Sensitivity of Leaf Spot Causing Pathogen of Bitter Gourd (Cercospora citrulline Cooke) To Different Fungicides

Abstract

Cercospora leaf spot disease caused by Cercospora citrullina Cooke is one of the most important diseases of bitter gourd. Effective fungicide against the causal pathogen has not been reported. This study was conducted at the Plant Pathology Laboratory of the Crop Protection Cluster, College of Agriculture, University of the Philippines Los Baños, College, Laguna to (a) determine the sensitivity of C. citrullina Cooke to different fungicides, and (b) determine the most effective fungicide against C. citrullina. Four fungicides, namely, benomyl (0.63 g a.i. L^-1) chlorothalonil (1.41 g a.i. L^-1), copper oxychloride (0.63 g a.i. L^-1) and mancozeb (3 g a.i. L^-1) were tested against the pathogen. Under laboratory condition, all conidia of C. citrulline did not germinate when treated with the test fungicides. Under screenhouse condition, the fungicides also effectively suppressed the development of the disease owing to low number and non-increasing of lesions in the leaves of bitter gourd. All test fungicides were very effective against leaf spot disease causing pathogen of bitter gourd.