White mold can be a significant limit to soybean production in Michigan. Although loses to white mold are worse in some years than others, there is always a part of the state that is affected by this disease. The purpose of these trials is to improve our understanding of when ascospores of the white mold fungus are released, so that we can improve fungicide or biological application timing.

Foliar fungicides can form part of an integrated management plan for white mold. However, selection of products with proven efficacy and appropriate timings are essential to maximize disease control and return on the foliar fungicide investment. In this proposal, we will determine the efficacy of foliar fungicides and biologicals for control of white mold and their impact on soybean yields. Foliar fungicides are being used more frequently for field crops, even in the absence of disease. Our trials will also examine the role of foliar fungicides on yield in the absence of significant disease pressure.
We will screen promising soybean germplasm for the University of Wisconsin and will facilitate the screening of Dr. Dechun Wang’s soybean germplasm.

1. Study of white mold epidemiology for improved management:
The main objective of this study will be to improve knowledge of the timing for apothecia development and ascospores release in order to develop a predictive model and to determine optimal timing of fungicide application. The specific objectives are:
• Determine the relationship between the apothecia germination and ascospores release and environmental variables (temperature and leaf wetness duration).
• Validate and improve Sporecaster a weather-based predictive model to improve soybean white mold understanding, forecasting and management.
Weather stations will be placed in soybean plots at the Montcalm research station, to determine the timing of spore release and the corresponding environmental conditions. We will also sample plants and take notes on plant stage development and flowering period to determine when plants are becoming infected.

2. Evaluate foliar fungicide and biological products and application timing for improved white mold management:
Establish a trial in collaboration with Dr. Erin Burns to examine the impact of Atrazine and Contans (separately) on the development of white mold.
Foliar fungicides and timings will be evaluated to determine optimal product and application timing, relative to crop development.
Investigate the profitability of foliar fungicides in the absence of disease
Fungicide efficacy and profitability trials will be conducted at locations without known white mold pressure, to determine the profitability of foliar fungicides in the absence of disease.

3. Screening of soybean germplasm for white mold resistance:
We will screen germplasm for University of Wisconsin-Madison and assist Dr. Wang’s lab in the set up and screening of germplasm for white mold resistance.

4. Provide white mold management education to growers and CCA’s:
Information collected regarding timing and conditions of spore release and plant infection and optimized fungicide timing will be shared with state of Michigan growers and colleagues in the Midwest, to improve management of white mold. Dr. Damon Smith from the University of Wisconsin and I have been exchanging information and are establishing a collaboration to maximize our research efforts on white mold management. Data from these studies will be used to update regional extension publications.

Research results will be distributed through field days, and extension meetings. A multi-state extension bulletin will be produced and made available through the Crop Protection Network www.cropprotectionnetwork.org and articles will be created for Michigan Soybean News and MSUE News for Ag. You-tube video’s will also be created to report results, and social media such as Twitter and Facebook will be used to relay take home messages to the Michigan agricultural community. Fungicide efficacy data is translated into national fungicide efficacy charts.