Laboratory study of an innovative concept to control aphid pests and mosquito vectors of pathogens to humans

BACKGROUND A great number of areas favourable for the proliferation of mosquitoes are found in farmland, the most favourable being market gardens and rice paddies. The only means of limiting crop pests (AGRI) and mosquito vectors of human pathogens (AC = antivectorial control) in agricultural environments consists of incorporating systemic or translaminar insecticides into fertilizers (AGRIAC). The plant used in this study was the chili pepper (Capsicum chinensis). Experiments were carried out with Myzus persicae aphid pests and Aedes albopictus mosquitoes. Fertilizers were applied in association with thiacloprid, cyromazine, azadirachtin and Bacillus thuringiensis var. israelensis (Bti) + Bacillus sphaericus (Bs) insecticides. Chili pepper seedlings were dried to assess the amount of insecticide in their tissues. RESULTS NPK + thiacloprid and NPK + azadirachtin remained efficient against aphids for 28 days, whereas Bti + Bs had to be added to both mixtures to make them efficient against Ae. albopictus larvae. NPK + cyromazine remained active against both aphids and mosquitoes for 15 days. The search for insecticide residues in chili pepper showed that untreated plants displayed natural toxicity to Ae. albopictus larvae. The toxic effects induced by the capsaicinoid compounds inside the plant add up to the insecticide action of thiacloprid, cyromazine and azadiractin. CONCLUSION The AGRIAC concept allows for an innovative vector control method that can manage aphid pests and mosquitoes while providing plants with the needed fertilizer.