EC 1463-E • Revised June 2009 Grape Phylloxera Biology and Management in the Pacific Northwest

P. Skinkis, V. Walton, and C. Kaiser

Contents

Chapter 1. The Biology of Grape Phylloxera...... 1

Chapter 2. Reducing Risk and Slowing Spread of Infestations...... 6

Chapter 3. Sampling Vines to Confirm Presence of Phylloxera...... 9

Chapter 4. Monitoring the Rate of Phylloxera Spread in the Vineyard...... 11

Chapter 5. Managing a Phylloxera-infested Vineyard...... 13

Chapter 6. Replanting Options for Establishing Phylloxera-resistant Vineyards...... 15

Chapter 7. Buying Winegrape Plants...... 19

Conclusion...... 21

Further Reading...... 23

Patty Skinkis, Extension viticulture specialist; Vaughn Walton, horticultural entomologist; and Clive Kaiser, Extension ­horticulturist (Umatilla County); all of Oregon State University

Chapter 1 The Biology of Grape Phylloxera

rape phylloxera, Daktulos- imported for use in grapevine Gphaira vitifoliae (Fitch) breeding programs due to their Name (Homoptera: Phylloxeridae), is an resistance to powdery mildew. By Daktulosphaira vitifoliae (Fitch) aphidlike insect that feeds aggres- 1900, two-thirds of all Vitis vini- Synonyms sively on grape roots. Phylloxera fera vineyards in Europe had been Daktulosphaira vitifolii Shimer is native to the eastern and south- destroyed. Since then, phylloxera Viteus vitifolii Shimer eastern United States, where native has spread to most grape-growing Peritymbia (Phylloxera) vitifolii per C.B. vastatrix (Planchon) American grape species coevolved areas of the world, including New P. pervastratrix (Börner) with the insect. Zealand, Australia, South Africa, Phylloxera vitifoliae (Fitch) The American grape species South America, Canada, and the Vitis rupestris, V. berlandieri, United States. and V. riparia are resistant to Phylloxera has been in the phylloxera. In contrast, the Ameri- Pacific Northwest for decades. It can grape species V. labrusca, was first discovered in Oregon in V. aestivalis, and V. vulpina are 1955; however, it was not identi- susceptible to phylloxera. Euro- fied in commercial vineyards until pean winegrapes, V. vinifera, are 1990. In 1988, phylloxera was the most susceptible. positively identified at eight sites There is no way to eradicate in Washington, one of which was a phylloxera from an infested V. vinifera vineyard. Phylloxera is vineyard. It will eventually kill sus- now distributed throughout every ceptible grapevines. The only way major grape-producing region to manage an infestation in the in Oregon, with the exception of long term is to replant the vine- Umatilla County, which is part of yard to vines grafted to a resistant the Walla Walla American Viticul- rootstock (see Chapter 6). tural Area (AVA). For more information on the History devastation caused by phylloxera Phylloxera was first found on throughout the history of grape grape roots in California in the production, see Phylloxera: How 1850s. In 1860, the pest was intro- Wine Was Saved for the World, by duced to France on American Vitis Christy Campbell (see page 23). species vines, which had been

1 Life cycle The full life cycle of phyllox- Asexual gallicoles and radicicoles era involves migration from the roots to the leaves and then back Fundatrix to the roots (Figure 1). The life cycle includes both sexual and Overwintering egg Crawler parthenogenetic (without mating) reproduction. L In the full life cycle, phylloxera Male Female can take four forms, although not all of these forms have been Sexuals identified in Oregon or the Pacific Northwest: R • Wingless, root-feeding form (radicoles) Alate • Winged form (alates) • Wingless sexual form Figure 1. The complete life cycle of phylloxera. L = leaf infestation. • Wingless, leaf-galling form R = Root infestation. In the Pacific Northwest, infestation occurs primarily on vine (gallicoles) roots. The fundatrix hatches from eggs that had overwintered and can start new development of phylloxera colonies. Image reproduced with permission from On V. vinifera grape cultivars, Granett et al. 2001. phylloxera normally infests only the underground parts of the plant Phylloxera strains from Australia ­parthenogenetically in bundles and undergoes an incomplete and the eastern United States have on the roots. Eggs hatch within cycle of seasonal development. also shown galling on V. vinifera. 10 days, producing new crawlers. Crawlers are mobile, but The leaf-feeding, gall-producing Root-galling phylloxera form is not present. In susceptible they leave the root where they The wingless, root-feeding American Vitis species, the full life hatched only if a high phylloxera form (radicole) is found year- cycle occurs, including the leaf- population has created feeding round on vine roots of infected feeding, gall-producing form. competition or when a vine is near vineyards. Radicoles overwinter The ability of phylloxera to death. In this case, they travel on in an inactive stage (hibernant) or form the leaf-gall-producing form the soil surface or through cracks as first- or second-instar nymphs. probably depends both on the in the soil to infest new roots. They begin feeding on the roots strain of phylloxera and the grape They also can climb the vine and as soon as root growth is initiated species. Phylloxera strains found be blown by the wind for consid- in the spring. The rate of develop- in California and most major erable distances. ment depends on vine sap flow, viticulture areas do not produce Crawlers are most numerous grape root growth, vine phenol- leaf-feeding gallicoles. In contrast, in late summer to early fall when ogy, and numerous environmental phylloxera strains found in the temperatures are optimal for factors, including humidity, soil eastern United States generally reproduction. Adults, eggs, and temperature (45 to 65°F), and air cause leaf galling on American crawlers are easiest to detect by temperature. grape species (e.g., Concord) or digging up grape roots at this time During the summer, larvae on interspecific hybrid cultivars or later in the season (see Chap- (known as crawlers) develop into that have ­American Vitis in their ter 3). The risk of spreading the adult females within 2 weeks. genotype (e.g., French-American insect is also greatest at this time Throughout the summer, these hybrids such as Marechal Foch). (see Chapter 2). females lay up to 400 eggs

2 Most larvae that hatch in the fall enter the overwintering stage (hibernant) soon after hatching and become brown and inactive. Alternatively, they may overwinter as first- or second-instar nymphs on nodules or galls on vine roots. During late summer, some crawlers may develop into winged nymphs, called alates. The rea- sons for alate formation are not fully understood, but it may be Figure 2. Phylloxera female (center) and eggs found on vine roots of an a response to crowding pressure Oregon vineyard. (high populations on the roots) or to high soil temperatures. This the spring (as early as bud break) numbers of galls per leaf. Up to form lives only a few days. During from eggs that were laid in the 20 galls per leaf have resulted in this time, it flies and deposits two soil by the final generation of gal- decreased photosynthesis and to six eggs on woody areas of the licoles the previous fall (Granett berry development of Seyval grapevine such as the trunk. These et al. 2005). The resulting gal- grapes (McLeod 1990). eggs hatch, producing the wing- licole emerges from the soil and Gallicoles occur on the Ameri- less sexual form. Eggs differ in migrates to young leaf tissues, can grape species V. labrusca size, and the larger ones produce where it feeds and forms a gall to and V. aestivalis. They have not females. house its eggs. A gall proliferates been found on V. riparia. Also, The wingless sexual forms to the underside of the leaf but they have not been observed in develop without feeding, since opens to the top of the leaf. About rootstock vineyards in Oregon or they lack functional mouth- 400 to 600 eggs are laid partheno- California. parts. Following four molts, they genetically inside each gall. are mature and mate. Fertilized After hatching, crawlers leave Identification females then lay a single egg in the gall and move to the soil or The root-infesting form of bark cracks or crevices. This egg begin new leaf galls. There may be phylloxera (radicole) is found survives the winter and may hatch four to six generations of gallicoles year-round on roots. Adult radi- in spring. Although it was previ- per growing season. Individuals coles are difficult to detect because ously believed that this egg gives of the final generation drop to of their extremely small size: 0.7 to 1 1 rise to the leaf-galling form in the the ground, burrow into the soil 1 millimeter ( ⁄30 to ⁄25 inch) long spring (see below), research now to a depth of 4 feet, and infest the and 0.4 to 0.6 millimeter wide. suggests that this is not the case roots. The eggs they lay in the soil On fresh, vigorous roots, imma- (Granett et al. 2005). will hatch the following spring, ture radicoles vary from pale green, yellowish-green, or olive Leaf-galling phylloxera restarting the cycle. On many American grape green to light brown. On weak- In addition to the radicole life species, the foliar life cycle is pre- ened roots, immature radicoles are cycle described above, phylloxera dominant, and the root form is brown or orange. Adults (Figure 2) can live out another stage of its life secondary (Downie et al. 2000). become brown or purplish-brown, cycle on leaves. This form is the This galling, if severe, reduces the no matter what kind of roots they gallicole and is generally­ observed photosynthetic ability of the vine, have fed on. on American Vitis species (not on but it generally is not of major Eggs are found on the roots Vitis vinifera). Gallicoles­ hatch in concern unless there are large throughout the summer (Figure 2)

3 and are yellow. Newly deposited products—into the root during Damage pattern eggs are lemon yellow and oval feeding, thus inducing gall forma- Above-ground symptoms usu- (0.5 to 0.7 mm long and about half tion. Alternatively, the feeding ally appear first as declining shoot as wide). process may stimulate the plant to growth and reduced fruit set in release hormones, such as auxin, a small, oval area in the vineyard Injury that initiate the gall. (Figure 4). However, if phylloxera Phylloxera damages Vitis vini- Root injuries impair absorption were brought in on own-rooted fera grapevines by feeding on of nutrients and water, causing a (ungrafted) planting material, roots, eliciting gall formation. decline in vine vigor and produc- the entire vineyard block may be Feeding generally occurs on the tivity. Secondary fungal infections weakened. tips of the rootlets, resulting in and subsequent feeding by other As the phylloxera spread, the the formation of yellowish-brown, insects and mites also hasten weak areas increase in size, with hook-shaped swellings or galls decomposition of roots. a progression of weaker vines known as nodosities (Figure 3). Above-ground symptoms are toward the center of the area. These galls may engulf the insect’s an indirect result of root damage. Other areas of infestation may also body. In most cases, the swell- Symptoms are visible as low-vigor appear in the same vineyard. ing stops rootlet growth, and the canopy growth and overall vine It may take 2 to 5 years from infested portion of the root even- decline over several seasons. Foli- the time of initial infestation for tually dies. age is lighter green than normal symptoms to appear, depending Feeding on larger roots causes foliage. Often, infested vines drop on vine vigor, method of infesta- rounded swellings (tuberosities), their leaves earlier than healthy tion, and location of the planting. which give the root a warty vines, or the foliage yellows more In warm areas such as California, appearance. The tuberosities may quickly. phylloxera can have four or five also decay, further weakening the The severity of above-ground generations per season, and vine- vine. symptoms depends partly on the yards may decline quickly (in as It is believed that phylloxera variety, age, and vigor of the vine; few as 3 to 5 years). Oregon likely inject toxic saliva or gut ­contents soil nutrient and water status; and has only two or three generations —amino acids and/or waste site drainage. of phylloxera per season, which

Figure 3. Root galls (nodosities) form at the Figure 4. Phylloxera infestation spreading through an end of young roots due to phylloxera feeding. Oregon vineyard. Notice the oval pattern of affected vines.

4 may contribute to the observed • Gophers and voles. Damage Phylloxera does not cause eco- slower rate of vine decline and to trunks is more random than nomic damage in soils with a phylloxera spread. damage from other causes. medium to fine sand content of Keep in mind that other factors There often is evidence of bur- more than 65 percent. Fine-texture­ can also cause low vigor and dete- rows or tracking next to the soils, such as clay, generally are riorating vine health: vine. Physical damage may be more favorable for infestation and • Shallow soil or drought. visible on the trunk above or damage. Weakened areas will not just below the soil surface. Infested vines live longer in spread annually unless ero- fertile, deep, well-drained soils Vine sampling (see Chapter 3) sion is occurring, nor will than in shallow soils or soils with can confirm whether phylloxera is there be a distinct pattern as is poor drainage. Vines growing in the cause of the problem. observed with phylloxera. heavy, shallow soils succumb to • Armillaria (oak root fungus). Factors affecting infestation most rapidly. Heavier The weak area is circular and infestation soils contract and crack when dry- ing, and these openings allow the related to an old oak savan- Phylloxera can survive under insect to crawl to and infest root nah, or an oak growing onsite virtually all climatic conditions systems. before vineyard establishment, tolerated by its host plant. Its Vigorous vines in a healthy or oaks currently growing development is influenced to a vineyard do not succumb to phyl- adjacent to the vineyard block. limited degree by temperature, loxera attack as quickly as weak • Viruses. Vines show a general rainfall, and humidity. Water- vines. Differences in vine vigor decline of vigor in addition to logging causes a decline in can be the result of several factors, other symptoms. ­phylloxera populations. including climate, cultivar, site • Nematodes. Vines are weak- In California, France, and South differences, and cultural practices ened, but symptoms do not Africa, the severity of phylloxera (e.g., pruning and training, fertil- necessarily appear in a circu- infestions has been shown to be ization, and irrigation). lar pattern. If nematodes are influenced by soil type, with sus- suspected, take soil samples ceptibility to damage decreasing­ and submit them to a lab for as the proportion of fine and nematode analysis. medium sand in the soil increases.

5 Chapter 2 Reducing Risk and Slowing Spread of Infestations

he only sure way to prevent Phylloxera has been found to Tphylloxera damage to grape- survive on several plant species. It n Plant phylloxera-free vines is to plant vines grafted to can endure transportation, crush- vines. phylloxera-resistant rootstock. ing, destemming, and pressing and Many of the first vineyards planted can be found in the must (Deretic n Restrict the movement in Oregon were on their own roots et al. 2003). of soil. (not grafted) and are now declin- Phylloxera can be spread from n Adopt sanitation ing in vigor, yield, and health vineyard to vineyard on soil or procedures. due to phylloxera infestation. If root pieces carried by any form of you have a phylloxera-free vine- traffic, including boots, picking yard of own-rooted Vitis vinifera, totes, vehicle tires, and animals. controlled access and sanitation Infested soil can also be exchanged procedures are required to pre- among vineyards via picking bins vent introducing phylloxera to the at the winery. Prevention primar- vineyard. ily means restricting movement of Any vineyard can be a source people, equipment, and materials of phylloxera, even if no visible among vineyards and thoroughly symptoms are present. Phyllox- cleaning all items that come in era usually is not diagnosed until contact with vineyard soil. Both several years after its introduction vineyards and wineries should into the vineyard, as populations implement measures to prevent must increase before vines show the movement of potentially symptoms. In addition, phylloxera infested soils. can live on resistant rootstocks. Prevention can be a daunting Although the resistant rootstock task, as sanitation methods can can tolerate phylloxera infesta- be impractical and difficult to tions and does not die as a result manage. For this reason, many of phylloxera feeding, it can sup- vineyards eventually succumb port populations of phylloxera to infestation despite prevention and serve as a source of new efforts. Experience in other viti- ­infestations. culture regions has shown that phylloxera will eventually reach

6 every vineyard in an infested dis- through blocks or vineyards • Thoroughly clean trucks trict despite intensive prevention with higher infestation rates. that deliver grapes to your efforts. The fact that phylloxera • Control access to your vine- vineyard/winery from other has spread throughout the world yard. Do not allow entry vineyards. Cleaning must be indicates the difficulty of prevent- without your approval. done onsite before the truck ing infestation. Nevertheless, the • Do not share tractors, trucks, enters your site. Use a 10- following preventive practices can trailers, or other field equip- percent bleach solution or hot delay initial infestations and slow ment with another vineyard. water with ­detergent in a pres- their spread once they do occur. sure washer. • Imprint the name of your • Thoroughly clean all equip- At the vineyard vineyard on your picking totes and bins; accept only returned ment, totes, and other items Plant phylloxera-free vines containers with your name. before they leave the vineyard and again before they reenter Because phylloxera can live on • Do not share picking totes or the vineyard. Use a 10-percent resistant rootstocks, vines grafted bins with other vineyards or bleach solution or hot water to resistant rootstocks can be a wineries. with ­detergent in a pressure source of infestation in your vine- • Load and unload trucks out- washer. yard. Make sure all planting stock side the vineyard on a paved is phylloxera-free (see Chapter 7). or graveled road. Where pos- Sanitation practices for workers sible, load grapes into bins Reduce insect movement and equipment can reduce spread or totes outside the vineyard but may not prevent spread com- The following methods of rows so that the bottoms of the pletely. Phylloxera crawlers can be preventing spread are meant for containers do not pick up soil. moved to new areas on equipment those vineyards that are currently • Use bins and totes that or clothing or by wind. Soil is not phylloxera free and are planted minimize the possibility of the only vehicle for ­movement. to own-rooted Vitis vinifera vines transporting soil; for exam- or to grafted vines that are not on ple, avoid bins with a waffle At the winery phylloxera-resistant rootstocks. In pattern on the bottom. Con- The following methods of this case, the only line of defense, tainers should be easy to clean. restriction and sanitation are other than replanting, is to make important for wineries that are every effort to restrict the move- Sanitation procedures adjacent to a phylloxera-free ment of people and equipment in • Develop a set of standard ­vineyard. and out of the vineyard. sanitation practices for your Restricted movement Restricting the movement of vineyard, and inform and • Restrict all vehicles to paved soil is most important, as infested instruct all workers. soil can be transferred via trac- areas. • Establish a sanitation station tor and truck tires or on bins at • Inspect all vehicles and bins where people can put on or harvest. The season of greatest for cleanliness prior to entry. clean their boots before enter- concern is when soil is moist and ing and leaving your vineyard. • Restrict delivery trucks to a has the potential to be moved The station should include sanitation pad. around the vineyard or into other “loaner” rubber boots and a • Keep picking totes and bins vineyards. tub containing a 10-percent separate for each vineyard. • Begin field work in blocks or bleach solution to sanitize • Do not share picking totes or vineyards known to be unin- boots. bins with other vineyards or fested and move progressively wineries.

7 Sanitation • Require that all vehicles, • Establish a concrete sanitation totes, bins, and other items pad for delivery trucks. Wash be cleaned at the originating down the pad daily during vineyard prior to delivery. harvest, using a 10-percent • Scrub picking totes and bins bleach solution or hot water before returning them to the with ­detergent in a pressure vineyard. washer.

8 Chapter 3 Sampling Vines to Confirm Presence of Phylloxera

rape phylloxera feeding weak- infestation, take root samples of Gens the grapes’ root systems, vines that line the perimeter of n Sample roots in late resulting in low-vigor canopy the damaged area, choosing vines growth and an overall weakened that show the first signs of decline. summer. appearance over several seasons. Also take samples from vines that n Sample around the Other factors can cause similar look healthy and vigorous. Sample trunk to a 4-foot depth. symptoms (see Chapter 1, page 5). as many suspect vines as possible. n Look for nodosities, Root sampling and monitoring Keep in mind that phylloxera adults, and eggs on for the pest can confirm whether can exist on resistant rootstocks phylloxera is causing the problem. without causing health problems roots. for the vine. Vines growing on n Use sticky traps to Sampling roots resistant rootstocks in close proxi- monitor for above- for infestation mity to own-rooted vines should ground forms It is difficult to find grape phyl- also be sampled. in late summer. loxera on infested roots in the Collect soil and root material early stages of an infestation. from the upper 4 feet of soil, as Therefore, sample roots in sus- most phylloxera are present to this pected weak areas over repeated depth. Sample within a 1.5-foot years. The best time to radius around the vine trunk sample for phylloxera in (­Figure 5). the Pacific Northwest is For each sampled vine, col- when populations are at lect 1 pint to 1 quart of roots and their peak, from late July associated soil (soil that is stuck through September. to the roots). Include a portion Phylloxera reproduce of a larger root (about 0.5 inch in most successfully on diameter) as well as feeder roots. healthy root systems. Remove roots and associated soil Dead and weakened vines carefully, immediately putting at the center of infested them in a sealed container. Figure 5. In late summer, collect soil samples to areas often have very detect phylloxera infestation. Collect samples to Root tips infested with phyl- a depth of 4 feet from a 1.5-foot radius around low populations on the loxera are club shaped or hooked the base of vines. Stunted shoots are evidence of roots. When sampling for (see Figure 3, page 4). Inspect new infestation. a suspected phylloxera fleshy growth on fine feeder roots

9 for nodosities (small swellings), adults and eggs can be detected On certain susceptible Ameri- which are symptoms of phylloxera with a stereoscope or 40X magni- can Vitis species, the leaf-feeding feeding. Although some nodosities fication. form of phylloxera feeds on vine are visible to the naked eye, it is leaves in the summer, producing best to examine roots with a 10X Above-ground galls on the undersides of leaves. hand lens. Nodosities may be yel- monitoring Phylloxera-produced galls are light low, turning brown as the roots get Use sticky tape on trunks and green and protrude to the under- older. After root death, they wither canes to look for the winged and side of the leaf. They are easily and decay, becoming impossible to wingless sexual stages of phyllox- distinguished from the brown or detect. Be aware that swellings on era in July and August. Two-sided white fuzz produced on the under- feeder roots may also be caused by sticky tape can be purchased sides of leaves by erineum mites. nematodes; however, to a trained from most stores and can be eas- However, the leaf-galling form is eye such swellings look different ily applied to the circumference generally not observed on V. vini- than those caused by phylloxera. of trunks, cordons, or canes. fera (see Chapter 1). Leaf galls Tuberosities (large swellings) Since movement is from the soil caused by phylloxera have not often can be seen on older, thicker upward, it is best to place the tape been reported in Oregon to date. roots. However, phylloxera often near the base of the vine trunk. are difficult to detect in advanced As the crawlers emerge from the Identification stages of an infestation as roots soil and move up the vine, they get Use a dissecting scope or become dry or spongy. caught on the sticky tape. Collect stereoscope to identify the pest Colonies of phylloxera are most the sticky tape on transparent film (see Chapter 1). If you need help, prevalent on larger, thicker roots. such as clear page protectors. Use contact your county office of the Often, phylloxera are found under a 40X magnifier or stereoscope OSU Extension Service. Finding sloughing bark or in cracks of the to look for phylloxera. Because one phylloxera when sampling is root. If colonies contain numerous of the small size and difficulty enough to verify an infestation. phylloxera, the colony may appear in identifying the pest, you may as yellow spots on the roots. Eggs wish to send samples to your local are smaller than adults, oblong, Extension agent or university and yellow (Figure 2, page 3). Both entomology lab for identification.

10 Chapter 4 Monitoring the Rate of Phylloxera Spread in the Vineyard

nce you know your vineyard Counting affected vines Ois infested, you should moni- Infestations often appear as a Monitoring options: tor the rate of spread and decline lens-shaped area of weak vines. n Counting affected vines in production to estimate how The easiest, but least accurate, long the vineyard will remain way to estimate rate of spread is to n Vigor ratings productive. This will help you con- count the number of vines within n Aerial photography and sider how (or whether) to make each lens. Do this in the fall, just “normalized difference the transition to a resistant vine- before or after harvest, when vegetative index” yard (see Chapter 6). symptoms are most apparent. imaging By the time an infestation is Annually counting affected confirmed, the insect is likely pres- vines will give a rough estimate of ent in a much wider area than is the economic rate of spread (that evident from the above-ground is, the rate at which the non- or symptoms. The phylloxera may low-producing area is increas- have infested the entire block or ing). Subtract the number of vines vineyard, as it takes a while for affected last year from the number populations to build to levels to affected in the current year and produce visible stress symptoms. divide by the number affected last Monitoring the rate of spread year. This will give you the percent within your vineyard means increase. For example, if 50 vines recording the rate and direc- show reduced vigor this year and tion of spread of above-ground 20 did last year, calculate the rate symptoms—not of the phylloxera of spread as: themselves. Economically, what (50 – 20) ÷ 20 = 1.5 matters most is not where the Thus, the rate of spread is 1.5, or insects are but how long the blocks 150 percent. will remain productive. The following methods can be Doing this for a few years will used to estimate rate of spread of give an idea of how quickly the above-ground symptoms. vineyard will succumb to the

11 infestation. In Oregon, we’ve Positioning System (GPS) unit to Many growers find that photo- seen rates of spread ranging from map the vineyard and track the graphs taken every 2 or 3 years 150 percent in an older vineyard infestation through the years. are adequate to detect vineyard (from a point-source infestation A modification of this system is problems and phylloxera spread. such as infested dirt on a boot or to keep records of pruning weights The photographic resolution and picking bucket) to 1,000 percent in vineyard blocks or affected altitude at which the vineyard in a 7-year-old vineyard where areas. As vine vigor declines due is photographed will determine phylloxera were introduced on the to infestation, pruning weight also the minimum size of weak areas plant material. should decline. Monitor pruning detected (for example, 1 vine Make sure to note any new weight and yield per vine in one or or 10). areas of symptoms separate from two long, narrow areas (transects) The NDVI method is superior the initial finding. New, apparently running through an infested area. for detecting changes in vine isolated areas of symptoms often The data will tell a great deal about health and vigor. Healthy vines appear when areas with weaker the rate of spread of phylloxera show up as a bright or dark color; vines succumb to infestations and its economic impact. weak and declining areas show up faster than more vigorous areas. as lighter colors, depending on the Aerial photography, color scheme used. Vigor ratings NDVI, and GPS Once weak areas are identified, This method is a modification Aerial photography and nor- ground surveys can be taken. GPS of the counting system described malized difference vegetative units can be used to map the loca- above and can be more accurate. index (NDVI) imaging are the tion of infestations in the vineyard The same person should rate vine most accurate way to evaluate and to track spread. Data also vigor each year. Document the size vine decline due to phylloxera. can be used in a GIS (geographic of the declining area(s) in your This method can’t identify a information system). vineyard by counting the number phylloxera infestation, but it can of affected vines. Then give a vigor provide information on variability rating to the vines (for example, in vine health across the vine- 1 = healthy; 2 = mildly stunted yard. This information can help or reduced growth; 3 = severely identify areas for sampling and stunted; 4 = dead). The ratings can ­monitoring. be added to a hand-held Global

12 Chapter 5 Managing a Phylloxera-infested Vineyard

hylloxera infestation in a self- ­phylloxera. Another is to slow the Prooted Vitis vinifera vineyard spread of infestation within the n Reduce or eliminate will eventually kill the grapevines. vineyard by altering management tillage during the The severity of infestation and practices. Both approaches should progression of vine damage can be used. Eventually, however, you growing season. differ among vineyards because of will have to decide when to replant n Practice good weed and varying site conditions and man- with vines grafted to a resistant pest management. agement practices. rootstock (see Chapter 6). n Increase water Although the first impulse Slowing the spread availability. upon discovering phylloxera in a vineyard may be to remove the of infestation n Prevent overcropping. visibly damaged vines, this does in the vineyard n Begin considering not eliminate the pest. Symptoms If phylloxera has been found options for replanting. of phylloxera damage take several within a vineyard block, take steps years to develop, and the infesta- to slow its spread to uninfested tion is unlikely to be limited to blocks. the area where the symptoms or If you use clean cultivation insects have been found. between rows to reduce competi- Removing infested vines actu- tion for water, restrict tillage to the ally increases the rate of phylloxera period between November and spread because it is not feasible May, when phylloxera populations to remove the entire root system are at their lowest. Tilling during when pulling vines. Phylloxera the growing season will accelerate living on remaining root pieces the spread of phylloxera within the will move to healthy vines as their vineyard. Tilled aisles also increase food supply is used up. Thus, it is the risk that rain or erosion will better to leave infested vines in the move infested soil downhill, and ground for as long as they are eco- tillage results in more mud on nomically productive, managing boots and equipment. them as described below. No insecticide effectively Prolonging the produc- controls phylloxera infestations tive lifespan of infested vines is in established plantings. Newly one approach to dealing with registered systemic insecticides

13 such as spirotetramat have shown is not possible, water availability • Replant infested blocks when some positive results in California can be increased by maintaining they become unprofitable to and are being trialed in Oregon a vegetation-free strip within the manage. for efficacy. However, years of vine row with herbicides or in-row • Replant the entire vineyard in additional research will be needed cultivation. It is also possible to a scheduled, piecemeal replant to understand the effect of these reduce soil moisture competition program. products. by removing between-row cover Previous research has shown crops or vegetation. Maintaining A decision to replant an infested that pesticides may slow the rate a clean, tilled vineyard, however, vineyard should come only after of spread of phylloxera. However, has several drawbacks, including careful consideration of the vine- in vineyards where above-ground soil erosion, increased dust in the yard operation and business. The damage is visible, root infections vineyard (which can exacerbate deciding factor should be the prof- by secondary pathogens may mite problems), and a tendency itability of each vineyard block. have already caused irreversible to spread phylloxera by tilling, Good record keeping is invalu- ­damage. especially during summer when able when making this important Soil treatments with pesticides populations increase. An alterna- decision. Review records of pro- show little promise because of the tive to tilling between rows is to duction, costs, and revenues for great depths at which phylloxera plant a less competitive vegetative past years. Monitor the rate of occur and because chemical pene- cover. A low-growing grass with a spread of phylloxera and vine tration is poor in heavier soils. shallow, noncompetitive root sys- decline to help predict how long tem, such as sheep fescue, is one the infested block can remain Prolonging vine lifespan option. profitable (see Chapter 4). Infested vines that are other- Finally, there is some evidence Also consider the existing fea- wise healthy and unstressed are that compost mulches might pro- tures of the vineyard. Replanting better able to tolerate phylloxera long the life of infested vineyards. provides an opportunity to change feeding than low-vigor or stressed Mulches can positively impact some of the features of the produc- vines. Therefore, conditions that vine health by improving soil tion system (e.g., cultivar, clone, promote vigor, such as deep, fertile health and nutrient availability spacing, and training system) soils and irrigation, may enable and by supporting soil microbes in order to improve production infested vines to live longer. that may keep diseases from efficiency, fruit quality, or crop It is important to maintain infecting damaged roots (Powell marketability. See Chapter 6 for or improve weed and pest man- et al. 2007). additional discussion of these and agement to prevent these stress other factors. factors from contributing to vine Analyzing your options If you decide to replant, decline. To help manage stress, Eventually, a decision will use only phylloxera-resistant prevent overcropping of phylloxer- need to be made as to whether ­rootstocks! ated vines; crop removal may be (and when) to replant an infested required in weak vines. vineyard with vines grafted to There are several management phylloxera-resistant rootstock. practices to manage vine health Several options are possible: by reducing competition. Irrigat- • Pull out vines after they ing infested vines to avoid water become unprofitable, and don’t stress is an important tool for replant. maintaining vigor. If irrigation

14 Chapter 6 Replanting Options for Establishing Phylloxera-resistant

Vineyards rowers with infested vine- business. For more information Gyards or those wishing to on establishment costs for vine- n Plan ahead. avoid infestation in own-rooted yards in Oregon, see the following n Replant blocks with blocks have several options for OSU Extension Service enterprise replanting with phylloxera- ­budgets: other problems first. ­resistant, grafted plants. You can • Vineyard Economics: Estab- n Use replanting as wait to replant until a confirma- lishing and Producing Pinot an opportunity to tion of phylloxera infestation, Noir Wine Grapes in Western correct other vineyard or you can replant to resistant Oregon. 2008. EM 8969-E. limitations. rootstocks before an infestation http://oregonstate.edu/dept/ is confirmed. Replant strategies n Let the ground lie fallow EconInfo/ent_budget/PDF/ may be different in each situation. EM8969-E.pdf for 5 years if possible. This chapter reviews the options • Vineyard Economics: Estab- n Minimize competition and discusses advantages and dis- lishing and Producing with new vines. advantages of various strategies. Cabernet Sauvignon Wine The primary objective of Grapes in Eastern Oregon. replanting is to establish a new 2009. EM 8974-E. vineyard that is resistant to http://oregonstate.edu/dept/ phylloxera. When consider- EconInfo/ent_budget/PDF/ ing replanting options, a related EM8974-E.pdf objective is to reduce the costs of the transition. Consider these Whatever replant strategy you two objectives together. Do not choose, you will have more flexi- use a replanting method that will bility if you plan the replant ahead impact the long-term health and of time. The more prepared you viability of the new vineyard. are, the more likely that replant- Likewise, carefully weigh the eco- ing will be an opportunity for nomic realities of the transition to improvement rather than a des- protect the financial health of your perate rescue of a dying vineyard.

15 When to replant materials from reputable nurseries Replanting schedules will be dic- All self-rooted Vitis vinifera well in advance and integrate the tated by the decline of phylloxera- vineyards in Oregon are at risk replacement process into a larger infested vines (see Chapter 4). from phylloxera infestation, and it plan for vineyard rejuvenation and Remove or replant blocks with is possible that all will eventually improvement. declining production when they become infested. However, infesta- Consider replanting vineyard no longer are profitable to manage. tion might take 1 year or 30. This blocks with other design problems Start replanting the least profitable uncertainty is due in part to the first. For example, replanting pro- blocks, regardless of whether they size and demographics of the vine- vides an opportunity to renovate are the most heavily infested. This yard or winery and of the growing or change trellis systems, change will allow you to begin vineyard region. vine and row spacing, change varie- improvement while providing Rates of phylloxera infestation ties or clones, or add an irrigation phylloxera resistance through are higher in the Willamette Valley system or drainage tile. In addition grafted vines. than in other parts of Oregon. This to conferring phylloxera resis- Keep in mind that planting region not only has a critical mass tance, rootstocks also can be used resistant rootstocks in an infested of vineyard acreage, but also larger to correct problems with excess site is not insurance against con- vineyard and winery operations vigor, water stress, poor fruit set, tinued spread of phylloxera in and more movement of people, or vine nutrition. own-rooted areas of the vineyard. equipment, and fruit among vine- Replanting profitable blocks Many phylloxera-resistant root- yards. Grape-growing regions such before a phylloxera infestation stocks will support phylloxera as the Columbia Gorge and south- is confirmed is a more difficult populations and can serve as a res- ern Oregon have lower incidences decision. Replanting still has ervoir for continued spread. of phylloxera-infested vineyards, advantages, particularly in the Remember that the distribu- and the threat of infestation might long term. A vineyard on resistant tion of phylloxera in the vineyard not be as strong. Infestation is still root­stock will provide a supply of is wider than the area of visibly possible in these regions, however. grapes that will not be compro- affected vines, and vines outside a mised by phylloxera, and resistant weak spot will continue to decline. Uninfested vineyards rootstocks substantially add to a Thus, extend the replanted area More replanting options are vineyard’s resale value. well beyond the borders of the vis- available if you replant before the It is vital to keep reestablish- ible infestation. vineyard is infested. In this case, ment time to a minimum in Replant infested areas on a replanting can be based on a long- any situation, but that objective row-by-row basis. Replanting in term plan of vineyard replacement becomes especially critical with complete rows will reduce man- and rehabilitation. Decisions are profitable production blocks. In agement difficulties caused by planned rather than dictated by these blocks, the time without variations in vine size and age. the spread of phylloxera and the fruit production must be kept as Replanting apparently healthy, pattern of vine decline. This allows short as possible. productive blocks can be difficult you to anticipate the financial due to temporary loss of revenue, implications of replanting and to Infested vineyards but it can increase vineyard value spread replanting costs over a lon- Because phylloxera eventu- as well as future marketability and ger period. Base the order of block ally will move throughout the productivity. removal and replacement on block vineyard, prepare a replanting profitability. Be sure to order plant schedule for the entire vineyard.

16 Replanting as an but this method is also the most old root system remains in place, opportunity to expensive due to the cost of however, and may supply inocu- improve the vineyard reestablishment and loss of pro- lum for viruses, root diseases, and Evaluate vineyard blocks before duction. Interplanting is the least insect infestations. Existing phyl- making replant decisions. Iden- expensive method initially, but has loxera populations could increase tify the vineyard’s limitations, a greater risk of failure of newly pressure on the new rootstocks. planted vines. and determine whether replant Interplanting strategies offer an opportunity to Complete reestablishment correct them. The goal of interplanting • Is the production system This is the only choice when the grafted vines between produc- ­efficient? existing vineyard has serious limi- ing, established vines is to get tations. For example: the new plants into production • What is the anticipated • Renovation allows deep rip- while the old ones continue to lifespan of the trellis? ping to loosen hardpans and supply revenue. It is possible that • Could the spacing or trellis pull up old vine roots. a new grafted vineyard could be system be changed to improve • Blocks can lay fallow to reduce established with little or no loss of quality or production? pest populations. Plant cover production. • Should an irrigation system be crops to improve soil health Do not consider interplanting installed or renovated? and reduce phylloxera and if the existing vineyard has serious • Are there limiting soil factors nematode populations. limitations that could be corrected such as compaction, nutrient • Soil treatments such as fumi- by vineyard renovation (e.g., dry deficiencies, acidity problems, gation and incorporation of farmed, poor trellis system, or or poor drainage? phosphorus, potassium, or wide spacing). • Are pathogenic nematodes or lime are possible only in the Interplanting has many poten- fungi present in the soil? absence of growing plants. tial problems. • It is difficult to remove old • Changing the trellis system Many of these factors can be plants before planting. corrected most effectively before or vine spacing or installing • Removing the old vines can planting, when existing plants or drainage tile also requires a exacerbate problems with trellises do not obstruct access to fresh start. nematodes, soil fungi, and the entire block. Replanting with high phylloxera populations. Replanting options the existing trellis • Interplanting results in com- There are several options for Replant with the existing trellis petition between new and old replanting infested vineyards. only if the plan and organization vines for water and nutrients, • Remove all vines and trellis of the vineyard are acceptable and thereby decreasing the rate of systems in an infested block, the trellis system will last at least development of the new vines. fallow, and replant. 10 more years. Many of the major • Interplanting makes vineyard • Remove all vines and replant vineyard modifications discussed management more difficult using the existing trellis above are not possible if the trellis due to variation in vine size ­structure. structure is retained. and age. Removing old vines may be dif- • Interplant vines between ficult with the trellis in place. In The most serious of these ­existing vines. some cases, large, old vines cannot problems is competition from the The most effective method be removed without damaging the existing vines. Poor establishment is complete reestablishment of trellis system, so they must be cut of young plants could result in a the vineyard and trellis system, off and killed with herbicides. The nonuniform vineyard with vines

17 of different ages, various cultivars Inarch grafting • Use herbicides. Apply a sys- or clones, and a mix of grafted and Self-rooted vines can be con- temic herbicide to the cut base own-rooted vines. verted to vines with resistant of the trunk during the grow- If you choose to interplant, the rootstocks by a grafting technique ing season. priority must be to establish the called inarching. This technique Fallow new vines. Adjust vineyard man- involves planting resistant root- agement to favor growth of the stocks next to the trunks of It is difficult to remove or kill new vines. Consider the following existing vines and grafting them all vine roots in the soil profile. management practices. onto the trunk. The goal is to Vine roots that persist in the soil • Irrigate the new plants. If the completely replace the root system may support populations of phyl- young vines are not irrigated of the self-rooted plant with the loxera for years. Phylloxera can during establishment, vine phylloxera-resistant stock. weaken young vines, even those failure can be significant. This technique has been tried on resistant rootstocks, if popula- • Remove or reduce permanent in California with mixed results. tions are high. The roots can also cover crops that compete Some growers were able to change serve as inoculum for viruses that with young vines. Completely the root system of established had infected the vine, and they can removing the cover crop is not vines without losing production. support populations of nematodes, always desirable, however. In However, this technique has not plant-pathogenic fungi, and other some cases, it is important to been reliable in Oregon, where insect pests. For this reason, a fal- maintain cover for traffic- cool, wet weather after grafting low period after vine removal is ability and to prevent soil often results in graft failure. Fur- suggested to allow populations erosion. In this case, competi- thermore, interplanting rootstock of phylloxera and other pests to tion can be reduced simply by into an established vineyard can decrease and to allow residual vine widening the weed-free in-row be difficult because of competi- roots to decompose. strip. tion from vines. In unirrigated A fallow period of 5 or 6 years • Root-prune the established vineyards, lack of water during has traditionally been recom- plants so that there is no sig- rootstock establishment is a prob- mended. It is often impractical nificant root competition with lem. This method is not advised to wait 5 years to replant, but it is the young vines. except in small-scale experiments. important to recognize potential problems associated with immedi- • Summer prune the canopy of ate replanting. The fallow period established plants to increase Replanting can be shortened to 3 years if the available light for the new Removing vines soil is fumigated. plants. • Remove phylloxera-infested There are two basic approaches vines within 2 years, by the to removing own-rooted vines: time the new planting is being • Use a backhoe to remove vines trained to the fruiting wire. and as many roots as possible.

18 Chapter 7 Buying Winegrape Plants

electing good plant material is ­availability of plant materials of Sa critical step in establishing a your choice, place your order at n Choose phylloxera- profitable vineyard. Considering least 1 year in advance. vineyard establishment costs and resistant rootstocks. potential longevity, it is important Choose phylloxera- n Choose rootstocks to start with clean plant material. resistant rootstocks suitable for your Clean plant material is defined as Although self-rooted location. material that is free of known pest (ungrafted) plants are about half the cost of grafted vines, it is not n Purchase vines from a and disease infestation. If possible, obtain certified plant material. recommended to plant self-rooted reputable nursery. Certified plant material refers to vineyards in the Pacific Northwest n Buy certified, virus-free vines that have been tested and due to the presence of phylloxera plants if possible. found to be free of harmful grape- and the potential for infestation in n If buying vines from vine viruses such as fanleaf or currently uninfested areas. Vines grafted onto a resistant rootstock out of state, observe grapevine leaf-roll virus. Choosing a reputable nurs- are the only insurance against quarantine restrictions. ery that sells certified, virus-free phylloxera. Grafted plants are well n Ask about nursery plants is an important step in worth the higher cost when com- treatment of plants to procuring good-quality, true-to- pared to the cost of reestablishing kill phylloxera. type, disease-free plants. For a list a vineyard after infestation. of commercial nurseries, see the Grafting, which combines two National Grape Registry (http:// different varieties or species to ngr.ucdavis.edu/index.cfm). form a new plant with the char- Consult your local Extension acteristics of the two parents, has horticulture agent for more infor- been used in both fruit trees and mation on reputable nurseries in viticulture since ancient times. It your area. has been used to change variety, The most popular rootstock– enhance vigor, or increase tol- scion combinations are in great erance to soil characteristics. demand. Often, nurseries will Grafting became a common not have adequate stock on hand practice in viticulture after the for immediate orders. To ensure European phylloxera epidemic.

19 Laliman, the French viticulturist, Interspecific hybrid be imported only if they have was the first to suggest grafting sus- grape cultivars grown in soilless, sterile media. ceptible wine varieties to rootstock Some American hybrid grapes For more information and the of resistant American Vitis species. are grown in the Pacific North- specific details of the quarantine, The rapid adoption of this practice west, including cultivars such as contact the Oregon Department of led to a chaotic period from 1880 Marechal Foch and Baco noir. Agriculture, or see the quarantine to 1930, when nurseries offered a Many of these hybrid cultivars rules online (http://www.oregon. confusing assortment of rootstocks. have both American Vitis species gov/ODA/PLANT/docs/pdf/ The use of inappropriate rootstocks and Vitis vinifera species in their quar_grape.pdf). caused new problems, particularly genetic lineage. Therefore, root- lime-induced chlorosis. Extensive stocks may be required to avoid Purchasing plant research on rootstocks after 1950 the susceptibility of these vines to materials in Oregon revealed that several aspects of attack by phylloxera over time. The above requirements do not scion (the grafted vine) behavior apply to plant material purchased depend on features of the root- Plant type in Oregon. Ask the nursery about stock. These include adaptation to Nurseries sell dormant field- the health status of vines you pur- growing conditions, susceptibility grown and greenhouse (green) chase and always purchase from to mineral deficiencies or toxici- potted plants. Green plants need a reputable source. For a list of ties, tolerance to soilborne pests to be hardened off before plant- reputable nurseries, contact your and diseases, vigor, productivity, ing and may need more careful local Extension horticulture agent and fruit quality. After more than irrigation after planting. Check or visit the National Grape Regis- a century of experimenting with with nurseries for availability and try Online (http://ngr.­ucdavis.edu/ rootstocks in Europe and through- ­recommendations. index.cfm). out the world, a considerable Plants purchased from Oregon amount of information on root- Grade grapevine nurseries commonly stock performance is now available. Dormant, field-grown plants are field-grown. Nursery inspec- There now are many types of are available in two grades, based tors check plants for phylloxera grafted rootstocks from which to mainly on plant size. Check with or symptoms of infestation in choose. The choice of a rootstock nurseries for availability and costs the winter when plants are dug. for a particular location depends for specific cultivars or clones. However, it is very difficult to find on complex interactions among phylloxera, particularly in winter, soil type and depth, soil physical Purchasing plant and no certification or inspection and chemical properties, pests, materials out of state method is without error. diseases, water availability, and The Oregon Department of As insurance against phylloxera environmental factors. Thus, Agriculture has a grape quarantine infestation, some nurseries treat onsite evaluation is imperative against grape phylloxera. If you plants with a hot water dip or for rootstock selection. For more plan to purchase plants from nurs- insecticide to kill phylloxera that information on selection of root- eries outside Oregon, you must may be present. Treated plants stocks for phylloxera resistance follow these regulations. may cost more. To be effective, and other qualities, see OSU Grape plant material imported plants must be dipped for 5 min- Extension publication Grapevine into Oregon must be accompanied utes at 110°F (to warm the roots) Rootstocks for Oregon Vineyards, by a phytosanitation certificate and for 5 minutes at 125°F to kill EM 8882 (http://extension.­ that certifies the plants are free phylloxera. Research has shown oregonstate.edu/catalog/pdf/em/ from any “known disease or infes- that this treat­ment eradicates phyl- em8882.pdf). tation.” Rooted grape plants may loxera without harming dormant plants (Stonerod and Strik 1996).

20 Conclusion

hile phylloxera can be dev- ­certified plant material if possible Wastating for commercial and always purchase from repu- viticulture, it can be managed with table nurseries. the use of resistant rootstocks. If own-rooted vines in an estab- This publication discusses ways lished vineyard exhibit decreased to avoid infestation in phylloxera- productivity (yield and canopy free sites. However, it is important growth), thoroughly analyze the to note that phylloxera has been vines and the vineyard site. Many identified in vineyards in nearly factors can result in reduced all regions of the state, and it is yield and vine growth, including only a matter of time before unin- mite infestation, high nematode fested vineyards will be infested. populations, drought stress, nutri- This is in part due to the rigorous ent deficiencies, virus, or other sanitation requirements needed diseases. Sampling for phylloxera for prevention and isolation. Only and testing for other problems— portions of eastern Oregon are for example, soil nutrient status believed to be phylloxera free. or nematodes—may reveal that However, that region likely will a vineyard has more than one eventually succumb to infestation. problem. Talk to your local OSU This has been the case in every Extension faculty or field rep/ area of the world, even with strict consultant for more information. sanitation efforts and quarantines. By diagnosing as many factors as The only way to avoid phyllox- possible, you can mitigate multiple era infestation is to use resistant problems through site renovation, rootstocks. When planting a new relocation, and selection of appro- vineyard, plant only vines grafted priate rootstocks. to phylloxera-resistant rootstocks. Phylloxera sampling is dis- For existing own-rooted vine- cussed in Chapter 3. For assistance yards, the only line of defense is in identifying phylloxera samples to replant to vines grafted to phyl- and assessing management prac- loxera-resistant rootstocks. When tices, contact the resources listed planting or replanting, obtain on page 22.

21 Local grower resources in commercial viticulture Local Oregon State University Extension offices throughout the state may be able to assist in phylloxera diagnosis and management. Please contact the following individuals for assistance or more information.

AVA OSU Extension county office Extension agent Phone

Umpqua Valley Douglas Steve Renquist 541-672-4461 http://extension.oregonstate.edu/douglas/

Southern Oregon* Jackson/Josephine Marcus Buchanan 541-776-7371 http://extension.oregonstate.edu/sorec/ Rick Hilton

Columbia Gorge Hood River Steve Castagnoli 541-386-3343 http://extension.oregonstate.edu/hoodriver/

Walla Walla Umatilla, Milton-Freewater Clive Kaiser 541-938-5597 http://extension.oregonstate.edu/umatilla/ mf/

*Includes the AVAs of the Umpqua, Rogue, Illinois, and Applegate valleys.

For specific information on entomology and verification of phylloxera infestation, contact the following.

OSU main campus Phone

Vaughn Walton, horticultural entomologist 541-737-3485 http://hort.oregonstate.edu/faculty-staff/walton

Patty Skinkis, Extension viticulture specialist 541-737-1411 http://hort.oregonstate.edu/faculty-staff/skinkis

22 Further Reading

Ahmedullah, M., and D.G. 2005. Grape phylloxera gal- McLeod, M.J. 1990. Damage Himelrick. 1989. Grape man- licole and radicole activity on assessment and biology agement. In: G.J. Galletta and grape rootstock vines. HortSci. of foliar grape phylloxera D.G. Himelrick (eds.). Small 40:150–153. (Homoptera: Phylloxeridae) in Fruit Crop Management, Granett, J., M.A. Walker, L. Kocsis, Ohio. PhD thesis, Ohio State pp. 383–471. Prentice Hall, and A.D. Omer. 2001. Biology University. Englewood Cliffs, NJ. and management of grape Pongrácz, D.P. 1983. Rootstocks Campbell, C. 2004. Phylloxera: phylloxera. Annu. Rev. for Grapevines. David Philip, How Wine Was Saved for the Entomol. 46:387–412. Cape Town, South Africa. World. HarperCollins Publish- Granett, J., and P. Timper. 1987. Powell, K.S., A. Burns, S. Norng, ers, Hammersmith, London. Demography of grape Phyllox- J. Granett, and G. McGourty. Carbonneau, A. 1985. The early era, Daktulosphaira vitifoliae 2007. Influence of composted selection of grapevine root- (Homoptera: Phylloxeridae) at green waste on the popula- stocks for resistance to different temperatures. J. Econ. tion dynamics and dispersal of drought conditions. American Entomol. 80:327–329. grapevine phylloxera Daktu- Journal of Viticulture and Hardie, W.J., and R.M. Cirami. losphaira vitifoliae. Ag Ecosyst. Enology 36:195–198. 1988. Grapevine rootstocks. Environ. 119:33–38. Deretic, J., K. Powell, and S. In: B.G. Coombe and P.R. Dry Stonerod, P., and B. Strik. 1996. Hetherington. 2003. Assessing (eds.). Viticulture, Vol. 1: Hot-water dipping eradicates the risk of phylloxera transfer Resources, pp. 154–176. Wine- phylloxera from grape nursery during post-harvest handling titles, Adelaide, Australia. stock. HortTech. 6:381–383. of wine grapes. Acta Hort. 617: Herbert, K.S., A.A. Hoffmann, and Wolpert, J.A., M.A. Walker, 61–68. K.S. Powell. 2006. Changes in E. Weber, L. Bettiga, R. Smith, Downie, D.A., J. Granett, and grape phylloxera abundance in and P. Verdegall. 1994. Use of J.R. Fisher. 2000. Distribution ungrafted vineyards. J. Econ. Phylloxera-resistant rootstocks and abundance of leaf galling Entomol. 99:1774–1783. in California: Past, present and and foliar sexual morphs of Howell, G.S. 1987. Vitis rootstocks. future. Grapegrower 26:10–17. grape phylloxera (Hemiptera: In: R.C. Rom and R.B. Carlson Wolpert, J.A., M.A. Walker, and Phylloxeridae) and Vitis spe- (eds.). Rootstocks for Fruit E. Weber. 1992. Rootstock cies in central and eastern Crops, pp. 451–472. John Seminar: A Worldwide Per- United States. Environ. Ento- Wiley & Sons, Inc., New York. spective. Reno, NV, 24 June mol. 29:979–986. Jackson, D., and D. Schuster. 1992. pp. 1–14. Granett, J., L. Kocsis, L. Horvath, 1994. Grapes and Wine in and L.E. Barasci Horvathne. Cool Climates. Gypsum Press, Christchurch, New Zealand.

© 2009 Oregon State University. This publication may be photocopied or reprinted in its entirety for noncommercial purposes. Extension work is a cooperative program of Oregon State University, the U.S. Department of Agriculture, and Oregon counties. Oregon State University Extension Service offers educational programs, activities, and materials without discrimination based on age, color, disability, gender identity or expression, marital status, national origin, race, religion, sex, sexual orientation, or veteran’s status. Oregon State University Extension Service is an Equal Opportunity Employer. Published November 1995. Revised June 2009.