Investigation on the Use of trapping in the Management of the Banana Weevil, Cosmopolites Sordidus (Germar)(Coleoptera: Curculionidae) in Mauritius

Abstract

The banana weevil, Cosmopilites sordidus (Germar) is an important pest of banana in Mauritius. At present, control of C.sordidus is achieved by soil treatment with insecticides by growers. No research has been conducted to understand the pest abundance and develop alternative methods to better manage C. Sordidus with minimum use of insecticides. In this 11-month study, the potential of two trap types (pseudostem and pheromone traps) to lure weevils in banana fields was determined at three different ecological sites (Clemencia, Nouvelle France and Rivière du Poste). The effect of treatment of pseudostem trap with insecticides (Imidachloprid, Cyfluthrin and Lambda-Cyhalothrin) was evaluated under field condition. The damage level in fields at Clamencia and Rivière du Poste was also determined. The pseudostem and pheromone traps were effective in luring banana weevils. The average number of weevil caught per week in pseudostem and pheromone traps were 2.03 and 5.92 respectively. Relatively more adults were caught at Nouvelle France. This indicates that weevils were in higher numbers in the super humid site (Nouvelle France) compared to humid Rivière du Poste and dry (Clemencia) sites. Pseudostem treated with Imidachloprid was more effective than the other two insecticides. Damage by C. Sordidus ranged from 15.5% to 31% at Clemencia and Rivière du Poste. Pseudostem and pheromone traps can be used for monitoring and mass trapping of C.Sordidus. A better weevil management can be easily achieved by the use of either pseudostem or pheromone traps and proper timing of soil drenching. This will, no doubt greatly reduce insecticide application in banana field.

Keywords: Banana, Cosmopolites sordidus, pseudostem and pheromone traps, insecticides, mass trapping