Bioefficacy of Bacillus thuringiensis against cabbage butterfly, Pieris brassicae
Samandeep Kaur, Adesh Kumar and Neelam Joshi
The present investigation was conducted to test the bioefficacy of Bacillus thuringiensis against cabbage butterfly, Pieris brassicae (L.). Thirteen B. thuringiensis isolates including six standard isolates (MTCC 868, MTCC 4715, 4D4, 4J3, PDBC Bt-1 and PDBC Bt-2) and seven native isolates (B1, B2, B3, B4, B5, B9 and B10) were evaluated for the morphological characteristics and further tested their efficacy against second instar larvae of P. brassicae (L.) in Biocontrol Laboratory, Department of Entomology, Punjab Agricultural University, Ludhiana during the cabbage crop season in 2013-14. Different concentrations of spore crystal complex of B. thuringiensis isolates (250, 500 and 750μg/ml) were studied along with one commercial formulation of B. thuringiensis var kurstaki (DELFIN® WG). It was found that DELFIN®WG recorded maximum mortality of 99.98 per cent against larvae of P. brassicae. Among procured and native isolates, MTCC 868 and B4 recorded maximum mortality of 88.87 and 74.43 per cent, respectively. However, all treatments were significantly better than untreated control.