Bacillus thuringiensis strains with high insecticidal activity against insect larvae of the orders Coleoptera and Lepidoptera

Abstract

The concept of sustainable agricultural development is aimed at reducing the use of chemical pest control agents. Since the use of chemical pesticides poses a significant environmental threat, one of the possible solutions to overcome this problem is the study of biological approaches, in particular, the use of entomopathogenic microorganisms as biological pest control agents. Insecticidal activity of over 220 strains of Bacillus thuringiensis (Bt) and Lysinibacillus sphaericus from the collection of the Laboratory of Spore-Forming Microorganisms of the Microbial Depository Center of the Scientific and Production Center “Armbiotechnology” and 15 strains isolated from samples of dead insects (imago) of representatives of various genera of the Coleoptera order was studied. The pathogenic effect of the strains was assessed in relation to the insect species Tenebrio molitor, Zophobas morio, Leptinotarsa decemlineata Say and Pieris brassicae, belonging to the Coleoptera and Lepidoptera orders. Among the test objects, the representative of Lepidoptera Pieris brassicae demonstrated the highest degree of sensitivity to B. thuringiensis strains up to 100%, with some Bt strains causing 60–100% mortality of Tenebrio molitor and Zophobas morio larvae of different ages. The larvae of the beetle Leptinotarsa decemlineata Say were also partially susceptible, presenting mortality levels of between 31 and 60%. The article is devoted to the study of Bt bacterial strains that have pronounced insecticidal activity against insect larvae of the orders Coleoptera and Lepidoptera.

Keywords

• entomopathogenic bacteria
• bacillus thuringiensis
• toxins
• insecticidal activity
• coleopteran pests