2014
Management and outreach for soybean insect and mite pests in South Dakota
Category:
Sustainable Production
Keywords:
Biotic stressCrop protectionField management Pest
Lead Principal Investigator:
Kelley Tilmon, South Dakota State University
Co-Principal Investigators:
Billy Fuller, South Dakota State University
Buyung Hadi, South Dakota State University
Louis Hesler, South Dakota State University
Guo-Liang Jiang, South Dakota State University
Ada Szczepaniec, South Dakota State University
+4 More
Project Code:
Contributing Organization (Checkoff):
Institution Funded:
Brief Project Summary:

Between existing expertise at SDSU and USDA-ARS, and the upcoming hire of a new entomology extension field specialist, we now possesses a critical mass of entomologists who can work together on a collaborative project focused entirely on soybean insect pests. This project encompasses a range of management-related objectives including experiments to assess the efficacy of seed treatments, foliar insecticides and miticides, and aphid-resistant varieties, on-farm pest surveys and monitoring for pest outbreaks; exploration for new aphid resistance genes; and the publication of outreach material to inform producers about soybean pests and their management. The ultimate goal of this work is to...

Unique Keywords:
#insect research, #insects and pests, #soybean aphid (sa), #soybean aphid - genetic resistance, #soybean educational activities, #spider mite
Information And Results
Final Project Results

Tilmon Objectives and Tilmon/Hesler Shared Objectives
• For the objective to examine the efficacy of insecticidal seed treatments for aphid control, the final FY14 South Dakota data were included in a multistate data analysis led by Dr. Christian Krupke at Purdue University, which is currently being prepared for publication. Dissemination of this project to producers has begun in the Soybean Aphid Management Webinar Series on the Plant Management Network: Management Using Neonicotinoid Treated Seed.
• In the resistant variety efficacy trial for advanced breeding lines of pyramided genes, South Dakota data was supplied to a multistate trial, which has been accepted for publication. We have used some of these results in FY14 extension presentation.
• For the objective to publish a new Japanese Beetle Extension Factsheet, we did not complete this objective. However, as of the 4th quarter, a first draft has been prepared, and extension material developed and delivered from it at field days. However, the final draft of the factsheet has not undergone final editing or distribution.

• In FY14, master’s student Phil Rozeboom conducted field and greenhouse experiments to determine the effects of a plant nutrient compound/fungicide (Milstop®)on soybean aphids. By the end of the project year, all data analysis was completed. Milstop decreased aphid populations on soybean plants over the season, with reductions ranging from 24 to 48%. Yield was 48% greater on Milstop treated than non-treated plants, although this difference was not statistically significant. However, aphid counts were generally lower and yield was greater on Warrior-treated plants than on Milstop-treated plants. The 2014 summer field study is currently underway and on schedule.
• In FY14, we concluded screening of soybean lines for aphid resistance sources MG I and II lines of domesticated and wild soybean. Overall, 14 lines showed strong resistance to soybean aphid. Four of the 14 resistant lines were found among 285 domesticated soybean germplasm entries screened, and 10 of 172 lines were from wild soybean. Follow-up tests are scheduled to confirm and characterize resistance in these 14 soybean lines. In addition, a follow-up test was completed that confirmed resistance in five wild soybean lines identified in FY 2013, and they are ready to be advanced.
• As reported previously, 350 soybean germplasm lines and 4 commercial Rag1 lines were planted in 2013 for field screening against soybean, but aphid populations in field plots were too low for meaningful evaluation in FY14.

Szczepaniec Objectives
• In the study on the interaction of neonicotinoid seed treatments and foliar insecticides on spider mites, low spider mite populations in FY14 precludes drawing definite conclusions on the effect of neonicotinoid seed treatments to encourage spider mite outbreaks. Our finding that mites were more prevalent in plots that received a combination of the seed and foliar applications of the neonicotinoid insecticides, however, suggests that the higher dose of these insecticides may increase spider mite numbers. Preliminary recommendations based on these limited data suggest that producers may want to refrain from using foliar neonicotinoid insecticides when measurable populations of spider mites are present on soybeans.
• In FY14 we ran a pilot greenhouse experiment examining how the interaction between drought stress and neonicotinoid seed treatments affect spider mite population. The results illustrate that when spider mites are present, their populations can be nearly 30% greater on neonicotinoid-treated plants (CruiserMaxx®) than on untreated plants. Because drought triggers increase in spider mite populations in the field, our preliminary greenhouse experiments suggest that in dry conditions fields exposed to neonicotinoid insecticides may suffer greater and more rapid growth in spider mite numbers. Further experiments to test if we can link the effects we see in the greenhouse to the field are necessary to confirm this conclusion.
• In the reporting year we published results of the twospotted spider mite pesticide efficacy trials: Soybean Pesticide Evaluation Report, Twospotted Spider Mite. This publication is geared for producers and includes an updated factsheet section on spider mite biology and management. Distribution of this publication to producers began in the 4th quarter.

Fuller Objectives
• In the 4th quarter we published the results of the soybean aphid pesticide efficacy trials conducted in the previous quarters: Soybean Pesticide Evaluation Report, Soybean Aphid 2011 and 2013. This publication is geared for producers and includes an updated factsheet section on soybean aphid biology and management. Distribution of this publication to producers began in the 4th quarter.
Hadi Objective
• This objective was completed during the second quarter, with the publication and printing of the 2014 South Dakota Pest Management Guide for Soybeans. In the remainder of the reporting year we made extensive efforts to distribute this book to producers, especially at extension events.

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.