Evaluation of Peanut and Four Green Manure Crops as Host Plants for Scepticus uniformis (Coleoptera: Curculionidae) in a Frame Field

We investigated the abundance of Scepticus uniformis Kono (Coleoptera: Curculionidae) on peanut Arachis hypogaea L. and four species of green manure crops in a frame field during summer to find plants antagonistic for nematodes that can be used in the habitat of this weevil. Weevils bred abundantly in the soil in plots of peanut and African marigold Tagetes erecta L., poorly in plots of showy crotalaria Crotalaria spectabilis Roth, and not at all in plots of sorghum Sorghum bicolor (L.) Moench or Sudan grass Sorghum X drummondii (Nees ex Steud.) Millsp. et Chase. Similar results were obtained in a connected frame field experiment using wild-collected adults which could migrate among frames planted with peanut, African marigold, sorghum, or nothing. These results suggest that showy crotalaria, sorghum, and Sudan grass are not suitable as hosts for S. uniformis, so we can use these nematode-suppressing green manure crops in areas where weevil are found. More detailed investigation of the actions of the plants on oviposition and the survival of weevils is needed to support their use in integrated pest management.