Pest Management & Crop Development Bulletin • No. 3 / April 8, 2005

Proceedings of the 1999Ð2005 Crop Protection Technology Conference Available Online

The proceedings from seven University of Illinois Crop Protection Technol- ogy Conferences are now available online at the IPM Web site at http:// www.ipm.uiuc.edu/education/proceedings/index.html. These proceedings include all of the papers written to support presentations at the Crop Protec- tion Technology Conferences held annually on campus at the University of Illinois. If you do not have Adobe Reader, you will be able to download it from our site. Although the proceedings currently are not searchable by key words or phrases, the tables of contents in each issue provide titles and page numbers so you can find a subject of interest relatively easily. We have hopes for providing proceedings from this conference and its predecessors— Illinois Agricultural Pesticides Conference (1987Ð1998) and Illinois Custom Spray Operators Training School (1949–1986)—online in the future. How- ever, such an effort will require considerable time and resources.

FOR IMMEDIATE RELEASE The most recent proceedings (http://www.ipm.uiuc.edu/education/ No. 3 / April 8, 2005 proceedings/icptcp2005.pdf) include papers on many topics, including a selected few that may have relevance during the 2005 growing season: ¥ Soybean rust Executive editor: Kevin Steffey, ¥ historical perspective, soybean resistance (pages 16Ð20) Extension Entomologist ¥ models and dispersal (pages 21Ð22) Available on the Web at ¥ management (pages 23Ð27) http://www.ipm.uiuc.edu/bulletin ¥ sampling protocol, thresholds, and scouting (pages 82Ð83) For subscription information, phone ¥Western corn rootworms 217.244.5166, or e-mail ¥ movement and resistance management (pages 28Ð34) [email protected] ¥ insecticidal seed treatments and soil insecticides (pages 35Ð40) ¥YieldGard Rootworm corn (pages 41Ð46) Copyright © 2005, Board of Trustees, ¥ distribution of the variant western corn rootworm (pages 47Ð49) University of Illinois ¥ Application of fungicides ¥ spray droplet size for ground and aerial applications (pages 63Ð66) Also in This Issue ¥ management of soybean diseases (pages 67Ð69) ¥ management of corn diseases (pages 70Ð71) ❏ Protecting Corn from Soil ¥ management of wheat diseases (pages 72Ð74) Insect Injury, 20 ¥ Glyphosate-resistant weeds (pages 78Ð80) ❏ Cruiser Registered for Use on ¥ Soybean aphids and their management (pages 86Ð91) Soybeans, 20 ¥ Herbicide injury (pages 92Ð94) ❏ Spring Moth Flights Have ¥ Early planting (pages 100Ð101) Begun, 21 ¥Western bean cutworm (pages 102Ð105) ¥Management of secondary insects (pages 130Ð132) ❏ Getting Ready for Alfalfa ¥ Corn nematodes (page 135) Weevils, 21 ❏ Proliferation of Premix We hope that the most recent proceedings provide timely information that Products, 22 you can use for your benefit in 2005 and beyond. And past proceedings provide historical perspective and references for issues that are still relevant ❏ What Weed Is That? 26 today.—Kevin Steffey ❏ Does Corn Seed Size Really Matter? 26 . . . and more

19 Pest Management & Crop Development Bulletin • No. 3 / April 8, 2005

ing season and in many previous arti- ¥ Use seed-applied insecticides at the INSECTS cles in the Bulletin, we have stated that rate indicated for the target no rootworm-control product is “bul- insect(s). Protecting Corn from Soil Insect letproof” and that producers should not Injury use these products expecting that root- ¥ Plant a non-Bt (i.e., non-YieldGard worm damage will never occur. Every Rootworm) corn refuge (20%) The fantastic weather in late March product currently labeled for rootworm within or adjacent to a field of and early April throughout much of control has provided less than adequate YieldGard Rootworm corn. (This Illinois got people all fired up for protection in some fields in some holds true also for YieldGard Corn planting corn. And so it has begun. As years. There are no exceptions. Occa- Borer corn and Herculex 1 corn for of April 3, the Illinois Agricultural sionally, performance problems are control of Lepidoptera pests, al- Statistics Service had reported that 1% widespread. We have discussed, in though the topic of this article is of the corn had been planted (http:// some detail, the factors that may con- control of corn soil insects.) The www.agstats.state.il.us/). A respected tribute to less-than-adequate control of non-Bt refuge is an insect resis- source in western Illinois estimated on soil insects—for example, soil too wet tance management practice that is April 5 that 10% of the corn in his or too dry; windy conditions at plant- required by the U.S. Environmental area had been planted. And planters ing; early planting (especially relevant Protection Agency (EPA) and en- continue to roll as the weather and soil again this year); inadequate incorpora- couraged by the National Corn conditions continue to be favorable for tion of soil insecticides (especially Growers Association and the Illi- planting. when corn is planted early); and inter- nois Corn Growers Association. A practice that often accompanies corn actions among the environment, corn Here’s wishing you a safe and suc- planting throughout much of the Mid- hybrid, and insect. So suffice it to say cessful planting season, as well as west is that of applying a soil insecti- that we should expect performance satisfied expectations for control of cide or planting transgenic seed or problems again in 2005. It’s almost soil insect pests in 2005.—Kevin insecticide-treated seed for control of inevitable. Steffey soil insect pests (e.g., black cutworms, We state once again that producers corn rootworms, white grubs, and should seriously consider leaving un- wireworms). A lot of producers use treated check rows in each field in Cruiser Registered for Use on these insect-control products as insur- which an insect-control product is Soybeans ance to protect against the potential used. Untreated check rows can reveal for economic damage. Although this essential information for a producer— By now, most of you know that the practice is not necessarily a tenet of presence or absence of soil insect nicotinoid insecticide Cruiser (active integrated pest management (IPM) pests, and injury and yield compari- ingredient thiamethoxam) was regis- and is an unnecessary expense if the sons between treated and untreated tered by the U.S. EPA for application target insects do not occur at economic rows. The need for or performance of to soybean seed to control bean leaf levels, applying insecticides as pro- an insect-control product can be mea- beetles, seedcorn maggots, soybean phylactics has been a common prac- sured only against an untreated check. aphids, and wireworms. The seed- tice for decades. We could debate (and One or more untreated check areas applied insecticide has been made have debated) the merits and negative provide a producer with an understand- available by Syngenta Crop Protection aspects of this practice in thousands of ing of the “background noise” of insect in CruiserMaxx Pak (a combination of written and spoken words, but for pressure in a field. Cruiser seed treatment insecticide and now, let’s accept the fact that this ApronMaxx seed treatment fungicide). practice is commonplace and instead As corn planting shifts into high gear, discuss reasonable expectations and we offer these last-second reminders: Here’s a question. Is the application of subsequent evaluations. a preventive insecticide necessary for ¥ Apply soil insecticides at the la- production of soybeans in Illinois, or We believe that every producer who beled rates. Applying insecticides at elsewhere in the Midwest for that uses an insect-control product has an greater-than-labeled rates is illegal. matter? The reason I ask is that many obligation to understand what the producers seem to believe that this product will and will not do. There- ¥ Place granular or liquid insecticides seed treatment is necessary for a crop fore, a producer should have reason- in a band over the row or in-furrow, that prior to 2000 rarely required an able expectations for the performance depending on label guidelines and insecticide application. Over the past of an insect-control product and un- advice from company representa- three decades, soybean producers derstand that performance may fall tives. occasionally had need of insecticides/ short of expectations for a number of ¥ Incorporate granular and liquid soil miticides for control of bean leaf reasons. Throughout the winter meet- insecticides into the surface soil. beetles, grasshoppers, twospotted

20 Pest Management & Crop Development Bulletin • No. 3 / April 8, 2005

spider mites, and sundry other insects. extension entomologist at the Univer- also armyworm moths this week. Occasionally, outbreaks of these insect sity of Wisconsin, has written two These armyworm moths will lay eggs or mite pests (in 1988, for example) excellent articles regarding Cruiser for the first armyworm generation this justified widespread use of insecti- and soybean aphids in the newsletter spring.—Kelly Cook cides or miticides. However, annual Wisconsin Pest Manager: application of insecticides to soybeans ¥ “Cruiser® 5FS Insecticide Supple- was not necessary and not common. Getting Ready for Alfalfa So what has changed? mental Label for Soybean and Potatoes,” January 17, 2005: http:// Weevils The most obvious answer is the arrival ipcm.wisc.edu/wcm/pdfs/2005/ It’s that time of year again. Not only of the soybean aphid in 2000, with wcm05-1.pdf has baseball season begun, but it’s time widespread and significant outbreaks ¥ “Performance of Soybean Seed to gear up for alfalfa weevils. There’s occurring in Illinois in 2001 and 2003. little correlation between the two, Another answer is the relatively recent Treatments for Soybean Aphid in UW-Madison Trials,” March 10, I know. But these warm spring days bean leaf beetle/bean pod mottle virus are great for playing ball and develop- scare. However, neither bean leaf 2005: http://ipcm.wisc.edu/wcm/ pdfs/2005/wcm05-3.pdf ment of alfalfa weevils. Here’s a brief beetles nor soybean aphids have scouting report. caused significant yield losses every I strongly encourage you to read both year since 2000, and expectations for articles before assuming that planting Larval hatch from eggs is expected to future occurrences of these insect insecticide-treated seed is the best occur after the accumulation of 300 pests still are uncertain. So why the approach for managing soybean degree-days from January 1. Currently, mad rush to add another cost to soy- aphids. alfalfa fields in southern Illinois have bean production? Will the addition of accumulated just over 200 degree-days seed treatments result in yield benefits We and other entomologists through- and will soon be experiencing larval greater than the cost of the seed treat- out the Midwest will continue to es- hatch (Figure 1). In fact, certain areas ments? tablish field trials to determine may already have alfalfa weevils feed- whether seed-applied insecticides will ing on new alfalfa growth. Some al- Quite honestly, I can’t answer these be an added benefit for soybean pro- falfa fields may warm up sooner than questions very well; limited data have duction. As with the use of prophylac- others. For example, in fields that are been generated. We have data that tic insect-control products in corn on south-facing slopes or protected by reveal clearly that Cruiser controls (refer to “Protecting Corn from Soil timber or wooded areas, alfalfa wee- early-season bean leaf beetles very Insect Injury” in this issue of the Bul- vils may develop sooner. In these situ- well. However, densities of bean leaf letin), the use of prophylactic insect- ations, scouting should begin earlier beetles are very difficult to predict. control products in soybeans is not than in other fields. One word of cau- For example, we established two necessarily a tenet of IPM. We encour- tion: clover leaf weevils can be present rather robust trials in northwestern age producers to gather more facts in alfalfa fields just before alfalfa Illinois in 2004 in soybean fields sur- before jumping on this bandwagon.— weevils are noticed. Be sure to identify rounded by woods and alfalfa fields— Kevin Steffey the weevil larvae that are present in the an ideal setting for bean leaf beetles. field before making any treatment Results? Almost too few bean leaf decisions. beetles to count. Under such condi- tions, waiting to use a foliar insecti- Spring Moth Flights Have Begun Growers across the state should brush cide only if necessary (and it wasn’t A few more black cutworms were up on scouting for alfalfa weevil lar- necessary) was the more economic caught in pheromone traps this week. vae. More information on identifica- approach. Mike Roegge, crop systems educator, tion, life cycle, scouting, and manage- Adams/Brown Unit, reported his first ment can be found on factsheets for So what about soybean aphids, cur- alfalfa weevil (http:/www.ipm.uiuc. rently the most dreaded insect pest of cutworm catch of the season in Adams County this past week. In eastern edu/fieldcrops/insects/alfalfa_weevil. soybeans? Some data have revealed pdf) and clover leaf weevil (http:// early-season suppression of soybean Illinois, Doug Gucker of Piatt County Extension and Dawn Thomson of www.ipm.uiuc.edu/fieldcrops/insects/ aphid populations. But acceptable clover_leaf_weevil.pdf). To get current control of soybean aphids with Cruiser Pioneer reported the first black cut- worms of the season in Piatt and Coles degree-day accumulations for alfalfa during a soybean aphid outbreak (i.e., weevils and other insect pests, visit our population densities held below eco- counties, respectively. Ron Hines’s trap line continues to be active catch- degree-day calculator (www.ipm.uiuc. nomic thresholds in late July, early edu/degreedays).—Kelly Cook August) is unlikely. Eillen Cullen, an ing not only black cutworm moths but

21 Pest Management & Crop Development Bulletin • No. 3 / April 8, 2005

Figure 1. Accumulated degree-days (base 48° F) for alfalfa weevils, beginning January 1, 2005.

WEEDS the tables is that a single application soybean herbicide premixes. Let’s rate of each product is presented, with examine the information in these product active ingredients and equiva- tables in a little more detail. Proliferation of Premix Products lents calculated based on that rate. If you would like to know product active The first column lists the commercial It’s no secret that while the introduc- ingredients and equivalents for a rate or trade name of the herbicide and its tion of novel herbicide active ingredi- different than the one presented, the formulation. The commercial or trade ents has slowed (i.e., reduced some text provides examples of how to do name is the name most familiar to inventory problems) recently, a ple- the calculations. We are working on an folks. Another list of names (arguably thora of premix packages has prolifer- online herbicide premix calculator, less familiar than the names in the first ated (i.e., added some inventory chal- where you can input your rate of inter- column) appears in the second col- lenges). For the past several years, we est and the calculator will determine umn; these are the common names for have published an article in the Bulle- all active ingredient application rates each herbicide component of a pre- tin that describes herbicide premix and product equivalents. When fin- mix. For example, in Table 1 we see products that are commercially avail- ished, this calculator will be accessible that Axiom (trade name) 68DF (for- able for corn and soybean production at the University of Illinois weed sci- mulation) is composed of the active systems, and we continue again this ence Web site. ingredients flufenacet (common name) year. The basic text hasn’t changed and metribuzin (common name). much over time, and we hope it re- Herbicide premixes can often be con- Common names are useful because mains useful to our readers. fusing with respect to components, they always refer to the same active product equivalents, application rates, ingredient; trade names don’t always Updated tables of corn and soybean and so on. Table 1 lists many of the refer to the same active ingredient. premixes always accompany the ar- corn herbicide premixes used in Illi- ticle and are described in detail within nois, while Table 2 is a similar list of Think back a few years to a herbicide the following text. One limitation of with the trade name Option. This

22 Pest Management & Crop Development Bulletin • No. 3 / April 8, 2005

Table 1. Corn herbicide premixes. If you apply/ Herbicide Components (ai/gal or lb) acre You have applied (ai) Product equivalents Accent Gold clopyralid = 0.517 lb ae 2.9 oz clopyralid = 0.094 lb ae Stinger 3S = 4 fl oz 83.8WDG flumetsulam = 0.191 lb flumetsulam = 0.035 lb Python 80WDG = 0.69 oz nicosulfuron = 0.065 lb nicosulfuron = 0.012 lb Accent 75DF = 0.25 oz rimsulfuron = 0.065 lb rimsulfuron = 0.012 lb rimsulfuron = 0.012 lb ai Axiom 68DF flufenacet = 0.544 lb 19 oz flufenacet = 0.646 lb Define 60DF = 17.23 oz metribuzin = 0.136 lb metribuzin = 0.162 lb Sencor 75DF = 3.45 oz Basis 75WDG rimsulfuron = 0.50 lb 0.33 oz rimsulfuron = 0.01 lb rimsulfuron = 0.01 lb ai thifensulfuron = 0.25 lb thifensulfuron = 0.005 lb Harmony GT 75DF = 0.11 oz Basis Gold rimsulfuron = 0.0134 lb 14 oz rimsulfuron = 0.012 lb rimsulfuron = 0.012 lb ai 89.46WDG nicosulfuron = 0.0134 lb nicosulfuron = 0.012 lb Accent 75DF = 0.25 oz atrazine = 0.8678 lb atrazine = 0.759 lb AAtrex 90DF = 0.844 lb Bicep II Magnum S-metolachlor = 2.4 lb 2.1 qt S-metolachlor = 1.26 lb Dual II Magnum 7.64E = 1.32 pt 5.5L atrazine = 3.1 lb atrazine = 1.63 lb AAtrex 4L = 3.26 pt Cinch ATZ Bicep Lite II S-metolachlor = 3.33 lb 1.5 qt S-metolachlor = 1.2 lb Dual II Magnum 7.64E = 1.31 pt Magnum 6L atrazine = 2.67 lb atrazine = 1.00 lb AAtrex 4L = 2 pt Cinch ATZ Lite Buctril + bromoxynil = 1.0 lb 2 pt bromoxynil = 0.25 lb Buctril 2E = 1 pt atrazine 3L atrazine = 2.0 lb atrazine = 0.5 lb AAtrex 4L = 1 pt Bullet 4CS alachlor = 2.5 lb 4 qt alachlor = 2.5 lb Micro-Tech 4CS = 2.5 qt atrazine = 1.5 lb atrazine = 1.5 lb AAtrex 4L = 1.5 qt Camix 3.67L S-metolachlor = 3.34 lb 2.4 qt S-metolachlor = 2.0 lb Dual II Magnum 7.64EC = 2 pt mesotrione = 0.33 lb mesotrione = 0.198 lb Callisto 4SC = 6.34 fl oz Celebrity Plus diflufenzopyr = 0.17 lb ae 4.7 oz diflufenzopyr = 0.049 lb ae diflufenzopyr = 0.049 lb ae 70WDG dicamba = 0.424 lb ae dicamba = 0.125 lb ae Clarity 4S = 3.98 fl oz nicosulfuron = 0.106 lb nicosulfuron = 0.031 lb Accent 75DF = 0.66 oz Degree Xtra acetochlor = 2.7 lb 3 qt acetochlor = 2.025 lb Degree 3.8CS = 2.13 qt 4.04CS atrazine = 1.34 lb atrazine = 1.00 lb AAtrex 4L = 1 qt Distinct 70WDG diflufenzopyr = 0.20 lb ae 4 oz diflufenzopyr = 0.05 lb ae diflufenzopyr = 0.05 lb ae dicamba = 0.50 lb ae dicamba = 0.125 lb ae Clarity 4S = 4 fl oz Epic 58WDG flufenacet = 0.48 lb 12 oz flufenacet = 0.36 lb Define 60DF = 9.6 oz isoxaflutole = 0.10 lb isoxaflutole = 0.075 lb Balance 75WDG = 1.6 oz Equip 32WDG foramsulfuron = 0.30 lb 1.5 oz foramsulfuron = 0.028 lb Option 35WDG = 1.28 oz iodosulfuron = 0.02 lb iodosulfuron = 0.0018 lb iodosulfuron = 0.0018 lb ai Expert 4.88L S-metolachlor = 1.74 lb 3 qt S-metolachlor = 1.31 lb Dual II Magnum 7.64EC = 1.37 pt atrazine = 2.14 lb atrazine = 1.61 lb AAtrex 4L = 3.21 pt glyphosate = 0.74 lb ae glyphosate = 0.56 lb ae Glyphosate 3L = 1.48 pt Field Master acetochlor = 2.0 lb 4 qt acetochlor = 2.0 lb Harness 7E = 2.29 pt 4.06S atrazine = 1.5 lb atrazine = 1.5 lb AAtrex 4L = 3 pt glyphosate = 0.56 lb ae glyphosate = 0.56 lb ae Roundup Ultra 3L = 1.5 pt FulTime 4CS acetochlor = 2.4 lb 4 qt acetochlor = 2.4 lb TopNotch 3.2CS = 3 qt atrazine = 1.6 lb atrazine = 1.6 lb AAtrex 4L = 1.6 qt G-Max Lite 5L dimethenamid-P = 2.25 lb 3 pt dimethenamid-P = 0.844 Outlook 6EC = 18 fl oz atrazine = 2.75 lb atrazine = 1.03 AAtrex 4L = 2 pt Guardsman dimethenamid-P = 1.7 lb 4 pt dimethenamid-P = 0.85 lb Outlook 6EC = 18.1 fl oz Max 5L atrazine = 3.3 lb atrazine = 1.65 lb AAtrex 4L = 3.3 pt Harness Xtra 6L acetochlor = 4.3 lb 2 qt acetochlor = 2.15 lb Harness 7E = 2.46 pt atrazine = 1.7 lb atrazine = 0.85 lb AAtrex 4L = 1.7 pt Harness Xtra acetochlor = 3.1 lb 2.5 qt acetochlor = 1.94 lb Harness 7E = 2.21 pt 5.6L atrazine = 2.5 lb atrazine = 1.56 lb AAtrex 4L = 3.13 pt Hornet WDG clopyralid = 0.50 lb ae 3 oz clopyralid = 0.094 lb ae Stinger 3S = 4 fl oz 68.5WDG flumetsulam = 0.185 lb flumetsulam = 0.035 lb Python 80WDG = 0.69 oz Keystone 5.25L acetochlor = 3 lb 3 qt acetochlor = 2.25 lb Surpass 6.4EC = 2.81 pt atrazine = 2.25 lb atrazine = 1.69 lb AAtrex 4L = 3.38 pt Keystone LA acetochlor = 4 lb 2 qt acetochlor = 2 lb Surpass 6.4EC = 2.5 pt 5.5L atrazine = 1.5 lb atrazine = 0.75 lb AAtrex 4L = 1.5 pt Laddok S-12 5L bentazon = 2.5 lb 1.67 pt bentazon = 0.52 lb Basagran 4S = 1 pt atrazine = 2.5 lb atrazine = 0.52 lb AAtrex 4L = 1 pt

23 Pest Management & Crop Development Bulletin • No. 3 / April 8, 2005

Table 1. Corn herbicide premixes (cont.) If you apply/ Herbicide Components (ai/gal or lb) acre You have applied (ai) Product equivalents Lexar 3.7L S-metolachlor = 1.74 lb 3.5 qt S-metolachlor = 1.52 lb Dual II Magnum 7.64 EC = 1.6 pt mesotrione = 0.224 lb mesotrione = 0.196 lb Callisto 4SC = 6.27 fl oz atrazine = 1.74 lb atrazine = 1.52 lb Aatrex 4L = 3 pt Liberty ATZ glufosinate = 1 lb 40 fl oz glufosinate = 0.313 lb Liberty 1.67L = 24 fl oz 4.3SC atrazine = 3.3 lb atrazine = 1.03 lb AAtrex 4L = 2.06 pt Lightning 70DG imazethapyr = 0.525 lb 1.28 oz imazethapyr = 0.042 lb Pursuit 70DG = 0.96 oz imazapyr = 0.175 lb imazapyr = 0.014 lb Arsenal 2AS = 0.896 fl oz Lumax 3.95L S-metolachlor = 2.68 lb 3 qt S-metolachlor = 2.01 lb Dual II Mangum 7.64EC = 2.1 pt mesotrione = 0.268 lb mesotrione = 0.201 lb Callisto 4SC = 6.4 fl oz atrazine = 1 lb atrazine = 0.75 lb AAtrex 4L = 1.5 pt Marksman 3.2L dicamba = 1.1 lb ae 3 pt dicamba = 0.4125 lb ae Banvel 4S = 0.825 pt atrazine = 2.1 lb atrazine = 0.7875 lb AAtrex 4L = 1.56 pt NorthStar primisulfuron = 0.075 lb 5 oz primisulfuron = 0.023 lb Beacon 75WDG = 0.50 oz 47.4WDG dicamba = 0.399 lb ae dicamba = 0.125 lb ae Banvel 4S = 4 fl oz ReadyMaster atrazine = 2 lb 2 qt atrazine = 1 lb AAtrex 4L = 2 pt ATZ 4SC glyphosate = 1.5 lb ae glyphosate = 0.75 lb ae Roundup 3L = 2 pt Shotgun 3.25F atrazine = 2.25 lb 2 pt atrazine = 0.56 lb AAtrex 4L = 1.13 pt 2,4-D = 1 lb ae 2,4-D = 0.25 lb ae Salvo 5E = 0.4 pt Spirit 57WDG prosulfuron = 0.142 lb 1 oz prosulfuron = 0.009 lb Peak 57WDG = 0.25 oz primisulfuron = 0.428 lb primisulfuron = 0.027 lb Beacon 75WDG = 0.57 oz Steadfast nicosulfuron = 0.5 lb 0.75 oz nicosulfuron = 0.023 lb Accent 75DF = 0.5 oz 75WDG rimsulfuron = 0.25 lb rimsulfruon = 0.012 lb rimsulfuron = 0.012 lb ai Steadfast ATZ nicosulfuron = 0.027 lb 14 oz nicosulfuron = 0.0236 lb Accent 75DF = 0.5 oz 89.3WDG rimsulfuron = 0.013 lb rimsulfuron = 0.0114 lb rimsulfuron = 0.0114 lb ai atrazine = 0.853 lb atrazine = 0.7464 lb Aatrex 90DF = 0.829 lb Yukon 67.5WDG halosulfuron = 0.125 lb 4 oz halosulfuron = 0.03 lb Permit 75WSG = 0.67 oz dicamba = 0.50 lb ae dicamba = 0.125 lb ae Banvel 4S = 4 fl oz

product contained the active ingredi- calculations in the fourth and fifth 60DF and 3.45 ounces of Sencor ent fenoxaprop (common name) and columns. The fourth column indicates 75DF, respectively. was used for postemergence control of how much of each active ingredient is grass species in soybean. The Option applied at the rate listed in the third The application rates listed in the (trade name) herbicide now on the column. Going back to the example of tables are meant to be used as a refer- market contains foramsulfuron (com- Axiom, we see that 19 ounces of ence. For some of these herbicides the mon name) and is used for postemer- Axiom provides 0.646 pounds of application rates will vary depending gence control of grass species in corn. flufenacet active ingredient and 0.162 on soil texture, organic matter, weed Needless to say, you don’t want to pounds of metribuzin active ingredi- species and size, and such. Always apply fenoxaprop to corn or foramsul- ent. Note here that while rates of com- consult the respective herbicide label furon to soybeans, hence the benefit of mercial products are usually expressed for appropriate application rates. If knowing herbicide common names. in ounces, pounds, pints, quarts, and you are interested in a rate different so on of product per acre, active ingre- from that listed for a particular herbi- The second column also provides the dients are usually expressed in units of cide, it’s relatively simple to do the amount of active ingredient or acid pounds of active ingredient or acid calculations for your rate of choice. equivalent of each component per equivalent per acre. We’ll work through an example to gallon or pound of formulated prod- make it a little easier to understand. uct. Finally, the last column lists product equivalents for each premix compo- The application rate of Harness Xtra The third column lists an application nent when applied at the rate listed in 5.6L listed in Table 1 is 2.5 quarts per rate for each premix. We tried to select the third column. So the 19-ounce rate acre. Instead of 2.5 quarts, you want to application rates that were representa- of Axiom provides the same amount know how much acetochlor and atra- tive for Illinois, but you may want to of flufenacet and metribuzin that is zine are applied at a 2-quart rate of select a different rate and redo the contained in 17.23 ounces of Define Harness Xtra 5.6L.

24 Pest Management & Crop Development Bulletin • No. 3 / April 8, 2005

Table 2. Soybean herbicide premixes. Components (ai/gal If you Herbicide or lb) apply/acre You have applied (ai) Product equivalents Axiom 68DF flufenacet = 0.544 lb 13 oz flufenacet = 0.442 lb Define 60DF = 11.78 oz metribuzin = 0.136 lb metribuzin = 0.111 lb Sencor 75DF = 2.36 oz Backdraft SL imazaquin = 0.15 lb 2.5 qt imazaquin = 0.094 lb Scepter 70DG = 2.14 oz 1.35L glyphosate = 0.884 lb ae glyphosate = 0.553 lb ae Roundup 3L = 1.47 pt Boundary 7.8EC S-metolachlor = 6.3 lb 2 pt S-metolachlor = 1.57 lb Dual Magnum 7.62E = 1.65 pt metribuzin = 1.5 lb metribuzin = 0.375 lb Sencor 75DF = 8 oz Boundary 6.5EC S-metolachlor = 5.25 lb 2.4 pt S-metolachlor = 1.57 lb Dual Magnum 7.62E = 1.65 pt metribuzin = 1.25 lb metribuzin = 0.375 lb Sencor 75DF = 8 oz Canopy EX chlorimuron = 0.107 lb 6 oz chlorimuron = 0.039 lb Classic 25DF = 2.56 oz 29.5WDG metribuzin = 0.643 lb metribuzin = 0.24 lb Sencor 75DF = 5.14 oz Canopy XL sulfentrazone = 0.469 lb 6.8 oz sulfentrazone = 0.199 lb Authority 75DF = 4.25 oz 56.3DG chlorimuron = 0.094 lb chlorimuron = 0.04 lb Classic 25DF = 2.56 oz Domain 60DF flufenacet = 0.24 lb 10 oz flufenacet = 0.15 lb Define 60DF = 4 oz metribuzin = 0.36 lb metribuzin = 0.225 lb Sencor 75DF = 4.8 oz Extreme 2.17L imazethapyr = 0.17 lb 3 pt imazethapyr =0.063 lb Pursuit 2AS = 4 fl oz glyphosate = 1.473 lb ae glyphosate = 0.552 lb ae Roundup 3L = 1.47 pt Fusion 2.56EC fluazifop = 2 lb 8 fl oz fluazifop = 0.125 lb Fusilade DX 2E = 8 fl oz fenoxaprop = 0.56 lb fenoxaprop = 0.035 lb Puma 1EC = 4.48 fl oz Gangster V&FR flumioxazin = 0.51 lb 2 oz (V) + flumioxazin = 0.064 lb Valor 51WDG = 2 oz Co-Pack cloransulam = 0.84 lb 0.6 oz (FR) cloransulam = 0.032 FirstRate 84WDG = 0.6 oz Gauntlet Co- sulfentrazone = 0.75 lb 5.33 oz sulfentrazone = 0.25 lb Authority 75DF = 5.33 oz Pack cloransulam = 0.84 lb + 0.6 oz cloransulam = 0.031 lb FirstRate 84WDG = 0.6 oz Pursuit Plus imazethapyr = 0.2 lb 2.5 pt imazethapyr = 0.063 lb Pursuit 2AS = 4 fl oz 2.9EC pendimethalin = 2.7 lb pendimethalin = 0.84 lb Prowl 3.3EC = 2 pt Rezult B&G Co- bentazon = 5 lb 1.6 pt (B) + bentazon = 1.0 lb Basagran 4S = 2 pt Pack sethoxydim = 1 lb 1.6 pt (G) sethoxydim = 0.20 lb Poast Plus 1E = 1.6 pt Sequence 5.25L S-metolachlor = 3 lb 3 pt S-metolachlor = 1.13 lb Dual Magnum 7.62ED = 1.18 lb glyphosate = 2.25 lb ae glyphosate = 0.84 lb ae Touchdown Total 4.17L = 26 fl oz Storm 4S bentazon = 2.67 lb 1.5 pt bentazon = 0.5 lb Basagran 4S = 1 pt acifluorfen = 1.33 lb acifluorfen = 0.25 lb Blazer 2S = 1 pt Synchrony STS chlorimuron = 0.318 lb 0.5 oz chlorimuron = 0.01 lb Classic 25DF = 0.64 oz 42DF thifensulfuron = 0.102 lb thifensulfuron = 0.003 lb Harmony GT 75DF = 0.068 oz

First, convert 2 quarts to gallons: 2 quarts 1 gallon x = 0.5 gallon acre 4 quarts

Next, we can calculate how much acetochlor and atrazine active ingredient are contained in 0.5 gallon of Harness Xtra 5.6L: 0.5 gallon 3.1 lb ai acetochlor x = 1.55 lb ai acetochlor per acre acre gallon

0.5 gallon 2.5 ai atrazine x = 1.25 lb ai atrazine per acre acre gallon

Finally, we can also determine product equivalents based on these active ingredient amounts:

1.55 lb ai acetochlor x 1 gallon Harness x 8 pints = 1.77 pints Harness 7E acre 7 lb ai gallon 1.25 lb ai atrazine 1 gallon AAtrex 8 pints xx = 2.5 pints AAtrex 4L acre 4 lb ai gallon

—Aaron Hager and Dawn Nordby

25 Pest Management & Crop Development Bulletin • No. 3 / April 8, 2005

Mature and Flowering Weeds whelming conclusion of those (includ- What Weed Is That? ing me) who have done such research Most of the weed identification re- is that seed size and shape do not have Weed identification is the first step in sources fall into this category, albeit weed management, introducing the consistent effects on seed quality. contrary to the idea that you need to Good-quality seed will produce simi- need to have various reference materi- identify weeds when they are small in als at your disposal. We have catego- lar stands and yields, regardless of its order to control them. Nonetheless, size and shape. rized several identification resources here are some of the better mature- into groups based on the emergence weed identification publications. What could have changed to make timing and maturity of the plant spe- Weeds of the Great Plains, spanning seed size “matter” now? A look at the cies they include. All but one of the over 600 pages, has been recently Farm Journal article showed that their publications in this article can be revised and now contains color images “proof” consisted of finding a seed lot found under the Weed Identification and text descriptions for 266 weeds. (hybrid and company not identified) section of the North Central Weed Another good book to have around is where one grade (small rounds) had Science Society Extension Publica- Weeds of the North Central States, subpar cold and accelerated aging test tions page, located at http://www. which contains 230 species with black scores. That grade apparently (and ncwss.org/ (please click on the Exten- and white line drawings of mature predictably) produced lower plant sion Publications button). From this plants and key characteristics. stands than the other grades, though Web site, you can view, print, and/or how much lower was never stated. order these publications. For the technologically savvy, the This reduced stand went on to produce Interactive Encyclopedia of North Early-Season Weeds lower yields in “replicated” tests, of American Weeds DVD offers more which we are given a summary of a Two publications that are extremely than 2,400 photographs covering 447 “representative” trial that gives only useful for identification of early- of the most important weeds and crops seed “stress” test numbers and yields, season weeds include the Early Spring in the United States and Canada. This not stands. This hardly forms the basis Weeds of No-till Crop Production and DVD also contains an illustrated inter- for the sweeping generalization that A Pocket Guide of Early Season Weed active identification key and a com- “seed size matters.” Species. The first publication, Early prehensive glossary of plant identifi- Spring Weeds of No-till Crop Produc- cation terminology. The article appears to have been aimed to some extent at promoting a tion, is in full color and 22 pages long. Finally, we are frequently asked to It contains a taxonomic key along with seed testing service that offers a test identify plants that are not usually that is slightly different from the usual many photos of 45 weeds and text “classified” as weeds, so we tend to descriptions. Also included is a guide cold test. The cold germination test, use wildflower identification guides. which typically uses soil to provide to herbicides for control of the weeds Wildflowers (Peterson Field Guide) included in the publication. A Pocket microbes that can attack seeds, is not and Newcomb’s Wildflower Guide are standardized among laboratories, Guide of Early Season Weed Species is great references for plants not typi- a pocket-sized reference to 19 early- mostly because what soil is used is not cally found in cultivated areas. These standardized. Standardizing soil season weeds with color photos and books can be found at libraries, book- descriptive text. Also of note is a one- among labs might be possible but is stores, and online book suppliers.— not desirable, given that soils should page identification sheet for several Dawn Nordby and Aaron Hager winter annual grasses. more or less represent soils the seed will be planted in and this could not be The Weed Seedlings of Summer CROP DEVELOPMENT the same for all locations. Virtually all corn seed is tested using a cold test, Only a few publications focus on sum- but such a test is not required by law mer annual weed seedlings. We are Does Corn Seed Size Really and results for the same seed will not going to highlight two of our favorites. Matter? be the same from different labs. Cold Weeds of the Northeast has 299 weeds, On the cover of the March 2005 issue scores might be available on request with color images of these weeds from or even on tags, but there’s no stan- seedling to mature. There are also of Farm Journal was the rather startl- ing headline “Seed Size Matters,” dard of what cold scores should be and many keys and helpful tables for dis- the cold test is used primarily by com- tinguishing closely related plants. against a background photo of corn seed. Corn seed size and grade (the panies in deciding whether or not to Common Weed Seedlings of the North sell seed. Central States is a 21-page bul-letin shapeÐsize combination related to with color images of 36 broadleaves, plantability, originally with different The accelerated aging test consists of 17 grasses, and 1 sedge along with text planter plates) have been the topic of maintaining seed in a “tropical” envi- descriptions. research for decades, and the over- ronment for a few days before the standard warm test. This measures the

26 Pest Management & Crop Development Bulletin • No. 3 / April 8, 2005

physiological soundness of seeds and lots identified as having problems by We hope these reports will provide will often give lower numbers than one of the stress tests may also be additional benefits for staying current the warm germ test, especially for discarded, though if the warm germi- as the season progresses. seeds that have been stored for a long nation is high, such seed might be time under less-than-ideal conditions held back for later planting or sent to Northern Illinois and seeds that have deteriorated due areas where soils are warmer at plant- Since April 1, fieldwork has in- to production or handling problems. It ing time and seed is less likely to creased, with the main activities fo- is thus a “stress test” like the cold test undergo stress after planting. cusing on anhydrous ammonia appli- but does not try to duplicate what Producers can certainly send seed cation and secondary tillage. Also, conditions the seed might be under in most of the oats and alfalfa scheduled the field. samples for further testing by inde- pendent labs, but such third-party tests to be seeded in the region have been The standard warm germination per- rarely identify problems. Mistakes seeded. Other activities include pri- centage is the number required on the occasionally happen, but if a company mary tillage and application of pre- seed tag and is standardized, such that fails to do the best job possible to sell plant herbicides. its value for the same seed should be only top-quality seed in today’s com- Wheat has greened up nicely because similar among laboratories. Under petitive environment, it doesn’t stay in of the constant warmer temperatures; good planting and emergence condi- business long. That’s probably the however, some fields are exhibiting tions, emergence is often close to the best protection we have.—Emerson small areas with reduced stands from warm germ, while under cold, wet Nafziger winter injury. conditions, it may be closer to the cold or accelerated aging germination Extension educators are monitoring score. Some lots can also have “ab- REGIONAL REPORTS several black cutworm moth traps normal” seedlings, from seed usually throughout the region, but no moths Extension center educators, unit edu- measured as germinable under the have been captured to date. cators, and unit assistants in northern, warm test but probably more prone to west-central, east-central, and south- emergence problems, especially when No or minimal precipitation has al- ern Illinois prepare regional reports to soil conditions are less than ideal. lowed fieldwork to continue, but rain- provide more localized insight into fall is expected throughout the region Are small rounds generally defective pest situations and crop conditions in on April 6. as seed compared to other grades? Illinois. The reports will keep you up Careful research has not shown this to to date on situations in field and for- Southern Illinois age crops as they develop throughout be the case, and so the general answer Field drying has occurred, and farmers the season. The regions have been is no. While seed lots and grades may are continuing with tillage and limited defined broadly to include the agricul- have quality problems that can affect corn planting. We had rain in parts of tural statistics districts as designated seed performance, such problems southern Illinois the morning of April by the Illinois Agricultural Statistics usually reflect genetics, production, or 6, and that will alter the schedule. handling conditions and are not Service, with slight modifications: closely tied to seed grade. Rounds Wheat is at growth stage 5Ð6 and ¥ North (Northwest and Northeast come from the ends of the ear, how- finally looking a little better. Some districts, plus Stark and Marshall ever, and are shaped such that their failed fields will be destroyed if con- counties) germ (embryo) can be exposed to ditions permit. mechanical stress more than flats. ¥West-central (West and West There have been some reports of small Seed with physical damage due to Southwest districts, and Peoria, alfalfa weevil larvae actively feeding. insects or birds can be separated out Woodford, Tazewell, Mason, Producers should scout for this pest. and discarded during processing, and Menard, and Logan counties from seed with mechanical damage can be the Central district) West-Central Illinois identified using germination tests. ¥ East-central (East and East South- Tillage and fertilizer/chemical appli- Different types of germination tests east districts [except Marion, Clay, cations seem to be the predominant are run on different lots and grades Richland, and Lawrence counties], activities this week. Soil is working after processing, so quality problems McLean, DeWitt, and Macon coun- excellent. seldom escape detection. If the warm ties from the Central district) germination test is low, seed is dis- A few corn planters are running, al- carded, since field germination per- ¥ South (Southwest and Southeast though many have yet to start. If we centage cannot normally be higher districts, and Marion, Clay, receive no rain this week, there will be than the warm test score. Grades or Richland, and Lawrence counties plenty of activity next week. The most from the East Southeast district)

27 Pest Management & Crop Development Bulletin • No. 3 / April 8, 2005

progressive corn planting is on the westernmost side of the state.

Wheat is greening up and tillering well. Mike Roegge, crops educator in the Adam/Brown Unit, caught his first black cutworm moth on Monday. Anhydrous ammonia is in short supply at some terminals. On the western side of the state, trucks are waiting up to 4 hours to load. However, most produc- ers have most, if not all, NH3 applied. Contributing Authors Kelly Cook ([email protected]), Ex- tension Entomology, (217)333-6651 Aaron Hager ([email protected]), Ex- tension Weed Science, (217)333-4424

Emerson D. Nafziger ([email protected]), Crop Sciences, (217)333-4424 Dawn Nordby ([email protected]), Extension Weed Science, (217)333- 4424 Kevin Steffey ([email protected]), Extension Entomology, (217)333-6652

28 Pest Management & Crop Development Bulletin • No. 3 / April 8, 2005 Helping you put knowledge to work.

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