Tropicultura (Jan 1992)
Efficacy of fungicides on the progress of early blight and yield of potato in Cameroon
Abstract
Five fungicides were evaluated during the 1990 and 1991 growing seasons in two locations in Cameroon for efficacy on the progress of early blight and yield of potato. Disease-progress curves fitted the logistic transformation better than the Gompertz. Fungicidal treatments reduced the rate of early blight progress and area under disease-progress curve (AUDPC). Early blight was more severe in the 1991 season and yields recorded in this season were lower than those in 1990. In both seasons, high yields were obtained in plots receiving six sprays maneb or mancozeb. Two sprays of Ridomil plus (12 % metalaxyl + 60 % cuprous oxide) and six of cupric hydroxide also produced appreciable yields, while fosetyl-AI (three sprays) provided the least yield increase. Yield losses in non-sprayed plots were estimated at 15.7-53.6 %. Yields were negatively correlated to AUDPC.
