Seasonal incidence of chilli thrips, Scirtothrips dorsalis hood in relation to weather parameters
G Venu Gopal, K Vijaya Lakshmi, B Sarath Babu and P Kishore Varma
During the present study field experiments were conducted during 2014-2015, Kharif to study the seasonal incidence and impact of weather parameters on chilli thrips. The results revealed that the infestation and severity of insect pests were highly influenced by weather parameters. Seasonal incidence of thrips was recorded from leaves and fruits at weekly intervals during the crop growth period. The population of thrips on leaves increased gradually from 43rdstd. Week and attained a peak during January 3rd week (3rdstd. week) (99.86/terminal). The peak population (169 thrips/50 fruits) of thrips on fruits was observed on 4thstd. The correlation coefficients of thrips population on leaves when compared with the preceding one week weather parameters showed significant negative correlation with maximum temperature (-0.54**), minimum temperature (-0.76**), mean temperature (-0.76**), rainfall (-0.49*), rainy days (-0.51*) and evaporation (-0.49*) with Scirtothrips dorsalis population. Preceding two weeks weather data stated that apart from the weather parameters which showed significant effect on thrips population with preceding one week data, wind velocity (-0.45*) which shown significant negative effect on thrips population when compared with the preceding two week weather data. The correlation coefficient studies carried out for S. dorsalis population on fruits with preceding one week and two weeks weather revealed that preceding one week weather did not exert any significant relation with S. dorsalis population. The preceding two weeks weather parameters showed significant and negative effect of minimum temperature (-0.58**), mean temperature (-0.54**) and morning relative humidity (-0.50*) with S. dorsalis population. Thus the multiple regression analysis studies revealed that preceding two weeks weather could predict the population fluctuation more effectively to an extent of 67% when compared to 56% variation observed with preceding one week weather.
G Venu Gopal, K Vijaya Lakshmi, B Sarath Babu, P Kishore Varma. Seasonal incidence of chilli thrips, Scirtothrips dorsalis hood in relation to weather parameters. J Entomol Zool Stud 2018;6(2):466-471.