A broad-spectrum Chromobacterium biolarvicide formulation disrupts mosquito development through gut damage and apoptotic cell death and compromises vector competence

Mosquito resistance to chemical insecticides, the cornerstone of current vector control strategies, continues to undermine disease prevention efforts. We have developed a stable non-live larvicidal microbial biopesticide pellet formulation of Chromobacterium species Panama (Csp_P) that effectively attracts larvae and demonstrates potent activity against a broad range of mosquito disease vectors by exerting toxicity to all stages from eggs to adults upon exposure in the larval aquatic environment. Larval ingestion of Csp_P pellets causes irreversible midgut tissue damage, disrupting development from the larval stage and reducing the fitness and vector competence of surviving adults. The observed midgut pathology differs from that induced by conventional biopesticides and is accompanied by molecular markers of stress-mediated apoptosis and autophagy. These findings provide mechanistic insights into Csp_P-induced larval killing and highlight the potential of this formulation as a biologically derived, scalable tool for integrated mosquito management programs. Chromobacterium Csp_P guar gum-based pellets induce irreversible gut damage, apoptosis, and high larval mortality across mosquito vectors, causing developmental collapse, reduced adult fitness, and decreased malaria and dengue transmission potential.