Selectivity of Bacillus thuringiensis (Bacillales: Bacillaceae) to the polyphagous predator Ceraeochrysa claveri (Navás, 1911) (Neuroptera: Chrysopidae)

Abstract

Abstract Biopesticides based on Bacillus thuringiensis (Bt) are widely used to control agricultural pests. These products are efficient and have high specificity to target insects. However, there are concerns about their impact on non-target organisms. Ceraeochrysa claveri, is a polyphagous predator with important value in the biological control of insect pests in crops of economic interest. This study aimed to analyze the effects of B. thuringiensis serovar aizawai CG-91 (Bta) on the post-embryonic development of C. claveri. Neonate larvae of C. claveri were fed with Diatraea saccharalis eggs contaminated with different concentrations of Bta (0.62, 1.25, 2.50, and 5.00 g.L-1) until your pupation. Samples of the midgut larvae were collected for histological and ultrastructural analysis, and the larval and pupal inviability data were collected at the end of the respective developmental stages. After the emergence of adult insects, were considered inviable those with morphological alterations. To evaluate the reproduction, adult insects couples were formed, and the oviposition was collecteds. No significant differences in the viability of eggs, larvae, pupae, and adults of C. claveri contaminated with Bta were reported. Midgut analyses did not reveal cellular damage in the epithelium, indicating a possible lack of insecticidal proteins receptors. The oviposition and their viability were similar between treated and control groups. Our results demonstrated that Bta did not affect the post-embryonic development of C. claveri. This illustrates that the combined use of Bta and C. claveri for the biological control of arthropod pests can be a sustainable strategy for integrated pest management.