Enhancing dissemination of Beauveria bassiana with host plant base incision trapfor the management of the banana weevil Cosmopolites sordidus

The banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) is an important pest of highland banana in East and central Africa. It causes yield loss of up to 100% in heavily infested fields. Studies were carried out in Uganda to evaluate the efficacy of the the plant base incision trap in attracting C. sordidus and to determine the potential of using the trap in enhancing dissemination of the entomopathogenic fungi, Beauveria bassiana for the pest control. Field experiments were carried out in an established banana field of C. sordidus susceptible East African Highland Banana cultivar, Nabusa (AAA-EA).  There were significantly more weevils recaptured in the incision trap (14.4%) than the conventional pseudostem trap (4.7%). After laboratory incubation, more weevils died due to pathogen infection  from plots where the incision trap was used in combination with B. bassiana (25.9%) compared to where the pathogen was applied around the plant base without the incision (15.9%). Weevils showing signs of mycosis were recovered at 6 and 9 m from the pathogen release point, suggesting that the weevils can pick the pathogen from the aggregation point and disperse it. This data  demonstrates that the incision trap is more attractive to C. sordidus than the conventional pseudostem trap and might be used to enhance dissemination of B. bassiana among adults.   Key words: Entomopathogenic fungi, horizontal transmission,  pseudostem trap.