Seasonal incidence and effect of abiotic factors on population dynamics of diamondback moth (Plutella xylostella L.) on cabbage (Brassica oleracea var. Capitata L.) crop

Field experiment was conducted at research farm of Indira Gandhi Krishi Vishwa Vidyalaya, Raipur (C.G.) during the rabi seasons of 2015-2016 and 2016-2017 to evaluate the seasonal incidence of diamondback moth in cabbage crop and impact of weather parameters on it’s population dynamics. Infestation of diamondback moth started from the end of December in 2015-2016 (0.075/ 20 plants) and first week of January in 2016-2017 (0.125/ 20 plants) and reached peak in the month of March in both years (6.85/ 20 plants and 5.25/ 20 plants). Correlation study revealed that the maximum temperature had non significant negative correlation (r = -0.005) with larval population but had positive correlation (r = 0.19) in year 2016-17. Minimum temperature had a positive correlation in both years(r = 0.24 and r = 0.21, respectively). Though, the relative humidity had negative and positive relation with the larval population of diamondback moth in both years (r = -0.26 and r = 0.11 respectively). Sunshine hours had negative but non-significant (r=-0.31) effect in 2015-16 while positive relation (r=0.38) was observed in 2016-2017. However rainfall had positive non significant relation (r=-0.05 and r= -0.08 respectively), in both years.