INTENSITIES OF POTATO LATE BLIGHT (Phytophthora infestans (Mont) de Bary) AND ITS ASSOCIATION WITH BIOPHYSICAL FACTORS IN MAJOR POTATO PRODUCTION DISTRICTS OF AWI ZONE, NORTHWESTERN ETHIOPIA

Abstract

Potato is an important food security crop. It is highly attacked by pathogenic fungi, Phytophthora infestans, which results in severe yield loss under favorable conditions. A survey of potato late blight disease was carried out in Fagita Lekoma and Banja districts of Awi Zone, Northwestern Ethiopia, to quantify the prevalence and intensities of late blight during the 2019 main cropping season. A semi-structured questionnaire was developed, and potato growers were interviewed. A total of 60 farmer fields were assessed, and a logistic regression model was used to analyze the associations of biophysical factors with late blight intensities. The result indicated that late blight of potato was prevalent in all farmer fields with varying incidence and severity. The mean maximum and minimum disease incidence (100% and 96%), and percent severity index (PSI) (87.50 and 66.66%) were recorded in Banja and Fagita Lekoma district, respectively. Fields with improved variety, fungicide-sprayed fields, altitude <2300 masl, previous crops planted with wheat, intercropping, vegetative growth stage of crop, and May planting reduced mean disease incidence and severity in the surveyed districts. The reduced variable model revealed that lower (<40%) late blight severity was associated with May-planted fields, previous crops with wheat and maize, and intercropping fields. Use of improved/resistant potato varieties, intercropping with cereal crops, potato rotation with non-host crops, early planting, and spraying novel fungicides reduced late blight intensities and could be used for the management of late blight. Further studies are needed on the late blight of potato in different agroecologies.