Effect of controlled atmospheres on the insect Callosobruchus maculatus Fab. in stored chickpea

Callosobruchus maculatus (Fab.) is the principal pest of the stored chickpea. The larvae of this insect feed on the grain, causing considerable damage that produces qualitative and quantitative losses. For control of this species, pesticides such as phosphine and methyl bromide have been used; the latter was withdrawn from use due to the reduction of the ozone layer. Therefore, it is important to develop novel, safe, and economical control alternatives such as Controlled Atmospheres (CA). In this study, the mortality was determined on four developmental states of C. maculatus, employing CA at different concentrations (50, 70, and 90% CO₂ with 10, 6, and 3% O₂, respectively) during 48, 72, and 120 h. 100% mortality of adult insects was observed with 50% CO₂ at 48 h. Cases of third instar exhibit higher resistance to CA than adults, with 18.9% mortality at 48 h. There were no significant differences in tests on water absorption, cooking time, texture, and color. Finally, the chickpea germination obtained was 93.5% with 90% CO₂ exposure during 120 h. In this latter treatment, significant differences were not presented between control and CA treatments. On comparison of means of vigor, the treatments are favored in terms of weight, rootlet number, plumule and radicle growth with the increase of CO₂ concentration and exposure time. In conclusion, the effect of CA was lethal on C. maculatus, did not affect chickpea quality, and it favored chickpea vigor.