EFFECT OF FUNGICIDES ON LATE BLIGHT AND YIELD OF POTATO IN THE WEST PROVINCE OF CAMEROON

Field trials were conducted at the university farms in Dschang and Bansoa in 1990 to assess the effect of five fungicides on the development of late blight and on tuber yields of a local potato cultivar Tezelfeu.
Treatment plots (3.2 x 4.5 m) were randomized in three complete blocks.
Fungicide treatments were made at recommended rates and intervals using a knapsack sprayer mounted with a single flat fan nozzle.
Disease severity was scored weekly using the Horsfall-Barratt scale.
Disease-progress curves were better described by the logistic model (R² = 92–98%) than the Gompertz (R² = 57–84%).

Fungicide sprays significantly reduced epidemic rates and areas under disease-progress curves.
Average total yields of tubers in sprayed plots increased by 37–96% in Dschang and 33–100% in Bansoa, while marketable yields increased by 37–111% and 44–119% in Dschang and Bansoa, respectively.
In Bansoa, the highest yields were obtained from plots treated with mancozeb (Mancozan® 70WP, 23 032 kg/ha), followed by maneb (Manessan® 80WP, 21 240 kg/ha), metalaxyl + copper oxide (Ridomil Plus® 72WP, 20 366 kg/ha), cupric hydroxide (Kocide® 101 77WP, 20 037 kg/ha), fosetyl-Al (Aliette® 80WP, 15 365 kg/ha), and the nonsprayed check (11 541 kg/ha). Yields recorded in Bansoa were consistently higher than those obtained in Dschang.

Symposium on Tropical Root Crops in a Developping Economy

D.A. Fontem, B. A. Aighewi

https://doi.org/10.17660/ActaHortic.1994.380.77