K. Archunan and M. Pazhanisamy
Department of Entomology, Faculty of Agriculture, Annamalai University, Annamalai Nagar-608 002 (Tamil Nadu),
India
*(e-mail : greenwld115@gmail.com; Mobile : 9047080349)
(Received : January 12, 2021; Accepted : March 17, 2021)
ABSTRACT
Population dynamics and impact of weather parameters of chilli thrips, Scirtothrips dorsali and natural
enemies were evaluated in different seasons during summer and kharif 2019. The results revealed that
thrip population density gradually increased and highest population was observed in 15the MSW (12.71/
leaf) followed by 16the MSW (11.06) in summer season, whereas 29the MSW (12.63/leaf) followed by 35the MSW (11.74/leaf) during kharif 2019. The natural enemies of different spiders and coccinellids were presented in entire cropping season and maximum population presented in 18the MSW (2.43/plant), 19the MSW during summer and 38th MSW (2.85/plant) followed by 36th MSW (2.38/plant) in kharif 2019. The thrip population exerted positive correlation with maximum and minimum temperature, whereas nonsignificant positive association with wind speed and sunshine hours. However, the relative humidity and rainfall negatively correlated with thrips population. The values of coefficient of determination (R2)
showed that there were 42.8 and 46.9% variations in thrip population caused due to meteorological factors and the natural enemies showed that there were 68.0 and 49.1% variations observed during the summer and kharif 2019.
Key words : : Seasonal incidence, correlation, regression, meteorological standard week