Effects of Annona squamosa leaf extract on the insects Aedes aegypti, Nasutitermes corniger, and Sitophilus zeamais and the microcrustacean Hyalella sp.

Abstract

The high environmental toxicity of currently used insecticides and the emergence of resistant insect populations have prompted the search for new agents to control insect pests. In this study, we characterized a saline extract from Annona squamosa L. leaf to determine its chemical constituents and effects on third instar Aedes aegypti L. larvae, Nasutitermes corniger Motsch. workers and soldiers, Sitophilus zeamais Motsch. adults, and Hyalella sp. juveniles. The extract showed a protein concentration of 22.9 mg/mL and included lectins (specific hemagglutinating activity of 21,333.33) and trypsin inhibitors (specific activity of 15.6 U/mg), as well as the secondary metabolites cinnamic acid derivatives, rutin, and chlorogenic acid. The extract killed third instar Ae. aegypti larvae (50 % lethal concentration of 1.9 %, w/v) and increased the permeability of the peritrophic membrane of Ae. aegypti larvae. The extract did not affect the survival of N. corniger workers or soldiers but killed S. zeamais adults with mortality rates of 51.2–63.8 %. A strong deterrent feeding effect was detected, making S. zeamais adults reject an artificial diet containing the extract. Juveniles of the microcrustacean Hyalella sp. were highly sensitive to treatment with the extract at the 50 % lethal concentration for Ae. aegypti. In conclusion, A. squamosa leaf extract kills Ae. aegypti larvae and S. zeamais adults by increasing the peritrophic membrane permeability and exhibiting a strong food deterrent effect, respectively. However, as an insecticide, the extract should be used with caution because of its high non-target toxicity. The effects of A. squamosa leaf extract may be linked to the actions of lectins, trypsin inhibitors, rutin, and chlorogenic acid.