Evaluation of mefenoxam and fludioxonil for control of Rhizoctonia solani, Pythium ultimum and Fusarium solani on cowpea

Abstract

Cowpea (Vigna unguiculata) is susceptible to pathogens such as Rhizoctonia solani, Pythium ultimum and Fusarium solani, which cause seedling diseases in cowpea and result in low yields. Three commercial synthetic fungicides containing mefenoxam 350 g ai L−1, mefenoxam 240 g ai L−1 and fludioxonil 100 g ai L−1, respectively, were evaluated against these pathogens on cowpea in the greenhouse following promising in vitro results. The fungicides were applied initially as a soil drench to seedling trays at planting and fortnightly as a drench according to the manufacturer's recommendations. All fungicides, except mefenoxam 350 g ai L⁻¹ in one trial, were able to reduce diseases caused by R. solani. With the exception of mefenoxam 350 g ai L−1 applied to medium inoculated with F. solani, all fungicides increased seedling emergence, and dry shoot and root mass of plants, and all fungicide treatments reduced disease of seedlings grown in medium inoculated with F. solani and P. ultimum. Although all three fungicides reduced the percentage of diseased seedlings, none gave complete control of the diseases caused by the three pathogens under the trial conditions.