Vegetos

Abstract

Early blight of tomato caused by Alter-naria solani, leads to severe yield losses in toma-to. The conidial spores are responsible for spread of the disease survives on rhizosphere and old dry lower leaves of the plant and dis-seminates when suitable climatic conditions are available. Macroclimatic study reveals that high-est concentration of Alternaria spores (167) ap-peared in May 2012–13 and lowest concentration (10) was recorded during January 2012–13. Over two years study reveals that maximum concen-trations of Alternaria spores were registered dur-ing last stage of the crop. This occurrence was favoured by high minimum, maximum and mean air temperature, low relative humidity (RH) and high wind speed. The objective of the study was to manipulate microclimatic conditions of toma-to crop canopy which may hamper conidial dis-persal and reduce severity of disease. We evalu-ated effect of marigold intercropping, plastic mulching singly and in consortia on A. solani conidial density, tomato leaf damage and micro-climatic parameters compared to tomato crop alone. Study reveals Tomato-marigold intercrop-ping-plastic mulching treatment (T-M-P) showed significant reduction in disease intensity of 38.9% in 2011–12 and 35.4% in 2012–13 as com-pare to tomato alone. When intercropped with tomato marigold serves as barrier to conidial movement and plastic mulching prevents soil moisture evaporation and reduce the canopy RH that results in less germination of A. solani spores.