Project Details:

Title:
Improving soybean insect management

Parent Project: Improving soybean insect management
Checkoff Organization:Iowa Soybean Association
Categories:Insects and pests, Crop management systems
Organization Project Code:
Project Year:2014
Lead Principal Investigator:Erin Hodgson (Iowa State University)
Co-Principal Investigators:
Keywords: Integrated Pest Management, Outreach and Education, Soybean Educational Activities, Soybean Insect Studies

Contributing Organizations

Funding Institutions

Information and Results

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Project Summary

The goal of this research project is to protect soybean yields by optimizing productivity and improving pest management strategies. This project will evaluate existing and emerging insect suppression tactics, like insecticides and host plant resistance, to protect yield and develop a suitable management plan. Insecticides will be evaluated and research findings will be communicated to Iowa soybean growers as part of the Extension educational program.

Project Objectives

1. Evaluate existing and emerging insect suppression tactics, like insecticides and host plant resistance.
2. Communicate results to Iowa soybean growers as part of the Extension educational program.

Project Deliverables

Progress of Work

Update:
Small plots were planted at the Northeast Research Farm (Floyd County) on 19 June 2013 with the help of Kenneth Pecinovsky (Farm Manager). The plots measure 6 rows by 50 feet and were planted into a no-till field at 180,000 seeds per acre. Plots were also planted at the Northwest Research Farm (O'Brien County) on 19 June 2013 with the help of Chad Huffman and Joshua Sievers (Farm Managers). The plots are 6 rows by 45 feet and were planted at 178,000 seeds per acre into a field with standard tilling practices. Each location was planted using a randomized complete block design; there were 35 treatments at Nashua and 25 treatments at Sutherland.

Weekly aphid scouting started at both locations at the VC-V1 growth stages. Randomly selected plants within each plot were selected and the number of aphids on each plant was recorded. Soybean aphids began to appear in the plots during the third week of July at both research farms. Foliar treatments for evaluation were made on 23 August 2013 at the Northwest Research Farm; and were made on 13 August and 21 August 2013 at the Northeast Research Farm. Peak aphid densities in the control plots were reached on 15 September 2013 at an average of 491 aphids per plant at the Northwest Research Farm, and on 31 August 2013 at an average of 477 aphids per plant at the Northeast Research Farm. This late-season accumulation is not typical but somewhat expected due to late planting dates. Weekly scouting concluded two weeks after aphid densities reached their peak for each farm, at which point soybean aphids were in considerable decline.

Cumulative aphid days (CAD) were calculated for each treatment in order to measure seasonal aphid exposure. Overall, the Northwest Farm had greater aphid pressure than Northeast Farm throughout the 2013 growing season. There were significant differences between foliar treatments and yield. However, most products labeled for soybean aphid kept seasonal accumulation below the economic injury level and protected yield. The untreated control and seed treatment has significantly more CAD and yield reduction. Plots at the Northeast Farm were harvested in late October but yield data has not been received yet. The Rag1 treatment did accumulate significantly more aphids on it and did surpass the economic injury level at the Northwest Farm. However, adding a seed treatment or foliar insecticide did decrease CAD). Varieties containing the Rag1 gene did not yield as well as the susceptible variety, however adding a seed treatment to the Rag1 treatments did not necessarily improve yield.

Plots are being prepared for the 2014 growing season at Nashua and Sutherland.

Final Project Results

Weekly aphid scouting started at both locations at the VC-V1 growth stages. Randomly selected plants within each plot were selected and the number of aphids on each plant was recorded. Soybean aphids began to appear in the plots during the last week of June at the Northwest Research farm and during the third week of July at the Northeast Research Farm. Foliar treatments for evaluation were made on 14 August 2014 at the Northwest Research Farm; and were made on 22 August 2014 at the Northeast Research Farm. Peak aphid densities in the control plots were reached on 5 August 2014 at an average of 29 aphids per plant at the Northwest Research Farm, and on 19 August 2014 at an average of 305 aphids per plant at the Northeast Research Farm. Weekly scouting concluded three weeks after aphid densities reached their peak for each farm, at which point soybean aphids were in considerable decline.

Publications-Two publications in ”In Integrated Crop Management News”..

Presentations- Eight presentations at field events at the Field Extension Education Laboratory, Iowa State University, Ames, IA.

Benefit to Soybean Farmers

Performance Metrics

Project Years