Purpose: My research lab has the nation’s largest soybean aphid efficacy evaluation program, and has mainly focused on foliar insecticide performance. I have access to new products or improved formulations before they are commercially available, and farmers can see performance data of new products compared to standard insecticides. I want to grow my program beyond foliar insecticides with additional management tools like host plant resistance. My research is novel in that I 1) use replicated plots to compare seed- and foliar-applied insecticides, 2) collect intense data on soybean aphid seasonal exposure, and 3) present unbiased data from multiple industry companies.

Proposed work: During the summers of 2021-2023, experimental plots will be used to evaluate insect management tactics, like seed treatments and foliar insecticides (see previous reports here: www.ent.iastate.edu/soybeanresearch/content/extension). These tactics will be evaluated alone and in combination to determine optimum yield protection. Plots will be established at high-risk locations in Iowa each summer.

1) Soybean aphid. At one location, 20-30 treatments will be replicated four times in a randomized complete block design using a 30" row spacing. Treatments will include a range of insecticidal groups and application sites. Aphid population dynamics will be monitored weekly in addition to secondary pest activity (e.g., beetles, mites, stink bugs, caterpillars, etc.). Foliar applications will be based on our established treatment threshold for soybean aphid. At the end of each season, yield will be collected and compared to cumulative aphid days for each treatment.
2) Soybean gall midge. At two locations, 20-30 treatments will be replicated four times in a randomized complete block design using a 30" row spacing. Midge larval will be monitored weekly in addition to secondary pest activity (e.g., soybean aphid, beetles, mites, stink bugs, etc.). A combination of seed-applied and foliar treatments will be evaluated. Foliar applications will be based on our observation of overwintering adult emergence (See 2a). At this point, that is our “best guess” for targeting adult movement into soybean. At the end of each season, yield will be collected and compared to insect activity for each treatment.
a. Adult emergence cages. To help determine spray recommendations, we will use “Illinois style” soil emergence cages in currently planted cornfields to collect adult soybean gall midges. During the summer, cages will be moved to currently growing soybean to help refine life table characteristics (life cycle duration, emergence duration, etc.).
b. Injury-severity model. As with corn rootworm, we plan to create a 0-3 plant injury scale for soybean gall midge and develop a model for yield loss prediction (Tinsley et al. 2012). The injury scale and model will help farmers and crop consultants better estimate larval infestations and expected yield loss in future growing seasons. The data collected from this proposed project will directly feed into validating the scale with the model. Preliminary data from 2019 is shown in Figure 1.
Communications and outreach strategies: I have a 70% field crops extension appointment at Iowa State University (ISU). Throughout the project, I will actively participate in extension programs that summarize efficacy data and promote sustainable soybean pest management. Field day demonstrations and winter programs will be coordinated with ISU Extension and Outreach, Iowa Soybean Association, industry partners, and other organizations. Potential ISU Extension and Outreach programs include: Integrated Crop Management Conference, Crop Advantage Series, and the numerous field day demonstrations with ISU. Participants will largely be farmers, but will also include crop consultants, agricultural professionals and other ISU personnel. In addition, I will publish annual research findings in a Yellow Book (www.ent.iastate.edu/soybeanresearch/content/extension). As a way to deliver real-time updates on soybean pests in the summer, I will continue posting informal articles to ICM Blog and contributing articles to ICM News.