Effect of Bacillus thuringiensis var. kurstaki on survival and mortality of immature and mature stages of Diadegma insulare parasitizing Plutella xylostella

作者：Ebrahimi Morteza^*; Sahragard Ahad; Talaei Hassanloui Reza

来源：Phytoparasitica, 2012, 40(4): 393-401.

DOI：10.1007/s12600-012-0240-6

• Biocontrol
• Diamondback moth
• Integrated pest management
• Parasitoid

Effects of Bacillus thuringiensis (Bt) on immature stages of Diadegma insulare (Cresson) (Hym., Ichneumonidae) within larvae of diamondback moth (DBM), Plutella xylostella (L.) (Lep., Plutellidae), and on the adult stage as a Bt-honey solution were evaluated at 25 +/- 1 A degrees C, 65 A +/- 10% r.h. and 16:8 h (L:D) photoperiod. P. xylostella and D. insulare pupae were collected from cabbage fields in Karaj, Iran. A commercial wettable powder formulation of Bt (var. kurstaki, serotype H-3a3b, strain Z-52) was used in these experiments. The value of LC50 for third instar larvae of P. xylostella was 210 ppm. Parasitoid%26apos;s adult mortality at field rate of Bt was not significantly different from that of control. Formation of parasitoid%26apos;s pupae in Bt-parasitoid combined treatments was significantly lower than parasitoid alone. Formation of parasitoid%26apos;s pupae in larvae treated with LC10, LC30 and LC50 of Bt and then exposed to parasitoids after 48 h was 5%, 3% and 2%, respectively, which was significantly lower than that of the parasitoid alone (41%). Mean percentage mortality of larvae of DBM in LC30 and LC50 concentrations of Bt combined with the parasitoid was approximately 100%. Our results showed that B. thuringiensis kills D. insulare larvae indirectly by killing susceptible hosts in which they are developing. Successful use of multiple biological control agents will depend on close monitoring of their compatibility in the field. Our results could be useful in this purpose.

• 出版日期2012-9