Studies on seasonal incidence and field efficacy of insect growth regulators against diamondback moth, Plutella xylostella (L.) infesting cabbage, Brassica oleracea var. capitata (L.)

A field experiment was conducted on cabbage (Brassica oleracea var. capitata) at the Research Farm, Sher-e-Kashmir University of Agricultural Sciences and Technology, Jammu, India. The infestation of Plutella xylostella, diamondback moth started from the 5th standard week (0.88 larvae plant-1) and reached peak (18.68 larvae plant-1) in 14th standard week. The maximum and minimum temperature showed significant positive correlation with larval population of diamondback moth whereas, non-significant correlation with relative humidity and rainfall. Regression studies revealed that the weather factors had 77.60 percent contribution towards larval population. Abiotic factors like temperature, relative humidity, extent and distribution of rainfall, influenced the infestation and stabilization of P. xylostella in cabbage. Amongst the different treatmentsfenvalerate showed higher efficacy against P. xylostella in reducing pest population. Mean population of P. xylostella after two sprays revealed that fenvalerate 0.004% was effective and superior. The next best were lufenuron 0.006% and novaluran 0.100% which were at par. chlorfenapyr 0.150% was found to be least effective against P. xylostella.