Use of host plant resistance for the management of the banana weevil Cosmopolites sordidus (Germar) requires development of rapid cultivar screening methods. A previous study showed prolonged development of larvae feeding on excised plant material of resistant cultivars and suggested partial breakdown of resistance in such plant material. In the current study, development and survivorship of larvae feeding on potted plants of banana cultivars with differing levels of resistance were evaluated. Weevil performance was evaluated on one susceptible (Atwalira), one intermediate (Kabula) and four resistant cultivars (FHIA 17, Kayinja, Kisubi and Yangambi Km5). Differences in development of larvae feeding on the susceptible Atwalira and intermediate/resistant cultivars became apparent at 15 days after infestation of plants. Differences in survivorship of larvae feeding on different cultivars were not statistically significant. Results of this study show that experiments using potted plants can be used to screen for resistance to banana weevil based on the development of larvae. The influence of previous feeding damage to banana plants on larval development and survivorship in a susceptible (Atwalira), an intermediate (Kabula) and a resistant cultivar (Kisubi) was also examined. While no effects on larval development rate were apparent, survivorship was reduced in previously attacked plants for the intermediate cultivar, indicating that resistance may be induced by previous weevil attack of plants.

Host plant resistance is an important tool in the management of the banana weevil Cosmopolites sordidus (Germar). Although ovipositing females do not discriminate between resistant and susceptible cultivars, plants of resistant cultivars have smaller larval populations and sustain less damage in the field. These observations suggest that lower damage levels observed in resistant cultivars reflect larval success. This study was carried out to evaluate laboratory screening of banana cultivars as a rapid screening method for resistance to the banana weevil by determining the influence of cultivars on weevil survivorship, development duration and adult weight. Larvae were raised on corm pieces of two susceptible, three intermediate and four resistant cultivars, resistance categories having been determined from a previous field screening trial. The developmental period was prolonged in resistant cultivars. However, cultivars had less influence on survivorship and adult weight. Moreover, the ranking of survivorship did not correlate with resistance levels observed in the field. The implications of these findings for laboratory screening of cultivars for resistance to C. sordidus are highlighted.