Use of Trichoderma spp. for induced resistance against gummy stem blight of melon

Abstract

The objective of this study was to evaluate the efficiency of Trichoderma spp. on induced resistance to gummy stem blight disease in melon which is caused by Didymella bryoniae (Auersw.) Rehm. Fifteen Trichoderma spp. isolates: T1, T4, T9, T10, T13, T14, T17, T18, T19, T20, T21, T24, T25, T30, and T35 were isolated from the cultivated soil of the Northeastern region. All 15 isolates were cultured in 3 different media to increase the number of spores using sorghum, broken rice and rice bran mixed with husks. The most suitable substrate for Trichoderma spp. cultivation was rice bran mixed with husks (1:2 v/v). The fungi were inoculated in the soil of melon potted plants. After soil infestation with Trichoderma spp., the pathogen was inoculated thereafter in greenhouse and small pot sized experiments. The results showed that T. virens (T10) induced resistance in melon, showing the smallest spot sizes on leaves with the lengths of 3.17 and 2.25 mm, resulting in the best disease reduction of 80.36 and 88.47% in greenhouse and small pot experiments, respectively. For symptoms in stem evaluation, Trichoderma erinaceum (T25) induced the melon plant to express stem lesions with the smallest spot sizes of 7.73 and 9.12 mm which resulted in the best disease reduction of 60.87 and 35.77% in greenhouse and small pot experiments, respectively. This study indicated the efficiency of Trichoderma spp. isolates on induced resistance against gummy stem blight in melon.