38 MR Lafitte 7290 67 - 70 Good 89 39 MS

Special Purpose

Dellrose 6789 63 - 71 Fair 94 40 HR Toro-2 6020 61 - 71 Fair 97 43 MR Della 5642 58 - 69 Fair 96 51 HS

Table 6. Field Standards

Factor Breeder Foundation Registered Certified Land requirement 1 year 1 year 1 year 1 year Other varieties None None 10 plants/A 25 plants/A Harmful diseases* None None None None Noxious weeds: Red Rice (including Black Hull Rice) None None None 1 plant/10 A Spearhead None None None 2 plants/A Curly Indigo None None 4 plants/A 4 plants/A * Diseases seriously affecting quality of seed and transmissible by planting stock.

31 Soils,Soils, PlantPlant Nutrition and Fertilization Patrick K. Bollich, John K. Saichuk and Eddie R. Funderburg

Rice requires an adequate supply of rapidly. It is important to flood a rice soil plant nutrients throughout the growing permanently once fertilizer N is applied. season. Four major nutrients and one micronutrient are required by rice in Phosphorus Louisiana. Nitrogen (N) is required on Phosphorus is present in the soil in virtually all soils where rice is produced, organic and inorganic forms. As with all and it is the single most important nutrient nutrients required by rice, organic forms necessary for maximizing yields. Rice also are not available to the plant. Since organic requires relatively large amounts of P is slowly converted to the inorganic phosphorus (P) and potassium (K) on form, fertilizer applications of P are very certain soils, especially the prairie and important on soils deficient in this nutrient. flatwoods soils of southwest Louisiana. The Flooding a rice soil increases the alluvial soils (clay and clay loams) in availability of soil P to the plant. central and northeast Louisiana are typically Alternating flooding and draining cycles high in these nutrients and do not respond has a significant effect on P availability. to P and K applications. Deficiencies in P When the soil is drained and aerated, P is and K can occur on these soils if much less available to the plant. landforming operations remove topsoil. Reflooding will enhance additional P Sulfur (S) is adequately supplied by most release but a short-term deficiency may rice soils unless native fertility is inherently occur even where adequate P is present. low or topsoil has been removed. Zinc (Zn) is the only micronutrient known to be Potassium deficient on some rice soils. As with S, Zn Soil K is less affected by flooding than deficiencies occur when native levels are N or P. Its availability changes very little low, where topsoil has been removed and with draining and flooding. Potassium is also when cool weather retards root growth less limiting to growth and grain yield than during the seedling stage. either N or P, and deficiencies in K have Behavior of nutrients in rice is quite been less frequent than in other nutrients. different from that of upland crops. Potassium nutrition is closely associated Because rice is cultured under flooded with the rice plants’ ability to resist disease, conditions, it is important to understand the and more emphasis is being placed on the relationship between nutrient availability role it plays in overall rice plant nutrition. and flooded soils to manage these nutrients properly. Sulfur Most of the S contained in the soil is in Nitrogen the organic form under both flooded and In drained soils, N is present in both the unflooded conditions. Inorganic S results ammonium and nitrate form, and the rice from the decomposition of organic matter, plant is capable of using either. Nitrate N and the S status of a soil is related to the cannot be maintained once a rice soil is amount of organic matter present. Some S flooded, and large losses of N occur is also provided by precipitation and through denitrification. Ammonium N is irrigation water. very stable under flooded conditions and remains available to the plant as long as Zinc the flood is maintained. Prolonged drainage Zinc availability is affected by flooding, and aeration of the soil convert the although the change in soil pH in response ammonium form of N from both the soil to flooding is the reason for the fluctuation and chemical fertilizers to nitrate. Once the in available Zn. It is more available when soil is reflooded, any nitrate N is lost the soil pH is acidic. Since soil pH moves 32 toward neutral under flooded conditions, for rice production and their proper Zn becomes less available in acid soils source, time of application and rate are over time and more available on alkaline discussed in the following sections. soils. Nitrogen Nutrition, Water Other Nutrients Management, Source and Timing Many other nutrients play a role in rice Nitrogen is the most limiting plant plant nutrition, and flooding has nutrient in rice. Maximum yields depend differential effects on their availability. on an adequate supply of N. Suboptimum Availability of calcium (Ca) and N applications can decrease yield potential magnesium (Mg) is not affected to a great and grain quality and increase the extent by flooding. Iron (Fe), manganese incidence of disease. Deficiency (Mn), boron (B), copper (Cu) and symptoms include yellowing of the older molybdenum (Mo) become more soluble leaves, reduced tillering, browning of leaf under flooded conditions. While these tips and shorter plants (Figs. 26-28). nutrient elements are known to play a role Excessive N causes lodging in some in rice plant nutrition and critical levels in varieties, increases the incidence of rice plant tissue have been established, disease and can cause grain sterility. documented deficiencies or toxicities have Because of the relation between N not been recognized in Louisiana. behavior and flooded soils, the efficiency of N in rice is greatly influenced by water Rice Plant Nutrition and Fertilization management. The most frequently limiting plant Rice is a semiaquatic plant that has nutrients in Louisiana rice in order of been bred and adapted to flooded culture. importance are N, P, K and Zn. Soil type, Flooding a rice soil (1) eliminates moisture native soil fertility, cropping history and deficiency, (2) increases the availability of agronomic management practices most nutrients essential to plant nutrition, determine when and to what extent (3) suppresses weed competition and (4) deficiencies of these nutrients occur. A soil provides a more favorable and stable test is valuable in predicting nutrient microclimate for plant growth and deficiencies and appropriate corrective development. measures. A sound fertility program is A permanent flood of 2 to 4 inches essential to maximize yields and use plant should be established as soon as possible nutrient inputs efficiently. Many nutrient and maintained throughout the growing deficiencies can be corrected once season. In dry-seeded rice, apply the recognized in the field, but providing permanent flood by the 4th or 5th leaf required nutrients in sufficient amounts to stage (20 to 35 days after planting). avoid deficiencies is the best approach to Uniform, level seedbeds allow earlier assure maximum rice yields. flooding, which improves nutrient Proper fertilizer management is availability and weed control. To avoid important to increase profitability, stand loss and reduced seedling vigor, dry- minimize inputs, improve nutrient seeded rice should not be submerged. In efficiency and mitigate environmental water-seeded rice, a shallow flood is concerns. Efficient fertilizer use requires: established before planting. Rice seedlings 1) proper water management in relation to either emerge through a permanent flood fertilizer application, 2) selection of the (continuous flooding) or the field is briefly proper fertilizer source, 3) timely drained to encourage seedling anchorage application of fertilizers by methods that and uniform stand establishment (pinpoint provide optimum rice growth, grain yield flooding). The field is then reflooded, and and crop quality and 4) application of the the seedlings emerge through the water as proper amount of fertilizers to ensure in the continuously flooded system. optimum grain yields and economic Avoid draining rice fields after returns. The major plant nutrients required permanently flooding unless extenuating 33 circumstances exist. Removing the be incorporated into a dry soil 2 to 4 floodwater can result in loss of N, may inches deep before flooding. Briefly affect the availability of many other draining the field after seeding to nutrients, encourages additional weed encourage seedling anchorage in a growth and increases the incidence of pinpoint flood system will not result in loss some diseases. Situations that justify of N unless the soil is permitted to dry. It draining include: 1) soils susceptible to is important to maintain the seedbed in straighthead, 2) severe Zn deficiency, 3) complete saturation to conserve applied N. application of some herbicides and 4) Additional N should be applied at control of the rice water weevil larvae. midseason as needed unless the total Ammonium sulfate and urea are the requirement was preplant incorporated. most common sources of N in rice. These In the delayed flood systems (drill, dry two sources are equally effective when broadcast or water seeded), the permanent properly applied. An advantage of urea is flood may not be established until three to its higher N analysis of 46 percent. It is a four weeks after seeding. It is impractical more economical source since less material to apply large amounts of N at seeding in is applied per unit of N. Ammonium these systems since fertilizer N cannot be sulfate contains 21 percent N, and more stabilized or maintained before than twice the amount of material needs to permanently flooding. On most soils, it is be applied per unit of N. Ammonium necessary to provide 15 to 30 pounds of N sulfate also contains 24 percent S, which during the seedling stage to encourage makes it an excellent fertilizer source for rapid growth and development. Only 10 avoiding or correcting S deficiencies. It percent of this amount should be included may be a slightly more effective N source in the total requirement. All or most of the when N must be applied to saturated soils required N should be applied to a dry soil during the seedling stage. Nitrate forms of by the 4th to 5th leaf stage just before N should never be used because of the permanently flooding. The floodwater potential for large losses of N caused by solubilizes the N and moves it down into leaching and denitrification. the soil where it is retained for plant use The ammonium form of N in either urea during the growing season. Apply or ammonium sulfate is very stable in additional N at midseason as needed unless flooded soils and remains available the total amount required was applied throughout the season. Once N has been preflood. applied and the field permanently flooded, In either a permanent or delayed flood soil drying should be avoided or the system, an adjustment in N management is ammonium N will be converted to nitrate necessary when rice fields are drained for N. This conversion process results in loss straighthead. Straighthead is a physiological of N through denitrification once the field disorder (Fig. 29) that occurs on sandy is reflooded. soils, on soils where arsenical herbicides Nitrogen fertilizer timing depends on have been previously used and on soils the cultural system used. A continuous, where large amounts of plant residue have available supply of N must be maintained been incorporated before planting. in the soil-plant system to maximize Significant yield losses can occur if fields production. The relationship between N are not drained and completely aerated timing and water management affects N before panicle initiation. The draining retention, efficiency and use. The procedure detoxifies arsenical compounds approach to N management in a and reduces the buildup of hydrogen permanently flooded system (continuous or sulfide. Since draining usually occurs pinpoint) and a delayed flood system (dry during midtillering, no more than 50 seeded, or water seeded with a delayed percent to 60 percent of the required N flood) is quite different. should be applied preplant or preflood, In the permanently flooded system, all with the remainder being applied before or most of the total N requirement should reflooding. 34 Nitrogen requirements vary with variety formation must be considered. Tissue and soil type. With the exception of N, analyses and visual assessment are soil tests can adequately predict the need excellent diagnostic tools to determine the for rice nutrients. Nitrogen needs cannot N status of rice at midseason. Nitrogen be accurately assessed by currently deficiency should be avoided to minimize available soil tests. Total N requirements the potential for grain yield reductions. are determined by conducting statewide Midseason N should be applied at the variety trials. Recommendations are earliest indication of N deficiency, even if expressed in ranges of application rates the green ring growth stage has not that consider soil type, environment and occurred. Late season N applications may variety. This information is updated each also be inefficient and could lead to grain year in the Louisiana Cooperative yield reductions. Research indicates that Extension Publication 2270, “Rice Varieties grain yields are not improved when N is and Management Tips.” applied later than four weeks after green Research shows that the total N ring. Yields may actually be reduced when requirement can be applied preplant in a N is applied after this time. continuously flooded system or preflood in a delayed flood system. Uniform Phosphorus Nutrition, Water application of N, familiarity with a Management, Source and Timing variety’s requirement, experience with a Phosphorus deficiency in rice occurs particular soil and proper water rather infrequently compared to N management are critical when using this deficiency. Stunting, reduced tillering, method. This approach may not be delayed maturity and yield reductions can practical commercially when these occur when P is limiting (Fig. 30). Unlike situations exist: 1) difficulty in applying N, water management has little effect on P large amounts of N fertilizer uniformly, 2) retention unless soil loss occurs through water management capabilities are erosion or removal of floodwater inadequate, 3) unfamiliarity with the containing high sediment concentrations. variety or land and 4) the seedbed is Phosphorus availability is influenced by saturated. Split applications may be more fertilizer placement, soil factors (pH, and desirable when any of these conditions Fe and aluminum content) and wetting/ exist. drying cycles. Soil flooding increases the Midseason N topdressings are used availability of P to rice, but alternating efficiently by rice provided adequate early wetting and drying cycles can result in season N was applied. A single midseason fixation of P in the soil and temporary application is usually sufficient to deficiency. maximize yield. Multiple applications of Water soluble sources of P, such as midseason N may not be cost effective superphosphate and diammonium and could reduce yield if the basal N phosphate, are effective in preventing and application was inadequate. Unlike N correcting mild deficiency. Consider cost applications into the flood on seedling effectiveness and the need for other rice, N applied into the floodwater at nutrients when choosing the most midseason is used efficiently by rice appropriate source. Factors to consider because of its large plant size and when determining rate of application extensive root system. include soil type, cropping history, grower Rice plant growth stages have been experience, and soil and plant tissue used to determine when to apply analyses. Typical applications of P range midseason N. The green ring growth stage from 25 to 50 pounds per acre. (similar to panicle initiation in many Phosphorus is most available to rice varieties) has traditionally been used for when applied at planting as a band or timing midseason N. While this growth broadcast and incorporated application. If stage is a good indicator, the overall health preplant applications are not possible, of the rice crop before green ring apply it before tillering occurs. Since 35 adequate P is essential for tiller formation, pounds of S, an adequate amount for deficiencies at this growth stage can avoiding or correcting a deficiency in an reduce yield potential significantly. existing crop. Water management has no Research has shown that P applications to effect on S availability or retention in the soils deficient in this nutrient are less soil, but may be important as it relates to effective when applied after tillering has the application of S-containing N begun (four to five weeks after planting). fertilizers.

Potassium Nutrition, Water Zinc Nutrition, Water Management, Management, Source and Timing Source and Timing Potassium deficiencies seldom occur in Zinc deficiency is a common Louisiana rice soils. Rice plants deficient in micronutrient deficiency in rice. Early K are lighter green, and the leaf edges deficiency symptoms include chlorosis and contain rust-colored spots that give the weakened plants that tend to float on the plant a brown appearance (Fig. 31). Plant floodwater surface (Fig. 32). Dark brown height may be reduced, but seldom is spots develop on the leaves; when yield reduction significant. The role K deficiency is severe, stand loss occurs. plays in plant nutrition is probably more Zinc deficiency is usually referred to as important as it relates to disease resistance. bronzing because of the rusty appearance Potassium behavior in the soil is that develops. Calcareous soils with an influenced little by water management. alkaline pH, inadequate Zn levels in the Potassium is a very soluble nutrient and is soil, removal of topsoil during accumulated by the rice plant throughout landforming, excessive lime applications, the growing season. Preplant or early deep water during seedling growth and season application in conjunction with N cool weather that retards root growth or P is recommended. Potassium chloride during the seedling growth stage may all and K sulfate are common sources to contribute to Zn deficiency. Deficiencies apply to avoid or correct existing most often occur in early planted, water- deficiencies. A single application (30 to 60 seeded rice because of low temperatures pounds per acre) is usually sufficient to and poor root growth. Since stand loss can maintain adequate K in the rice plant. Split occur when deficiency is severe, it is applications are not necessary unless the important to recognize deficiency soil is very sandy and leaching occurs. symptoms early. Since most rice soils, even those with a A soil test can identify soils prone to Zn sandy plow layer, contain a clay hardpan deficiency. Inorganic Zn salts, such as Zn that restricts water infiltration, split sulfate or Zn chloride, may be applied applications are seldom necessary. with other required fertilizer nutrients at planting. In dry-seeded rice, incorporate Sulfur Nutrition, Water Management, Zn to a shallow depth. In water-seeded Source and Timing rice, Zn is more available when applied to Sulfur deficiency is difficult to diagnose the soil surface in close proximity to the because it resembles N deficiency. Sulfur developing root system. is not mobile in the rice plant, and, when Plant uptake of Zn is affected by deficiency occurs, the entire plant tends to temperature and adequate root growth. yellow. Inadequate S in the soil and Preplant applications of Zn do not removal of topsoil during land-forming guarantee that deficiencies will not occur. operations contribute to S deficiencies. A If Zn deficiencies begin to develop in soil test can be helpful in identifying soil seedling rice, corrective applications need areas where deficiencies might occur. to be considered. Favorable growing Ammonium sulfate is an excellent source conditions that include high temperatures of S for correcting existing deficiencies. and sunlight may help correct mild Zn An application of 100 pounds of deficiencies. Removal of the floodwater ammonium sulfate per acre will supply 24 for a brief period will also alleviate mild 36 deficiency. When deficiency is severe and situations when fall application of some the potential for stand loss exists, apply Zn nutrients may be a suitable alternative. as a foliar application. Chelated and These include: 1) no-till and stale seedbed ligninsulfonate complex sources are most rice production when soil incorporation at effective for correcting deficiency. planting is not possible, 2) rice fields Either inorganic salts or chelated forms worked in the water prior to planting of Zn may be applied preplant. Inorganic when there is concern of fertilizer forms should be applied at a rate of 8 to movement and nonuniform redistribution 10 pounds of actual Zn per acre. Apply after mudding in and 3) where scumming chelated sources at a rate to deliver 1 to 2 is a problem when fertilizer is applied into pounds of actual Zn. Foliar sprays should the floodwater on seedling rice. be applied in a chelated form at a rate of Advantages to fall application of P and K one-half to 1 pound of actual Zn per acre. include more flexibility in early season N Use the higher rate when deficiency is applications and more opportunity to severe. apply these nutrients by ground application. Disadvantages include poor Fall Fertilizer Applications retention of K on sandy soils because of Fertilizer nutrients are most efficiently leaching and fixation of P on low pH soils used by rice when applied immediately containing high levels of iron and before seeding and no later than aluminum. Never apply nitrogen and Zn in permanent flood establishment. There are the fall.

PestPest ManagementManagement

Weed Management management strategy is not implemented. David Jordan and Dearl E. Sanders Rice weed control is best accomplished by using a combination of cultural, Introduction mechanical and chemical control practices. Weeds compete with rice for water, Relying on a single control practice nutrients, space and light. Direct losses seldom provides adequate weed control. from weed competition are measurable A thorough knowledge of the weeds and can be great. Indirect losses such as present in each field is critical in increased costs of harvesting and drying, developing appropriate management reduced quality and dockage at the mill, strategies. and reduced harvest efficiency are not readily measured but can reduce profits. Cultural Control Numerous grasses, broadleaf weeds Purchasing seed rice that is weed free and sedges can be economically damaging is an important first step in preventing in rice. Weeds can grow and thrive in weeds from becoming established, aquatic or semiaquatic environments especially in the case of red rice. Red rice common to rice culture. Barnyardgrass has been spread largely by planting (Figs. 33, 34), broadleaf signalgrass (Fig. commercial seed that is contaminated with 35), red rice (Fig. 36), hemp sesbania red rice. Red rice is a wild rice that is (Figs. 37, 38), alligatorweed (Fig. 39), similar to commercial rice. Besides dayflower (Fig. 40), ducksalad (Fig. 41), reducing commercial rice yields, the red redstem, jointvetch (Fig. 42) and annual pericarp (Fig. 46) of this noxious rice can and perennial sedges (Figs. 43-45) are contaminate milled rice. Additional milling among the most common weeds. Although can help remove the red discoloration but weeds vary in their ability to compete often will lead to reduced head rice yields with rice, most fields contain a complex through breakage of kernels. Cooking of weeds which will reduce yield and attributes of rice can be altered if quality if an appropriate weed significant amounts of red rice are present 37 in milled rice. No herbicides are available In water-seeded systems, Bolero or that selectively control emerged red rice in Ordram are applied before seeding to a commercial rice field, so preventing red suppress aquatic weeds and grasses. After rice from becoming established is critical. seedling establishment, propanil, Arrosolo Presence of red rice dictates production and Facet are used to control grasses and systems and weed control options and broadleaf weeds. These herbicides are decreases flexibility. Rotating rice with often supplemented with Basagran to other crops can reduce future weed control ducksalad and red stem. The field problems. Successful rotations with is generally drained briefly to expose soybeans primarily and to a lesser extent weeds to herbicides. When doing so, it is with corn, sorghum, soybeans or cotton important that the soil remain wet in fields have reduced levels of red rice in later where red rice is present. Allowing the rice crops. soil to dry can result in reinfestation by red Proper water management is a key rice. component in controlling weeds. Several Granular Ordram also controls grasses different water management schemes have and can be applied directly in the evolved in Louisiana. Permanent flood and floodwater. Londax has become a standard pinpoint flood cultures were developed in for use in water-seeded rice to control water-seeded rice to reduce weed ducksalad and other difficult-to-control problems. These practices attempt to aquatic weeds. Applying Londax at the maintain a saturated seedbed. Saturated appropriate timing is critical to control. seedbeds prevent weed seeds from Londax is applied into the floodwater germinating because of the absence of before aquatic weeds have surfaced, and a oxygen. stationary flood must be maintained for Establishing a good stand of rice and seven days for acceptable control. Some providing an environment that promotes dealers offer fertilizer materials rapid growth also help to minimize weed impregnated with Londax, an effective interference. Optimum plant populations application that reduces cost. and adequate fertility, insect, disease and Several herbicides are available for water management contribute to the ability post-flood weed control in both water- and of rice plants to compete with weeds. dry-seeded systems. Facet, Blazer, Management of weeds is critical for Basagran, Grandstand, Londax and 2,4-D optimum rice production in both water- are registered for use. Selection of these and dry-seeded systems. Although herbicides should be based on the herbicide options and management spectrum of weeds and restrictions on use. strategies differ under these systems, For example, 2,4-D use is prohibited managing herbicides and water in a timely where rice is grown in close proximity to manner is critical. cotton and other 2,4-D-sensitive crops. Although registered for use, apply Whip Water-seeded rice 360 only in salvage situations when other Most of the rice grown in Louisiana, herbicides have failed to control grass especially in the southern part of the state, weeds. Excessive rice injury can occur. is water seeded to control red rice (see Precautions on variety selection and red rice section). Weed populations shift cultural practices that may contribute to from terrestrial weeds in dry-seeded injury should be considered before use. systems to aquatic weeds in water-seeded systems. Red stem, ducksalad, Dry-seeded production alligatorweed and rushes are prevalent in In this system, four to six weeks may water-seeded systems. Grasses such as elapse between planting and permanent barnyardgrass and broadleaf signalgrass as flood establishment, and controlling weeds well as some warm-season perennial during this period is critical for maximizing grasses (such as water bermuda) (Fig. 47) yields. During this period barnyardgrass, in some areas can be a problem also. broadleaf signalgrass, sprangletop (Fig. 38 48), morningglories (Fig. 49), texasweed Facet are generally needed for grass (Figs. 50, 51), eclipta (Fig. 52), jointvetch, control, and these broadleaf herbicides are smartweeds (Fig. 53) and hemp sesbania used to broaden the spectrum of control. can become established. Timely herbicide Grandstand controls morningglories, applications made to small weeds, flushes jointvetch and alligatorweed. Londax and to activate herbicides, and establishment Basagran are used to control sedges and and maintenance of a permanent flood as certain broadleaf and aquatic weeds. soon as possible will improve weed Herbicide programs should be control. developed based on the complex of The residual herbicides Prowl, Facet weeds present in each field. Scouting and Bolero can provide residual weed fields and accurately identifying weeds are control up to permanent flood critical in formulating herbicide programs. establishment, and these herbicides have For example, Facet provides excellent proved valuable in dry-seeded production. control of barnyardgrass but does not They are especially beneficial when control sprangletop. Relying on Facet delays in permanent flood establishment alone for weed control will result in are anticipated or on clay soils where sprangletop escapes which can compete cracking of soil promotes numerous weed with rice. An additional herbicide flushes as well as difficulty in establishing application will be needed to control and maintaining a permanent flood. sprangletop, and the delay in application Although these herbicides do not always caused by misidentification can make provide complete control, when applied in sprangletop more difficult to control. a program with propanil or Arrosolo, these Annual sedges can often be controlled herbicides generally provide adequate with propanil or Arrosolo, but these control up to permanent flood herbicides seldom control yellow nutsedge establishment. These herbicides, and in adequately when applied alone; Basagran particular Facet, are more effective when or Londax is generally needed. fields are flushed or when adequate In dry-seeded systems, pulling levees rainfall occurs for activation. as soon as possible after planting can Propanil, Arrosolo and Facet are used improve weed control by allowing fields routinely to control emerged weeds before to be flushed and flooded in a timely flood establishment. Propanil is a contact manner. Without levees, using water as a herbicide with no residual activity. management tool is impossible. On coarse- Arrosolo contains both propanil and textured, silt loam soils, pulling levees is molinate, and it provides contact and much easier than on finer-textured, clay limited residual weed control. Facet soils. Although rainfall shortly after controls emerged weeds, but, unlike planting is beneficial for establishing a rice propanil and Arrosolo, root absorption of stand and reducing the need for flushing, Facet is important. Flushing or adequate excessive rainfall can prevent levee rainfall shortly after application of Facet is construction on clay soils. Pulling levees as needed for activation regardless of soon as the rice is planted when the soil is whether or not weeds have emerged. still relatively dry can prevent or reduce Combinations of contact herbicides such as problems in preparing levees on wet soils. propanil and Arrosolo with the residual herbicides like Facet, Bolero or Prowl are Adjuvants and Spray Additives often more effective than single herbicide Postemergence herbicide performance applications. Weeds that are not under can be greatly influenced by adjuvants. moisture stress and are actively growing Grandstand, Londax, Basagran, Facet and are controlled more easily than stressed the dry formulations of propanil must be weeds. applied with a suitable adjuvant to control Grandstand, Londax, Basagran, Storm emerged weeds. Gramoxone Extra and and Blazer can be applied preflood in dry- Harmony Extra applied as burndown seeded systems. Propanil, Arrosolo and treatments require adjuvants. In contrast to 39 these herbicides, adjuvants will not weed spectrum. Gramoxone Extra has the improve control with emulsifiable advantage of rapid kill of weeds and propanil, Arrosolo or Whip 360. Bolero, requires only a two-day period before the Facet (preemergence or delayed flood can be established for seeding in preemergence), Prowl or Ordram applied water-seeded systems. This is an to the soil before weed emergence does advantage in controlling red rice. not require adjuvants. When a liquid These herbicides also have restrictions propanil formulation or Arrosolo is applied on preplant intervals which can potentially with Grandstand, Londax, Facet or limit utility. For example, Harmony Extra Basagran, additives are not needed. When cannot be applied within 45 days of Facet or dry formulations of propanil are planting. Additionally, various formulations mixed with these predominantly broadleaf of 2,4-D are available, and labels vary on herbicides, however, an adjuvant should rates and preplant intervals. Applying be included. Roundup and Gramoxone Extra with Adjuvant cost is much lower than the residual herbicides such as Bolero, Prowl cost of a herbicide application, especially and Facet can improve early-season weed when several herbicides are applied as a control. Bolero can be applied in dry- and mixture. Not using an adjuvant or selecting water-seeded systems, and Prowl can be a poor quality adjuvant can reduce weed applied only as a delayed preemergence control greatly. Consult the herbicide label application in dry-seeded systems. Facet for recommendations of the type of can be applied preemergence or delayed adjuvant (crop oil concentrate, nonionic preemergence in dry-seeded systems. It is surfactant, etc.) and the proper rate to use. critical to establish a weed-free seedbed for the emerging rice in dry- and water- Reduced-tillage and stale seedbed seeded systems. When weeds are not systems controlled and rice has emerged, control Producing rice in stale seedbed, can be difficult with in-season herbicides reduced-tillage or no-till systems requires for most winter annual and perennial use of burndown herbicides applied weeds. Also, summer annual weeds that before seeding in water-seeded systems are not controlled before rice emergence and before rice emergence in dry-seeded will be older, larger and often harder to systems. Timing of application will control with propanil or other rice depend on the spectrum and size of herbicides. weeds, anticipated planting date and label restrictions. The key is to have a weed- Weed Resistance free seedbed when the rice emerges (dry- Some weeds have developed resistance seeded rice) or when the flood is to herbicides. In situations where weeds established in water-seeded systems. A are not controlled with labeled rates of problem associated with no-till, water- herbicides applied under environmental seeded rice is poor water quality and low conditions which are favorable for oxygen resulting from decaying plant herbicide activity, these weeds may be residue. Timely vegetation management resistant. Repeated use of propanil has can minimize this situation. Roundup Ultra, resulted in development of biotypes Gramoxone Extra, 2,4-D and Harmony throughout the Mid-South that can no Extra are registered for use in rice. longer be controlled with propanil. Aquatic Applying combinations of Roundup Ultra weeds in California have developed with 2,4-D or Harmony Extra increases resistance to Londax. Rotating herbicides control of some broadleaf weed species and crops, and applying tank mixtures and may broaden the spectrum of control. consisting of herbicides with different Each of these has strengths and mechanisms of action, may prevent or weaknesses, and herbicide programs delay development of resistance in should be tailored to control the existing Louisiana. For example, mixtures of

40 propanil with Facet, Bolero or Prowl stand. After rice seedlings have anchored, include at least two different mechanisms the flood is brought up slowly until the of action and reduce selection pressure. permanent flood is established. Rotating rice with soybeans or other crops Maintenance of flooded soil conditions will allow use of soil-applied herbicides or reduces emergence of red rice and other postemergence grass herbicides which can weeds. Water management in this system is control barnyardgrass and red rice. These critical, and breakdowns in control usually herbicides have mechanisms of action that result from inadequate flood maintenance. differ from most rice herbicides. Although Bolero and Ordram suppress If weed resistance is suspected, contact red rice, they do not provide complete your county agent so an alternative control. Using these herbicides in herbicide program can be developed and combination with water management, resistance can be monitored. In addition to however, can minimize interference from developing potential weed resistance, red rice. Rotating rice with soybeans or repeated use of a single herbicide will other crops and controlling red rice with exploit the weakness of the herbicide and effective herbicides are important in may shift the weed spectrum to weeds managing red rice. that may be more difficult to control. This Summary. Numerous herbicides and has been especially true in continued use tank mixtures of herbicides are available for of Facet only, which has resulted in a shift use in rice, and, with the exception of red from barnyardgrass as the primary grass rice, adequate weed control can be weed to sprangletop. obtained when these herbicides are applied in a timely manner coupled with Red Rice Management appropriate water management. Early- Because red rice and commercial rice season weed interference can be very are so closely related genetically, detrimental and can reduce yields even herbicides that control red rice will though control practices are implemented generally kill commercial rice. Water later. Failure to apply herbicides in a timely management alone can often effectively manner may result in poor weed control suppress red rice and reduce competition. and the need for repeat applications. These Presence of red rice mandates that rice be situations allow more early-season weed produced in a water-seeded system, competition and generally less effective preferably the pinpoint production system. control. Uniform, level seedbeds are critical for Before using a herbicide, follow all success. In this system, a flood is directions and precautions. In addition to established with dry or presoaked rice being illegal, failure to follow the label can seeded directly into the flood. Presoaked result in poor weed control, excessive rice seed is preferred because it gives the injury and environmental and safety commercial rice an additional advantage hazards. over the red rice. Before flying on the rice seed, the field is tilled to muddy the water Herbicide Options and kill germinated red rice that would Herbicides in these tables have been otherwise emerge through clear water. evaluated by Louisiana Agricultural This type of tillage can be difficult on clay Experiment Station researchers under a soils. Depending on environmental variety of environmental conditions. conditions, the flood is removed and rice Recommendations and ratings reflect the seedlings are allowed to peg into the soil. average expected performance used in An advantage of presoaked seed is that accordance with label specifications. The the flood can be removed sooner than efficacy of these herbicides on important with dry rice. This can reduce the time rice weed species is presented in Tables 7 seeds are exposed to wind and drift within and 8. Specific recommendations for bays and can help lead to a more uniform herbicide use are in Table 9.

41 Table 7. Weed response to preplant and preemergence burndown herbicides. 1. Poor (P) = less

than 49%, Fair (F) = 50-69%, Good (G) = 70-89%, Excellent (E) = 90-100%, “-” = not rated.

Smartweed

Swinecress

Sibara/bittercress

Shepardspurse

Speedwells

Marestail

Henbit

Cutleaf Evening Primrose Evening Cutleaf

Curley Dock Curley

Chickweed

Carolina Geranium Carolina

Buttercup

Little Barley Little

Carolina Foxtail Carolina

Annual Ryegrass Annual Annual Bluegrass Annual Gramoxone Extra E P-F G E E E E P F F F G E E P P

Gramoxone Extra E F G E E E E F G E G E E E F-G E + Harmony Extra

Gramoxone Extra E P G E E E E G E G F G E E G G + 2,4-D

Roundup Ultra E F-G E E E G E F F G E E E E G G

Roundup Ulta E F-G E E E G E E G E E E E E E E + Harmony Extra

Roundup Ultra E F-G E E E E E G E G E E E E G G + 2,4-D

2,4-D P P P P E G P G E P F G E G F F

1.Burndown herbicides control only emerged weeds. A residual herbicide can be tank-mixed to extend the weed control. Follow label directions.

42 Table 8. Weed response to in-season herbicides and herbicide combinations. Poor (P) = less than 49%, Fair (F) = 50-69%, Good (G) = 70-89%, Excellent (E) = 90-100%, “-” = not rated. Palmleaf Morningglory Eclipta Barnyardgrass Red Rice Sprangletop Signalgrass Sedges Alligatorweed Ducksalad Redstem Hemp Sesbania Waterhyssop Jointvetch Dayflower Texasweed

PREPLANT BURNDOWN Roundup Ultra F G E F-G E E F F G E F - E E E 2,4-D1 E EPPPPP-FG-EEEEEEEE Gramoxone Extra F G G-E G G G F-G P G E G - E G F-G

PREEMERGENCE Bolero (PPS)2. PGGG3. GFEPEGFEFEP Ordram (PPS)2. FPEG3. -FEPPPPPPPP Bolero (Delayed)2. PPGPGF-PEEPEPEP Facet E - E P P E P P P P G P - - P Prowl (Delayed)4. PPGPGGPPPPPPPPP

POSTEMERGENCE Arrosolo G G E P E5. EE6. PG5. G5. E-G5. G5. E Propanil F G E P E5. EE6. PG5. G5. E-G5. G5. G Ordram2. PPGP-PGPPPPPPPP Grandstand E G-E P P P P F G-E P G G P-F E G G 2,4-D Amine E EPPPPP6. GEEEEGEE Blazer F F P P P P P P - - E - P - F Basagran F G P P P P E P F E F G P E P Prowl + Propanil F-G G E P E5. EE6. PG5. G5. E-G5. G5. G Facet5. EGEPPEPFPPG-G- F Bolero2. + Propanil G G E P E E E P G5. G5. E-G5. G5. G Londax G G P P P P E F E E P E P G G Facet + Propanil E G E P E5.EE6. FG5. G5. E-G5. G5. E Londax + Propanil E E E P E5. EEFEEEEG5. G5. E Granstand + Propanil E E E P E5. E E G-E G E E - E G G Granstand + Arrosolo E EEPEEEEGEE -EGE Granstand + Facet E EEPPEFEPEGFEGG

1.2,4-D labels differ in the length of time required between applications and planting. 2.See label for variety susceptibility. 3.With proper water management. 4.Drill-seeded rice after susceptibility. 5.Controlled only when small (less than 2 leaves). 6.A few sedges are controlled.

43 Table 9. Recommended herbicides, application methods and rates, and comments concerning use in rice in Louisiana.

.

44 45 46 47 .

48 49 .

.

.

.

.

.

.

50 Disease Management associated with special cultural practices Donald E. Groth, Milton C. Rush and that reduce disease, but may not be condu- Clayton A. Hollier cive to producing maximum yields. The major diseases of rice in the United Introduction States are the fungal diseases blast, caused Disease damage to rice can greatly by Pyricularia grisea (Figs. 54-57); stem impair productivity and sometimes destroy rot, caused by Magnaporthe salvinii (Scle- a crop. The United States does not have rotium oryzae) (Figs. 58, 59); sheath any of the destructive viral diseases blight, caused by Thanatephorus present in other rice-growing areas of the cucumeris (Rhizoctonia solani) (Figs. 60- world, but fungal diseases are prevalent 63); brown spot, caused by Cochiobolus and very destructive to Louisiana rice. miyabeanus (Fig. 64); narrow brown spot, Several bacterial diseases have been caused by Sphaerulina oryzina found, but no significant yield losses have (Cercospora janseana) (Figs. 65, 66); and been associated with them. kernel smut, caused by Neovossia horrida Direct losses to disease include reduc- (Fig. 67). Seedling diseases caused by tion in plant stands, lodging, spotted species of Achlya and Pythium (Figs. 68, kernels, fewer and smaller grains per 69) also are important in water-seeded plant, and a general reduction in plant rice. efficiency. Indirect losses include the cost Minor diseases include crown rot (Fig. of fungicides used to manage disease, 70), causal agent unknown; leaf scald, application costs and reduced yields caused by Gerlachia oryzae (Figs. 71, 73); 51 leaf smut, caused by Entyloma oryzae determining the probability of having (Fig. 73); sheath rot, caused by problems warranting preventive Sarocladium oryzae (Fig. 74); stackburn management measures. Commercial disease, caused by Alternaria padwickii varieties and their resistance levels to (Fig. 75); sheath spot, caused by Rhizocto- major diseases are in Table 12. Scouting nia oryzae (Figs. 76,77); crown sheath rot, information or disease thresholds and caused by Gaeumannomyces graminis var. management information are summarized graminis (Fig. 78); black kernel, caused by for the major diseases in Table 13. Curvularia lunata; seedling blights, caused Use of foliar fungicides to manage rice by various fungi (Fig. 79); bacterial leaf diseases is often justified under severe blight (Fig. 80); false smut, caused by disease conditions. Some factors which Ustilaginoidea virens (Fig. 81); root rots, affect the probability of fungicide use caused by several fungi; and several being warranted include disease history in miscellaneous leaf, the field, the stem and glume resistance of the spotting diseases. variety, the yield Several diseases potential, use (seed caused by sclero- or grain), date of tial fungi are also planting and ratoon found in Louisiana crop potential. but are not signifi- Always follow cant. label directions. A disorder Since the list of known as panicle labeled fungicides blight (Fig. 82) has may change, become increasingly important. Little is contact your Cooperative Extension known about its cause. Service agent for current information on An undefined pathogen complex acting fungicides available for rice disease alone or with insect damage (feeding) also management. causes the grain and kernel discoloration called “pecky” rice (Fig. 108). Rice Disease Identification The physiological disorders straighthead Each year the Louisiana rice crop is (Fig. 83) and bronzing or zinc deficiency affected by many diseases. Severity of (Fig. 32) occur throughout the southern rice symptoms often varies because of varietal area and are locally severe. Cold injury resistance, environmental conditions and (Fig. 84), salt damage (Fig. 85) and nutrient plant growth stage. Also, not all deficiencies often mimic disease symptoms. symptoms typical of a disease occur on a Two minor diseases of rice in Louisiana single plant. It is important to look at are caused by small parasitic round worms several plants, from all over the field, to called nematodes. These are white tip, establish an accurate diagnosis. In the caused by Aphelenchoides besseyi (Fig. 86), text, all symptoms known to occur are and root knot, caused by Meloidogyne described, but not all will be expressed. species (Fig. 87). Use the guide to the identification of rice The first step toward disease diseases present in Louisiana to decide management is identification followed by which diseases are present. The diseases careful field scouting. Diseases known to are divided into sections based on what occur in Louisiana and their causal agents plant part is affected. Several diseases are listed in Table 10. A guide for rapid may affect more than one part of a rice identification of the major diseases is given plant, however. When a disease is in the following section (Table 11). identified, more information is in the text Knowing the level of resistance of the and in Table 13. variety to major diseases can be useful in

52 Table 10. Rice diseases and disorders in Louisiana.

Common Name Pathogen name or cause

Bacterial diseases

Bacterial blight Xanthomonas oryzae pv. oryzae (Ishiyama) Swings et al. = X. campestris pv. oryzae (Ishiyama) Dye

Foot rot Erwinia chrysanthemi Burkholder et al.

Pecky rice (kernel spotting) Damage by bacteria (see also under fungal and miscellaneous diseases)

Fungal diseases

Black kernel Curvularia lunata (Wakk.) Boedijn (teleomorph: Cochiobolus lunatus R.R. Nelson & Haasis)

Blast (leaf, neck [rotten neck], nodal and collar) Pyricularia grisea Sacc.=P. oryzae Cavara (teleomorph: Magnaporthe grisea (Hebert) Barr)

Brown spot Cochliobolus miyabeanus (Ito & Kuribayashi) Drechs. ex Dastur (anamorph: Bipolaris oryzae (Breda de Haan) Shoemaker)

Crown sheath rot Gaeumannomyces graminis (Sacc.) Arx & D. Olivier

Downy mildew Sclerophthora macrospora (Sacc.) Thirumalachar et al.

Eyespot Drechslera gigantea (Heald & F.A. Wolf) Ito

False smut Ustilaginoidea virens (Cooke) Takah.

Kernel smut Tilletia barclayana (Bref.) Sacc. & Syd. in Sacc. = Neovossia horrida (Takah.) Padwick & A. Khan

Leaf smut Entyloma oryzae Syd. & P. Syd.

Leaf scald Microdochium oryzae (Hashioka & Yokogi) Samuels & I.C. Hallett = Rhynchosporium oryzae Hashioka & Yokogi

Narrow brown leaf spot Cercospora janseana (Racib.) O. Const. = C. oryzae Miyake (teleomorph: Sphaerulina oryzina K. Hara)

Pecky rice (kernel spotting) Damage by many fungi including Cochliobolus miyabeanus (Ito & Kuribayashi) Drechs. ex Dastur, Curvularia spp., Fusarium spp., Microdochium oryzae (Hashioka & Yokogi) Samuels & I.C. Halett, 53 Sarocladium oryzae (Sawada) W. Gams & D. Hawksworth and other fungi

Root rots Fusarium spp., Pythium spp., P. dissotocum Drechs., P. spinosum Sawada

Seedling blight Cochliobolus miyabeanus (Ito & Kuribayashi) Drechs. ex Dastur, Curvularia spp., Fusarium spp., Rhizoctonia solani Kuhn, Sclerotium rolfsii Sacc. (teleomorph: Athelia rolfsii (Curzi) Tu & Kimbrough), and other pathogenic fungi.

Sheath blight Thanatephorus cucumeris (A.B. Frank) Donk (anamorph: Rhizoctonia solani Kuhn)

Sheath rot Sarocladium oryzae (Sawada) W. Gams & D. Hawksworth = Acrocylindrium oryzae Sawada

Sheath spot Rhizoctonia oryzae Ryker & Gooch

Stackburn (Alternaria Alternaria padwickii (Ganguly) M.B. Ellis leaf spot)

Stem rot Magnaporthe salvinii (Cattaneo) R. Krause & Webster (synanamorphs: Sclerotium oryzae Cattaneo, Nakataea sigmoidae (Cavara) K. Hara)

Water-mold (seed-rot and seedling disease) Achlya conspicua Coker, A. klebsiana Pieters, Fusarium spp., Pythium spp., P. dissotocum Drechs., P. spinosum Sawada

Disorders

Bronzing Zinc deficiency

Cold injury Low temperatures

Panicle blight Cause undetermined

Pecky rice (kernel spotting) Feeding injury by rice stink bug

Straighthead Arsenic induced, unknown physiological disorder

Nematodes

Root-knot Meloidogyne spp.

White tip Aphelenchoides besseyi Christie 54 F I G U R E S

55 56 Figure 1. Germination

Figure 2. Coleoptile and radicle development

Figure 3. Mesocotyl development

Figure 4. Primary leaf

Figure 5. Primary leaf elongates

Figure 6. Sheath, collar and blade

Figure 7. First leaf

Figure 8. Second leaf 57 Figure 10. First primary tiller

Figure 11. Second primary tiller

Figure 12. Crown and modes

Figure 13. Green ring

Figure 9. Shoot and root parts

Figure 14. Second internode Figure 15. Panicle differentiation 58 Figure 18. First heading Figure 20. Milk stage

Figure 16. Early boot

Figure 17. Late boot

Figure 21. Dough stage

Figure 19. Full heading/pollination

Figure 22. Firm endosperm 59 Figure 26. Nitrogen deficient rice

Figure 23. Harvest maturity

Figure 27. Nitrogen deficient rice Figure 28. Nitrogen deficient rice

Figure 29. Straighthead

Figure 32. Zinc deficiency

60 Figure 30. Phosphorus deficiency Figure 31. Potassium deficiency Figure 34. Barnyardgrass

Figure 35. Broadleaf signalgrass

Figure 33. Seedling barnyardgrass

Figure 37. Hemp sesbania

Figure 38. Hemp sesbania

Figure 40. Dayflower

Figure 36. Red rice Figure 39. Alligatorweed 61 Figure 41. Ducksalad Figure 42. Jointvetch Figure 43. Perennial sedges

Figure 45. Perennial sedges

Figure 46. Red pericarp of red rice

Figure 44. Perennial sedges

Figure 48. Sprangletop

Figure 47. Water bermuda

Figure 49. Morningglories

62 Figure 50. Texas weed seedling

Figure 51. Texas weed seedling

Figure 52. Eclipta

Figure 54. Leaf blast Figure 55. Node blast

Figure 53. Smartweed

Figure 58. Stem rot Figure 57. Rotten neck blast

Figure 59. Stem rot

Figure 56. Collar blast Figure 60. Sheath blight (early lesion) 63 Figure 61. Sheath blight (sclerotia) Figure 62. Sheath blight Figure 63. Sheath blight (leaf lesion)

Figure 66. Narrow brown spot (sheath) Figure 64. Brown spot Figure 65. Narrow brown spot (leaf)

Figure 67. Kernel smut Figure 68. Water molds Figure 69. Water molds

64 Figure 70. Crown rot Figure 71. Leaf scald Figure 73. Leaf smut Figure 72. Leaf scald

Figure 74. Sheath rot

Figure 75. Stackburn

Figure 76. Sheath spot Figure 77. Sheath spot

Figure 78. Crown sheath rot

Figure 79. Seedling blight

Figure 80. Bacterial leaf blight Figure 81. False smut

65 Figure 82. Panicle blight

Figure 83. Straighthead Figure 84. Cold injury

Figure 86. White tip

Figure 85. Salt injury

Figure 89. Seed midge tubes

Figure 87. Root knot

Figure 88. Downy mildew 66 Figure 90. Seed midge damage

Figure 91. Chinch bugs Figure 92. Rice leaf miner larva

Figure 93. Leaf miner damage

Figure 94. Leaf miner stand reduction

Figure 95. Adult rice water weevils

Figure 96. Rice water weevil larva on roots Figure 98. Rice water weevil leaf scars

Figure 97. Rice water weevil pupa

Figure 101. Rice stem borer adult Figure 99. Water weevil damage (pruned roots)

Figure 100. Water weevil sampling bucket 67 Figure 102. Rice stem borer larva Figure 103. Sugarcane borer larva on rice

Figure 106. Rice stink bug adult

Figure 104. Stalkborer injury Figure 105. Stalkborer (white-head condition)

Figure 109. Skipper larva

Figure 107. Rice stink bug adult

Figure 110. Skipper adult

Figure 108. Pecky rice

68 Table 11. A guide to the identification of rice diseases present in Louisiana

For identification of the major diseases, determine the part of the plant affected by the disease then refer to that section of Table 11. A list of the causal agents of all rice diseases known to occur in Louisiana is in Table 10.

I. Planted Seeds and Seedlings Water-seeded rice: seeds rotted after draining water from field, copper or greenish-brown spots on soil surfaces around or above rotted seeds; coarse, bristly mycelium radiating from seed (Achlya spp.) (Fig. 68) or gelatinous matrix surrounding each affected seed (Pythium spp.) (Fig. 69). Water Mold.

Water-seeded rice: seedlings 1 to 4 inches tall dying in seedling flood or after flushing seeded field. Pythium Seedling Blight.

Drill-seeded or dry broadcast rice: seedlings 1 to 4 inches tall dying: a) Brown spot on coleoptile or growing point (Fig. 79), seedlings suddenly dying. Seedling Blight. b) Seedlings dying or turning white in patches or in short strips of drill row; fluffy white mycelium and small, round sclerotia (tan) may be present on soil surface at the base of affected seedlings after flushing seeded field. Sclerotium Seed- ling Blight.

Seedlings at three- to five-leaf stage dying, often in patches, may have linear reddish-brown lesion on sheath of small seedlings, older seedlings with purple- brown blotches made up of small spots aggregating, leaves yellow or bronze (Fig. 32), lower leaves floating on surface of flood water, seedlings dying in deeper water and disappearing below surface of water. Bronzing. See also Salinity and Cold Injury.

II. Roots and Crown (Root-Stem Interface) Crown area decayed with soft rot, black or dark brown with streaks extending to the lower internodes of culms (Fig. 70), fetid odor of bacterial soft rot, tillers dying one at a time; roots dying and turning black, adventitious roots produced at node above crown area. A similar discoloration of the crown may be caused by applying hormonal herbicide such as 2,4-D too early. Crown Rot.

Roots turning black or brown, decayed, reduced root volume, roots dying. Root Rot. Roots with swollen areas, found only under dry-land conditions (Fig. 87). Root knot.

III. Leaf Blades Lesions varying from small round, dark-brown spots, to oval spots with narrow reddish-brown margin and gray or white center with dark circular line (eyespot lesion) (Fig. 54), spots becoming elongated, diamond-shaped or linear with gray dead area in center surrounded by narrow reddish-brown margin. Leaf Blast.

Round to oval, dark-brown lesions with yellow or gold halo (Fig. 64); as lesions enlarge, they remain round, with center area necrotic, gray and lesion margin reddish-brown to dark brown. Brown Spot. 69 Long, narrow brown or reddish-brown lesion (Fig. 65); lesions 0.5 to 3 cm long, parallel with leaf veins, and usually restricted to the area between veins; lesions may occur on leaf sheaths. Narrow Brown Leaf Spot.

Lesions consist of alternating wide bands of white, greenish-gray or tan with narrow bands of reddish-brown or brown (Fig. 63); lesions begin at base of blade, spreading from leaf sheath or from infection point on leaf blade. Sheath Blight.

Lesions consist of wide bands of gray, dying tissue alternating with narrow reddish-brown bands (Fig. 71); band pattern in chevrons from leaf tip or edges of the leaf, sometimes lesions are gray blotches at leaf edge with reddish-brown margin, advancing edge of lesion usually has a yellow or gold area (Fig. 72) between reddish-brown margin and green, healthy tissues. Leaf Scald.

Small 1-2 mm, black linear lesions on leaf blade (Fig. 73), usually more lesions on upper half of the leaf blade, lesions may have dark gold or light brown halo, leaf tip dries as plants approach maturity, lesions on sheaths of upper leaves. Leaf Smut.

Round or oval white or pale tan spot with narrow red or reddish-brown margin (Fig. 75); often two adjacent spots coalesce to form an oval double spot; lesions are from 0.5 to 1 cm in diameter, spots with small black fruiting structures in the center. Stackburn.

Leaf tips turn white with a yellow area between the white tip and the healthy green area (Fig. 86); white areas sometimes occur on leaf edges; flag leaf blade twisted with poor emergence of the panicle; kernels aborted or poorly filled; grain distorted or discolored. White Tip.

Lesions consist of elongated lesions near the leaf tip or margin and start out water soaked in appearance; lesions, several inches long, turn white to yellow and then gray because of saprophytic fungi (Fig. 80). Bacterial Leaf Blight.

IV. Leaf Sheath and Stem Water-soaked, gray-green lesion at water line (Fig. 60) during tillering or early jointing stages of growth, lesions becoming oval, white or straw-colored in center with reddish-brown edge (Fig. 62), lesions 1 - 2 cm wide and 3 - 4 cm long, lesions spreading up leaf sheaths and onto leaf blades, lesions discrete or forming a continuous band on sheath (Fig. 62) or leaf (Fig. 63) of alternating wide necrotic areas with narrow reddish-brown bands. Sheath Blight.

Black, angular lesions on leaf sheaths at water line on plants at tillering or early jointing stages of growth (Fig. 58); at later stages outer sheath drying, inner sheath discolored or with black angular lesion; culms discolored with dark-brown or black streaks; raised areas of dark fungus mycelium on surface; gray mycelium inside of culm or at maturity culm collapsed with small, round black sclerotia in dead sheath tissues and inside of culm (Fig. 59). Stem Rot.

Lesions oval, pale green, turning cream or white in the center with a broad dark reddish-brown margin (Fig. 76, 77). Lesions remain separate, not forming large continuous lesions. Sheath Spot.

70 Black to brown diffuse lesions on the sheath near the water line (Fig. 78). Perithecia necks protruding from upper surface and a thick fungal mat between leaf sheath and culm. Crown Sheath Rot.

Reddish- or purple-brown, netlike pattern on sheath below the collar of lower leaf blades (Fig. 66), lesion oval, 1 to 2 cm wide and 3 to 5 cm long, leaf blades turning yellow and drying. Cercospora Net Spot. (See Narrow Brown Leaf Spot.)

General reddish discoloration of flag leaf sheath or reddish-brown or yellow-tan spots with dark, irregular ring pattern inside of spots (Fig. 74); panicles emerging poorly; stem of panicle twisted; white “frosting” of conidia on inside of leaf sheath, florets of panicles on affected tillers discolored a uniform reddish-brown or dark brown. Grain does not fill or kernels are lightweight. Sheath Rot.

Narrow red-brown lesions on flag leaf sheath or penultimate leaf sheath after panicles emerge; lesions 0.5 to 1.5 mm wide and up to 1 to 3 cm long; lesions run parallel with veins in sheaths, affecting the tissues between veins (Fig. 66). Narrow Brown Leaf Spot.

Collar of flag leaf discolored brown or chocolate-brown; leaf blade detaches from sheath as lesion dies and dries (Fig. 56). Blast on Flag Leaf Collar.

Culm nodes turn black or nodes become shriveled and gray as plants approach maturity (Fig. 55); nodes purple to blue-gray with conidia of the pathogen; culms and leaves straw-colored above affected node; culms lodge at affected nodes. Node Blast.

V. Panicle, Florets and Grain Panicle Node and surrounding area at base of panicle discolored brown or chocolate- brown (Fig. 57); stem of panicle shrivels and may break; node purplish or blue-gray with conidia of the fungal pathogen; panicle white or gray; florets do not fill and turn gray; panicle branches and stems of florets gray-brown lesions. Rotten Neck Blast.

Panicles upright, not falling over or slightly bent over because of sterility. Hulls distorted, beak-shaped. Plants may not head at all (Fig. 83). Straighthead.

Internodal area above or below node at the base of the panicle turns light brown or tan-brown; affected area dies and shrivels; kernels in florets of lower portion of the panicle do not fill. Neck Blight. (See Brown Spot and Narrow Brown Leaf Spot for more information.)

Single florets or several florets on a panicle branch turn light brown or straw- colored; floret stem with brown lesion; grain stops developing; florets turn gray. Panicle Blast.

Panicles irregular, unable to emerge from the leaf sheath, and becoming twisted (Fig. 88); the panicle is small, normally remaining green longer than usual; no seeds produced. Downy Mildew.

71 Panicles small, reduced number of spikelets, and lemmas and paleas often absent on terminal portions of panicles. White Tip.

Florets and Grain Single florets or several florets per panicle with brown, reddish-brown, purple or white surrounded by purple-brown spots (Fig. 108). Grain Spotting or Pecky Rice.

Maturing grain partially filled with or without grayish cast; powdery black mass on surface of the kernel and at seam between palea and lemma (Fig. 67) (rubs off easily onto fingers). Kernel Smut. See black kernel.

Single florets or more commonly several florets in a panicle turn reddish-brown to dark brown. Sheath Rot.

Single florets or several florets on a panicle branch turn light brown or straw- colored (Fig. 82). The grain stops developing, and the florets turn gray. Panicle Blight.

Maturing grain partially filled, shriveled, chalky, fuzzy black mass covering surface of the grain or at seam between palea and lemma (will not easily rub off on fingertips). Brown Spot.

Large orange fruiting structure on one or two grains in maturing panicle; when orange membrane ruptures, a mass of greenish-black spores is exposed (Fig. 81); grain replaced by one or more sclerotia. False Smut.

Rice Diseases in Louisiana Contact your Cooperative Extension Service agent if you suspect this disease. Bacterial Leaf Blight Accurate identification is important since Bacterial leaf blight is caused by the the symptoms can be confused with other bacterium Xanthomonas campestris pv. diseases, especially leaf scald, herbicide oryzae. It was first identified in the United damage and other plant stress. States in Texas and Louisiana in 1987. No Management practices include rotating major losses have been associated with to nongrass crops, tilling to destroy plant this disease in the United States, but debris and avoiding contaminating the field bacterial leaf blight in other parts of the through infected plant materials or world causes severe damage. irrigation water. The blight bacterium overwinters in rice debris in the soil and on weed hosts. Black Kernel There is also a slight chance that seed may The fungus Curvularia lunata causes transmit the pathogen. The pathogen is black kernel. The fungus causes severe spread by wind-blown rain, irrigation grain discoloration, and after milling the water, plant contact and probably on plant kernels appear black. When infections are debris on machinery. High humidity and heavy, the fungus can cause seedling storms favor disease development. Water- blights or weakened seedlings. This soaked areas appear on the leaf margins disease is rarely severe enough that near the tips, enlarge and turn white to management practices are recommended. yellow. As the lesions mature, they Seed treatments to manage other diseases expand, turn white and then gray because should reduce seedling damage. No other of growth of saprophytic fungi (Fig. 80). management measures are warranted. The lesion may be several inches long. 72 Blast the high areas of the field where the flood Rice blast is caused by the fungus has been lost or is shallow. Areas of heavy Pyricularia grisea. The disease is also nitrogen fertilization and edges of the called leaf blast, node blast, panicle blast, fields are also potential sites of infection. collar blast and rotten neck blast, If leaf blast is in the field or has been depending on the portion of the plant reported in the same general area, and if affected. Blast has been one of the most the variety is susceptible, fungicidal important diseases in Louisiana, causing applications are advisable to reduce rotten severe yield losses to susceptible varieties neck blast. under favorable environmental conditions. The pathogen overwinters as mycelium Blast can be found on the rice plant and spores on infected straw and seed. from the seedling stage to near maturity. Spores are produced from specialized The leaf blast phase occurs between the mycelium called conidiophores and be- seedling and late tillering stages. Spots on come windborne at night on dew or rain. leaves start as small white, gray or blue The spores are carried by air currents and tinged spots, which enlarge quickly under land on healthy rice plants. The spores moist conditions to either oval diamond- germinate under high humidity and dew shaped spots or linear lesions with pointed conditions and infect the plant. Generally ends with gray or white centers and lesions will appear four to seven days narrow brown borders (Fig. 54). Leaves later, and additional spores are produced. and whole plants are often killed under Plants of all ages are susceptible. Medium severe conditions. Lesions on resistant grain varieties are more susceptible to plants are small brown specks that do not blast, especially during the leaf phase, enlarge. than the long grain varieties grown in On stem nodes (Fig. 55), the host tissue Louisiana. turns black and becomes shriveled and Environmental conditions that favor gray as the plant approaches maturity. The disease development are long dew peri- infected area may turn dark purple to ods, high relative humidity and warm days blue-gray because of the production of with cool nights. Agronomic practices that fungal spores. Culms and leaves become favor disease development include exces- straw-colored above the infected node. sive nitrogen levels, late planting and dry Plants lodge or break off at the infected soil (loss of flood). Several physiologic point, or they are connected only by a few races of P. grisea exist, and disease devel- vascular strands. Some varieties are opment varies, depending on variety-race infected where the flag leaf attaches to the interactions. sheath at the collar (Fig. 56). The lesion The disease can be reduced by planting turns brown or chocolate brown to gray, resistant varieties (Table 12), maintaining a and the flag leaf becomes detached from 4- to 6-inch flood (Kim, 1986), proper the plant as the lesion area becomes dead nitrogen fertilizer, avoiding late planting and dry. and by applying a fungicide recommended Rotten neck symptoms appear at the by the Louisiana Cooperative Extension base of the panicle starting at the node Service. (Fig. 57). The tissue turns brown to choco- late brown and shrivels, causing the stem Brown Spot to snap and lodge. If the panicle does not Brown spot, caused by the fungus fall off, it may turn white to gray, or the Cochiobolus miyabeanus, is one of the florets that do not fill will turn gray. most prevalent rice diseases in Louisiana. Panicle branches and stems of florets also It is also called Helminthosporium leaf have gray-brown lesions. spot. When C. miyabeanus attacks the Scouting a field for blast should begin plants at emergence, the resulting seedling early in the season during the vegetative blight causes sparse or inadequate stands phase and continue through the season to and weakened plants. Leaf spots are heading. Leaf blast will usually appear in present on young rice, but the disease is 73 more prevalent as the plants approach usually associated with the variety Saturn. maturity and the leaves begin to senesce. Symptoms first appear during tillering. The Yield losses from leaf infection or leaf crown area is decayed, with soft rotting, spots are probably not serious. When the becoming black or dark brown with fungus attacks the panicle, including the discolored streaks extending into the lower grain, economic losses occur. Heavy leaf internodes of culms (Fig. 70). There is a spotting indicates an unfavorable growth fetid or putrid odor characteristic of factor, usually a soil problem. bacterial soft rots, and tillers start dying The pathogen also attacks the one at a time. The roots also die and turn coleoptiles, leaves, leaf sheath, branches black. Adventitious roots are produced at of the panicle, glumes and grains. The the node above the crown area. A similar fungus causes brown, circular to oval spots discoloration of the crown can be caused on the coleoptile leaves of the seedlings by misapplied herbicides. Control practices (Fig. 79). It may cause seedling blight. are not available. Leaf spots are found throughout the season. On young leaves, the spots are Crown Sheath Rot smaller than those on older leaves. The Crown sheath rot is caused by the spots may vary in size and shape from fungus Gaeumannomyces graminis var. minute dark spots to large oval to circular graminis. Other names for this disease spots (Fig. 64). The smaller spots are dark include brown sheath rot, Arkansas foot rot brown to reddish-brown. The larger spots and black sheath rot. It has been have a dark brown margin and a light, considered a minor disease of rice, but reddish-brown or gray center. The spots recent reports from Texas suggest severe on the leaf sheath and hulls are similar to damage can occur. The pathogen kills those on the leaves. lower leaves, thus reducing photosynthetic The fungus attacks the glumes and activity, causes incomplete grain filling causes a general black discoloration. It also and plants can lodge. attacks the immature florets, resulting in no Symptoms appear late in the season, grain development or kernels that are usually after heading. Sheaths on the lower lightweight or chalky. part of the rice plant are discolored brown Brown spot is an indicator of to black (Fig. 78). Reddish-brown mycelial unfavorable growth conditions including mats are found on the inside of infected insufficient nitrogen, inability of the plants sheaths. Dark perithecia are produced to use nitrogen because of rice water- within the outside surface of the sheath. weevil injury, root rot or other unfavorable Perithecia are embedded in the sheath soil conditions. As the plants approach tissues with beaks protruding through the maturity, brown spot becomes more epidermis. This disease can easily be prevalent, and the spots are larger on confused with stem rot (Fig. 58). senescing leaves. The fungus survives as perithecia and Damage from brown spot can be mycelia in plant residues. Ascospores are reduced by maintaining good growing windborne in moist conditions. The fungus conditions for rice by proper fertilization, has been reported to be seedborne. crop rotation, land leveling, proper soil Management practices have not been preparation and water management. Seed- worked out for this disease. protectant fungicides reduce the severity of seedling blight caused by this Downy Mildew seedborne fungus. Some varieties are less Downy mildew is caused by the fungus susceptible than others (Table 12). Sclerophthora macrospora. In early growth stages, infected seedlings are dwarfed and Crown Rot twisted with chlorotic, yellow to whitish Crown rot is suspected to be caused by spots. Symptoms are more severe on the a bacterial infection (possibly Erwinia head (Fig. 88). Because of failure to chrysanthemi). It is a minor disease emerge, panicles are distorted, causing 74 irregular, twisted and spiral heads that 40 percent of the florets affected on 10 remain green longer than normal. No percent or more of the panicles in a field. control measures are recommended. Smutted grains produce kernels with black streaks or dark areas. Milled rice has a dull False Smut or grayish appearance when smutted False smut, caused by the fungus grains are present in the sample. Because Ustilaginoidea virens, is a minor disease in fewer kernels break when parboiled rice the United States. The disease is is milled, kernel smut can be a severe characterized by large orange to brown- problem in processed rice. Growers are green fruiting structures on one or more docked in price for grain with a high grains of the mature panicle (Fig. 81). incidence of smut. When the orange covering ruptures, a This disease is usually minor in mass of greenish-black spores is exposed. Louisiana, but it can become epidemic in The grain is replaced by one or more local areas. Some varieties are more sclerotia. All varieties appear to have a susceptible and should be avoided where high level of resistance, and disease smut is a problem. Spores of the fungus control measures are not required. are carried on affected seeds and overwinter in the soil of affected fields. Grain Spotting and Pecky Rice The pathogen attacks immature, Many fungi infect developing grain and developing grain and is more severe when cause spots and discoloration on the hulls rains are frequent during flowering. or kernels. Damage by the rice stink bug, Specific control measures are not Oebalus pugnax F., also causes available. discoloration of the kernel. Kernels discolored by fungal infections or insect Leaf Scald damage are commonly called pecky rice This disease, caused by Gerlachia (Fig. 108). This is complex disorder oryzae, is common and sometimes severe involves many fungi, the white-tip in Central and South America. It is present nematode and insect damage. High winds in the southern rice area of the United at the early heading stage may cause States and in Louisiana annually. It affects similar symptoms. Proper insect control leaves, panicles and seedlings. The and disease management will reduce this pathogen is seedborne and survives problem. between crops on infected seeds. The disease usually occurs on maturing leaves. Kernel Smut Lesions start on leaf tips or from the edges This fungal disease is caused by of leaf blades. The lesions have a chevron Neovossia barclayana. Symptoms are pattern of light (tan) and darker reddish- observed at or shortly before maturity. A brown areas (Fig. 71). The leading edge of black mass of smut spores replaces all or the lesion usually is yellow to gold (Fig. part of the endosperm of the grain. The 72). Fields look yellow or gold. Lesions disease is easily observed in the morning from the edges of leaf blades have an when dew is absorbed by the smut spores. indistinct, mottled pattern. Affected leaves The spore mass expands and pushes out dry and turn straw-colored. of the hull, where it is visible as a black Panicle infestations cause a uniform mass (Fig. 67). When this spore mass light to dark, reddish-brown discoloration dries, it is powdery and comes off easily of entire florets or hulls of developing on fingers. Rain washes the black spores grain. The disease can cause sterility or over adjacent parts of the panicle. abortion of developing kernels. Affected grains are a lighter, slightly Control measures are not grayish color compared with normal grain. recommended, but foliar fungicides used Usually only a few florets may be to manage other diseases have activity affected in a panicle, but fields have been against this disease. observed in Louisiana with 20 percent to 75 Leaf Smut Plant breeders have found differences Leaf smut, caused by the fungus in susceptibility among rice varieties Entyloma oryzae, is a widely distributed, (Table 12), but resistance is an unreliable but somewhat minor, disease of rice. The control method because new races fungus produces slightly raised, black develop readily. Some fungicides used to spots (sori) on both sides of the leaves reduce other diseases also may have (Fig. 73) and on sheaths and stalks. The activity against narrow brown leaf spot. blackened spots are about 0.5 - 5.0 mm Low nitrogen levels favors development of long and 0.5 - 1.5 mm wide. Many spots this disease. can be found on the same leaf, but they remain distinct from each other. Heavily Root Knot infected leaves turn yellow, and leaf tips Species of the nematode Meloidogyne die and turn gray. The fungus is spread by cause root knot. Symptoms include airborne spores and overwinters on enlargement of the roots and the formation diseased leaf debris in soil. of galls or knots (Fig 87). The swollen Leaf smut occurs late in the growing female nematode is in the center of this season and causes little or no loss. Control tissue. Plants are dwarfed, yellow and lack measures are not recommended. vigor. The disease is rare and yield losses low. The nematode becomes inactive after Narrow Brown Leaf Spot prolonged flooding. Narrow brown leaf spot, caused by the fungus Cercospora janseana, varies in Root Rot severity from year to year and is more Root rots are caused by several fungi severe as rice plants approach maturity. including Pythium spinosum, P. Leaf spotting may become very severe on dissotocum, other Pythium spp. and the more susceptible varieties and causes several other fungi. The rice plant is severe leaf necrosis. Some premature predisposed to this disorder by a ripening, yield reduction and lodging combination of factors including occur. physiological disorders, insect feeding, Symptoms include short, linear, brown especially feeding of rice water weevil lesions most commonly found on leaf larvae, extreme environmental conditions blades (Fig. 65). Symptoms also occur on and various other pathogens. leaf sheaths, pedicels and glumes. Leaf Symptoms can be noted as early as lesions are 2-10 mm long and about 1 mm emergence. Roots show brown to black wide, tend to be narrower, shorter and discoloration and necrosis. As the roots darker brown on resistant varieties and decay, nutrient absorption is disrupted, the wider and lighter brown with gray necrotic leaves turn yellow and the plants lack centers on susceptible varieties. On upper vigor. With heavy root infections, plants leaf sheaths, symptoms are similar to those lack support from the roots and lodge, found on the leaf. On lower sheaths, the causing harvest problems. Often plants symptom is similar to a “net blotch” or with root rot show severe brown leaf spot Cercospora sheath spot in which cell walls infection. The disease is referred to as are brown and intracellular areas are tan to feeder root necrosis when the small fine yellow (Fig. 66). roots and root hairs are destroyed. When The primary factors affecting disease this happens, no lodging occurs and development are (1) susceptibility of symptom development is not as apparent varieties to one or more prevalent on the upper plants. pathogenic races, (2) prevalence of Fertilizer usually reduces the above- pathogenic races on leading varieties and ground symptoms although actual nutrient (3) growth stage. Although rice plants are use is impaired. Rice water weevil control susceptible at all stages of growth, the greatly reduces root rots. Draining fields plants are more susceptible from panicle stimulates root growth but can cause emergence to maturity. 76 problems with blast, weeds or efficiency The soilborne seedling blight fungus, of nutrient use. Sclerotium rolfsii, kills or severely injures large numbers of rice seedlings after they Seedling Blight emerge when the weather at emergence is Seedling blight, or damping off, is a humid and warm. A cottony white mold disease complex caused by several develops on the lower parts of affected seedborne and soilborne fungi including plants. This type of blight can be checked species of Cochiobolus, Curvularia, by flooding the land immediately. Sarocladium, Fusarium, Rhizoctonia and Treatment of the seed with a fungicide Sclerotium. Typically, the rice seedlings is recommended to improve or ensure are weakened or killed by the fungi. stands. Proper cultural methods for rice Environmental conditions are important in production, such as proper planting date disease development. Cold, wet weather is or shallow seeding of early planted rice, the most detrimental. will reduce the damage from seedling Seedling blight causes stands of rice to blight fungi. be spotty, irregular and thin. Fungi enter Water- and soil-borne fungi in the the young seedlings and either kill or genus Pythium attack and kill seedlings injure them. Blighted seedlings that from germination to about the three-leaf emerge from the soil die soon after stage of growth. Infected roots are emergence. Those that survive generally discolored brown or black, and the shoot lack vigor, are yellow or pale green and suddenly dies and turns straw-colored. do not compete well with healthy This disease is most common in water- seedlings. seeded rice, and the injury is often more Severity and incidence of seedling visible after the field is drained. It may blight depend on three factors: (1) also occur in drill-seeded rice during percentage of the seed infested by prolonged wet, rainy periods. seedborne fungi, (2) soil temperature and Seed treatment, planting when (3) soil moisture content. Seedling blight is temperatures favor rapid growth of more severe on rice that has been seeded seedlings and draining the field are the early when the soil is usually cold and best management measures for seedling damp. The disadvantages of early seeding disease control. can be partially overcome by seeding at a shallow depth. Conditions that tend to Sheath Blight delay seedling emergence favor seedling Sheath blight has been the most blight. Some blight fungi that affect rice economically significant disease in seedlings at the time of germination can Louisiana since the early 1970s. The be reduced by treating the seed with disease is caused by Rhizoctonia solani, a fungicides. fungal pathogen of both rice and Seeds that carry blight fungi frequently soybeans. On soybeans, it causes the have spotted or discolored hulls, but seed aerial blight disease. can be infected and still appear to be Several factors have contributed to the clean. Cochiobolus miyabeanus, one of the development of sheath blight from minor chief causes of seedling blight, is to major disease status. They include the seedborne. A seedling attacked by this increased acreage planted to susceptible fungus has dark areas on the basal parts of long-grain varieties, the increase in the the first leaf (Fig. 79). acreage of rice grown in rotation with If rice seed is sown early in the season, soybeans, the increased use of broadcast treating the seed is likely to mean the seeding and the higher rates of nitrogen difference between getting a satisfactory fertilizers used with the modern stand or having to plant a second time. commercial rice varieties. The disease is Little benefit is received from treating rice favored by dense stands with a heavily seed to be sown late in the season, unless developed canopy, high temperature and unfavorable weather prevails. high humidity. 77 Sheath blight is characterized by large crops are formed on the surface of lesions oval spots on the leaf sheaths (Fig. 62) and on these weed grasses, as well as on rice irregular spots on leaf blades (Fig. 63). and soybeans. The sclerotia are tightly Infections usually begin during the late woven masses of fungal mycelium tillering-joint elongation stages of growth. covered by an impervious, hydrophobic The fungus survives between crops as coating secreted by the fungus. structures called sclerotia or as hyphae in Disease severity can be reduced by plant debris. Sclerotia (Fig. 61) or plant integrating several management practices. debris floating on the surface of irrigation Dense stands and excessive use of water serves as sources of inoculum that fertilizer both tend to increase the damage attack and infect lower sheaths of rice caused by this disease. Broadcast seeding plants at the waterline. Lesions about 0.5 - tends to increase stand and canopy 1 cm in width and 1 - 3 cm in length are density. Rotation with soybeans or formed a little above the waterline on continuous rice increases the amount of infected culms (Fig. 60). Fungus mycelium inoculum in field soils. Fallow periods, grows up the leaf sheath, forms infection with disking to control growth of grass structures, infects and causes new lesions. weeds, will reduce inoculum in the soil. The infection can spread to leaf blades The pathogen also is known to infect (Fig. 63). The lower leaf sheaths and sorghum, corn and sugarcane when blades are affected during the jointing environmental conditions are favorable for stages of growth. After the panicle disease development. emerges from the boot, the disease Medium grain rice varieties are more progresses rapidly to the flag leaf on resistant to sheath blight than most of the susceptible varieties. With very susceptible long grain varieties. Several recently varieties, the fungus will spread into the released long grain varieties are more culm from early sheath infections. Infected resistant to sheath blight than the older culms are weakened, and the tillers may long grain varieties (Table 12). lodge or collapse. Fungicides are available for reducing The fungus can spread in the field by sheath blight. Ask a Cooperative Extension growing from tiller to tiller on an infected Service agent for the latest information on plant or across the surface of the water to fungicides for sheath blight management. adjacent plants. The fungus also grows across touching plant parts, for example Sheath Rot from leaf to leaf, causing infections on This disease is caused by the fungal nearby plants. Infected plants are usually pathogen Sarocladium oryzae. Symptoms found in a circular pattern in the field are most severe on the uppermost leaf because the fungus does not produce sheaths that enclose the young panicle spores and must grow from plant to plant. during the boot stage. Lesions are oblong The lesions have grayish-white or light or irregular oval spots with gray or light- green centers with a brown or reddish- brown centers and a dark reddish-brown, brown margin (Fig. 63). As lesions coalesce diffuse margin (Fig. 74), or the lesions on the sheath, the blades turn yellow- may form an irregular target pattern. On orange and eventually die. As areas in the U.S. rice varieties, the lesion is usually field with dead tillers and plants increase, expressed as a reddish-brown discoloration they may coalesce with other affected of the flag leaf sheath. Early or severe areas to cause large areas of lodged, dead infections affect the panicle so that it only and dying plants. Damage is usually most partially emerges. The unemerged portion common where wind-blown, floating debris of the panicle rots, turning florets red- accumulates in the corners of cuts when brown to dark brown. Grains from seedbeds are prepared in the water. damaged panicles are discolored reddish- Sheath blight also affects many grasses brown to dark brown and may not fill. A and weeds other than rice, causing similar powdery white growth consisting of symptoms. Sclerotia that survive between spores and hyphae of the pathogen may 78 be observed on the inside of affected diameter), oval or circular, with a dark sheaths. Insect or mite damage to the boot brown margin or ring around the spot or leaf sheaths increases the damage from (Fig. 75). The center of the spot is initially this disease. tan and eventually becomes white or This disease affects most rice varieties. nearly white. Mature spots have small The disease is usually minor, affecting dark or black dots in the center. These are scattered tillers in a field. Occasionally, sclerotia of the fungus. Grain or seeds larger areas of a field may have significant affected by the disease have tan to white damage. Control measures are not spots with a wide, dark brown border. recommended. Fungicidal sprays used in a The disease causes discoloration of general disease management program kernels, or the kernels stop development reduce damage, but recent studies show and grains are shriveled. that several bacterial pathogens commonly This fungus is the most common cause similar sheath rot symptoms on rice seedborne fungus in Louisiana and may in Louisiana. Fungicides would have little cause seedling blight. It is more common effect on these pathogens. on panicles and grain than on leaves in Louisiana. Sheath Spot No specific control recommendations This disease is caused by the fungus are available, but seed-protectant Rhizoctonia oryzae. The disease fungicides will help reduce the seedling resembles sheath blight, but is usually less blight caused by this pathogen and will severe. The lesions produced by R. reduce the number of spores available to oryzae are found on sheaths midway up cause leaf infections. the tiller or on leaf blades (Fig. 76). Lesions are oval, 0.5 - 2 cm long and 0.5 - Stem Rot 1 cm wide. The center is pale green, Stem rot caused by the fungus cream or white with a broad, dark Sclerotium oryzae is an important disease reddish-brown margin (Fig. 77). Lesions in Louisiana. Often, losses are not are separated on the sheath or blade and detected until late in the season when it is do not form the large, continuous lesions too late to initiate control practices. Stem often found with sheath blight. The rot causes severe lodging, which reduces pathogen attacks and weakens the culm combine efficiency, increases seed under the sheath lesion on very sterility and reduces grain filling. susceptible varieties. The weakened culm The first symptoms are irregular black lodges or breaks over at the point where angular lesions on leaf sheaths at or near it was infected. Lodging caused by sheath the water line on plants at tillering or later spot usually occurs midway up the culm. stages of growth (Fig. 58). At later stages This disease is usually minor on of disease development, the outer sheath Louisiana rice. Some fungicides used to may die, and the fungus penetrates to the manage sheath blight also reduce sheath inner sheaths and culm. These become spot. discolored and have black or dark brown lesions. The dark brown or black streaks Stackburn have raised areas of dark fungal mycelium This disease was first observed on rice on the surface and gray mycelium inside growing in Louisiana and Texas. Stackburn the culm and rotted tissues. At maturity, or Alternaria leaf spot is caused by the the softened culm breaks, infected plants fungal pathogen Alternaria padwickii. It is lodge and many small, round, black now common on rice around the world. sclerotia develop in the dead tissues (Fig. The disease is present in all rice fields 59). in Louisiana. Only occasional spots are The pathogen overwinters as sclerotia observed, but the disease may be more in the top 2 - 4 inches of soil and on plant severe in restricted areas of a field. The debris. During water-working and spots are typically large (0.5 - 1 cm in establishment of early floods, the 79 hydrophobic sclerotia float on the surface certain Fusarium spp. also have been of the water and often accumulate along found associated with molded seeds. The the edge of the field and on levees disease is caused by a complex of these because of wind action. fungi infecting seeds. The severity of this After a permanent flood is established, disease is more pronounced when water the sclerotia float to the surface, contact temperatures are low or unusually high. the plant, germinate and infect the tissues Low water temperatures slow the near the waterline. The fungus then germination and growth of rice seedlings, penetrates the inner sheaths and culm, but do not affect growth of these often killing the tissues. The fungus pathogens. In surveys conducted in continues to develop, forming many Louisiana during the early 1970s and sclerotia in the stubble after harvest. 1980s, an average of 45 percent of water- Most commercial varieties of rice are planted seeds were lost to water-mold. not highly resistant to stem rot. The In addition to the direct cost of the lost disease is favored by high nitrogen levels. seeds and the cost of replanting, water- Early maturing varieties are usually less mold also causes indirect losses caused by affected by stem rot. In addition, the reduced competitiveness of rice with applications of potassium fertilizer reduce weeds in sparse or irregular stands. Also, disease severity in soils where potassium replanting or overseeding the field causes is deficient. Stem rot is more serious in the rice to mature late when conditions are fields that have been in rice production for less favorable for high yields because of several years. unfavorable weather and high disease Suggested management measures pressure. include using early maturing varieties, Water-mold can be observed through avoiding very susceptible varieties, clear water as a ball of fungal strands burning stubble or destroying by surrounding seeds on the soil surface. cultivation after harvest to destroy After the seeding flood is removed, seeds sclerotia, using crop rotation when on the soil surface are typically possible, applying potassium fertilizer, surrounded by a mass of fungal strands avoiding excessive nitrogen rates and radiating out over the soil surface from the using foliar fungicides recommended by affected seeds (Figs. 68). The result is a the Cooperative Extension Service. Several circular copper-brown or dark green spot cultural practices may reduce stem rot. about the size of a dime with a rotted seed These include fluctuating the water level in the center. The color is caused by in the field so stagnant water does not bacteria and green algae which are mixed remain at the same level on the lower leaf with the fungal hyphae. sheaths, and draining water from the field Achlya spp. (Fig. 68) normally attack at the tillering and early jointing stages of the endosperm of germinating seeds, growth, while keeping the soil saturated. destroying the food source for the growing These practices may lead to the embryo and eventually attacking the development of leaf blast and other embryo. Pythium spp. (Fig. 69) usually problems, however. attack the developing embryo directly. When the seed is affected by the disease, Water-Mold and Seed-Rot the endosperm becomes liquified and With the extensive use of the water- oozes out as a white, thick liquid when the seeding method of planting rice, it has seed is mashed. The embryo initially turns become more difficult to obtain uniform yellow-brown and finally dark brown. If stands of sufficient density to obtain affected seeds germinate, the seedling maximum yields. The most important shoot and root are attacked and the biological factor contributing to this seedling is stunted. When infection by situation is the water-mold or seed-rot Pythium spp. takes place after the disease caused primarily by fungi in the seedling is established, the plant is stunted, genera Achlya and Pythium. Recently, turns yellow and grows poorly. If the 80 weather is favorable for plant growth, Physiological Disorders seedlings often outgrow the disease and Cold Injury are not severely damaged. Cold weather affects rice development The disease is less severe when rice is most at the seedling or reproductive water-seeded when weather conditions stages of growth. Seedling damage is favor seedling growth. High and low expressed as a general yellowing of the temperatures averaging above 65 degrees plants or as yellow or white bands across F favor seedling growth, and water-mold the leaves where a combination of wind is less severe. Seeds should be vigorous and low temperature damaged the plants and have a high germination percentage. at the soil line (Fig. 84). Cold weather Seed with poor vigor will be damaged by (less than 60 degrees F) present during water-mold fungi when water-seeded. the reproductive stages causes panicle Treat seed with a recommended blanking or blighting. Individual florets or fungicide at the proper rate to reduce the whole panicle may be white when water-molds and seed diseases. A list of emerging. To eliminate this problem, recommended fungicides is available adjust planting date to avoid low through Cooperative Extension Service temperatures. agents. Most rice seed is treated by the seedsman and is available to the grower Panicle Blight already treated. Seed-protectant The cause of panicle blight is fungicides differ in their effectiveness. unknown. It can be severe on certain Information on recent results from seed- varieties of rice. The disease is protectant fungicide trials can be obtained characterized by brown or straw-colored from an extension agent or the Rice discoloration of florets on a panicle Research Station. In field tests, these branch (Fig. 82). Lesions are not apparent fungicides have increased stands over below the grain, thus panicle branches those produced by untreated seeds from remain green. The grain stops developing 25 percent to 100 percent. and the florets turn gray. It is more severe in late planted rice where the rice is White Tip maturing and late night temperatures are This disease is caused by the high. nematode Aphelenchoides besseyi. Characteristic symptoms which appear Salinity after tillering include the yellowing of Soil alkalinity, or salinity, and water leaf tips, white areas in portions of the salinity injure rice and are characterized leaf blade (Fig. 86), stunting of affected by areas of stunted, chlorotic plants in the plants, twisting or distortion of the flag field (Fig. 85). Under severe conditions, leaf, and distortion and discoloration of leaves turn from yellow to white, and panicles and florets. Leaf tips change plants die. Affected areas usually have from green to yellow and eventually dead or dying plants in the center or on white. The tip withers above the white high spots, with stunted yellow or white area, becoming brown or tan and tattered plants surrounding that area and green, or twisted. Resistant varieties may show less affected, plants in lower areas. Salt few symptoms and still have yield loss. deposits may be seen on the edges of The nematode infects the developing leaves, on clods of soil and other high grain and is seedborne. areas of the field. Damage is reduced by This disease is present endemically in flushing with water low in salt. Louisiana, but is considered a minor rice disease. Fumigation of seeds in storage Straighthead will reduce the nematode population. No This physiological disorder is other specific control measures are associated with sandy soils, fields with recommended. arsenic residues or fields having large amounts of plant residue incorporated into 81 the soil before flooding. Panicles are mimicked by herbicide damage. Manage upright at maturity because the grain does by using resistant varieties (Table 12) and not fill or panicles do not emerge from the draining at the first internode elongating flag leaf sheath. Hulls (palea and lemma) stage of growth to dry the soil until it may be distorted and discolored, with cracks. Do not plant susceptible varieties portions missing or reduced in size. under conditions favorable for straighthead Distorted florets with a hook on the end development, which include very sandy are called “parrot beak” (Fig. 83) and are soils, soils with high levels of typical of straighthead. Plants are darker undecomposed plant residue or fields with green or blue-green and often produce a history of arsenical herbicide (such as new shoots and adventitious roots from the MSMA) applications. lower nodes. These symptoms can be

Table 12. Reaction of rice varieties commonly grown in Louisiana to common diseases and disorders

Narrow Sheath brown Brown leaf Leaf Cultivar Blast blight spot spot smut Straighthead Long grain

Akitakomachi MR S MR R MR S Alan S S MS MR S MS Cypress MS S MR MR MS MR Della S S MR S MS S Dellrose S S MS MS MS MR Dixiebelle S S-VS MR MS MR VS Drew MR S MR MR MR MS Gulfmont S VS R S MS-S MR Jackson S S MR MS MR MR Jasmine 85 R R MS-S R R VS Jefferson MS S MR MR MR MS Jodon S S MR MS MS VS Katy MR MS R MR MS MS Kaybonnet R-MR MS-S MS MS MS S Lacassine S S-VS MS MR R MS LaGrue S-VS S R-MR R R S Lemont S S-VS MS-S S S MR Litton MS MS — — — MS Maybelle S S MR MS S MR Millie MS-S MS R MR MR MS Priscilla MS MS — — — MS TORO-2 R MS-S MR-MS MS MR-MS VS Medium grain

Bengal S MS MS MR MS VS Lafitte MR MS MR R MS VS Mars S MS MS MR MS VS Rico-1 S MS S MS MS MR Saturn MR MS-S MS S S S

R = resistant, MR = moderately resistant, MS = moderately susceptible S = susceptible, and VS = very susceptible. Varieties labeled S or VS for a given disease or disorder may be severely damaged under conditions favoring disease development.

82 Table 13. Scouting and management practices recommended for major rice diseases.

BLAST Scouting or Determining Need Varieties with low levels of resistance should be scouted for leaf blast during the vegetative stages of growth. Leaf blast is more likely when the flood is lost, excessive nitrogen is used or rice is planted late in the growing season. Sandy soils and tracts near tree lines are probable areas where blast will occur. There are no predictive systems to foresee when rotten neck blast will occur. Since significant damage is already done when the disease is first detected, preventive sprays are required on susceptible varieties, especially when blast has been detected in the region.

Management Practices Plant varieties resistant to blast. Avoid late planting. Plant as early as possible within your recommended planting period. For leaf blast, reflood if field has been drained. Maintain flood at 4 - 6 inches. Do not overfertilize with nitrogen. Apply a fungicide if necessary. Contact your county agent for the latest information on available fungicides and timing.

SHEATH BLIGHT Scouting or Determining Need Rice following rice or soybeans is more likely to be affected. Dense stands and excessive nitrogen favor disease development. Scout varieties from mid-tillering until heading. The field should be sampled at several locations to determine the percentage of tillers infected. Spraying a fungicide is warranted if 5 percent to 10 percent or 10 percent to 15 percent of the tillers are infected on susceptible or moderately susceptible varieties, respectively.

Management Practices Avoid dense stands and excessive nitrogen fertilizer. Most long grain varieties have little resistance to sheath blight. Medium grain varieties are more resistant. Timing and rate of fungicide applications are critical for good sheath blight management. Check with your county agent for the latest information on fungicides. Fallow periods, with disking to control grasses in the field (which serve as sources of inoculum) and break down crop residue, help reduce disease pressure.

BROWN SPOT Scouting or Determining Need Disease is most severe when plants are nitrogen deficient or under other stresses. Plants become more susceptible as they approach maturity.

Management Practices Maintain good growing conditions through proper fertilizer, land leveling, good soil preparation and other cultural practices. Use recommended seed protectant fungicides to reduce inoculum. Correct stress conditions in the field. All varieties are susceptible, but some more than others.

NARROW BROWN LEAF SPOT Scouting or Determining Need Disease is most severe from panicle emergence to maturity. Several pathogenic races are present, and new races develop to affect resistant varieties.

83 Management Practices Many commercial varieties have acceptable levels of resistance to this disease. Check with your Cooperative Extension Service agent for latest information on the use of available fungicides. Apply fungicides at recommended rate and timing.

STEM ROT Scouting or Determining Need Most commercial varieties are susceptible. Infection takes place at the waterline, and angular black lesions form. The number of infected tillers may reach 100 percent in areas of the field where debris and sclerotia from the previous crop have collected after being windblown on the water surface.

Management Practices Applying potassium will reduce disease severity where potassium is deficient. Early maturing varieties are less affected by stem rot. Destroying the sclerotia in stubble by crop rotation, tillage or burning can reduce disease pressure.

WATERMOLD AND SEED-ROT Scouting or Determining Need The fungi causing this disease are soil- and waterborne. They occur in most rice fields. The seed-rot and water mold disease is most severe under flooded conditions when the water is cold.

Management Practices Seed should be treated with recommended fungicides. Check with your county agent for recent information on effective seed-protectant fungicides. Draining the seeding flood and flushing as needed help prevent watermold. Seeding should not begin until the mean daily temperature reaches 65 degrees F.

SEEDLING BLIGHT Scouting or Determining Need The fungi causing this disease can be seedborne or soilborne. They are common and are normally present on seeds or in soil. Seedling blight is common in drillseeded or dry broadcast rice.

Management Practices Treating seed with seed-protectant fungicides effectively reduces seedling blight. Check with your extension agent for recent information on effective seed-protectant fungicides.

GRAIN SPOTTING AND PECKY RICE Scouting and Determining Need Since these diseases are normally associated with insect damage, scout for the rice stink bug. Monitor fields from immediately after pollination until kernels begin to harden. Sample with a sweep net and count the number of insects collected. If the number of stink bugs exceeds 30 per 100 sweeps during the first two weeks after heading, treat the field with a labeled insecticide. During the dough stages, fields should be treated when 100 or more stink bugs are collected per 100 sweeps.

Management Practices Control of the stink bugs with insecticides is the only management measure for grain spotting and pecky rice.

84 KERNEL SMUT, LEAF SMUT, SHEATH ROT, SHEATH SPOT, LEAF SCALD, STACKBURN, ROOT ROT, ROOT KNOT, WHITE TIP, PANICLE BLIGHT, DOWNY MILDEW, FALSE SMUT, BACTERIAL LEAF BLIGHT, BLACK KERNEL, CROWN ROT, CROWN SHEATH ROT Scouting or Determining Need These diseases rarely occur with enough severity to warrant control measures or scouting.

Management Practices Control measures are not available or recommended for these diseases. Varieties differ in their reaction to these diseases, but extensive evaluations have not been conducted. Fungicides used to manage other major diseases reduce several of these diseases. Check with your county agent for the latest information.

Insect Management and other bodies of water. Adult midges Dennis R. Ring, James Barbour, William resemble small mosquitoes but lack the C. Rice, Michael Stout and Mark Muegge needle-like mouthparts and hold their forelegs up when resting. Eggs are Insects can be a major factor limiting elongate and laid in strings, usually on the rice production in Louisiana. The rice water surface of open water. The strings are held weevil and the rice stink bug are key together by a sticky material that forms a pests. They cause significant reduction in gelatinous coat around the eggs. After the quantity and quality of rice produced emerging, the larvae move to the soil each year in Louisiana. Other insects surface, where they live in spaghetti-like attacking rice, though not key pests, can tubes constructed from secreted silk, plant occasionally reduce rice yield and quality debris and algae (Fig. 89). The larvae go significantly. These include the rice seed through four instars before pupating under midge, rice leaf miner, fall armyworm, water in the tubes. The life cycle from egg chinch bug, rice stalk borer and sugarcane to adult requires 10-15 days. borer. This section contains information about Injury the identification, life cycle, injury to rice Midge larvae injure rice by feeding on and current scouting and management the embryo of germinating seeds and on practices for these pests. The scouting and the developing root and shoot of young management recommendations are based rice seedlings. Most economic injury to rice on the best available information and will is the result of stand loss caused by larvae be modified as additional research is feeding on the embryo of germinating conducted. Current treatment seeds. Reports of injury caused by rice recommendations are summarized in Table seed midge have increased in recent years. 14, but consult your county agent and the most recent “Insect Control Guide” Scouting and Management (Louisiana Cooperative Extension Service Rice seed midge is a problem only for publication 1838) to get the latest rice seeds and seedlings in water-seeded recommendations for specific insect pests. fields. Midges are not a problem in rice more than 2 to 4 inches tall. Scout fields RICE SEED MIDGE, Chironomus spp. for midges and midge injury within five to Description and life cycle seven days after seeding. Repeat scouting Adult midges can be seen in swarms at five- to seven-day intervals until rice over rice fields, levees, roadside ditches seedlings are about 3 inches tall. Midge 85 presence is indicated by larval tubes on the 30-40 days, and adults may live two to soil surface (Fig. 89). There are many three weeks. midge species, most of which do not attack rice, and the presence of midge tubes alone Injury does not indicate the need to treat a given Chinch bugs are a sporadic pest of rice field. in Louisiana. Economic injury to rice Midge injury is indicated by the generally occurs when favorable weather presence of chewing marks on the seed, conditions and production practices allow roots and shoots and by the presence of chinch bugs to build in corn, sorghum and hollow seeds (Fig 90). If midge injury is wheat fields. As these crops mature and are present, and plant stand has been reduced harvested, large numbers of chinch bugs to fewer than 15 plants per square foot, may move to young plants in nearby rice treatment may be necessary. The only fields. Serious economic losses have available method for control of rice seed resulted from chinch bug infestations in midge is to drain fields to reduce numbers north Louisiana. The trend toward increasing of midge larvae. Re-seeding of heavily acreage of small grains increases the infested fields may be necessary. The potential for chinch bug problems. potential for damaging levels of seed midge Chinch bug injury results when adults can be reduced or prevented by using and nymphs feed on the leaves and stems recommended water and crop management of rice plants. Feeding on young seedlings practices. Holding water in rice fields for causes leaves and stems to turn light brown. more than two to three days before seeding High numbers of chinch bugs can kill encourages the buildup of large midge young plants, severely reducing plant numbers before seeding and should be stands. avoided. Practices that encourage rapid seed germination and seedling growth, such Scouting and Management as using pre-sprouted seed and avoiding Check unflooded rice near small grain planting in cool weather, will help to speed fields every three to five days from rice through the vulnerable stage and seedling emergence until application of reduce the chances for serious damage. permanent flood. Check foliage in rice fields for chinch bugs. Thresholds for Chinch bug, Blissus leucopterus chinch bugs in rice are not available. If high leucopterus (Say) numbers of chinch bugs are present and Description and life cycle plant stands are being reduced, the field Chinch bugs overwinter as adults in should be treated. Cultural and chemical grass clumps, leaf litter and other protected control methods are available. Cultural areas, emerging in early- to mid-spring to control consists of flooding infested fields to feed and mate on grass hosts including kill chinch bugs or to force them to move small grains such as wheat, rye, oats and onto rice foliage where they can be treated barley. Adults are small, black insects about with an insecticide. This tactic requires that 1/6-inch long, with white front wings (Fig. levees be in place and that rice plants be 91). Each wing has a triangular black spot sufficiently large to withstand a flood. near the outer wing margin. Adults lay Cultural control may be more expensive white, elongate eggs 1/24-inch long behind than chemical control. Contact your county the lower leaf sheaths or in the soil near the agent for specific recommendations if roots. Eggs turn red as they mature and chemical control is needed. larvae emerge in seven to 10 days. There are five nymphal instars. Early instar The Fall Armyworm, Spodoptera nymphs are red with a yellow band on the frugiperda (J. E. Smith) front part of the abdomen. Last instar Description and Life Cycle nymphs are black and gray with a The fall armyworm feeds on most conspicuous white spot on the back (Fig. grasses found in and around rice fields. It is 91). The life cycle from egg to adult takes also a serious pest of corn and pasture 86 grasses. Since rice is not its preferred host, and third area of the field. Treat when the fall armyworm is only an occasional there is an average of one armyworm per pest on rice. Adult moths are about 1 inch two plants. long with gray-brown sculptured front Fall armyworm management consists of wings and whitish hind wings. The front cultural, chemical and biological control. wings of male moths have a white bar near Parasitic wasps and pathogenic the wing tip. This bar is absent in female microorganisms frequently reduce moths. Females lay masses of 50 to several armyworm numbers below economical hundred whitish eggs on the leaves of rice levels. Since adults lay eggs on grasses in and other grasses in and around rice fields. and around rice fields, larval infestations Egg masses are covered with moth scales can be reduced by effective management and appear fuzzy. of grasses. When fall armyworm numbers The larvae emerge in two to 10 days, reach threshold levels, cultural or chemical depending on temperature, and begin control is needed. Cultural control consists feeding on rice plants. They vary from light of flooding infested fields for a few hours green to brown to black, but have to kill fall armyworm larvae. This requires distinctive white stripes along the side and that levees be in place and that rice plants back of the body. Larvae feed for two to be large enough to withstand a flood. three weeks, developing through four Cultural control may be more expensive instars. Mature larvae are about 1 inch long than chemical control. Contact your county and have a distinctive inverted “Y” on the agent for specific recommendations if head. Mature larvae prepare a cocoon and chemical control is needed. pupate in soil or decomposing plant material. Moths emerge in 10 to 15 days, The Rice Leaf Miner, Hydrelia griseola mate and disperse widely before laying (Fallen) eggs on new plants. At least four Description and Life Cycle generations per year occur in Louisiana. Adults are dark flies with clear wings and a metallic blue-green to gray thorax. Injury Less than 1/4 inch long, they can be seen Fall armyworm larvae feed on the flying close to the water and lighting on leaves of young rice plants, destroying rice leaves. White eggs are laid singly on large amounts of tissue. Leaf loss of 25 rice leaves that float on the water. percent in the seedling stage can reduce Transparent or cream-colored legless larvae rice yields by about 130 pounds per acre. emerge in three to six days and begin When large numbers of armyworms are feeding between the layers of the rice leaf. present, seedlings can be pruned to the Larvae become yellow to light green as ground, resulting in severe stand loss. Fall they feed. Mature larvae are about 1/4 inch armyworm infestations generally occur long (Fig. 92). The larvae feed for five to along field borders, levees and in high 12 days before pupating. Adults emerge areas of fields where larvae escape after five to nine days and live two to four drowning. The most injurious infestations months. Under ideal conditions the life occur in fields of seedling rice that are too cycle can be completed in as little as 15 young to flood. Larvae from the first days. In cool weather the life cycle can overwintering generation, occurring in early extend for more than one month. spring, are the most injurious. Infestations later in the season may cause feeding injury Injury to rice panicles, although this is rare. The rice leaf miner is a sporadic problem in Louisiana. Problems are more Scouting and Management severe in continuously flooded rice than After germination of seedlings, scout in periodically flooded rice, and when fields weekly for larvae on plants. Sample water is more than 6 inches deep. Injury plants every 10 feet along a line across the is usually greatest on the upper side of field, and repeat this process in a second levees where water is deepest. The rice 87 leaf miner attacks rice during the early Adults fly in the early evening, with little spring. Injury is caused by larvae feeding flight occurring when night-time between the layers of the rice leaf (Fig. temperature falls below 60 degrees F. 93). Leaves closest to the water are Adults will invade either unflooded or attacked and killed. As larvae move up flooded rice fields and begin feeding on the plant, additional leaves die. When leaf the leaves of rice plants. The flight miner numbers are high, entire plants can muscles degenerate again as the weevils die, reducing stands severely (Fig. 94). In become established, and the adults cannot Louisiana, rice leaf miner seems to attack fly. Females begin egg laying in flooded fields in the same vicinity year after year. fields or in areas of unflooded fields that contain water, such as low spots, potholes Scouting and Management or tractor tire tracks. Females deposit Scout fields for rice leaf miners by white, elongate eggs in the leaf sheath at walking through flooded rice fields and or below the waterline. White, legless, C- gently drawing the leaves of rice plants shaped larvae with small brown head between the thumb and forefinger. Bumps capsules emerge from the eggs in about in the leaves indicate the presence of leaf seven days. miner larvae or pupae. If leaf miners are First instar larvae are about 1/32 inch present and plant numbers are reduced to long and feed in the leaf sheath for a less than 15 per square foot, treatment is short time before exiting the stem and necessary. Rice leaf miner management falling through the water to the soil, involves cultural control or insecticide where they burrow into the mud and application, perhaps both. Maintaining begin feeding on the roots of rice plants water depth at 4-6 inches will usually (Fig. 96). The larvae continue to feed in prevent problems with rice leaf miner. If or on the roots of rice plants developing leaf miners are present, lowering the through four instars in about 27 days. water level in rice fields so that rice Larvae increase in size with each leaves can stand up out of the water also succeeding molt. Fourth instar larvae are will help to prevent injury. Contact your about 3/16 inch long. Larvae pupate in county agent for specific control oval, watertight cocoons attached to the recommendations. roots of rice plants. The cocoons are covered with a compacted layer of mud Rice Water Weevil, Lissorhoptrus and resemble small mud balls (Fig. 97). oryzophilus Kuschel Adults emerge from the cocoons in Description and Life Cycle five to seven days, are able to fly a short The rice water weevil is the most time after emerging and may attack rice in injurious insect pest in Louisiana rice the same or a different field. The life production. Yield losses of more than cycle from egg to adult takes about 35 1,000 pounds per acre can occur from days. The length of the life cycle is severe infestations. The total annual loss temperature-dependent, however, and can in Louisiana attributed to this pest is vary from 25 to 45 days in warm and cool between $9 million and $10 million. weather, respectively. The number of Rice water weevil adults are grayish- generations per year vary with latitude. brown beetles about 1/8 inch long with a Two and a partial third generation occur dark brown V-shaped area on their backs in the southern rice-growing areas of (Fig. 95). Rice water weevils overwinter Louisiana. One and a partial second as adults in grass clumps and ground generation occur in the northern rice- debris near rice fields. Wing muscles of growing areas. Most adult weevils overwintering adults degenerate so these emerging in late July to early August (first insects cannot fly. When spring or second generation weevils in north or temperatures rise to 65 degrees F, wing south Louisiana, respectively) fly to muscles begin to regenerate and adults overwintering sites and remain inactive begin moving out of overwintering sites. until the next spring. 88 Injury forces water up through the screen bottom Adult rice water weevils feed on the and helps to separate larvae from any upper surface of rice leaves, leaving plant debris remaining in the bucket. After narrow longitudinal scars that parallel the a few seconds, larvae will float to the midrib (Fig. 98). Adult feeding injury can surface where they can be counted and kill plants when large numbers of weevils removed. Repeat the washing procedure attack very young rice, but this is rare and several times to make sure all larvae in a is usually localized along the field borders. sample have been counted. If you don’t Most economic injury is caused by larvae find larvae in any sample, sample the field feeding in or on rice roots. This feeding again in five to seven days. If the average or root pruning reduces root surface area, number of larvae per sample is fewer than resulting in decreased nutrient uptake by five, sample the field again three to five the plant. Plants with severely pruned root days later. If the average number of larvae systems (Fig. 99) turn yellow and appear per sample is five or more, the field to be nitrogen deficient. At harvest, plants should be treated. Sampling should cease from heavily infested fields will be shorter when the field has been treated or when than normal and have lower yields. Each plants have reached the 2 mm panicle larva found in a 4-inch (diameter) by 3- stage of development. inch (deep) core sample reduces rice yield Timing of Karate is crucial, and more by 40 pounds per acre. than one application may be required. One day after permanent flood has been Scouting and Management established, begin scouting for adults. Management practices for the rice Examine plants in a one square foot area water weevil are changing. Furadan is in five to 10 locations per field for expected to be available on a limited basis presence of adults. Continue scouting to producers in the 1999 growing season. every three to four days until treatment is At the time of writing, the only other needed. Treat when there is one adult compound which has received a label for weevil per square foot. Check at least 10 use is Karate. locations before making a decision. Scout Numbers of larvae on rice roots peak and treat as needed until green ring, when 21-35 days after flooding. At this time plants are no longer susceptible. Do NOT most of the larvae will be large, and a make more than five applications at the significant amount of root pruning will 3.84 fluid ounce per acre rate. Do NOT have occurred. Early scouting of fields can apply within 21 days of harvest. indicate if and when treatment is required Karate kills adult weevils, but not eggs to prevent damaging infestations resulting and larvae. Egg laying (oviposition) must in reduced insecticide costs and higher be prevented. Once eggs are laid in rice yields. stems or larvae are in the roots, Karate is Take the first larval count seven to 14 not effective. Applying Karate for eggs or days after establishment of the permanent larvae is a waste of money in addition to flood in a drill-seeded system or 10 to 14 the loss caused by weevils. Sampling days after plants have emerged from the plans and economic injury levels for the water in a water-seeded system. At least rice water weevil are being developed. six sites should be randomly selected in Recommendations for the management of each field. At each site, remove a single the rice water weevil with foliar core of plants and soil 4 inches in insecticides may change. diameter and 3 inches deep and place it in a 10-quart bucket with a 40-mesh screen Management of the Rice Water Weevil bottom (Fig. 100). Wash the soil from the using Cultural Control plant roots through the screen bottom in Fields may be drained to reduce rice the bucket by thoroughly stirring the soil water weevil numbers. Draining fields is in the water. Push the bucket up and down the only rice water weevil control method vigorously in the water several times. This available for rice grown in rotation with 89 crawfish. Draining fields for rice water Description and Life Cycle, weevil control requires careful planning so The Sugarcane Borer conflicts with weed, disease and fertilizer The sugarcane bore is also a sporadic management programs can be avoided or pest of rice in Louisiana. Like the stalk minimized. Contact your county agent for borer, sugarcane borers overwinter as last specific information on variety and instar larvae in the stalks of rice and other management practices for cultural control plants. These larvae pupate in the spring, or for specific chemical control and adult moths emerge as early as May, recommendations. mate and live on various hosts until rice stem diameter is large enough to support The Stem Borers: The Rice Stalk larval feeding. Adults are straw-colored Borer, Chilo plejedellus (Zink) moths about 1 inch long with a series of The Sugarcane Borer, Diatrea black dots, arranged in a V-shaped pattern, saccharalis (F.) on the front wings. Egg laying on rice can Description and Life Cycle, The Rice begin as early as May, but economically Stalk Borer damaging infestations generally do not The rice stalk borer is a sporadic pest occur until August or September. The flat, of rice in Louisiana. Rice stalk borers oval, cream-colored eggs are laid at night overwinter as last instar larvae in the stalks in clusters of two to 100 on the upper and of rice and other host plants. Larvae lower leaf surfaces over one to six days. pupate in the spring, and adult moths Larvae emerge in three to five days, crawl emerge in early to late June, mate and live down the leaf and bore into the plant on various hosts until rice stem diameter is stem. They move up and down the stem, large enough to support tunneling larvae. feeding for 15 to 20 days before chewing Adults are about 1 inch long with pale an exit hole in the stem and pupating. white fore and hind wings tinged on the Larvae are pale yellow-white in the edges with metallic gold scales. Front summer, with a series of brown spots wings are peppered with small black dots visible on the back (Fig. 103). (Fig. 101). Although egg laying may begin Overwintering larvae are a deeper yellow in late May, injurious infestations usually and lack the brown spots. The lack of occur from August through September. stripes distinguishes sugarcane borer Flat, oval cream-colored eggs are laid in larvae from rice stalk borer larvae, which clusters of 20 to 30 on the upper and have stripes in winter and summer (see lower leaf surfaces. Eggs are laid at night above). Mature larvae are about 1 inch over one to six days. Larvae emerge in long and do not enclose themselves in a four to nine days and crawl down the leaf silken web before pupation. The pupae toward the plant stem. Larvae may feed are brown, about 1 inch long and roughly for a short time on the inside of the leaf cylindrical in shape, not smoothly tapered sheath before boring into the stem. They as are rice stalk borer pupae. are pale yellow-white with two pairs of Overwintering sugarcane borer larvae are stripes running the entire length of the usually found closer to the plant crown body (Fig. 102). These stripes distinguish than rice stalk borer larvae. The pupal rice stalk borer larvae from sugarcane stage lasts seven to 10 days. There are borer larvae, which have no stripes. three generations per year. Mature larvae are about 1 inch long. Larvae move up and down the stem Injury feeding for 24 to 30 days before moving Injury to rice results from stalk and to the first joint above the waterline, sugarcane borer larvae feeding on plant chewing an exit hole in the stem and tissue as they tunnel inside the stem. constructing a silken web in which to Injury is often first noticed when the pupate. Pupae are about 1 inch long, youngest partially unfurled leaf of the brown and smoothly tapered. There are plant begins to wither and die, resulting in two to three generations per year in rice. a condition called deadheart (Fig 104). 90 Later in the growing season, these rice Immature stink bugs (nymphs) emerge stems are weakened and may lodge before from eggs in four to five days in warm harvest. Stem feeding that occurs during weather or as long as 11 days in cool panicle development causes partial or weather. Nymphs develop through five complete sterility and results in the white- instars in 15-28 days. Newly emerged head condition (Fig. 105). The white, nymphs are about 1/16 inch long, with a empty panicles are light in weight and black head and antennae and a red stand upright. abdomen with two black bars (Fig. 107). Nymphs increase in size with successive Scouting and Management molts and the color of later instars becomes Unfortunately by the time signs of field tan-green. There are four generations per infestations (deadhearts, white-heads) are year in Louisiana, two on weed hosts and noted, it is usually too late to apply two on rice. Only one generation develops effective chemical treatments. For chemical in a given field, however. treatments to be effective, you must time application to coincide with larval Injury emergence so small larvae are killed Rice stink bugs feed on the rice florets before they enter rice stalks. Once larvae and developing rice kernels. Feeding on enter the stalks, pesticides are not florets reduces rough rice yields, but most effective. Extensive scouting of rice fields economic loss results from stink bugs is required to time pesticide applications feeding on developing kernels. Kernel properly. Scouting can be conducted for feeding results in discolored or “pecky” stem borer adults or egg masses. Eggs are rice kernels that have lower grade and laid over an extended period, however, poor milling quality (Fig. 108). Both adult and although some injury may be and nymph rice stink bugs feed on prevented, satisfactory control using developing rice grains, but adults alone chemical treatments is difficult and has not account for most economic losses in rice. been generally successful. No pesticides Relationships between stink bugs and stink are labeled specifically for stem borer bug injury developed in Texas show a control in rice. Stem borer eggs and larvae strong increase in percentage of pecky rice are parasitized by the wasps, and a strong decrease in percentage of Trichogramma minutum Riley and Agathis head yield with increasing numbers of stigmaterus (Cresson), respectively. It is adult stink bugs during the heading period. believed these parasites play an important When numbers of immature stink bugs role in maintaining stem borer numbers were included, this relationship did not below economic levels. change.

Rice Stink Bug, Oebalus pugnax (F.) Scouting and Management Description and Life Cycle Several natural enemies are important in Adult rice stink bugs are shield-shaped, reducing rice stink bug numbers in rice. metallic-brown insects about ½ inch long Adults and nymphs are parasitized by the (Fig. 106). Rice stink bugs overwinter as flies, Beskia aelops (Walker) and Euthera adults in grass clumps and ground cover. tentatrix Lav. Rice stink bug eggs are They emerge from overwintering sites in parasitized by the tiny wasps, Oencyrtus early spring and feed on grasses near rice anasae (Ashm.) and Telonomus podisi fields before invading fields of maturing (Ashm.). Management relies significantly rice. Adults live 30-40 days. Females lay on the activity of these naturally occurring masses of light-green cylindrical eggs on biological control agents. Insecticidal the leaves, stems and panicles of rice control based on the results of field plants. Eggs are laid in parallel rows with scouting is recommended when rice stink about 20-30 eggs per mass. As they bugs escape from the control provided by mature, eggs become black with a red tint. natural enemies.

91 Rice fields should be sampled for stink 100 sweeps) should be treated with an bugs using a 15 inch diameter insect insecticide. After the first two weeks of sweep net once each week beginning heading, treat fields when an average one immediately after pollination and or more stink bugs per sweep (100 or continuing until kernels harden. Do not more per 100 sweeps) is found. Do not sample fields at midday when stink bugs treat fields within two weeks of harvest. may be seeking shelter from the heat in Contact your county agent for specific the shade at or near the ground. Avoid treatment recommendations. sampling field borders, where stink bug numbers are often higher than in the field Other Insect Pests of Rice interiors, also. A sample consists of 10 Several other insects may occasionally consecutive 180 degree sweeps made attack rice in Louisiana. They include the while walking through the field. Hold the southern green stink bug, Nezara viridula net so that the lower half of the opening is (L.), several grasshopper species and the drawn through the foliage. After 10 larvae of several species of skippers (Figs. successive sweeps, count the number of 109, 110) and tiger moths. The numbers of rice stink bug nymphs and adults. these insects in rice fields are usually Normally 10 samples of 10 sweeps each below levels justifying treatment, but they are made per field. Alternatively, 100 may increase rapidly under favorable random sweeps may be taken per field. conditions and yield losses can occur. During the first two weeks of heading, Contact your county agent for specific fields averaging one or more rice stink treatment recommendations. bugs per three sweeps (30 or more per

92 Table 14. Rice insect control recommendations.

Dosage Per Acre Insect Treatment Active Ingredient Limitations Remarks

Armyworms1 Methyl l/2 lb. ec l5 days Treat when there is one Parathion armyworm per two plants.

Malathion2 1.5 lb ec 15 days B.t.2,3 0.5 lb 0 days

Chinch Bugs3 Methyl 3/4 lb. ec l5 days Flood fields first. Parathion

Rice Leaf Miners Methyl l/4 lb. ec 5 days Treat when stands are Parathion reduced to less than 15 plants per square foot.

Rice Stink Bug Malathion l/2 lb. ec 7 days Treat when there are 30 stink Sevin l to l l/4 lb. WP l4 days bugs per 100 sweeps during the first two weeks of heading. Methyl l/4 lb. ec l5 days Treat when there are Parathion 100 stink bugs per 100 sweeps Penncap M 1/4 lb. ec 15 days from two weeks after heading begins until two weeks before Malathion2 0.5 lb 15 days harvest.

Rice Water Furadan4,5 l/2 lb. (l6 to 20 lbs. Treat when 40% of the plants Weevil5 of 3% sand core granules) have feeding scars on the newest unfurled leaf, and/or Water management2,6 when there is an average of 5 rice water weevil larvae per core.

Rice Seed Drain fields Treat when stands are reduced Midge to less than 15 plants per square foot.

1 Flooding is effective for armyworm control if plants are sufficiently developed. Do not use Methyl Parathion within 14 days of applying propanil. 2 For rice grown in rotation with crawfish. 3 There are several formulations available. Follow label directions. 4 Apply from one day before to four days after permanent flood for dark rice field mosquito control. 5 Do not apply propanil after applying furadan. Do not apply to fields used for crawfish production. Do not apply more than once per season. 6 Consult your county agent for specific water management procedures.

WARNING: Re-entry times for workers entering treated fields should be strictly observed. Be sure to check the label for this information.

93 Blackbird Control James F. Fowler and Joseph A. Musick

Blackbirds (Icterinae), are among the devices, chemical repellents and restricted most numerous birds in rice-growing areas. use toxicants. The red-winged blackbird (Agelaius phoeniceus) is the most abundant breeding Cultural Practices bird in the rice-growing area of 1. Drill seed rice on a well-prepared southwestern Louisiana. Red-winged seedbed. Water-plant only where a blackbirds are responsible for most rice continuous uniform flood of 2 to 6 depredation. Brown-headed cowbirds inches can be kept on the rice. (Molothrus ater), common grackles 2. Delay planting rice in high blackbird (Quiscalus quiscula) and boat-tailed infested areas (such as coastal areas) grackles (Quiscalus major) cause the rest until after April 1. Arrange planting of rice damage. Blackbirds are responsible programs so fields near roost areas or for significant economic loss during coastal marshes are planted last. Begin sprouting and ripening stages each year. planting nearest the farm headquarters Damage to sprouting rice can be and progress to more sensitive areas particularly severe in water-seeded rice. later in the season. Most damage occurs in southwestern 3. Block planting in areas of traditionally Louisiana where rice is seeded before severe bird damage, such as in fields resident flocks of blackbirds have adjacent to coastal marshes, can be dispersed to breed and before the effective in reducing damage on indi- departure of all wintering migrants. As vidual farms. This method requires that many as 50 winter roost sites in Louisiana a group of farmers in a given area plant may be used by more than 125 million all or most of their rice on, or near, the blackbirds annually. Economic losses same date. caused by blackbird damage are most 4. Consider alternate crops in high bird severe in fields located within five miles pressure areas where there has been a of winter roost sites. These areas are history of extreme damage to rice crops. traditionally adjacent to coastal marshes. 5. Habitat modification and clean cropping Both federal and state governments may be helpful in reducing the number recognize that blackbirds are important of resident blackbirds damaging rice depredators of agricultural commodities. crops at maturity. Removing brush and Blackbirds are migratory birds and are trees from ditch banks, levees, fence provided protection under provisions of rows and keeping fields free of weeds the Migratory Bird Treaty Act. They may will eliminate blackbird habitat in and be controlled without a federal permit around field areas. when found depredating agriculture crops, however. Louisiana considers blackbirds Scare Devices pests that may be taken any time by any 1. Propane exploders with timers to turn legal means. them off and on automatically each day No conventional agricultural pesticides are the most effective scare devices are labeled for use in reducing blackbird used to move feeding blackbirds from damage in rice production. No lethal freshly planted rice fields and after chemical compound that will control maturity. There should be a least one blackbirds in agricultural crops safely and exploder for every 25 acres of crop to effectively is likely to be registered for be protected. They should be elevated general use by producers in the near on a barrel, stand or truck bed to “shoot” future. Methods of control involve over the crop. They should be moved alternative cultural practices, scare around the field every few days. Ex-

94 ploders should be reinforced with live usually die. Avitrol is for sale to and use ammunition fired from shotgun and .22 only by certified applicators or persons caliber rifles. In addition, pyrotechnics under their direct supervision and only such as 12-gage shell crackers, rope fire for those uses covered by the Certified crackers and rocket bombs can be Applicators Certification. Distribution of helpful when used with live ammunition Avitrol should be limited to scattered and propane exploders. spot placements that will provide 2. Aircraft can be used to harass birds in feeding opportunities only for the newly planted fields, but this method is necessary number of target birds. After costly under most situations. the birds’ feeding pattern has been established through prebaiting, untreated Chemical Repellents bait is removed and diluted treated bait 1. Chemical repellents are compounds applied only at sites where the target which must be registered by EPA. When birds are actively feeding. Do not apply placed on rice seed or other bait, this product where nontarget bird repellents will deter consumption of species are feeding. Treated bait should newly planted seed by blackbirds. They be picked up and removed from the work by causing olfactory, gustatory or field each day. digestive irritation in the target animal. 2. Compound DRC-1339 is an avicide At present, no chemical repellents are registered for use in parts of southwest- registered to protect newly planted rice ern Louisiana under a 24 (C), local- seed. needs label. It can be used only by 2. Methyl anthranilate is a chemical com- personnel of the USDA Animal Damage pound that holds promise for protecting Control Program and those working seed rice. Testing is under way. under their supervision. DRC-1339 is applied to brown rice baits broadcast on Restricted Use Toxicants blackbird staging areas near winter and 1. Avitrol (4-aminopyridine) is a poison spring roosting sites. Depending on the with flock-alarming properties used to number of birds killed, the product is control blackbirds and starlings in, on or sometimes effective in reducing rice around the area of feedlots, structures, depredations associated with large nesting, roosting and feeding sites. It concentrations of roosting blackbirds. acts in such a way that only a part of DRC-1339 has not been effective when the flock feeding on the bait will ingest used in areas where blackbirds are treated bait, react and frighten the rest widely dispersed. away. Birds that react and alarm a flock

Harvest and Storage

Harvesting Rice certain insects and disease. Management William A. Hadden losses are caused by premature draining and improper harvest moisture. Harvest Considerations Combine losses can be minimized with Proper adjustment of harvesting proper harvester adjustment. Losses equipment is essential for reducing harvest generally occur at the header (gathering loss and monitoring optimum harvest unit loss), at the cylinder or during efficiency, but preharvest losses and separation. Gathering loss includes management losses can both result in poor shattering, loose stalk and lodged stalk harvest efficiency. Preharvest losses are loss. Shatter loss occurs when loose grains caused by factors such as adverse weather, or panicles fail to enter the header. Loose bird depredation or damage caused by stalk losses occur when panicles are cut 95 but do not enter the header. Lodged stalk Where: loss occurs when panicles are broken over C = Capacity in acres per hour or separated from the plant before cutting. S = Speed, MPH Cylinder loss includes those grains of W = Width, feet rice which are left on the heads and are carried out the rear of the combine. Field Efficiency = 50 to 80 percent Separation loss is that portion of threshed grain carried out of the combine with the Example: straw residue. C = 2 x 20 x 60 = 2.9 acres/hour Rice harvest losses may be determined ______by counting the number of grains per 825 square foot found to have been missed by the combine. A count of 33 to 42 grains Where: S = 2, W = 20, Field Efficiency per square foot (depending on the variety) = 60 equals 100 per acre. Rice losses can be reduced by taking Rice Drying and Storage certain measures. The moisture status of Douglas L. Deason the crop needs to be determined before harvest. In general, most rice should be The rice grain on a plant, and even on harvested when grain moisture ranges a single panicle, may vary considerably in from 18 percent to 22 percent. moisture content as the plant nears The combine should be operated at readiness for harvest. This is because of proper forward speed, platform height and grain location on the plant and because of reel speed. Cut as high as possible but the time interval over which a plant with enough straw to ensure efficient blooms. When a sample is cut to threshing. Proper reel adjustment will determine moisture content, an average prevent shattering and provide a uniform moisture is determined; some grains are feed into the header. wetter and some drier than this average The proper cylinder speed maintains moisture. Harvesting at 18 percent to 22 good threshing while preventing cracking percent wet basis moisture content gives and hulling of the rice. Excessive cylinder the best milling yields. Most varieties speeds at lower moisture will increase harvested at 23 percent and above tend to kernel breakage. If the cylinder speed is have too many chalky immature kernels. If too slow, some of the grain will not be rice is allowed to field-dry to moistures removed, especially at higher moisture. less than 16 percent, the driest kernels are Separation losses can be decreased by subjected to wetting and drying cycles maintaining proper setting at the chaffer caused by air drying potential changes and sieves. Adjust air flow to remove as from day to night. This causes stress cracks much trash as possible without losing grain (checks) in some of the kernels, reducing from the rear of the combine. milling yields. This reduction of milling yield as the rice dries is more severe in Combine Capacity some varieties than others. Rapid A combine typically operates 50 rewetting by rain, once rice reaches 15 percent to 80 percent of the time it is in percent or less moisture content, is a key the field. This is known as its field cause of lower head rice yields. To obtain efficiency. Harvesting speed usually the highest milling yields, some method of ranges from one to four miles per hour. artificially drying rice from harvest The capacity of the combine can be moisture to a safe storage level of 12 determined with this formula: percent to 13 percent is necessary. For a drying system to produce a high C = S x W x Field Efficiency milling, quality rice, the system must (1) ————————————— operate so the rice is not overdried and (2) 825 provide a controlled drying rate adequate 96 to reduce rice from 22 percent to 16 In general axial-flow fans will work percent or below in no more than seven satisfactorily for drying up to a depth of 8 days. If drying rates are slower than this, feet if sized to deliver 2 ½ to 3 cfm (cubic damage from molds and fungi will discolor feet of air per minute) per bushel of rice. the milled kernels. This is called heat For use in bins where depths are more damage or stackburn. At 16 percent than 8 feet, or in bins equipped with moisture or less, the rice does not provide stirrers and drying depths to 16 or 17 feet, a favorable environment for mold and the centrifugal fan is an absolute necessity. fungi growth, and moisture content can be safely reduced at a slower rate. A moisture Drying Rice Without Stirrers content of not more than 13 percent in any This method of drying rice would be portion of the bin is recommended for safe described as drying a static bed of rice storage. Rice mills prefer 12 percent to with supplemental heat as necessary to 12.5 percent moisture for best milling keep drying air at a desired humidity results. level. A minimum air flow rate of 9 cubic Certain precautions should be taken feet per minute per barrel (9 cfm/bbl) or before placing the season’s first rice in 2.5 cubic feet per minute per bushel (2.5 bins for drying. The bins and plenum area cfm/bu) is necessary to accomplish drying should be cleaned thoroughly, allowed to without stackburn. A larger cfm/bu airflow dry and treated for insects. Air leaks rate will dry more rapidly. For most bin- around the base of bins and doors should fan combinations as installed, you can get be caulked and rodent-proofed. Every 2.5 cfm/bu with 7 to 9 feet of rice (a half- effort should be made to place clean rice bin). Centrifugal fans can be selected to in the drying bins. This includes careful supply 2.5 cfm/bu at depths of more than adjustment and supervision of the harvest- 9 feet. The use of stirrers would not be ing equipment and providing for additional necessary, but design depth should be cleaning at the bin location if necessary. limited by a static pressure requirement of Excessive foreign material in the grain not more than 5.5 inches. In principle this samples will cause uneven drying in the drying method uses a humidistat to turn on bins and increase the moisture content of heat when the plenum air is above 65 the rice. If levees have more weeds than percent relative humidity. Generally, only the fields, levee rice should be harvested a slight increase in temperature is and dried separately. necessary to reduce humidity below the humidistat cut-off point. Under normal Drying, Storage and Equipment operation of this system, burners will not The corrugated metal bin with full add heat when the air humidity is less than perforated metal floors, tightly constructed 65 percent. The amount of heat added to protect the rice from weather, insects with this method is small, making this the and rodents, is the centerpiece of rice most energy-efficient system. With this drying on farms in Louisiana. Other neces- system supplying 2.5 to 3 cfm/bu, clean sary items include drying fans and heaters, rice at 22 percent moisture should dry to combination humidistat-thermostat control, 14 percent moisture in six to seven days. adequate grain handling equipment, In this static bed method of drying rice, plenum temperature thermometers and drying moves from the bottom of the bin ample roof ventilators. Optional equip- upward, with the top layers drying last. ment includes grain stirring devices, grain Sample the top of the rice regularly as spreaders and grain temperature monitor- drying progresses, and stop adding heat ing equipment. when the top 12 to 15 inches of rice are at Modern rice drying bin systems should 15 percent moisture. be equipped with centrifugal fans although This static bed system of using a some older farm bins with axial-flow fans humidistat to control supplemental heat adequately dry rice in shallow rice depths. has several shortcomings. Often the rice will not dry evenly throughout the half- 97 bin; the bottom will be drier than the top, probably provide faster drying when and rice in the center of the bin will have compared to a humidistat controlled higher moisture content than grain near system. Using this temperature control walls. Transfer of the half-bin of 14 system in Louisiana, with a 90 degree F percent rice to another bin mixes the rice. control point, relative humidity will be This second bin can be filled with 14 reduced to 50 percent to 55 percent. percent rice for completing drying to 12.5 Producers have reported excellent milling percent. For best milling yield, complete quality on rice dried with this equipment. the drying and cooling without adding heat. This can be done by running the fans Drying Rice With Stirring Equipment during the daylight hours when the air Stirring equipment for moving rice from humidity is less than 65 percent. bottom of bin to top has some important Another shortcoming of this system is advantages for rice producers. (1) It that it is rather slow because only one-half reduces the risk of uneven drying from bin is dried at a time and small overdrying of lower layers caused by temperature increases are used. Fast poorly constructed and managed harvest and large acreage will require humidistats. Rice directly in the bin’s numerous bins or other methods of drying. center is not stirred and generally remains A third drawback is that good results at a higher moisture level than rice in depend on a properly operating humidistat other areas. This must be carefully to control the addition of heat to the drying monitored. (2) It reduces the problem of air. Check the humidistat for proper hot spots and uneven drying caused by operation each year and service or replace trash separation in the bin. Vertical screws as necessary. The work of the fan will do a good job of evenly distributing lower the relative humidity of outside air foreign material and leveling the top about 5 percent. Turn heat on when surface. (3) It allows the addition of a outside air humidity is 70 percent or above larger amount of heat and provides more to obtain 65 percent or less relative drying capacity with the same bin and fan humidity under the grain. If the humidistat equipment; most systems with stirrers can is not operating properly, excessive heat dry at least twice as much rice in a given may be added, the bottom layers of the period as can static bed - humidistat bin will be overdried and milling yields controlled drying. (4) It requires only a will be reduced. thermostat. When using the thermostat in The stirring device should be turned on combination with the humidistat, set the and started when 2 feet of rice cover the thermostat at 95 degrees F. Used in this floor evenly. The stirrers should be manner, the humidistat should control the operated constantly throughout the drying burners to add heat, and the thermostat period and until rice is dry enough to should serve as a safety device to turn cease adding heat to the air. Initial heat off above 95 degrees F. Efforts to dry thermostat setting should be 90 degrees F deep layers of 8 to 9 feet of rice with only until depth of rice is equal to one-fourth of a thermostat for controlling heat will total drying fill. For example, if 16 feet of generally give poor results if a stirring rice will be dried, the thermostat should be device is not used. set to 90 degrees F for up to 4 feet of In recent years, several manufacturers depth; from 4 to 8 feet, the thermostat have offered low temperature rise, should be set to 95 degrees F. Increase the modulating valve controlled heaters. These thermostat setting gradually to a maximum units can provide precise temperature of 105 degrees F at maximum fill of 16 to control of air under the drying floor. This 17 feet. Airflow should be a minimum of type of controller is more energy efficient 1.25 cfm/bushel or 4.5 cfm/barrel at than the older on-off controls. Drying deep maximum stirred drying depth. A 15 HP layers of rice (8 to 9 feet) with this centrifugal fan is required for a 27 feet temperature controlled system will diameter bin, 20 HP for 30 feet diameter 98 and 30 HP for 36 feet diameter bin. Two energy-efficient relative to energy 20 HP fans may provide a more even air required per pound of water removed. and heat distribution with the 36 feet This type of continuous flow system also diameter bin than will one 30 HP fan. With provides a relatively large volume of wet 16 to 17 feet of rice and this airflow, the grain storage ahead of the dryer. fans will operate against a static pressure The dryers should be operated at 4 to 6 of about 6 inches of water. feet of rice depth with an intended air Properly managed stirrer equipped bins flow of about 10 cfm/bu of rice. The rice increase drying capacity, reduce drying leaving the dryer should not have a grain risk and result in more uniform milling. temperature of more than 100 degrees F to 105 degrees F. Base decisions on this Other Rice Drying Methods exit grain temperature on milling yield of Large farm operations may have harvest the rice samples. The grain from this dryer and drying rates that necessitate (16 percent to 17 percent rice) is placed consideration of methods other than the in nearly full bins at reduced risk to two research-proven methods discussed. complete drying. Do not expect this One alternative to increasing drying continuous bin dryer to remove 4 or more capacity of a farm bin drying system is to percent of moisture from rice with initial use a continuous flow dryer to remove no moisture of 20 percent or less without more than 3 percent or 4 percent of milling yield loss. Most desirable operation moisture initially. A continuous flow dryer of this continuous flow bin drying system needs a large holding capacity, a low requires a level grain surface across the heated air temperature and good mixing full bin width and uniform air temperatures action within the dryer. Rice grain under the bin. Both requirements are temperatures coming from the dryer difficult to achieve. should not exceed 95 degrees F. Rice coming from a continuous flow dryer at Management of Stored Rice about 17 percent to 18 percent moisture After rice has been dried and cooled to should be transferred to a stirred bin to a moisture of 12 percent to 13 percent, complete the drying operation. Beginning sample it for temperature and moisture with rice at a 22 percent moisture, this content during storage. Sample several system must be managed carefully to times in the first couple of weeks after prevent significant milling yield losses. completion of drying because percentage Using a continuous flow dryer to remove 4 of grain moisture often increases because percent to 5 percent moisture from rice of moisture migrating to the kernel initially at 19 percent to 20 percent surfaces. Aeration is required when this moisture will probably cause significant occurs. Once grain moisture stabilizes, milling yield losses. No research has check moisture and temperature no less shown this to be possible without costly than once a month, preferably every two reduction of whole grain and total milling weeks. High temperature spots indicate yield. locations with excess moisture and require Another type of drying system now aeration. being marketed in rice-growing areas is a As winter approaches, aeration can be high airflow in-bin continuous flow used to lower the temperature of the grain concept. This system consists of a bin with mass. This will reduce temperature a perforated floor and one or two fans differences in the bin which cause designed to provide five to 10 cfm/bu of moisture migration in the grain mass. High airflow to as much as a 10-feet drying moisture grain is most likely to occur in depth of grain. Unloading augers are the top center portion of the bin and along installed on the floor of the bin and are the walls. For aeration cooling purposes, controlled to operate so that a layer of operate fans when outside air temperature grain is removed from the bottom of bin as is 10 degrees F or more below grain it becomes sufficiently dry. This system is temperature. In Louisiana, relative 99 humidity of the air blown during aeration layers in the bin. Preferred relative must be considered. Extended aeration at humidity for aeration is in the 60 percent high air flows and low humidities can to 70 percent range. Do not operate fans cause severe overdrying of the bottom rice during fog or rain.

RiceRice EconomicsEconomics L. Eugene Johnson, G. Grant Giesler and Michael E. Salassi

For many decades rice has been among list of projected expenditures and returns the top cash crops produced in Louisiana. associated with a given crop production Rice production supports an infrastructure system. The budget includes the total input of storage, processing, transportation and requirements for that enterprise based on agricultural supply industries larger than the sequence of operations. Its purpose is that of many other agricultural commodities to summarize enterprise cost and return produced in the state. projections for use in management Other major rice-producing states are decisions. Much of the information needed Arkansas, California, Mississippi, Missouri to construct an enterprise budget is and Texas, which, together with Louisiana, available from historical farm records and accounted for an average of about 1.4 current projections of input costs and percent of world rice production from output prices. Two illustrations of 1986 - 1997. During the same period, enterprise budgets for rice are provided in about 35 percent of this production was Tables 15 and 16. exported, accounting for about 19 percent In Table 15, the budget is typical of a of total world trade in rice. More than 97 water-planted owner-operator situation in percent of the world’s rice was southwestern Louisiana. Owner-operators domestically consumed in the country can compare their cost estimates with the where produced during this period. budget in Table 15 using the “Your Farm” column. Similarly, tenant-operators can Farm Management compare their situations with the projected A key to successful farm management is budget presented in Table 16. In analyzing understanding and estimating enterprise crop enterprise budgets, it is extremely production costs. This is particularly true important to evaluate the levels of for rice growers because rice is relatively profitability associated with various levels expensive to produce compared to other of product price and yield projections. field crops typically grown in Louisiana. Not all items in these tables are direct Several production decisions which must cash outlays. Interest on operating capital be made during the growing season based and certain items included in the fixed on the current status of the rice crop may expenses section of the budgets are not impact costs significantly. Examples of always direct cash costs. Noncash expense these include insecticides, fungicides and items are used to approximate the fertilizer. All these decisions are partially a economic cost associated with devoting function of environmental conditions that capital and machinery resources to the rice have prevailed since planting and enterprise. An interest charge on operating subsequent effects on the yield potential of capital indicates that money tied up in the a particular field of rice. Unfortunately, current year’s rice crop could be used these effects cannot be accurately elsewhere. Items such as depreciation predicted on a yearly basis, so their (economic, not tax, depreciation), impacts on production costs are among the insurance and housing (for equipment) are most difficult to estimate before they occur. typically included under the fixed A systematic method for estimating expenses category. These cost items must production costs is an enterprise budget. be covered if the farm business is to be An enterprise budget is simply an itemized profitable in the long run. 100 Using the cash expense information in Mid-East, 39.51 percent; North America, the enterprise budget, a farmer can 18.26 percent; Caribbean Islands, 7.17 develop a whole-farm cash flow analysis percent; Africa, 9.73 percent; Asia, 7.39 for the business. Cash flow analysis percent; Europe, 11.83 percent; and South summarizes the sources and uses of cash America, 6.11 percent. These percentages in the business and requires estimating are somewhat skewed because of large total expenditures and receipts which purchases by Japan in 1993. Other occur during specified periods of the year relatively large exporting countries are (usually quarters). Cash flow deficits in a Thailand, Pakistan, Burma, Italy and, at given quarter indicate the need for cost times, China, Japan and Taiwan. control measures or possible borrowing. Aggregated world rice production and The best source of data for developing a trade data are in Table 18. cash flow statement is historical farm Because of the relatively large number records. (Monthly bank statements can of buyers and public auctions operating in provide much of the needed information.) Louisiana, and the state’s proximity to both An important, yet often neglected, domestic markets and export facilities, aspect of farm management is the control Louisiana growers have perhaps a wider phase. Just as it is important to project range of marketing choices than growers expenditures and receipts for the in other rice-producing states. Louisiana upcoming season, it is important to ranks second to Arkansas in number of compare actual events and outcomes with operating rice mills. earlier projections. Deviations in the actual Historically the South’s largest producer outcome from the initial projection can be of medium grain rice, Louisiana was edged analyzed and become the basis for next out by Arkansas in 1995 in production of year’s plan of action. This type of medium grain. From 1992 to 94, medium continual monitoring of the business grain acreage has fluctuated from 30 allows the farmer to control his or her percent to 40 percent of total rice acreage operation better and to detect potential in Louisiana, but fell to 23 percent in 1995 problems. and 13 percent in 1996. Long grain rice generally commands a Marketing higher price than medium grain rice of the Contrasted to that of other high energy same grade (Table 19). Anticipating foods, rice consumption in the United premiums the market will pay for long States has been increasing for many years, grain rice is one of the most important, but especially since the early 1980s. In fiscal more difficult, marketing tasks many 1993 it reached nearly 20 pounds of Louisiana growers face. milled rice per capita, which does not Anticipating probable market prices for include more than four pounds per capita either class has also become more difficult used in brewing. Projections for fiscal since 1972. Further development of 1996 indicate expected consumption per futures trading for rice holds some capita to increase to more than 21 pounds promise in this regard as well as to create and four pounds respectively for food and a large number of marketing alternatives brewers’ use. Of the milled rice consumed not previously available. In any case, a domestically, about 80 percent to 85 grower must choose when to sell, and the percent is used directly for food and choice will likely affect income processed food, and 15 percent to 20 significantly in any given year. There is percent for brewing. On a rough rice often no way to predict prices with any basis, forecasted total domestic per capita degree of certainty, and the choice of use now amounts to more than 35 pounds when to sell is often dictated by financial per year (Table 17). circumstances of individual growers. From fiscal years 1988 to 1995, U.S. Figure 111 (p. 105) shows the products rice exports were distributed as follows: derived from milling 100 pounds of long

101 grain rough rice. The exact proportions of changing triggers for acreage reduction each of the products produced depend on programs (ARP) and 5) introducing normal a number of management and and optional flexibility acres (NFA and environmental factors. OFA). Provisions continued under the Rice is exported mainly in 100-pound 1990 Act included: voluntary compliance, and 50-kilo bags in the form of either raw marketing loans, nonrecourse loans based or parboiled milled rice, but significant on a loan rate, deficiency payments based amounts also move to the export market on a target price, crop acreage base, in bulk form as rough and brown rice, and acreage reduction program, flexibility in consumer packages. acres and payment limitations. With the passage of the new farm bill, U.S. Farm Policy for Rice the Federal Agriculture Improvement and In general, the historical objectives of Reform Act of 1996, the role of the government farm policy have been to 1) federal government in price support ensure a secure and wholesome food activities for agricultural commodities, supply, 2) to maintain a viable agricultural including rice, will change dramatically. industry and 3) to support the income of The new program basically consists of a farmers. Government intervention into the seven-year transition period, during which domestic agricultural industry began with time government support payments for the Agricultural Adjustment Act of 1933, agricultural commodities will be reduced and rice was designated as one of the annually and producer returns from Act’s original seven commodities. production of these commodities will Succeeding Acts have all had significant depend more and more on market prices. influence on the rice industry, resulting in A summary of the rice provisions of a 92 percent to 95 percent participation the new farm bill is in Table 16. The new rate of rice farmers in the rice program farm program eliminates the rice target nationwide. price/deficiency payment price support Government programs for rice in the system which has been in effect for many first half of the 1990s were governed by years. Eligible producers would enter into the Farm Bill of 1990. This bill resulted a seven-year, production flexibility from two statutes, The Food, Agriculture, contract for the 1996-2002 period. Conservation and Trade Act of 1990 and Producers would receive guaranteed, The Agricultural Reconciliation Act of direct, fixed payments on 85 percent of 1990. Goals of the 1990 Farm Bill were eligible rice base acreage. These to: 1) further reduce the federal deficit by payments would generally decline over reducing payment acres, 2) help maintain the seven years and would not be tied to farm income growth through increased market prices. Total annual commodity planting flexibility and expanding exports spending would be set in advance and through market-oriented loan rates and 3) divided between commodities, based enhance environmental quality through partly on previous payment history. The the Conservation Reserve Program and the share of total commodity spending Water Quality Protection Program. allocated to rice is estimated at 8.47 Important provisions of the 1990 Farm percent under this new bill, compared to Bill (as compared to the 1985 bill) 12 percent to 13 percent paid to rice applicable to rice were: 1) freezing of producers over the previous several minimum target prices for five years at years. $10.71/cwt, 2) maintaining the current Transition payments for rice under the method of loan rate calculation, 3) new farm program are projected to range maintaining the current method of from $2.94 down to $2.03 per deficiency payment rate calculations for hundredweight over the 1996-2002 1991-93 crop years, with subsequent period. Payments would be based on changes for the 1994-95 crop years, 4) established rice program yields and paid

102 on 85 percent of eligible rice base program crop, oilseed crop or industrial or acreage. These payment rates compare experimental crop on their paid rice base with a maximum deficiency payment rate acreage and could plant in excess of their of $4.21 per hundredweight under the base. Planting fruits and vegetables would 1985 and 1990 farm bills. be prohibited on payment acres. Haying Nonrecourse loans for commodities, and grazing would be permitted as a flex including rice, were retained from the crop on payment acreage. All acreage previous farm program. The maximum reduction (set-aside) programs were loan rate for rice over the life of the bill eliminated. Current payment limitations was set at the 1995 level of $6.50 per were reduced from $50,000 to $40,000 hundredweight. Marketing loan provisions per entity, although the three-entity (LDP program) for rice were extended provisions of the previous farm program from previous legislation with repayment were retained. The bill extends provisions at world prices or 70 percent of loan, if limiting marketing loan gains and loan world market prices are below the loan deficiency payments to $75,000 per rate. Producers would be free to plant any person per year.

Table 15. Estimated costs and returns per acre. Rice, water planted, owner-operators, Southwest Louisiana, 1998. ______Item Unit Price Quantity Amount Your Farm ______dollars dollars INCOMEa/ Rice cwt 10.00 48.0000 480.00 ______Rice checkoff cwt 0.08 -48.0000 -3.84 ______———— TOTAL INCOME 476.16 ______

DIRECT EXPENSES CUSTOM Fertilizer Truck acre 3.50 1.0000 3.50 ______Airplane seed cwt 4.55 1.4000 6.37 ______Global Pos. System acre 0.45 6.3500 2.86 ______Airplane Stam acre 5.15 2.0000 10.30 ______Airplane furadanb/ acre 4.00 0.5200 2.08 ______Airplane 2,4-D acre 5.10 1.0000 5.10 ______Airplane Fert cwt 4.05 1.4000 5.67 ______Airplane benlateb/ acre 4.50 0.7000 3.15 ______Airplane Insectb/ acre 3.95 0.1300 0.51 ______Drying Rice cwt 0.95 53.9300 51.23 ______Storage Ricec/ cwt 0.40 48.0000 19.20 ______FERTILIZER Nitrogen lbs 0.23 120.0000 27.60 ______Phosphate lbs 0.26 51.0000 13.26 ______Potash lbs 0.14 51.0000 7.14 ______FUNGICIDES Quadrisb/ oz. 2.19 4.2000 9.20 ______Benlate 50% WPb/ lbs 16.50 0.3500 5.77 ______

103 HERBICIDES Stam M4 qt 4.58 6.0000 27.48 ______2,4-D-LV4 pt 1.78 1.0000 1.78 ______HIRED LABOR Other labor hour 7.50 1.0000 7.50 ______Item Unit Price Quantity Amount Your Farm ______INSECTICIDES Furadan 3Gb/ lbs 0.80 8.8400 7.07 ______Methyl parathion 4Eb/ pt 3.31 0.1300 0.43 ______OTHER Plastic sqft 0.08 13.5000 1.08 ______SEED Rice seed lbs 0.21 140.0000 28.70 ______OPERATOR LABOR Tractors hour 7.50 1.5934 11.95 ______Self-Propelled Eq. hour 7.50 0.3800 2.85 ______IRRIGATION LABOR Irrig sys 9 fl WP hour 7.50 0.3150 2.36 ______OWNER LABOR Self-Propelled Eq. hour 12.00 0.4180 5.02 ______DIESEL FUEL Tractors gal 0.74 9.4218 6.97 ______Self-Propelled Eq. gal 0.74 2.6980 2.00 ______Irrig sys 9 fl WP gal 0.74 77.9450 57.68 ______GASOLINE Self-Propelled Eq. gal 1.17 1.9000 2.22 ______REPAIR & MAINTENANCE Implements acre 3.04 1.0000 3.04 ______Tractors acre 8.89 1.0000 8.89 ______Self-Propelled Eq. acre 12.78 1.0000 12.78 ______Irrig sys 9 fl WP acin 0.16 35.0000 5.46 ______INTEREST ON OP. CAP. acre 11.23 1.0000 11.23 ______———— TOTAL DIRECT EXPENSES 379.43 ______RETURNS ABOVE DIRECT EXPENSES 96.73 ______

FIXED EXPENSES Implements acre 5.37 1.0000 5.37 ______Tractors acre 12.72 1.0000 12.72 ______Self-Propelled Eq. acre 27.40 1.0000 27.40 ______Irrig sys 9 fl WP acre 32.07 1.0000 32.07 ______———— TOTAL FIXED EXPENSES 77.55 ______———— TOTAL SPECIFIED EXPENSES 456.98 ______RETURNS ABOVE TOTAL SPECIFIED EXPENSES 19.18 ______

ALLOCATED COST ITEMS Overhead (owner) acre 64.31 1.0000 64.31 ______

104 L&W, SWWP Conv. Riced/ acre 29.00 1.0000 29.00 ______RESIDUAL RETURNS -74.13 ______a/ Includes estimated market income only. b/ Prorated use based on survey results of percentage of rice acreage actually treated in 1991 and expert opinion of these percentages in more recent years. c/ Drying cost charged on green weight. d/ This charge represents net income to a land/water lord based on budgets applicable to a tenant version of the above budget, incorporating relevant cost share items, and may be interpreted as an opportunity cost to an owner/operator. It does not represent an estimated cost of land.

Table 16. Estimated costs and returns per acre. Rice, water planted, tenant-operators, Southwest Louisiana, 1998. ______Item Unit Price Quantity Amount Your Farm ______dollars dollars INCOMEa/ Rice cwt 10.00 48.0000 480.00 ______Land share rent cwt 10.00 -9.6000 -96.00 ______Water share rent cwt 10.00 -9.6000 -96.00 ______Rice checkoff cwt 0.08 -28.8000 -2.30 ______———— TOTAL INCOME 285.70 ______

DIRECT EXPENSES CUSTOM Fertilizer Truck acre 3.50 1.0000 3.50 ______Airplane seed cwt 4.55 1.4000 6.37 ______Global Pos. System acre 0.45 6.3500 2.86 ______Airplane Stam acre 5.15 2.0000 10.30 ______Airplane furadanb/ acre 4.00 0.5200 2.08 ______Airplane 2,4-D acre 5.10 1.0000 5.10 ______Airplane Fert cwt 4.05 1.4000 5.67 ______Airplane benlateb/ acre 4.50 0.7000 3.15 ______Airplane Insectb/ acre 3.95 0.1300 0.51 ______Drying Ricec/ cwt 0.95 32.3580 30.74 ______Storage Rice cwt 0.40 28.8000 11.52 ______FERTILIZER Nitrogen lbs 0.23 72.0000 16.56 ______Phosphate lbs 0.26 30.6000 7.96 ______Potash lbs 0.14 30.6000 4.28 ______FUNGICIDES Quadrisb/ oz. 2.19 2.5200 5.52 ______Benlate 50% WPb/ lbs 16.50 0.2100 3.47 ______HERBICIDES Stam M4 qt 4.58 3.6000 16.49 ______2,4-D-LV4 pt 1.78 0.6000 1.07 ______

105 HIRED LABOR Other labor hour 7.50 1.0000 7.50 ______INSECTICIDES Furadan 3Gb/ lbs 0.80 5.3040 4.24 ______Methyl pt 3.31 0.0780 0.26 ______parathion 4Eb/ OTHER Plastic sqft 0.08 13.5000 1.08 ______SEED Rice seed lbs 0.21 140.0000 28.70 ______OPERATOR LABOR Tractors hour 7.50 1.5934 11.95 ______Self-Propelled Eq. hour 7.50 0.3800 2.85 ______IRRIGATION LABOR Irrig. sys. 10 fl WP hour 7.50 0.3150 2.36 ______OWNER LABOR Self-Propelled Eq. hour 12.00 0.4180 5.02 ______DIESEL FUEL Tractors gal 0.74 9.4218 6.97 ______Self-Propelled Eq. gal 0.74 2.6980 2.00 ______GASOLINE Self-Propelled Eq. gal 1.17 1.9000 2.22 ______REPAIR & MAINTENANCE Implements acre 3.04 1.0000 3.04 ______Tractors acre 8.89 1.0000 8.89 ______Self-Propelled Eq. acre 12.78 1.0000 12.78 ______Irrig. sys. 10 fl WP acin 0.16 35.0000 5.46 ______INTEREST ON acre 7.58 1.0000 7.58 ______OP. CAP. ———— TOTAL DIRECT EXPENSES 250.04 ______RETURNS ABOVE DIRECT EXPENSES 35.66 ______

FIXED EXPENSES Implements acre 5.37 1.0000 5.37 ______Tractors acre 12.72 1.0000 12.72 ______Self-Propelled Eq. acre 27.40 1.0000 27.40 ______———— TOTAL FIXED EXPENSES 45.48 ______———— TOTAL SPECIFIED EXPENSES 295.52 ______RETURNS ABOVE TOTAL SPECIFIED EXPENSES -9.82 ______

ALLOCATED COST ITEMS Overhead (tenant) acre 53.29 1.0000 53.29 ______RESIDUAL RETURNS -63.11 ______*Assumes a 1/5 crop share for land and a 1/5 crop share for water with landlord and waterlord each paying 1/5 of fertilizer, chemicals, drying and storage costs, and the waterlord paying all irrigation fuel costs. a/ Includes estimated market income only. b/ Prorated use based on survey results of percentage of rice acreage actually treated in 1991 and expert opinion of these percentages in recent years. c/ Drying cost charged on green weight. 106 Source: Rice Miller’ Association, (Arlington, Virginia)

Figure 111. Rice Milling Process for 100 Pounds of Rough Rice

Table 17. U.S. Supply and Use of Rice, Selected Years. Item 1990/91 1991/92 1992/93 1993/94 1994/95 1995/96 ————Million Cwt. of Rough Rice Equivalent———— Production 156.1 159.4 179.7 156.1 97.8 174.2 Supply 187.2 189.3 213.2 202.5 230.9 213.9 Total Domestic 91.6 95.4 96.7 101.5 98.6 104.2 Use and Residual Food 63.767.1 69.0 71.2 74.0 77.0 Seed 3.6 3.9 3.6 4.2 4.1 4.1 Brewers 15.3 15.4 15.1 15.1 15.1 15.1 Exports 71.0 66.4 77.0 75.2 100.9 86.0 Total Use 162.6 161.8 173.7 76.7 199.5 190.2 Ending Stocks 24.6 27.5 39.5 25.8 31.4 23.7

———————Units as Specified——————-———— Area Harvested 2.82 2.88 3.18 2.92 3.35 3.12 (mil. acres) Yield (cwt./acre) 55.29 57.31 57.36 55.1 59.64 56.35 Avg. Market Price 6.68 7.58 5.89 7.98 6.78 7.00-8.00 ($/cwt.) Per Capita Consumption Food and Brewers (lbs. - rough equiv.)31.92 32.18 33.18 33.66 34.41 35.26

*Source: Rice Outlook and Situation Yearbook and various other USDA publications. 107 Table 18. Selected World Rice Production and Trade Data, 1997/98

Country Productiona/ Exportsb/ Importsb/ (mmt) (tmt) (tmt)

Bangladesh 27.8 —— 100 Burma 16.6 100 —— China 195.7 1000 1000 India 122.3 1750 —— Indonesia 51.2 0 1500 Japan 12.4 —— 650 Philippines 11.2 —— 1000 South Korea 7.4 —— —— Pakistan 6.5 1700 —— Thailand 21.2 5250 —— Vietnam 27.3 3500 —— Selected Asian Country Sub-Totals 499.4 13300 4250 Australia 1.2 650 —— Brazil 9.6 —— 1000 EC-12 2.5 350 700 Iran —— —— 1250 Saudi Arabia —— —— 700 Senegal —— —— 500 South Africa —— —— 500 All Others 46.5 2106 10306 Total Non-U.S. 559.1 16406 19206 United States 8.2 2800 —— World Total 567.3 19206 19206 a/ Production on Million Metric Tons, Rough Rice Equivalent b/ Imports and Exports on Thousand Metric Tons, Milled Rice Equivalent Exports and Imports Projected for Calendar Year 1998. ** A dashed line indicates this country was not counted independently of other. *** Source: Rice Outlook and Situation Yearbook and various other USDA publications. ****Totals may not add due to rounding procedures.

Table 19. Selected U.S. Rice Industry Data, 1993 Through 1997 Crop Year 1993 1994 1995 1996 1997 ———————(Dollars per Cwt.—————

Target Price per cwt. of 10.71 10.71 10.71 — — Rough Rice Price Support Loan per cwt. 6.50 6.50 6.50 6.50 6.50 of Rough rice U.S. Average Rough Rice Price 7.98 6.78 9.15 9.90 9.75 per cwt. (12 months) Deficiency Payments per cwt 3.98 3.79 3.22 — — of Rough Rice Loan and Purchase Rates per cwt. Projected Milled Rice as Determined by Official Test: Long Grain Variety Head Rice 10.75 10.72 10.69 10.77 10.69 Medium & Short Grain Variety Head rice 9.75 9.72 9.69 9.77 9.69 Brokens (second heads, screenings and brewers) 5.37 5.36 5.35 5.35 5.35

108 *Source: Rice Situation and Outlook Yearbook and other USDA publications. Table 20. Rice Provisions of the Federal Agriculture Improvement and Reform Act of 1996.

Contract Payments: • Eligible producers can enter into seven-year market transition contracts for 1996-2002. • Guaranteed direct fixed payments not tied to market prices. Target prices and deficiency payments are eliminated. • Payments received on 85% of eligible base acreage and is based on historical program yield . • Projected rice payments per unit on paid base acreage: (Dollars/cwt.) 1996 - $2.75/cwt 1997 - $2.71/cwt 1998 - $2.94/cwt 1999 - $2.81/cwt 2000 - $2.58/cwt 2001 - $2.09/cwt 2002 - $2.03/cwt Loan Provisions: • Establishes a loan rate for rice at $6.50/cwt. • Extends marketing loan provisions for rice with repayment at a lower rate if world prices are below loan rate. Planting Flexibility: • No minimum program crop planting requirements. • Triple base provisions of 1990 farm bill are eliminated • Producers are free to plant any program crop or oilseed crop on rice base acreage without restriction. • Fruits and vegetables planting prohibited on 85% of base eligible for payment. No restrictions on remaining 15% of base. • Haying and grazing are permitted on payment acreage during the five principal growing months. • All acreage reduction programs (ARP) eliminated. Payment Limitations: • Current payment limitation on direct payments reduced from $50,000 to $40,000. • Extends limit on marketing loan gains and loan deficiency payments at $75,000. • Extends three-entity provisions.

109 Glossary

Active ingredient (ai) - Component of a pesticide that has toxic activity against the pest in contrast to the inert or inactive ingredients. Adventitious - Refers to a structure arising from an unusual place, such as roots grow- ing from stems or leaves. Amylographic - Spectrographic analysis of starch. Amylose - Type of starch in rice grain; higher content makes rice cook drier. Anaerobic - Refers to an organism able to live and grow without air or free oxygen. Antagonistic - Decreased activity of an organism from the effect of another organism or compound. Bacterium (pl. bacteria) - A one-celled microscopic organism that lacks chlorophyll and multiplies by fission (splitting apart). Biological control - Disease control by means of predators, parasites, competitive microorganisms and decomposing plant material, which restrict or reduce the popula- tion of the pathogen. Biotype - Genetic varient of a species. Boot - Growth stage of rice when the panicle is more than 1 inch long but before emergence (heading). Brewers - Smallest size of broken milled rice, which is less than one-quarter of the whole kernel. Broken yield - Pounds of broken grain milled from 100 pounds of rough rice (total milling yield - head milling yield). Brokens - Milled rice kernels which are smaller than three-fourths of the whole kernel. This includes second heads, screening and brewers. Brown rice - Rice with only the hulls removed. Carbohydrate - A class of organic chemicals composed of carbon, hydrogen and oxygen; in plants, photosynthesis-produced sugars and starch are examples. Chevrons - Stripe-like pattern consisting of several curved or V-shaped bands. Chlorophyll - Green pigment associated with photosynthesis. Chlorosis - Yellowing of normally green tissue caused by the destruction of the chloro- phyll or the partial failure of the chlorophyll to develop. Coalesce - The coming together of two or more lesions to form a large spot or blotch. Coleoptile - The protective covering of an emerging shoot, is not a true leaf. Commingled rice - Rice which has been blended with other rice of similar grain type, quality and grade. Conidiophore - Specialized hypha bearing conidia. Conidium (pl. conidia) - A spore formed asexually, usually at the top or side of a specialized hypha (conidiophore). Crown - Junction between stem and root. Culm - The jointed stem of grass. Damage - Economic loss to a crop caused by an insect. Debris - The crop residues left from the previous crop. Denitrification - Conversion of nitrate nitrogen to gaseous nitrogen. Dough - The stage when the endosperm of the grain has begun to solidify. Drift - The spread of airborne spray droplets to adjacent, non-target areas. Drying - Removal of kernel moisture to obtain a safe storage condition (about 12.5 percent moisture). Drying is achieved by forcing heated air through grain mass. Economic injury level - The lowest pest density that will cause damage equal to the cost of control. Economic threshold - The density of a pest at which control action must be taken to prevent a pest from reaching the economic injury level.

110 Embryo - The microscopically small plant under the lemma near the point of attach- ment of the rice seed to the panicle. Endemic - The normal presence of a pest in a crop year after year in less than epi- demic amounts. Endosperm - Primarily carbohydrate in the form of starch comprising most of the rice seed and used during germination and early plant growth. Enzyme - Protein specialized to catalyze chemical reactions related to metabolic activity necessary for growth. EPA - Environmental Protection Agency, an agency of the U.S. government. Epiphytotic or epidemic - The extensive development of a disease in a geographical area. Fissuring - The cracking or breaking of grains prior to harvest caused by alternating periods of wetting and drying. Flag leaf - The uppermost leaf of the rice plant, immediately below the panicle. Floret - The rice flower including the lemma, palea and reproductive floral parts. Flush - Flooding of the field with drainage soon after for the purpose of keeping the seed bed moist. Foliar - Dealing with the foliage of a plant. Fungus (pl. fungi) - An undifferentiated plant lacking chlorophyll and conductive tissues. Gelatinization temperature - Index to classify the cooking types of long, medium and short grain. Gibberellic acid (GA) - Plant growth hormone which stimulates elongation. Green rice - Rough rice from which the excess moisture has not been removed (usu- ally 18.5 percent to 22.5 percent moisture). Green ring - Rice plant growth stage during which the tissue of the first internode appears green because of the accumulation of chlorophyll, indicates a change from vegetative to reproductive growth. GPA - Gallons per acre. Heading - The period during which panicles exert from the flag leaf sheath. Head rice - Milled rice kernels which are more than three-fourths of the whole kernel. Head milling yield - Pounds of head rice milled from 100 pounds of rough rice. Horizontal resistance - A uniform resistance against all races of a pathogen. The level of resistance is usually only moderate and often influenced by temperature. Hulling - A process of removing husks from rough rice. Hulls - Outer husk of the rice grain, usually a waste product, but can be used in rice millfeed and as a filler for feed products. Hydrophobic - Resistant to wetting. Hypha (pl. hyphae) - A single thread or filament of a fungus. Imbibed - Absorption of water. Infestation level - Percent of the population affected by a pathogen, or density of a pest in a unit area. Inflorescence - A flower cluster. Injury - Feeding by an insect on a crop but not necessarily causing economic loss. Instant rice - Milled rice which is cooked, cooled and dried under controlled conditions and packaged in a dehydrated form. Before packaging, it is enriched with thiamine, riboflavin, niacin and iron. Instar - The stage of an insect between molts. Internode - The tissue of a rice stem between two nodes (joints). Internode elongation - Jointing, the rapid lengthening of the tissue between nodes of a rice stem. IPM - Integrated pest management; the reduction of plant pests through the combined use of various control practices. 111 Joint - A node. Key pest - A pest that causes economic loss in most years. Label - Document accompanying a pesticide container giving specific information about a pesticide, also a legal document specifying how and when a product can be used. Larva - The second stage of insects with complete metamorphosis (egg, larva, pupa, adult). Larvae look different from adults, live in different places and feed on differ- ent food. Lemma - The larger of two enclosing structures which form the hard outer covering of a rice seed. Lesion - A localized area of diseased tissue of a host plant. Lodging - The leaning or falling over of rice plants before harvest. Long-grain rice - Rice that is long and slender, measuring one-quarter of an inch or more in length. Kernel size is 6.5 mm or more long, and the length-width ratio is from 3.27 to 3.41:1. Main shoot - The first noticeable above-ground portion of a rice plant originating directly from the seed. Medium-grain rice - Rice that is plump, measuring less than one-quarter of an inch long. Kernel size is from 5.37 to 6.06 mm and has a length-width ratio of from 2.09 to 2.49:1. Mesocotyl - Portion of the shoot between the seed and the cotyledon. Metamorphosis - A change in form during development. Milk - The stage when the endosperm of the grain is the consistency of milk. Milled rice - Rice grain from which husks, bran and germ have been removed. Milling - Processing the rough rice into milled or brown rice. Mycelium (pl. mycelia) - A mass of fungus hyphae; the vegetative body of a fungus. Neck - Region of the head consisting of the joint below the panicle. Necrotic - dead. Nematode - Generally microscopic, unsegmented roundworm, usually threadlike, free- living or a parasite of plants or animals. Node - The pronounced area of a rice stem from which a leaf originates. Nymph - The immature stage of insects with incomplete metamorphosis (egg, nymph, adult). Nymphs look similar to adults, live in the same place as adults and feed on the same food. Occasional pest - A pest that occasionally causes economic loss. Overwinter - A term used to describe an insect’s ability to survive the winter. The overwintering stage and site are important. Palea - The smaller of two enclosing structures which form the hard outer covering of a rice seed. Panicle - The main axis (which is branched) of an inflorescence. Panicle 2mm - Same as panicle differentiation. Panicle differentiation (PD) - Rice plant growth stage during which the panicle is recognizable as a small tuft of fuzz about 2 mm (1/8 inch) long. Panicle initiation (PI) - Rice plant growth stage during which a specialized group of cells in the growing point begin to actively divide. It often corresponds to or closely follows green ring and can be positively identified only with magnification. Parboiled rice - Rough rice soaked in warm water under pressure, steamed and dried before milling. Parboiling - A process by which rough rice is steeped in water, steamed or heated to gelatinize starch, then subsequently dried. Pathogen - A specific agent that causes infectious disease. Pest - An organism that competes with humans. pH - A measure of the acidity or alkalinity of soil, water or solution. Values range from 0 to 14 with 7 being neutral, less than 7 acidic and above 7 alkaline. 112 Photosynthesis - The process by which plants absorb light and use the energy for growth and development. Phytotoxic - Causes toxic or harmful effects on a plant. Pollination - Transfer of pollen from the male to female flower structures. Precooked rice - Milled rice which has been processed by various methods to make it cook quickly. Processed rice - Rice used in breakfast cereals, soups, baby foods and packaged mixes. Pupa - The third stage of insects with complete metamorphosis (egg, larva, pupa, adult). Pupae do not feed and are in a resting stage. Radicle - First root of a germinating seed. Ratoon crop (second crop) - Regrowth of rice from the stalks harvested earlier. Resistance - The inherent ability of a host plant to suppress, retard or prevent entry or subsequent activity of a pathogen or other injurious factor. Rice bran - Layer directly beneath the hull containing the outer bran layer and parts of the germ. Bran is rich in protein and vitamin B. It is used as livestock feed and vitamin concentrates. Rice polish - A layer removed in the final stages of milling which was composed of the inner white bran. It is rich in protein and has high fat content; used in livestock feed and baby food. Rough rice (paddy) - Rice grains with the hulls, but without any part of stalk; consists of 50 percent or more of paddy kernels (whole or broken unhulled kernels of rice). Saturated - Condition when all soil pore spaces are full of water. Sclerotium (pl. sclerotia) - Dense, compacted mass of hyphae, resistant to unfavor- able conditions and can remain dormant for long periods; able to germinate when favorable conditions return. Screenings - Broken milled rice which is less than one-half of the whole kernel and more than one-quarter of the whole kernel. Second heads - Largest size of broken milled rice which is more than one-half of the whole kernel size. Semidwarfs - Plants changed genetically to a reduced plant height. Senescence - The process of aging leading to death after the completion of growth in plants and individual plant parts. Shoot - A collection of leaves originating from a crown in rice before stem formation occurs. Short-grain rice - Rice that is almost round. Kernel size ranges from 4.56 to 5.01 mm in length, and the length-width ratio varies from 1.66 to 1.77:1. Skipper - A group of insects closely related to moths and butterflies. Adult skippers have knobs on the end of their antennae (similar to butterflies), and the antennae are widely spaced on the head (similar to moths). Spikelet - Consists of a single floret below which are two reduced bracts. Spore - A minute propagative unit that functions as a seed, but differs from it in that a spore does not contain a preformed embryo. Stale seedbed - Seedbed prepared about planting time in which vegetation is allowed to grow usually. Stooling - Tillering. Straighthead - Physiological disorder characterized by sterile, deformed seeds and an upright seedhead. Sun checking - Fissuring. Susceptibility - The inability of a plant to resist the effect of a pathogen or other damaging factor. Suppression - The act of reducing or holding back rather than eliminating. Tiger moth - A group of moths with hairy caterpillars (the woollybear). 113 Tiller - A young vegetative shoot arising from nodes at the base of the plant; most can produce a panicle. Tillering - The period during which tillers are formed, usually beginning at the 4- to 5- leaf stage and continuing until early reproductive growth. Tolerance - Amount of pesticide that can safely remain in or on raw farm products at time of sale, or the ability of a plant to yield equally under diseased condition as healthy. Total milling yield - Pounds of head, brewers, second heads and screenings milled from 100 pounds of rough rice. White rice - Total milled rice after the hulls, bran layer and germ are removed. This includes head rice and brokens. Y-leaf - The most recently expanded leaf, at least 3/4 unfurled. This leaf is usually selected for tissue analysis.

114 CONTRIBUTING AUTHORS

Clayton A. Hollier, Specialist (Plant Pathology), Louisiana Cooperative Extension Service, Baton Rouge, and Editor.

James Barbour, Assistant Professor (Entomology), University of Idaho (formerly with the Louisiana Agricultural Experiment Station, Department of Entomology, Baton Rouge).

Patrick K. Bollich, Professor (Agronomy), Louisiana Agricultural Experiment Station, Rice Research Station, Crowley.

Douglas L. Deason, Specialist (Agricultural Engineering), Louisiana Cooperative Extension Service, Baton Rouge.

Richard T. Dunand, Professor (Plant Physiology), Louisiana Agricultural Experiment Station, Rice Research Station, Crowley.

James F. Fowler, Specialist (Wildlife), Louisiana Cooperative Extension Service, Baton Rouge.

Eddie R. Funderburg, Specialist (Agronomy), Louisiana Cooperative Extension Service, Baton Rouge.

G. Grant Giesler, Research Associate (Agricultural Economics), Louisiana Agricultural Experiment Station, Department of Agricultural Economics, Baton Rouge.

Donald E. Groth, Professor (Plant Pathology), Louisiana Agricultural Experiment Station, Rice Research Station, Crowley.

William A. Hadden, Specialist (Agricultural Engineering), Louisiana Cooperative Extension Service, Baton Rouge.

Farman L. Jodari, Assistant Professor (Agronomy), Louisiana Agricultural Experiment Station, Rice Research Station, Crowley.

L. Eugene Johnson, Specialist (Agricultural Economics), Louisiana Cooperative Extension Service, Baton Rouge.

David Jordan, Assistant Professor (Weed Science), North Carolina State University (formerly with the Louisiana Agricultural Experiment Station, Northeast Louisiana Research Station, St. Joseph).

Steven D. Linscombe, Professor (Agronomy), Louisiana Agricultural Experiment Station, Rice Research Station, Crowley.

Kent S. McKenzie, Rice Breeder, Rice Research Station, Biggs, CA (formerly an agronomist with the Louisiana Agricultural Experiment Station, Rice Research Station, Crowley).

Mark Muegge, Assistant Professor (Entomology), Texas A&M University (formerly a postdoctoral associate, Department of Entomology, Baton Rouge).

Joseph A. Musick, Resident Director of the Rice Research Station and Professor (Agricultural Economics), Louisiana Agricultural Experiment Station, Crowley.

James H. Oard, Associate Professor (Agronomy), Louisiana Agricultural Experiment Station, Department of Agronomy, Baton Rouge. 115 William C. Rice, Insect Pathologist, USDA/ARS, Rice Research Station, Crowley.

Dennis R. Ring, Associate Specialist (Entomology), Louisiana Cooperative Extension Service, Baton Rouge.

Milton C. Rush, Professor (Plant Pathology), Louisiana Agricultural Experiment Station, Department of Plant Pathology and Crop Physiology, Baton Rouge.

John K. Saichuk, Associate Specialist (Agronomy), Louisiana Cooperative Extension Service, Rice Research Station, Crowley.

Michael E. Salassi, Associate Professor (Agricultural Economics), Louisiana Agricultural Experiment Station, Department of Agricultural Economics, Baton Rouge.

Dearl E. Sanders, Specialist (Weed Science), Louisiana Cooperative Extension Service, Baton Rouge.

K. Paul Seilhan, formerly Coordinator, Rice Educational Programs (Agronomy), Louisiana Cooperative Extension Service, Baton Rouge.

Michael Stout, Assistant Professor (Entomology), Louisiana Agricultural Experiment Station, Department of Entomology, Baton Rouge.

Lawrence M. White III, Research Associate/Coordinator (Rice Foundation Seed Program), Louisiana Agricultural Experiment Station, Rice Research Station, Crowley.

116 Visit our website @ http://wwwagctr.lsu.edu/wwwac

Louisiana State University Agricultural Center, William B. Richardson, Chancellor Louisiana Cooperative Extension Service, Jack L. Bagent, Vice Chancellor and Director Pub. 2321 (7 M) Rev.11/98 Issued in furtherance of Cooperative Extension work, Acts of Congress of May 8 and June 30, 1914, in cooperation with the United States Department of Agriculture. The Louisiana Cooperative Extension Service provides equal opportunities in programs and employment.