In vitro efficacy of fungicides against Phytophthora nicotianae causing Buckeye rot disease of tomato

Tomato (Solanum lycopersicum L.) is most important “Protective food” as it has special nutritive and antioxidant properties due to the presence of lycopene and flavonoids. Tomato is infected by a number of fungal, bacterial and viral diseases which adversely affect the production and productivity of the crop. Among various diseases of tomato, buckeye rot of tomato caused by Phytophthora nicotianae has assumed alarming threat to the crop production in India. Buckeye rot is a significant soil-borne disease that affects fruit quality and yield, especially under warm and moist conditions. In India, losses due to this disease range between 30 and 70 per cent. The tomato fruits showing typical characteristic symptoms of buckeye rot were collected during survey and from field research trial of PGI, research farm. The pathogen was isolated from infected samples by standard tissue isolation method and purified by hyphal tip method. Pathogen was identified as Phytophthora nicotianae on the basis of morphological, cultural and molecular studies. Pathogenicity was proved by Koch’s postulates. Also, on the basis of observations and report of nucleotide homology and phylogenetic analysis given by Centyl Biotech Private Limited, pathogen identified and confirmed as Phytophthora nicotianae. In vitro evaluation of fungicides by dual culture technique noticed that, Metalaxyl-M 4% + Mancozeb 64% WP was most effective which inhibited 100% growth of the fungus followed by Cymoxanil 8% + Mancozeb 64% WP and Fenamidone 10% + Mancozeb 50% WP.