Cover cropping reduces the abundance of the banana weevil Cosmopolites sordidus but does not reduce its damage to the banana plants

•The cover crop Paspalum notatum reduced the abundance of adult weevils.•The proportion of newly emerged adults was increased by the cover crop.•The proportion of newly emerged adults was negatively correlated with earwig number.•Corm damage was higher in cover crop plots than in bare soil plots.•Fruit biomass was lower in cover crop plots than in bare soil plots.

Diversification of cropping systems raises new questions in the functioning of arthropod communities and biological control of pests. In banana cropping systems, the addition of a cover crop can increase biodiversity in general and the diversity and abundance of arthropod generalist predators in particular. We measured the abundance of a major pest of bananas, the banana weevil Cosmopolites sordidus, in plots with a cover crop, Paspalum notatum, and in plots with bare soil; all plots had banana plants. We also measured the effect of the cover crop on the damage done to corms by weevil larvae and on banana fruit biomass. The addition of the cover crop reduced numbers of mature C. sordidus adults but failed to reduce damage to corms. The proportion of young adults, which reflects survival of eggs and larvae, was higher in cover crop plots than in bare soil plots and was negatively correlated with the abundance of the earwig Euborellia caraibea. Fruit biomass was lower in cover crop plots, perhaps because of competition between the banana crop and the cover crop.