2015
Determining soybean pest and pesticide interactions as a means to optimize soybean yield
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Contributor/Checkoff:
Iowa Soybean Association
Category:
Sustainable Production
Keywords:
Biotic stressCrop protectionField management Pest
Parent Project:
Evaluation plant pest interactions to optimize soybean yield
Lead Principal Investigator:
Erin Hodgson, Iowa State University
Co-Principal Investigators:
Aaron Gassmann, Iowa State University
Gregory Tylka, Iowa State University
+1 More
Project Code:
Contributing Organization (Checkoff):
Iowa Soybean Association
(n/a)
Institution Funded:
Iowa State University
(n/a)
Brief Project Summary:

With new seed treatment products and resistance in soybean varieties, research needs to evaluate how these tactics interact, effecting interaction of soybean aphids and soybean cyst nematodes on resistance and susceptible soybean varieties. It is also important to understand the effects of these management tactics on naturally occurring soil-borne organisms, which may play a critical role in keeping pest population densities in check. This project determines optimal yield potential using combinations of pest management tactics, evaluates interactions among host plant resistance, pesticides and pests to optimize yield, conducts greenhouse experiments to measure treatment effects on pest-killing pathogens and key soybean pests, and promotes optimal yield recommendations with multiple pest-suppression tactics.

Key Benefactors:
farmers, agronomists, Extension agents

Information And Results
Final Project Results

During the summers of 2013-2015, two field locations were established each year. Plots were set up in a randomized complete block design with eight replications, including four soybean varieties (susceptible, SBA resistant, SCN resistant, and SBA+SCN resistant), and three seed treatments (naked, ApronMaxx, Avicta Complete). Soybean aphid (SBA) populations were monitored during the summer and cumulative aphid days were estimated for each treatment. Soybean cyst nematode (SCN) eggs were sampled at planting and harvest.

Results of the 3-year study:
• SBA- and SCN-resistant varieties support lower populations of aphids (Fig. 1) and nematodes, respectively.
• SCN-resistant varieties yield higher than SCN-susceptible varieties (Fig. 2).
• Seed treatments did not consistently improve yields, even with SBA- and SCN-susceptible varieties (Fig. 2).

Conclusions of the 3-year study:
• SBA resistance (Rag genes) is an effective suppression tool and may reduce the reliance on foliar insecticides.
• SBA-resistant variety breeding needs to improve yield potential.
• SCN resistance (PI88788) reduces SCN populations and is an important consideration for variety selection.
• Using host plant resistance with seed treatments did not consistently produce higher yields.
• Prophylactic use of pesticidal seed treatments may not provide higher soybean yields, particularly on host plant resistance soybean varieties.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.