Effect of Intercropping on Potato Late Blight, Phytophthora infestans (Mont.) de Bary Development and Potato Tuber Yield in Ethiopia

Abstract

The study assessed the effect of intercropping on potato late blight, Phytophthora infestans disease epidemiology and potato tuber yield. The experiment was conducted at two locations in Ethiopia. Potato Solanum tuberosum (L) was intercropped with garlic, Allium sativum (L), at the ratios of 1:1; 1:2; 1:3; 2:1 and 3:1 plant population. These treatments were compared with fungicide (Dithane M-45) sprayed and unsprayed monoculture potato plant with respect to disease development and potato tuber yield. An improved potato variety (Wechecha), CIP-392640.513 clone and local susceptible variety were used for the study. The experiment was conducted in two factorial randomized complete block design with three replications. The results prevailed that, all potato-garlic ratios exhibited superior performance when compared to the fungicide unsprayed treatment. Among the proportions, 75 % garlic with 25 % potato (3:1) intercropped plots showed significantly (p< 0.05) low disease development and high tuber yield. Moreover, at 3:1 combination of garlic to potato the land equivalent ratio (LER) was greater than 1 and the monetary values were high at both testing sites. Significant (p< 0.05) differences were also observed among potato varieties with regards to the disease development and tuber yield. The study also demonstrated that fungicide treatment provided significant low (p<0.05) disease development and higher potato tuber yield when compared to the untreated monoculture control treatment. The findings of this study suggested garlic as a potential intercropping plant for the management of potato late blight disease under Ethiopian condition.