CBN-V Video Archives - S8-17
Contributions Towards the Knowledge on the Biology, Behavior and Distribution of the Stem Borer (Chilomima clarkei; Lepidoptera: Pyralidae) in Tolima, Colombia

Ramirez C.¹, C.J. Herrera², P. Chavarriaga³, J. Tohme³ and A. Bellotti²

1. Department of Agronomic Engineering, Universidad del Tolima, Ibagué, Colombia
2. Integrated Pest Management Project
3. Biotechnology Research Unit, International Center for Tropical Agriculture -CIAT-, A.A. 6713 Cali, Colombia a.bellotti@cgiar.org

        The stemborer C. clarkei greatly reduces cassava yields in several regions of Colombia, but especially in the Caribbean Coast. The nocturnal adult females oviposit on cassava stems, usually around the buds or nodes. The egg stage is about 6 days at 28°C. Upon hatching, the first to forth instar larvae feed on the outer bark or stem epidermis. Fifth instar larvae penetrate the stem, where they complete their cycle in six to 12 instars. Overlapping pest cycles complicate implementing effective control measures. The recent arrival of C. clarkei in Tolima is expected to cause serious yield losses in cassava as pest populations have increased dramatically during the last year. Transgenic plants, expressing Bt genes, are among the strategies being developed to control the pest. Alternatively, natural enemies (fungi and parasitoids) of larval stages have been identified for biological control. The enemies are usually collected in the fields, identified, and reared as isolated colonies. Laboratory colonies have been developed at the CORPOICA/Nataima (Tolima) experimental station. The colonies provide a constant source of eggs, 12 to 80 eggs/day, at least for 5 days of the adult life cycle. Eggs are shipped to CIAT where they hatch and the larvae are used to test diets, which can be used to rear the insect in vitro. Artificial diets will be useful to test the effect of purified Bt proteins on insect development.

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