Sublethal effects of Bacillus thuringiensis Berliner subsp. kurstaki on laboratory biology of Helicoverpa armigera (Lep.: Noctuidae)

The entomopathogen of Bacillus thuringiensis Berliner is one of the biocontrol agents for combatingHelicoverpa armigera Hübner. In the present study, sublethal effects (LC5, LC10, LC15, LC20 and LC25) ofBiolep (commercial formulation of B. thuringiensis with the mixture of spores and crystals of this pathogen)on laboratory biology of H. armigera was investigated at 25±1ºC, 60±5 r.h. and a photoperiod of L16: D8 h.According to the obtained results, duration of preimaginal development in control and LC5, LC10, LC15,LC20 and LC25 treatments was 31.86, 34.82, 35.64, 34.75, 36.17 and 37.17 days, respectively. Asconcentration increased, duration of adult longevity significantly decreased. The highest value of adultlongevity for male (18.80 days) and female (13.14 days) was recorded in control treatment and the lowestvalue of this period was obtained in LC25 treatment (8.13 and 7.25 days for male and female, respectively).Furthermore, total fecundity of H. armigera was significantly affected by used concentrations and withincreasing concentration total fecundity of this moth decreased (789.50 eggs in control, 665.10 eggs in LC5,601.00 eggs in LC10, 532.50 eggs in LC15, 376.00 eggs in LC20 and 98.40 eggs in LC25). The obtainedresults in the current study can be used in integrated management programs of H. armigera.

کلیدواژه ها:

Bacillus thuringiensis ، Helicoverpa armigera ، sublethal concentrations ، laboratory biology