Evaluation of the Effect of Different Fungicides on Potato Brown Leaf Spot Alternaria alternata in Greenhouse

Abstract

One of the successful strategies to increase the yield of potatoes is the management of diseases and pests during the whole growing period. Potato brown spot caused by Alternaria alternata (Fr) Keissler is one of the most destructive diseases of potatoes worldwide. The present study compared two different fungicide programs under greenhouse conditions during 2022. Firstly, the resistance of five local potato varieties (Lora, Kofre-hemaloni, Kofre-Gibson, Evalovetion, and Morabell) was evaluated under greenhouse conditions to the pathogen to find the most susceptible variety for further experiment. The degree of infection by the pathogen was calculated. The study demonstrated that the Lora variety had the most tolerance, and the Morabell variety was sensitive to the pathogen. Then, the effects of three common chemical fungicides (Mancozeb®80%, Penconazole®20%, and Topguard®30% (Flutriafol (6.94% + tebuconazole (20.8%) were tested against the pathogen using the most sensitive potato variety (Morabell) in CRD (Completely Randomized Design) under greenhouse condition. The means of infection was calculated over ten days. Specific doses of the fungicides had a significant effect in reducing disease. The severity of the disease decreased with the increased use of all the applied fungicides. The study revealed that Mancozeb and Penconazole with 1g per liter doses were the most effective treatment in controlling brown leaf spots in potatoes