Monday, December 10, 2007 - 9:29 AM

Movement patterns of the banana weevil (Cosmopolites sordidus Germar) in relation to its host plant

Ruth M. Dahlquist,, Fresno Pacific University, 1717 S. Chestnut Ave, Fresno, CA, Nilsa A. Bosque-Pérez,, University of Idaho, Department of Plant, Soil and Entomological Sciences, PO Box 442339, Moscow, ID, Sanford D. Eigenbrode,, University of Idaho, Plant Soil and Entomological Sciences, Ag Sci 242, Moscow, ID, and Luko Hilje,, Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), Department of Agriculture and Agroforestry, Apdo. 7170, Turrialba, Costa Rica.

The banana weevil (Cosmopolites sordidus Germar) is a major pest of bananas and plantains (Musa spp.) throughout the tropics, and has been shown to be attracted to volatiles of its host plant. Previous studies on banana weevil orientation to volatiles found that weevils oriented upwind to volatiles under conditions of constant airflow in the lab. In order to test orientation to host plant volatiles under field conditions, we used harmonic radar to track nightly movement of individual weevils. Harmonic radar tags consisting of a diode and wire antenna were glued to the elytra. Tagged weevils were released in hexagonal arrays of six weevils. Each replication consisted of four arrays: 1 m from a banana stem piece, 2 m from a banana stem piece, and control arrays 1 and 2 m from a center point that did not contain a banana stem piece. After each night, individual weevils were located with harmonic radar and their distance, bearing, and depth in soil recorded. Weevils released in the presence of banana stem pieces moved significantly farther and burrowed less deeply in a 24-hour period than weevils in control arrays. However, presence of banana stem had no effect on the orientation of weevil movement. A separate double-marking experiment found that tag attachment did not affect ability to reach a banana stem piece.

Species 1: Coleoptera Curculionidae Cosmopolites sordidus (banana weevil)