Resistance of Cowpea Genotypes to Zabrotes subfasciatus (Boheman, 1833) (Coleoptera: Chrysomelidae: Bruchinae)

Abstract

Cowpea (Vigna unguiculata (L.) Walp.) when stored is mainly attacked by bruchid Coleopterans. The control of these pests is done primarily through chemicals, however, with problems related to the selection of resistant insects, alternative forms of control are searched. Seeking an alternative control, the objective this work was to evaluate the resistance of cowpea genotypes to the attack of Z. subfasciatus. In the first selection of genotypes were evaluated 35 cowpea genotypes, being observed the variables: number of eggs, number of insects emerged and weight loss (%). In this first selection of cowpea were selected 10 genotypes. In the second selection of genotypes, the 10 most resistant from the first selection were used, but with eight repetitions per genotype, besides evaluating the egg viability (%) and instantaneous rate of population growth. The cowpea genotypes showed significant differences for resistance to attack by Z. subfasciatus. The most resistant to Z. subfasciatus were BRS Tracuateua, 31 MNC03-720C-20, 26 MNC00-553D-8-1-2-2 and 37 MNC05-832B-234-5