Statewide survey of Quinone Outside Inhibitor (QoI) fungicide resistant populations of frogeye leaf spot (Cercopsora sojina) in Indiana 

Darcy Telenko, Extension Field Crop Pathologist


By Kaitlin Waibel

Quinone outside Inhibitor (QoI) fungicides are effective against a wide range of pathogens on many crop species including C. Sojina in soybeans. QoI fungicides are at high risk of developing resistance. Frogeye leaf spot has become a key disease in the Midwest as a consequence of warmer winter temperatures, usage of susceptible soybean varieties, and reduced tillage. Populations of frogeye leaf spot resistant to quinone outside inhibitor (QoI) fungicides have been confirmed in Indiana by (Zhang et al. 2018) and (Pineros Guerrero, 2021). Continued surveys in Indiana are need to alert farmers to the widespread resistance risk and encourage responsible integrated pest management and effective disease management decisions. 

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