1. Soybean Aphids in Iowa – Past and Present Marlin E. Rice Extension Entomologist Iowa State University

2. Acknowledgment Extension Field Specialists-Crops Brian Lang, Decorah (northeast Iowa) Todd Vagts, Carroll (west central Iowa)

3. Soybean Aphids in 2000 (year 1, confirmed counties)

4. Soybean Aphids in 2001 (year 2, movement west, sprayed fields) 145,000 acres sprayed aphids move into western Iowa

5. Soybean Aphids in 2002 (year 3, few aphids, few sprayed fields) research plots

6. Soybean aphids: an early warning in 2003 Aphids in NE Iowa June 16 = 10/plant June 22 = 100/plant June 30 = 315/plant July 6 = 640/plant July 14

7. Northwest IA, August, 2003 Warrior, 15 bushels Courtesy: Jeff Ashland, Great Lakes Co-op Untreated Treated 1 mile rows with same variety planted straight through

8. Hancock County, IA, August 14, 2003 1 pt. Lorsban, 18 bushels

9. Soybean Aphids in 2003 (year 4, outbreak, Iowa pilots spray 734K ac.)

10. Each day delay = 0.5 bushel

11. Each day delay = 0.6 bushel

12. The Des Moines Register August, 2003

13. Soybean & Corn Yields 2003 Iowa Ag Statistics, Annual Crop Summary Soybean 32 bushels/acre Down 16 bushels/acre from 2002 Reduction of 32 percent Lowest yields since 1993 flood Corn 157 bushels/acre Down 8 bushels/acre from 2002 Reduction of 4 percent Second highest average yield

14. Summary Economic damage 2 out of 4 years Yield losses greatest in late July & early August in 2003 “drought” may enhance aphid survival & yield impacts 2001 NE Iowa 2002 SW Iowa 2003 northern 2/3 Iowa Scouting is critical in 2004

15. Soybean Aphid Research in Iowa Marlin E. Rice Extension Entomologist Iowa State University

16. Acknowledgment Extension Field Specialist-Crops Brian Lang, Decorah Northeast Iowa Research Farm Ken Pecinovsky, Nashua

17. Approximate aphids per plant Soybean Aphid Populations, Decorah, Iowa, 2001 – 2003 Brian Lang, Iowa State University Extension 2003-1 2001-1 2002-2 2002-3 2003-2 2003-3 2002-1 X X X X X X X X X XX Year - Sites 2001 - 1 2002 - 1, 2, 3 2003 - 1, 2, 3 X = Peak in winged aphid activity.

18. 2001

19. Plot 1, Harvested Oct. 4 Plot 2, Harvested Sept. 28 Date of insecticide application Date of insecticide application. July 12 July 26July 12 & 26 July 12 July 26July 12 & 26 Insecticide ----------- bu./acre ----------------- ------------- bu./acre ----------------- Dimethoate 28 26 29 40 40 41 Pounce 28 27 32 42 41 50 Warrior 25 25 34 43 41 50 Average 27 26 32 42 41 47 Check 21 35 1112 Soybean Aphid Insecticide Trials 2001 Decorah, Iowa (Brian Lang, Iowa State University Extension)

20. Soybean Aphid Research Plots 2002 & 2003 Decorah Nashua

21. Soybean Aphid & Bean Leaf Beetle Insecticide Trial #1, Nashua Research Farm, 2003 (sprayed Aug 7, bean leaf beetle = 24 per 20 sweeps, highest soybean aphid = 214/leaflet Aug 25) Bushels/acre 8.5 bu.

22. Bushels/acre 7.0 bu. Soybean Aphid & Bean Leaf Beetle Insecticide Trial #2, Nashua Research Farm, 2003 (sprayed Aug 8, bean leaf beetle = 44 per 20 sweeps, highest soybean aphid = 69/leaflet Aug 18)

23. Aphids per plant Insecticides & Seed Treatments on Soybean Aphid Brian Lang, ISU Extension, Decorah, IA 2003 R1 R3 R5

24. Summary Several liquid insecticides provide good control of soybean aphids Seed treatments offer promise of early- season suppression of soybean aphids