Effect of Dry Conidia Formulations of Metarhizium anisopliae on Sitophilus zeamais (Coleoptera: Curculionidae) Mortality, Progeny Emmergence and Maize Grain Damage

Abstract

The efficacy of dry conidia formulation of Metharhizium anisopliae (PPRC-2) produced on locally available grains was assessed against Sitophilus zeamais (Coleoptera: Curculionidae) in the laboratory. Conidial suspension was inoculated into glass jars containing 200 grams of maize, rice, wheat and sorghum grains sterilized and were incubated at 27°C and 70 ± 5% RH for 21days. Each grain substrate was air-dried and grounded to powder using a sterile coffee grinder. The powdered dry conidia were applied to the maize grain infested with S. zeamais. High mortality to the maize weevil was recorded 7-days after the fungus grown on rice (91%) and maize (84%) substrates were applied. The number of F1 progeny emerged was 0, 0.5 and 1, for primiphos methyl, rice and maize, respectively. Percentage grain protection ranged from 41% to 83% for fungal treatments. The number of grain damaged and percent grain weight loss were reduced in dry conidia treated maize grain than in the control. Therefore, the use of M. anisopliae holds promising prospect in managing S. zeamais.