Impact of Introduced Tomato Cultivars and Chemical Fungicides on the Occurrence and Intensity of Late Blight in Western Cameroon

Abstract

Late blight, caused by Phytophthora infestans, is the main constraint to tomato production and exportation in Cameroon. The objective of this study was to evaluate the impact of chemical and tomato varieties in the control of tomato Late blight in the field for the improvement of tomato production in the west region of Cameroon. Seedlings of 7 tomato varieties produced in the nursery were transplanted into pits each containing 100 g of fowl droppings and 30 g of the nematicide Carbofuran 5%. From the 21st day after transplanting, the different fungicides were applied every four days. Data were collected on the incidence, severity of the disease at different stages of plant growth and development and on yields. The results showed that the AVTO1219 and AVTO1311 varieties were less sensitive to Late blight. The control plants of AVTO1219 variety showed incidences of 7.7, 11.7 and 16.7% and severities of 1.7, 14.9 and 17.2% in the vegetative, flowering and fruiting phases respectively. Control plants of CLN1462A, CLN1464A, CLN1464B, RIOGRANDE 2 and RIOGRANDE + varieties showed incidence of 100% from the flowering phase. Control plants of varieties AVTO1213 (17.29 t ha-1) and AVTO1311 (11.33 t ha-1) produced the highest yields. Bonsoin was the more effective fungicide and AVTO1311 was the more effective variety to manage disease. However, the combination of Bonsoin with the AVTO1219 and AVTO1311 varieties was most effective in controlling late blight of tomatoes in the field. These results suggest that to improve tomato production, Late blight resistant varieties should be used and effective fungicides applied as treatments.