Ovicidal and repellent activity of citronella powder on cowpea-bean weevil

Abstract

The rot Callosobruchusmaculatus (Fabr.) is considered the main pest of grains and stored seeds of cowpea-been, as it causes direct and indirect damages, which can lead to quantitative and qualitative losses, making commercialization or consumption impossible.To the control of this pest, synthetic insecticides we have been used, which over the years have caused many problems to human health and to the environment.Botanic insecticides have become a promising alternative in the control of pests on stored grains.The objective of this work was to evaluate the ovicidal and repellent activity of citronella, Cymbopogonnardus, on C. maculatus.In the confinement experiment, the insects were kept for 24 hours in a container containing 10g of cowpea beans cv. BRS Guariba with concentrations 1.0g; 0.1g; 0.01g; 0.001g of the powder of the referred species and witness (grain without dust), and in the repellency experiment, a six-way arena was used, where the insects had the possibility to choose between the grains with the tested concentrations or witness. The delimitationused was completely randomized with five replicates and five treatments for the two experiments.The concentration of 1.0g of the citronella powder presented ovicidal and repellent activity to C. maculatus, allowing, on average, a lower number of eggs laid and an unexpressive appearance of insects when compared to the other concentrations and control.