Sclerotinia sclerotiorum: Yield Loss of Brassica carinata in the Southeastern United States and Effect of Fungicides and Light Wavelength.

Abstract

Sclerotinia sclerotiorum is a major pathogen of over 400 plant species around the world and is considered to be the biggest threat to the production of Brassica carinata in the southeastern United States. Brassica carinata is an oil seed crop commonly grown during the summer in parts of Canada and the midwestern United States. It is currently being investigated for suitability as a winter cash crop in the southeastern United States. The present work addressed several topics concerning S. sclerotiorum isolates from the southeastern United States. A study on the effect of light wavelength on carpogenic germination was inconclusive. A study on the effect of light wavelength on biomass accumulation indicated that light wavelength was inconclusive but indicated that photoperiod may be important. In the study on B. carinata production, no treatment had a significant effect on yield or disease incidence/severity. It should be noted that environmental conditions in the 2021/2022 growing season were severe and likely skewed the results of this study. Finally, several commercially available fungicides were tested for in vitro efficacy against S. sclerotiorum. Fungicides included Caramba (metconazole), Sphaerex (metconazole + prothioconazole), Endura (boscalid), and Quadris (azoxystrobin). Quadris’ inhibition was significantly lower than the inhibition of all other tested fungicides.