Studies on the efficacies of combinations of Bacillus thuringiensis with neem extracts [Bacillus thuringiensis ile Neem ekstraktlarinin ve karişimlarinin etkinlikleri üzerinde incelemeler]

This study was carried out to overcome delayed and less effectiveness that are the main disadvantages of biopesticides compared to conventional pesticides. The use of combination of Bacillus thuringiensis and azadirachtin based biopesticides was evaluated for efficacies. The penultimate instar larvae of Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) as test insect, Bacillus thuringiensis var. kurstaki (Delfin® WG, Certis), Bacillus thuringiensis var. aizawai (XenTari® WG, Valent BioSciece), oil based neem (Neem Azal T/S®, Trifolio-M), and neem (Neemix® 4.5, Certis) as biopesticides were used in this study. The biopesticides were applied to the test insect larvae at the doses of 50 ppm, 100 ppm individually and in combinations, and also half doses in combinations through feed. It was concluded that rapid slowdown of feeding behavior, accordingly reduction in larval growth, and premature deaths from the first day were determined when the biopesticides were treated in combination compare to that of individual applications. Combinations of XenTari+Neem Azal and XenTari+Neemix had the highest efficacies in terms of the larvae weight. In those groups, larvae weight chanced between 48-51 mg and 42-63 mg respectively. Following treatments in combination of Delfin+Neem Azal, and Delfin+Neemix were also found effective compare to that of their individual applications and untreated ones (up to 410 mg). Highest lethal effects had also observed mostly in seven and nine days after application in combination of biopesticides