Studies on population dynamics of thrips on tomato crop were carried out during two consecutive kharif seasons (2016 and 2017). The observations viz., number of adult thrips and associated GBNV disease and natural enemies were recorded at weekly intervals. The results revealed that, thrips activity found throughout the cropping period. The population of thrips was increased gradually from first week after transplanting to flowering and fruit development stage and later it was decreased as crop matures. During 2015-16 kharif crop, maximum thrips population (8.40 thrips/three leaves) was observed during the last week of November and first week of December. Similarly during 2016-17 kharif crop, maximum thrips population (10.30 thrips/three leaves) was observed during third and last week of December. The population of zoopytophagous miridbug, Nesidiocoris tenuis Reuter was found linear with the population of thrips during both the seasons. The percent disease incidence of GBNV on tomato crop was linier with the thrips population during both the seasons. The cumulative disease incidence was 42.50 % and 45.10 % during first and second seasons respectively. Correlation studies indicated that, minimum temperature, rainfall, rainy days and evening relative humidity were found significant negative correlation with the thrips population, while sunshine hours and morning relative humidity found significant positive correlation with the thrips population.
Bean dip bioassay was performed with six insecticides on the mortality response in tomato thrips- Thrips palmi Karny and Scirtothrips dorsalis Hood. The LC50 values ranged from 1.591 to 17.018 ppm, and spinosad with the least LC50 value of 1.591 ppm at 95% confidence limit was the most toxic. It was followed by cyantraniliprole (2.425 ppm), diafenthiuron (2.396 ppm), imidacloprid (5.110 ppm), fipronil (13.560 ppm) and dimethoate (17.018 ppm). Thus, spinosad, diafenthiuron and cyantraniliprole were observed to be more toxic.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.