2016
Effects of Drought, Flooding, and Insect Herbivory across Soybean Varities
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Contributor/Checkoff:
Indiana Soybean Alliance
Category:
Sustainable Production
Keywords:
Biotic stressCrop protectionField management Pest
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Punya Nachappa, Indiana University
Co-Principal Investigators:
Project Code:
Contributing Organization (Checkoff):
Indiana Soybean Alliance
(n/a)
Institution Funded:
Purdue University
(n/a)
Brief Project Summary:

Environmental stresses such as drought and flooding are among the most important factors that severely limit soybean productivity. Yield losses during extreme weather conditions can result from several factors including pests and disease outbreaks. Indiana farmers need to know what needs to be done, when growers should scout for pests, what are plant injury signs and how it can be managed. This research investigates the effects of drought, flooding, and insect feeding on plant growth and yield.

Key Benefactors:
farmers, agronomists, ag retailers, Extension specialists

Information And Results
Project Deliverables

results will be published and distributed appropriately

Final Project Results

Update:
refer to final report

I investigated the interaction between water stress and neonicotinoid seed treatments on soybean pests. Specifically, we determined whether drought and flooding affects the efficacy of CruiserMaxx in reducing early-season soybean pests, aphids and thrips.

Experimental design
There were 3 water stress treatments: 1)drought, 2)flooding, 3)well-watered or control and 3 soybean genotypes: 1)CruiserMaxx, 2)ApronMaxx, 3)untreated seeds, AG3334.
All plants were in the V4-V5 stage and the experiments were conducted in the greenhouse at the Indiana University-Purdue University campus in Fort Wayne (IPFW).

Outcomes/Impacts
Since the last quarterly report, we have completed three replications of the experiment with soybean aphids. Our results suggest that drought stress reduces the efficacy of CruiserMaxx . In contrast, efficacy of CrusierMaxx was not reduced during flooded conditions. We believe that drought-stressed plants will have a decreased turgor pressure and water content, which may reduce the uptake of insecticide into the plant cells. Thereby, allowing increased populations of soybean aphids on these plants. In plants that are under flooded conditions, the insecticides is present in the constant pool of water, allowing the plants to continually uptake the chemical into plant cells which reduces the aphid populations.

Experiments are underway in our greenhouse to determine the interaction between water stress and neonicotinoid seed treatments on thrips. We hope to complete three replications similar to the aphid experiment by the end of the year. Finally, we would like to analyze plant tissues which have been collected from each treatment to determine the amount of active ingredient (neonicotinoid chemical) in plants after exposure to water stress.

Our results provide new information to soybean growers about the effects of soil moisture on efficacy of seed treatment in controlling early-season soybean pests. For instance, drought stress has shown to increase populations of several insect pests including aphids and given the reduced efficacy of CruiserMaxx during drought growers may want to consider additional control options.

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.