2015
Enhancing soybean yield through strategic use of seed treatments for seedling disease and insect pest management
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Contributor/Checkoff:
Iowa Soybean Association
Category:
Sustainable Production
Keywords:
Crop protectionDiseaseField management
Parent Project:
Enhancing soybean yield through strategic use of seed treatments for seedling disease and insect pest management
Lead Principal Investigator:
Alison Robertson, Iowa State University
Co-Principal Investigators:
Erin Hodgson, Iowa State University
Gary Munkvold, Iowa State University
Gregory Tylka, Iowa State University
+2 More
Project Code:
Contributing Organization (Checkoff):
Iowa Soybean Association
(n/a)
Institution Funded:
Iowa State University
(n/a)
Brief Project Summary:

The use of seed treatments on soybean has increased dramatically within the past decade. Considerable interest exists in the value of neonicotinoids as seed treatments in soybean, a crop which pollinators can use as forage. Plus, several new products have become available. This project evaluates commercial seed treatments in small plot trials and in fields. Work compares the effect of commercial seed treatments on seedling disease, soybean cyst nematode, insect pests and yield potential and evaluates fungicide sensitivity of pathogens recovered from diseased soybean seedlings and baseline fungicide sensitivity for Pythium, Fusarium and Rhizoctonia species to new commercial fungicides.

Key Benefactors:
farmers, agronomists, Extension agents

Information And Results
Project Deliverables

• Evaluated 13 commercial seed treatments in small plot trials at each of 3 locations in Iowa.
• Collected the following data: emergence, stand count, seedling disease incidence, sudden death syndrome (SDS) index, SCN egg counts, and insect counts.
• Conducted 37 field trials in collaboration with the ISA On-Farm Network: 7 evaluating ethaboxam for seedling disease management; 13 evaluating Clariva for SCN management; 17 evaluating ILeVO for SDS management. Yield data were also collected for all trials
• Recovered isolates of Pythium and Fusarium from small plot trials to be evaluated for fungicide sensitivity.
• 4 extension publications, 5 national webinars, 6 media interviews and 18 presentations were given to over 3700 stakeholders from Iowa and beyond.

Final Project Results

All data from small plot and on-farm strip trials for this period are currently being analyzed.

The sensitivity of Fusarium populations from soybean to the commonly used seed treatment fungicides fludioxonil, ipconazole, pyraclostrobin, and trifloxystrobin was evaluated. Fungicide formulations were incorporated into potato dextrose agar at a range of concentrations (0.01 to 100 µg/ml). Radial growth and spore germination were visually assessed and measured for representative isolates of F. graminearum, F. oxysporum, F. solani, and F. acuminatum from Iowa and surrounding states. These data were compared to results obtained using image analysis software. Mycelial growth inhibition differed significantly among the fungicides and among Fusarium species and strains. Fludioxonil had a stronger effect than ipconazole on radial growth of F. graminearum; in contrast, ipconazole strongly inhibited mycelial growth of F. oxysporum, F. acuminatum and F. solani. Spore germination was strongly affected by both trifloxystrobin and pyraclostrobin. EC50 frequency distributions were generated for each combination of species and fungicide; this information will be valuable for tracking potential future changes in sensitivity.

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.