Control of the Mexican bean weevil Zabrotes subfasciatus with kaolin

Abstract

The Mexican bean weevil Zabrotes subfasciatus (Coleoptera: Chrysomelidae: Bruchinae) is an important pest of stored beans in tropical regions. The efficiency of kaolin [with or without neem (Azadirachta indica) oil] and diatomaceous earth (DE) (standard treatment) was studied in laboratory aiming to obtain alternatives for chemical control of this insect. Insects were confined in plastic vials containing beans treated with kaolin (2, 4 and 8g kg-1), kaolin + neem [2g kg-1(5% neem oil)], diatomaceous earth (1g kg-1) and control. Mortality of adult insects, number of eggs and F1generation beetles emergency were assessed. Kaolin caused mortality of Z. subfasciatus, however higher periods and doses than DE were necessary to promote high mortality (100% or close). Kaolin treatments also affected female behavior because many eggs were placed in the vials walls. Number of emerged adults (F1) was similar between DE and kaolin; hence, kaolin constitutes a promising tool to the management of Z. subfasciatus. The mixture of kaolin and neem oil was not efficient in the control of Z. subfasciatus.