Biological control of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. by epiphytic bacteria isolated from Vitis vinifera (cv Thompson Seedless) grape berry

Anthracnose leaf spot and ripe rot disease, caused by Colletotrichum gloeosporioides in India, is of economic importance. The objective of the investigation was to isolate and characterise bacterial antagonists from the grape berry surface. Nine bacteria out of the 46 that were isolated significantly inhibited C. gloeosporioides in a dual culture assay. Six of these nine microorganisms demonstrated pathogen inhibition by producing extracellular volatile and non-volatile compounds. Bacteria SB5, SB13, and SB15 were chosen for the polyhouse experiment because they demonstrated the best disease control in a detached leaf assay. At 1 × 106 CFU/ml of bacterial concentration, both curative and preventive trials showed significant disease inhibition. Based on morphological and molecular characterisation the bacteria were identified as Bacillus species. All three strains could be effectively used for the biological control of C. gloeosporioides.