Abstract
The present study aimed to investigate new insecticidal compounds used as environmentally safe alternative to synthetic insecticides. A laboratory study was conducted to investigate the effects of Bacillus biofilms and their extracellular matrix (ECM) on the adult’s mortality and reproduction of the cowpea weevil, Callosobruchus maculatus (F.) (Coleoptera: Bruchidae). Among 30 bacterial isolates, only 4 exhibited high abilities to form biofilm and showed potentials against the pest at different concentrations 5, 10 and 20%. Results showed that the mortality percentage of C. maculatus adults ranged between 13.36 and 63.43% overall and it increased significantly with raising the concentration of ECMs. While the latent larval mortality did not exceed 31.42%, which was recorded with ECM of isolate no. 13 at the highest concentration (20%). Further, all tested concentrations reduced female fecundity and egg hatchability. The most potent biofilm-producing isolate having the highest adverse activity of ECM extract was identified as Bacillus flexus S13, using 16S rDNA gene sequence and submitted in GenBank under accession number MK292147. These results demonstrated that B. flexus S13 biofilm is a good strategy for the development of new biocontrol agents against C. maculatus.
Highlights
Legumes are a sustainable and inexpensive meat alternative because of its high protein content, are considered the second most important food source after cereals
Reda (2019) reported that Bacillus cereus isolated from the milky machine surface was a good biofilm producer
The results revealed that the mortality percentage of cowpea weevil was gradually increased by raising concentrations of extracellular matrix (ECM) in all tested isolates
Summary
Legumes are a sustainable and inexpensive meat alternative because of its high protein content, are considered the second most important food source after cereals. Production of cowpea is affected by the cowpea weevil, Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) which causes economic losses It is considered a cosmopolitan pest ranked as the principal post-harvest pest of cowpea in Misuse of insecticides harmed the non-target pests and may accelerate resistance development, so various strategies have been developed to control the target pest in a safe manner; microorganisms are an inexhaustible source of wide range of novel useful bioactive molecules to be used as biological control agents on different economic pest. In this status, fetching economic, ecologically safe, and sustainable strategies became a priority. Some species of the genus Bacillus fulfill all the above-mentioned requirements; exploitation and trading have been recommended by the U.S Food and Drug Administration
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
