Augmentative on-farm releases of parasitoids to control the millet head miner in Niger

The head miner (MHM) Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae) is a chronic insect pest of pearl millet in Niger. Damage is due to larvae that feed on the panicle and caused up to 85% yield losses. Augmentative biological control with releases of the parasitoid braconid wasp Habrobracon hebetor Say is the most promising strategy for controlling MHM. In order to identify the number of H. hebetor adult needed per millet acreage we tested releases of different numbers of parasitoids in 24 villages in Niger for controlling the MHM. The experimental design includes four treatments: i) six villages each supplied with 400 parasitoids; ii) six villages each supplied with 800 parasitoids; iii) six villages each supplied with 1600 parasitoids and iv) six control villages that did not receive any parasitoids. Data on MMH parasitism by H. hebetor were recorded 30 days after releases. The releases of the parasitoids significantly increased the parasitism of MHM as compare to control villages, which did not, received any parasitoid. The highest parasitism was recorded in villages where 1600 parasitoid were released. Large-scale extension of the biocontrol program is discussed.