Life Sciences Commons^™

Fungicide Resistance: Surveillance, Risk Assessment And Evolution In Two Soil-Borne Pathogens, Nikita Gambhir

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Fungicide-resistant pathogens are an increasing threat to fungicide efficacy and plant health. The goal of this dissertation was to advance the foundational knowledge required to prevent and detect fungicide resistance development in the seedling disease pathogen, Rhizoctonia zeae and the white-mold pathogen, Sclerotinia sclerotiorum. Corn and soybean fields in 12 states (IA, IL, IN, KS, KY, MI, MN, MO, ND, NE, SD, and WI) were surveyed for R. zeae. In vitro fungicide sensitivity was determined for 91 isolates to fludioxonil, sedaxane, and/or prothioconazole. Rhizoctonia zeae was sensitive to all fungicides (EC₅₀ < 3 µg/ml) except azoxystrobin (EC₅₀ > 100 µg/ml). In planta application of …