Timeline: projected research and extension activities will be the same:
• Winter: present lectures at meetings.
• Spring: hire undergraduate student; treat seeds; purchase field and spray equipment; establish plots; plant seed; and present at summer meetings.
• Summer: collect agronomic and pest-related data; and apply foliar treatments.
• Fall: harvest plots; and write summary reports (e.g., Yellow Book and AMT).

Expected Outputs: Data collected every summer will become publically available:
• Yellow Book for Soybean Insects is free and available electronically at my lab website.
• Arthropod Management Tests publication will be generated annually. These publications are nationally recognized for insecticide efficacy evaluations and available to Entomological Society of America members.
• Regular updates about soybean aphid and other pests are available throughout the year through ICM News, ICM Blog, and podcasts.

Update:
Spring planting conditions throughout Iowa were first cold and wet, and most soybean fields were planted later to accommodate corn planting. Then May was warmer than normal and June turned exceptionally wet throughout most of Iowa. Population fluctuations between locations and years is typical soybean aphid dynamics for Iowa. Soybean aphids arrived on soybean in July, slightly behind average infestation dates. Soybean aphid colonization was initially patchy and continued to grow at a slow pace, likely due to hot evenings providing little relief to adults. Some commercial fields experienced exponential growth of soybean aphid after bloom, especially in northern Iowa. However, few fields in northwestern and northcentral counties had soybean aphid exceed the economic threshold. Some populations did persist until after seed set (R5–R6), but very quickly crashed at most locations by mid-September. When applications had sufficient coverage and applied at the labeled rate, efficacy for soybean was good (i.e., >95% knockdown within three days after application) throughout most of Iowa.

In addition to soybean aphid, Japanese beetle, bean leaf beetle and soybean gall midge were prevalent in some Iowa soybean fields. We conducted a “on the fly” efficacy evaluation at the ISU Johnson Research Farm and hope to have yield data summarized for the next reporting cycle.

I was able to complete proposed work, including research and extension related to soybean aphid management. I established a foliar insecticide efficacy evaluation at two locations in 2018 (northwest and northeast Iowa). I had 25+ treatments at each location. My extension efforts are summarized here:

View uploaded report

View uploaded report 2

Treatment Recommendations. Population fluctuations between locations and years is typical soybean aphid dynamics for Iowa. Our recommendation for soybean aphid management in Iowa is to:

• Strongly consider using host plant resistance if soybean aphid populations are persistent and the seed agronomic traits are appropriate for the area. The use of a pyramided gene will result in lower CAD and reduce the need for foliar insecticides.

• Plant early if the field is in an area with persistent soybean aphid populations.

• Scout for soybean aphid, especially during R1–R5, and use a foliar insecticide if aphids exceed the economic threshold of 250 per plant.

• Use a product labeled for soybean aphid; most well-timed applications of foliar insecticides will provide yield protection if applied at the economic threshold and coverage is sufficient.

• Evaluate foliar insecticide efficacy three days after application to ensure soybean aphid populations were sufficiently reduced.

• Understand that late-season accumulation of CAD (i.e., after R5) may not impact yield like it does in early reproductive growth; a foliar insecticide applied after seed set may not be an economically profitable choice.