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Corn Rootworm Situation in 2004

Corn Rootworm Situation in 2004. Distance Education Workshop February 4 and 11, 2005. Mike Gray and Kevin Steffey Department of Crop Sciences University of Illinois. Corn Rootworm Management Issues Illinois, 2004. Severe rootworm larval damage (northern half of Illinois)

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Corn Rootworm Situation in 2004

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  1. Corn Rootworm Situationin 2004 Distance Education Workshop February 4 and 11, 2005 Mike Gray and Kevin Steffey Department of Crop Sciences University of Illinois

  2. Corn Rootworm Management IssuesIllinois, 2004 • Severe rootworm larval damage(northern half of Illinois) • JuneReports of poor performance of granular and liquid insecticides, insecticidal seed treatments • July, AugustCorn rootworm control trials; numerous reports of lodging; reports of greater-than-expected damage in YieldGard Rootworm corn • More widespread distribution of variant western corn rootworm—distribution extended west and south

  3. Corn Rootworm Management IssuesIllinois, 2004 • Performance issues with corn rootworm control products • Granules, liquids, seed treatments • Planting time (~80% of corn planted in IL by 4/30/04) • Windy conditions during planting • Soil conditions • Application and incorporation • YieldGard Rootworm Corn • Low dose • Planting time (declining expression of Bt) • Hybrid and environmental interactions

  4. Survey for CRW larval injury Corn after soybeans 2004 1.18 1.91 1.6 2.12 1.44 2.74 1.9 1.9 1.91 2.86 2.02 2.0 1.84 Numbers are average root ratings: 10 fields per county 5 roots per field 2.0 2.06 2.04 1.64 1.82 1.8 1.98 1.97 2.0 1.9 1.74 Orange = confirmed variant WCR Yellow = “fringe”

  5. Corn Rootworms:Lessons (re)learned in 2004 • No corn rootworm control product is “bulletproof.” • Despite our best expectations, environmental conditions can affect the performance of any rootworm-control product. • Some products do not perform well when corn rootworm larval pressure is heavy. • Accurate granular insecticide application and incorporation is particularly important in early planted fields.

  6. Overheard “solutions” to CRW problems • Control adults in soybeans, use rootworm control product in corn the following year • Low-rate insecticidal seed treatment + soil insecticide • YieldGard Rootworm corn + soil insecticide • Control adults in soybeans +YieldGard Rootworm corn following year +High-rate insecticidal seed treatment

  7. Corn Rootworm Situation 2004 Indiana Larry Bledsoe Purdue University

  8. Western Corn Rootworm Hatch

  9. Exceptionally wet during egg hatch and initial larval feeding period

  10. Western Corn Rootworm Adults

  11. Statewide WCRW Survey Late July-Early August About 70 of 92 Counties 1-3 Fields Per County 5 X 20 Sweeps/Field

  12. Western Corn Rootworm Sweep Net Surveys in Soybean (#/100 Sweeps) 1997 1998 1999 2000 2001 2002 2003 2004

  13. 2004 Western Corn Rootworm Sweep Net Survey in Soybean (#/100 Sweeps)

  14. Perceived First-Year Corn Rootworm Risk Areas

  15. Western Corn Rootworm - Variant • Management strategies: • recognize high risk areas • be observant of damage in unconfirmed areas • monitor for WCRW beetles in soybean fields • rootworm soil insecticides, treated seed, and Bt RW

  16. Western Corn Rootworm In Indiana 2004 Questions?

  17. Corn Rootworm Situation in Iowa. 2004 Dr. Jon Tollefson Professor of Entomology Iowa State University

  18. Corn Rootworm Situation in IA • 2004 • weather • corn rootworm phenology • rotation-resistant western corn rootworm • extended diapause northern corn rootworm • insecticide performance

  19. Flooding in June

  20. Flooded Corn; Drowned Larvae?

  21. Adult Corn Rootworm Emergence, 2004 July August Sept.

  22. Rotation-Resistant Western in IA? Durant ☻

  23. Corn Rootworm Situation in IA • 2004 • weather • corn rootworm phenology • rotation-resistant western corn rootworm • extended diapause northern corn rootworm • insecticide performance

  24. Corn Rootworm Situation in Minnesota Ken Ostlie Department of Entomology - University of Minnesota ostli001@umn.edu (612) 624-7436 office (612) 750-0993 cell

  25. Corn Rootworms in Minnesota • WCR reach the northern edge of their distribution in MN, SD and ND. WCR most common in areas with higher incidence of corn following corn (e.g., SE MN). • NCR distributed statewide, but are most common in areas with rotated corn. NCR also exhibit S →N gradient. • Severe, open winters have only slight impacts on NCR, but routinely knock back WCR populations. NCR typically comprise 90% or more of the corn rootworms in MN. • 2003-4 winter was fairly severe and open until late January • Heavy, repeated rains and cool weather dominated early summer. • The MDA Plant Pest Survey Program conducts an annual survey of corn rootworms (3 continuous and 3 rotated fields per county) in corn during the first two weeks of August.

  26. What Happened with Corn Rootworms in 2004? • Corn rootworm survival was better than expected, perhaps due to deeper egg laying during the drought of 2003. • Widespread insecticide use in soybean for soybean aphid potentially reduced corn rootworm populations foraging in soybean. • Early season rainfall favored shallow root systems and enhanced leaching of insecticides. • Later-season thunderstorms were common leading to greater lodging problems than observed in drought of 2003.

  27. Corn Rootworm Dynamics:Continuous Corn in SE MinnesotaData supplied by MDA – Plant Pest Survey Program Mild Winters Favor WCR

  28. Corn Rootworm Dynamics:Relative Species SuccessData supplied by MDA – Plant Pest Survey Program Mild Winters Severe Winters ?

  29. Western Corn Rootworm: Abundance and Distribution in MN - 2004 WCR populations declined dramatically from 2002-3 levels. Probably reflects winter mortality and heavy early-season rains.

  30. Crop Rotation and Extended Diapause: A Minnesota Problem Since Late 1970s 2-Crop Rotation 3-Crop Rotation Jim Boersma Picture taken south of Olivia Minnesota 2002

  31. NCR Exhibit Similar Patterns Regardless of Crop Rotation Map supplied by MDA - Plant Pest Survey Program

  32. Comparative Population Dynamics of Rootworms and Soybean Pests, 2003Ostlie – Rosemount, MN Timing of Insecticide Application

  33. Risk Management of Corn Rootworms is Becoming More Complicated Western corn rootworms have lost their fidelity to corn and now lay eggs in other crops. Northern corn rootwormshave extended their overwintering diapause to 2 or even 3 years. Different Strategies to Succeed in Rotated Corn!

  34. Rootworm Situationin Nebraska, 2004 Lance J. Meinke Robert Wright University of Nebraska

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