Foliar and stem diseases have been problematic in Indiana soybean fields in recent years and wet conditions during the 2018 season led to increased problems with pod and seed quality. Successful disease management first starts with proper identification of the disease and then using variety resistance when available. Foliar fungicides can provide good disease control if targeted properly for each specific disease.

A number of factors can contribute to reduced fungicide effectiveness and loss of disease control and include:
1) Inaccurate diagnosis and fungicide selection;
2) Applying at an improper rate, coverage, or timing;
3) Environmental conditions; and
4) Resistance development and weak mode of action on pathogen population.

Frogeye leaf spot resistance to QoI fungicides has been reported in four counties in Indiana (Zhang et al., 2018). In order to prescribe proper management options for farmers it is important to determine the distribution of fungicide resistance in Indiana. We propose two objectives that will proactively continue research on gaining a better understanding of soybean disease distribution and management in Indiana: 1) Continue to document and confirm the distribution of soybean foliar diseases and fungicide resistance, and 2) Field evaluation of integrated management options for soybean foliar disease in Indiana. The ultimate goal of this research is to understand the distribution of foliar and stem diseases and fungicide resistance in Indiana and then identify new options that may improve foliar disease control, yield, and seed quality. These results will be used to provide unbiased information to Indiana farmers about when and where fungicide treatments will improve disease control and seed quality.

Objective 1: Continue to identify, document, and confirm the distribution of foliar diseases of soybean (frogeye, Cercospora blight, Septoria brown spot, and/or other disease issues that may be detected) and evaluate these populations for baseline sensitivities and/or development of fungicide resistance.

Objective 2: Evaluate fungicide efficacy and timing for management of foliar disease in soybean.

Communication of objective: Research results will be used to develop Extension materials, including written factsheets and videos. These will be distributed to Indiana farmers through the weekly Pest & Crop newsletter, social media platforms, the Purdue Field Crop Pathology website, and made available to ISA for their website and distribution. Results will also be presented to Indiana farmers, agribusiness, and other soybean stakeholders at meetings and field days during the summer of 2019 and winter of 2020. These meetings target a wide range of clientele from agribusiness personnel to individual farmers at county-level meetings. Summaries of results and seasonal updates will be integrated into new and existing resources that provide the most current and updated management recommendations to farmers in Indiana.