Potential biological control agents for management of cogongrass (Cyperales: Poaceae) in the southeastern USA.
Cogongrass, Imperata cylindrica (L.) Palisot de Beauvois (Cyperales: Poaceae), is a serious invasive weed in the southeastern USA. Surveys for potential biological control agents of cogongrass were conducted in Asia and East Africa from 2013 to 2016. Several insect herbivores were found that may have restricted host ranges based on field collection data and life histories. Stemborers in the genus Acrapex (Lepidoptera: Noctuidae) were collected from cogongrass in Tanzania, Uganda, and Japan. In the Philippines, larvae of Emmalocera sp. (Lepidoptera: Pyralidae) and Chilo sp. (Lepidoptera: Crambidae) were found boring in cogongrass. Cecidomyiid midges were found in both Japan and Indonesia. A Japanese midge identified as a Contarinia sp. (Diptera: Cecidomyiidae) caused deformation of the stem, whereas the Indonesian midge Orseolia javanica Kieffer & van Leeuwen-Reijinvaan (Diptera: Cecidomyiidae) induced the formation of a basal stem gall. Previous research suggested that the host range of O. javanica was restricted to cogongrass.