The effective antagonistic potential of phylloplane microbes against Alternaria solani causing early blight disease in tomato plant

Early blight disease of tomato caused by Alternaria solani, economically important disease which causes considerable yield losses. Management using chemicals poses environment hazards, hence the use of biological agents implicates safer to crop and environment. Purposive sampling survey was conducted in Thrissur and Palakkad district of Kerala during December 2021 to record the incidence of early blight of tomato and isolated different strains of potential antagonists from different locations caused by A. solani. Early blight was prevalent in all the areas surveyed, the disease severity on foliage varied from 23 to 78% at various locations. Based on the results of in vitro screening, five promising phylloplane anatagonists were selected for evaluation of their efficacy in a pot culture study. The results of antagonistic isolates have clearly indicated that the Trichoderma spp. (PF2 and PRF1) showed 91.2% and 90% inhibition followed by Bacillus subtilis MNB2 (89.4%) as an efficient bio-control agent with good in vitro and in vivo antagonistic activity against A. solani. However, the phylloplane fungal antagonist Trichoderma sp. (PF2) recorded the maximum seed germination (100%) and seedling vigour index (2110) with lower per cent disease severity (22.6%) of tomato variety Anagha. © 2023, Indian Phytopathological Society.