Kingdom Animalia Class Insecta Section Cossina Scientific name Bactra venosana | Phylum Arthropoda Order Lepidoptera Family Tortricidae Rank Species | |
Similar Bactra, Bactra lancealana, Crocidosema plebejana, Tathorhynchus exsiccata, Stenoptilodes taprobanes | ||
Bactra venosana, the nutgrass borer or nutsedge borer, is a moth of the Tortricidae family. It has a wide distribution, from southern Europe, North Africa and Asia Minor to India, Sri Lanka, southern China, Malaya, Australia and into the Pacific where it is found on Java, Borneo, the Philippines, Taiwan, Timor, the Solomons, the Carolines and Fiji. It was introduced to Hawaii in 1925 to control nutsedge. It is now found on Kauai, Oahu, Molokai, Maui, Lanai and Hawaii.
The larvae feed on Cyperus rotundas and Kyllingia species, including Kyllingia brevifolia and Kyllingia monocephala. They bore the stem of their host plant.
Affected plants first show a withering of the inner leaves, which become yellow and finally die. Young larvae are pale, glassy yellowish, with a shining black head. Full-grown larvae are green or pale yellowish. They spin a tube of silk in the stem and in this cocoon sheds its skin to turn into a pupa of about 5–7 mm long.