Prevalence of leaf blight disease of litchi caused by Alternaria alternata in Bihar state, India

Abstract

Litchi (Litchi chinensis) is one of the commercially important fruit crop belonging to family Sapindaceae. Alternaria alternata has been an important pathogen of litchi causing blights of leaf, panicle, and fruits besides causing post-harvest fruit decay. Studies were conducted to assess the prevalence of leaf blight disease in different nurseries at ICAR-National Research Centre on Litchi (NRCL), Muzaffarpur, Bihar during 2017 and 2018 in continuous monitoring of disease programme. The extent of leaf blight disease developed due to natural inoculums in various nurseries was assessed. Incidence of the disease among plants (DI), percent infected leaves (IL), and percent disease severity index (PDI) were recorded. Observations were taken at monthly interval. Results showed that during both years, range of mean DI, IL and PDI were 6.63-16.83%, 17.89-48.60 % and 39.03-63.84, respectively. Higher DI, IL and PDI were recorded in July, August and September months, while it was lower in November to January. The study gives information about extent and temporal variation in occurrence of disease in nursery, which is crucial for spray scheduling to manage this disease.