Trichoderma asperelloides 5R and Bacillus licheniformis TL‑171 reduce epiphytic colonization and post‑harvest berry decay due to Cladosporium sp. and improve the shelf life of grapes

Abstract

Fungal rot caused by Cladosporium sp. is one of the causes of post-harvest decay of grape berries. This fungus is present in a ‘quiescent’ state in the vineyard during the early stages of berry development and causes berry rot after harvest. The aim of the study was to assess the antagonistic capabilities of Trichoderma asperelloides and Bacillus licheniformis against Cladosporium sp., isolated from different stages of berry development. The fungus was identified as C. cladosporioides C1 by molecular identification method. In in vitro dual culture assay, T. asperelloides strain 5R overgrew C. cladosporioides and caused distortion of its hyphae. B. licheniformis strain TL-171 also inhibited the growth of the pathogen. The percent inhibition of C. cladosporioides by toxic volatile and non-volatile metabolites produced by T. asperelloides was 64.74 and 61.76 and by B. licheniformis it was 24.61 and 16.66 respectively. Both antagonists showed reduction in colonization of berries by C. cladosporioides from initial stage of berry development in vineyard situation. At harvest, colony forming unit of C. cladosporioides on Vitis vinifera L. cv. Thompson seedless grape berry was 30 CFU/berry as compared to 650 CFU/ berry in untreated control in Trichoderma-treated vines. This was also reflected in the increase in shelf life from 11 days in control to 15 days in tests. The study is important as it shows that early season foliar application of T. asperelloides and B. licheniformis can be included in the spray program for management of grape diseases through a safer and an environment friendly approach.