Comparative Efficacy of Bacillus thuringiensis Berliner formulations with Insecticides against Plutella xylostella (L.) and their Effect on Cotesia plutellae Kurdj. on Cauliflower

Field evaluation of Bacillus thuringiensis Berliner formulations against the diamondback moth, Plutella xylostella (L.) revealed that all the Bt. formulations except Spicturin were significantly superior in reducing the larval population. Dipel and Centari though less effective than Delfin were significantly better than all other insecticides. The highest yield was observed in Delfin-treated plots which was higher than the other treatments. All the insecticidal treatments exhibited a significant reduction in the number of Cotesia plutellaecocoons over control except the biopesticide Delfin in most of the observations over control. However, the pest: parasitoid ratio was maximum in Delfin-treatment followed by Dipel and Centari. Fenvalerate recorded the lowest ratio which was almost equal to the control and this was followed bv ouinalphos. Neem formulations recorded a relatively higher ratio than the chemical insecticides.