Evaluation of the Effectiveness of Entomopathogens for the Control of Colorado Potato Beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) damages potato, tomato, and eggplant, and is one of the most serious agricultural pests all over the world. Due to its resistance against chemical insecticides and some biopesticides, new biocontrol agents compatible with different ecological conditions are needed urgently for the integrated pest management programs of this pest. For this purpose, we studied the insecticidal effects of thirteen indigenous microbial isolates including entomopathogenic bacteria, fungi, and nematodes from our culture collection against L. decemlineata with screening and dose-response tests under laboratory conditions. Bacillus thuringiensis strain Xd۳ caused ۸۳% and ۷۳% mortality against larvae and adults of the pest at ۱۰۹ CFU mL-۱ concentration within ۱۰ days, respectively. While fungal isolate Metarhizium anisopliae Gg-۱۲ yielded ۹۸% mortality with ۱۰۷ conidia mL-۱ concentration on larvae at ۱۵ days, mortality provided by Gg-۱۲ on adults reached ۱۰۰% at the same concentration and period. Steinernema websteri AS۱ was determined as the most effective entomopathogenic nematode with ۹۲% mortality within seven days on larvae. Based on probit analysis, the LC۵۰ values of B. thuringiensis Xd۳ against larvae and adults were calculated as, respectively, ۱.۷۳×۱۰۶ and ۱.۶۹×۱۰۷ CFU mL-۱, and that of M. anisopliae Gg۱۲ were ۱.۱۸×۱۰۴ and ۶.۲×۱۰۳ conidia mL-۱, and that of S. websteri AS۱ was ۱۱۷ IJs mL-۱. Considering these results, the biopesticides developed from these isolates can be used safely and successfully in the pest management control programs of Colorado potato beetle.

کلیدواژه ها:

Microbial control ، Bacillus thuringiensis ، Metarhizium anisopliae ، Steinernema websteri ، Insecticidal activity