Heavy frogeye leaf spot pressure in soybeans

Much of the country is currently experiencing hot, humid weather, both of which are favorable conditions for frogeye leaf spot development. Whether resistant or non-resistant pathogens are common in your area, both can put a strain on your soybean yields.

Although more common in the South, strobilurin-resistant frogeye leaf spot has been confirmed in northern regions as well. Just this May, Iowa State University confirmed the presence of strobilurin-resistant frogeye leaf spot in IA soybean fields. Whether resistant or susceptible, the frogeye pathogen can be carried short distances by wind and requires sustained warm, humid conditions with heavy dews to germinate. If you’ve experienced these weather conditions recently, make sure you’re scouting fields for signs of frogeye leaf spot.

Purdue University Extension says infection can occur at any stage of soybean development, but the most common time for frogeye leaf spot infection is after flowering. Small, yellow lesions on leaves indicate early stages of infection. These lesions eventually grow to a diameter of about 1/4”. Although it’s less common, lesions also develop on the stems and pods of soybean plants. The more lesions that are present, the greater your yield loss will be, making it crucial to scout often and apply a fungicide as soon as symptoms are spotted.

If you have confirmed strobilurin-resistant frogeye leaf spot in your fields, we recommend Quadris Top® SBX fungicide. With 2 active ingredients, it has proven efficacy against strobilurin-resistant frogeye leaf spot, helping to preserve yield and ROI.

For susceptible frogeye leaf spot, we recommend Trivapro® fungicide, which provides preventive and curative disease activity against several yield-robbing diseases, including frogeye leaf spot and Septoria brown spot. As the hardest-working, longest lasting fungicide on the market, Trivapro will protect plant-health benefits and help produce fuller pods and higher yields.

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