Effectiveness of Selected Fungicides for Managing Phytophthora Blight ( Phytophthora capsici ) of Processing Pumpkin in Central Illinois, 2025

This study was conducted to evaluate the effectiveness of selected fungicides for managing Phytophthora capsici in processing pumpkin fields. The experimental field was naturally infested with P. capsici. Plots of 15 treatments were established on 15 May and harvested on 18 August 2025. Applications of fungicides, at 7-day intervals, began on 3 July and ended on 14 August. The incidence of infected vines and fruits in treated plots was significantly ( P = 0.05) lower than untreated plots. The highest number of marketable fruits (33.25 fruits/plot) and the highest fruit yield (57,194 lbs./acre) were in the plots treated with Orondis Ultra. The incidence of infected fruits was the lowest (0.83%) in the plots treated with Revus. The lowest marketable fruit number (4.25 fruits/plot) and the lowest fruit yield (6,535 lbs./acre) were in untreated plots. Overall, Orondis Ultra and Revus fungicides were more effective for managing Illinois isolates of P. capsici in processing pumpkin.