Epidemiological studies on mosaic disease of ridge gourd

Abstract

Ridge gourd [Luffa acutangula (Roxb.) L.] is one of the important vegetable crops which belong to cucurbitaceae family and grown in different parts of India. Environmental factors play a great role in buildup of disease development. Epidemiological studies was carried out at Pathology Block of ICAR-Central Institute for Arid Horticulture, Bikaner during rainy season of 2016 to determine the effect of weather parameters in relation to incidence of mosaic disease on ridge gourd germplasm ‘Bikaner Local’ which was sown on 25th July, 2016. Weekly observations were taken on mosaic disease and per cent disease index (PDI) was calculated during crop period. Weekly meteorological data like average maximum temperature, minimum temperature, maximum RH, minimum RH, rainfall, wind velocity, evaporation and bright sun shine hours (BSSH) per day were also taken from meteorological observatory of ARS, SKRAU, Bikaner. The initiation of mosaic disease was first appeared in August, 2016 and it was found that minimum PDI (6.67%) of this disease was recorded at average maximum temperature (34.40C), minimum temperature (26.20C), av. maximum RH (86.0%) and minimum RH (61.6%), av. rainfall (16.0 mm) and bright sun shine hours (6.2) on 34th standard week while maximum PDI (26.64%) was found at average maximum temperature (36.30C), minimum temperature (23.500C), av. maximum RH (84.7%) and minimum RH (47.9-61.6%), rainfall (24.2 mm) and BSSH (6.6) on 40th standard week of the year. Thereafter, correlation between PDI and different meteorological parameters were determined. Among these parameters, maximum temperature, evaporation and bright sun shine hours had positive correlation with PDI (r = 0.588, r = 0.385 and r = 0.310). While minimum temperature, maximum RH, minimum RH, rainfall and wind velocity showed negative correlation with PDI (r = -0.320, r = -0.378, r =-0.467, r = -0.230 and r = -0.183).