Potentials of entomopathogenic fungi in controlling the menace of maize weevil Sitophilus zeamais Motsch (Coleoptera: Curculinidae) on stored maize grain

The effectiveness of different strains of Metarhizium anisoplae Metchn (V275, V245 Ma23), Verticillium lecanii Zimm (KV71, KV181 and KV183) and Paecilomyces lilacinus Thom (P251) as biological control agents were evaluated against Maize Weevil (Sitophilus zeamais Motsch). The experiments were laid down in completely randomised design with eight treatments. Each treatment was replicated three times. Overall assessment of the bioassay experiments showed that all the fungal isolates tested were significantly (P<0.05%) better than the control treatment. However, the percentage cumulative mortality of S. zeamais was observed to be higher in treatments where insects were treated with higher concentrations of conidia. Among all the strains evaluated V275, V245 and KV 183 proved to be more effective than the rest of the isolates. In other words, the mortality of S. zeamais was found to be highly dependent on conidia concentration and isolates V275, V245 and KVL183 provided a higher protection of maize grain against S. zeamais at all the levels of conidial concentrations tested. In conclusion, all the tested isolates especially V275, V245 and KV183 have potential value to provide protection to maize grain against S. zeamais. The result also highlights the need for screening of more virulent isolates against S. zeamais in the management of the insect.