Activity of the Entomopathogenic Fungus Beauveria bassiana (Deuteromycota: Hyphomycetes) Against Three Coleopteran Pests of Stored Grain

Abstract

A Beauveria bassiana isolate from the rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), was evaluated as a conidial powder against 3 coleopteran pests of stored grain: the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae); the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae); and the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Bioactivity of B. bassiana isolate 22292A was assessed on 3 types of food substrates (red flour beetle media, medium grain brown rice, and long grain rough rice) at 27°C and 60% RH. Adult mortality was 80–100% at the higher dosage levels for all insects tested on all media types at 21 d after treatment. Emergence of adult progeny on brown and rough rice was reduced by 83–99% at the 2 highest dosage level. The abrasive nature of rice hulls on the rough rice may contribute to the accelerated mortality seen on this medium.