Effects of Cymbopogon Winterianus and Ocimum Basilicum against the Stored Phaseolus Vulgaris Bean Pest, Acanthoscelides Obtectus

Acanthoscelides obtectus Say (Coleoptera: Chrysomelidae: Bruchinae) is an insect pest that attacks wild and cultivated common beans (Phaseolus vulgaris L.). To control insect plagues, it is a priority to choose compounds with different modes of action, greater selectivity, and less environmental persistence. There is an increasing demand in the search for new active substances and natural plant products for pest control for the reduction of adverse effects on human health and the environment. Therefore, this investigation evaluated under laboratory conditions, three doses (24, 60 and, 120 µL) of Cymbopogon winterianuss and Ocimum basilicum essential oils over bean seeds placed in Petri dishes in which A. obtectus insects were previously placed. Different doses of essential oils provided different survival on A. obtectus adults. The essential oils affected the development of A. obtectus since the greatest doses applied on beans decreased the emergence of the weevil. Besides, they reduced the number of exit holes per damaged bean and the bean weight loss, which ranged from 2.987% in the control treatment to 1.014% and 1.221% with 120 µL of C. winterianuss and O. basilicum, respectively. The ability of both C. winterianuss and O. basilicum to reduce the insect longevity, the subsequent emergence of new adults, and to protect the bean seeds make these essential oils a suitable tool for the control of this insect pest in small storages.