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MATERIALS AND METHODS Various experiments have been carried out to fine-tune rearing techniques for H. hebetor and releases techniques. For op<mal rearing techniques, we tested: Ø Different stages of host larvae that induced higher produc<on of offspring Ø Different sizes of ma<ng container (30, 50, and 70 cc) and ma<ng <me (15 min, 1h, 12h, 24h, and 48h) for ma<ng success Ø Different feeding medium (water, honey, sugar) to support longest lifespan For releases techniques the following have been tested: Ø Different numbers of parasitoids (0, 400, 800, 1600) were released in 28 villages in two districts of Niger in 2014 and 2015 to iden<fy numbers needed per millet acreage Ø Parasitoids were released at different pearl millet development <me (Panicle emergence, flowering stage, grain filling stage) in 18 villages in Niger to iden<fy best <ming for effec<ve control of the pest Ø Parasitoids were also released 4 weeks and 6 weeks aSer first flights of the head miner moths in 12 villages to also determine best <ming of releases DISCUSSIONS These results have several implica<ons: i) The current rearing technique can be significantly improved for cost-effec<ve mass parasitoid produc<on; ii) Parasitoid mul<plica<on can start 4 weeks prior to on-farm release in mid-July when the rainy season is well established and temperatures have cooled; iii) Parasitoid adults can be stored for 2 weeks for <mely release as long as they are fed with sugar or honey solu<on, thereby allowing a constant supply to control MHM; and iv) Parasitoids can be released more than 2 weeks before MHM larvae are present in the field and survive on other food sources, such as nectar, fruit, pollen, and honeydew. REFERENCES – Ba et al. (2014). Augmenta<ve on-farm delivery methods for the parasitoid Habrobracon hebetor Say (Hymenoptera: Braconidae) to control the millet head miner Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae) in Burkina Faso and Niger. BioControl 59, 689–696. RESULTS Ø Highest produc=on of parasitoid is achieved when H. hebetor are given later larval stage of C. cephalonica to parasi=ze. Ø Honey and sugar solu=on are the best medium suppor=ng longest parasitoid lifespan (up to one month) for use in a =mer manner. Ø Op=mal =me for ma=ng, egg fer=liza=on, and highest progeny produc=on is achieved when females are confined with males for 24h in 30ml capacity vial. Ø Parasitoid numbers can be increased by 50% when adding a small propor=on of cowpea flour to the millet-based diet of C. cephalonica larvae. Ø Releases of the parasitoids significantly increased the parasi=sm of MHM as compared to control villages. Ø Significantly higher parasi=sm was recorded in villages where 1600 parasitoid were released Ø Best =ming for parasitoid releases is either at panicle emergence or 4 weeks aZer first flights of the moth ABSTRACT:Augmenta<ve biological control by the parasitoid braconid wasp Habrobracon hebetor (Say) (Hymenoptera: Braconidae) is the most promising strategy to control millet head miner (MHM), a major insect pest of pearl millet in the Sahel. Because there is not a suitable host to maintain the parasitoid popula<on in the field between millet growing seasons, there needs to be a sufficient supply of parasitoids for release each year. Therefore, the aim of this study was to: i) fine tune parasitoid rearing process, for cost-effec<ve produc<on to meet increasing demands; and ii) fine-tune parasitoid releases for effec<ve control of the MHM. Our findings lay basis for standardize produc<on of parasitoids for industrial use in the Sahel. INTRODUCTION 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 loss. Augmenta<ve biological control with releases of the parasitoid braconid wasp Habrobracon hebetor Say is the most promising strategy for controlling MHM (Ba et al., 2014). To make the biological control program sustainable, parasitoids need to be available for use every year. For this, an available op<on is the establishment of a codage industry to scale up parasitoids produc<on. Parasitoid produc<on needs to be op<mized to make the codage industry viable and to meet farmers’ needs. Since 2013, different experiments have been carried out to fine-tune and standardize the rearing and release techniques for H. hebetor for industrial use. 1 ICRISAT, 2 UoM, 3 INERA, 4 INRAN, 5 Virginia Tech, Acknowledgements: The feed the future InnovaKon Lab for CollaboraKve Research On sorghum and Millet; and the Mcknight FoundaKon Ba 1 M., Baoua 2 I., Kabore 3 A., Amadou 4 L., Karimoune 1 L., 5 Muniappan R.,. On-farm augmentative releases of parasitoid wasps for biological control of the millet head miner WCA A global alliance for improving food security, nutri;on and economic growth for the world’s most vulnerable poor
