Control of Acanthoscelides obtectus with Trichoderma harzianum applied alone or in combination with diatomaceous earth on a stored common bean

Abstract

A laboratory assay was designed to determine the insecticidal efficacy of Trichoderma harzianum Rifai and diatomaceous earth (DE) against Acanthoscelides obtectus Say (Coleoptera: Chrysomelidae: Bruchinae). The fungus T. harzianum was applied at 0.0, 3.3 × 106, 6.6 × 106 and 2.1 × 107 spores/kg of the common bean individually and mixed with 0, 200, 400 and 800 ppm of DE. The mortality counts were made after 1, 2, 4 and 7 days. All of the dead adults were removed after each count, and the vials were kept for the next 60 days to assess the emergence of any progeny. The highest mortality (93.88%) was achieved after 7 days using 800 ppm of DE and 2.1 × 107 spores/kg of T. harzianum and it suppressed emergence of the second generation after 60 days of treatment. These results concluded that DE can be used successfully along with T. harzianum against A. obtectus in stored common beans.

Keywords

• chrysomelidae
• phaseolus vulgaris
• dry bean beetle
• fungi
• bruchinae