Agricultural and Forest Entomology (2011), 13, 405–412 DOI: 10.1111/j.1461-9563.2011.00535.x Migration potential of the banana weevil Cosmopolites sordidus Ole Tobias Rannestad*†, May-Guri Sæthre* and Amon P. Maerere† * Plant Health and Plant Protection Division, Bioforsk, Norwegian Institute for Agricultural and Environmental Research, ˚ As, Norway and †Department of Crop Science and Production, Sokoine University of Agriculture, Morogoro, Tanzania Abstract 1 The banana weevil Cosmopolites sordidus Germar (Coleoptera: Curculionidae) is a major pest in banana (Musa spp.) growing areas. The weevil is known to be relatively sedentary and closely associated with its host plant but little is known about the species’ ability to migrate between banana fields and in nonhost habitats. 2 Mark–recapture experiments were conducted to assess the weevils’ migration potential, possible differences between the sexes, and the relative attractiveness of pseudostem and pheromone baits. 3 One thousand two hundred marked weevils were released in the nonhost habitat at five distances (5, 10, 20, 40 and 70 m) from fresh pseudostem, and from pitfall traps baited with 45 mg of sordidin. 4 Two hundred males and 200 females were marked and released at five distances (5, 10, 20, 40 and 70 m) from the pheromone traps. 5 Distance and distance/bait interactions had a significant effect on recaptured weevils (binary logistic regression). The two baits were almost equally attractive to weevils in the range 0–10 m, whereas the pheromone was more attractive in the range 10–100 m. 6 Distance, bait and distance/bait interactions had a significant effect on the time elapsed from release to recapture (regression with life data) but the pattern observed was not consistent. 7 There was no significant difference between males and females with respect to distance or time elapsed from release to recapture. 8 The results obtained in the present study show that the migration potential of the banana weevil is greater than previously reported. This should be taken into account when new banana fields are established with clean planting material. Keywords Banana weevil, Cosmopolites sordidus, males and females, migration potential, nonhost habitat, pseudostem and pheromone bait. Introduction The banana weevil Cosmopolites sordidus Germar (Coleoptera: Curculionidae) is an important pest in all major banana grow- ing areas of the world (Rukazambuga et al., 1998; Gold et al., 2004). The species is narrowly oligophagous in all four devel- opmental stages associated with cultivars of the genus Musa (McCarthy, 1920; Masanza et al., 2005). Adults are nocturnally active and attracted to the host plants by volatiles emanat- ing from fresh and decomposing banana material (Budenberg et al., 1993b; Braimah & van Emden, 1999). The males produce Correspondence: May-Guri Sæthre. Tel: +47 922 53 213; fax: +47 6494 9226; e-mail: may-guri.saethre@bioforsk.no an aggregation pheromone, attractive to both sexes, in which sordidin is the major component (Budenberg et al., 1993a; Beauhaire et al., 1995). The weevil displays a K-selected life cycle (Pianka, 1970), with a lifespan of up to 4 years (Rukazambuga et al., 1998) and low fecundity (Gold et al., 2002). Although adult weevils feed mostly on banana residues (Gold & Bagabe, 1997), the larvae cause crop damage by tun- nelling into the corm, pseudostem and true stem of the living plant (Rukazambuga, 1998). This leads to a reduction in water and nutrient uptake abilities, which in turn reduce plant size and vigour, causing toppling and snapping, a lower number of suckers and a delay in flowering (Seshu Reddy et al., 1995; Rukazambuga et al., 1998, 2002). These, combined with other Published 2011. This article is a U.S. Government work and is in the public domain in the USA.