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Biological control of the millet head miner in Niger and Senegal

  1. Biological control of the millet head miner in Niger and Senegal Malick Ba, PI, ICRISAT Ibrahima Sarr, Co-PI, ISRA Ibrahim Baoua, Co-PI, University of Maradi, Niger Muniappan Rangaswamy, Co-PI, Virginia Tech George Norton Collaborator, Virginia Tech Laouali Amadou, INRAN SMIL incepHon meeHng, Saly-Senegal, April 23-25
  2. The Pearl Millet •  In the Sahelian region of West Africa, pearl millet, is a major cereal food crop. •  In addiHon to the extreme climaHc condiHons, the millet crop suffers from many constraints, including insect pests. •  The millet head miner (MHM), Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae), is one of the key insect pest of PM in the Sahel region.
  3. The millet head miner •  Damage to the crop is due to larvae that feed on the panicle •  As the larvae chew between the rachis and flowers, they liX the destroyed flowers or developing grains, leaving a characterisHc spiral paYern •  Typical yield losses range from 40 to 85%
  4. MHM biological cycle
  5. Why biological control? •  Control with insecHcides is not realisHc for subsistence farmers because of prohibiHve cost and risk to health and the environment. •  Furthermore, aYempts to develop insect resistance varieHes to the MHM have thus far been unsuccessful. •  Cultural management has limited applicability •  EffecHve biocontrol agents are available
  6. Why biological control? •  Availability of effecHve biocontrol agent •  The braconidae parasitoid wasp Habrobracon (=Bracon) hebetor Say naturally inflicted significant mortality to MHM. •  H hebetor can be easily mass reared
  7. How augmenta=ve releases are made? •  The parasitoids were released in 15 cm × 25 cm jute bags (+200 g of millet grains + 100 g of millet flour + 25 larvae of the rice moth Corcyra cephalonica (Stainton) + two mated H. hebetor females). •  The jute bags were suspended to the ceiling of tradiHonal straw granaries. •  Parasitoid offspring’s was able to escape through the jute meshes and straw granaries and dispersed to parasiHze MHM larvae in millet fields.
  8. 0 5 10 15 20 25 30 6 7 8 9 10 11 12 13 14 Number of parasitoids emerging from the jute bags Days aCer confinement Daily H. hebetor adults emerging from the jute bags Total: 70 parasitoids Emerging =me: 8 days How effec=ve it is?
  9. How effec=ve it is? 2007 2008 0 20 40 60 80 100 120 Burkina Faso Mali Niger % parasi=zed larvae H. hebetor releases villages Control (no releases) 0 20 40 60 80 100 120 Burkina Faso Mali Niger % parasi=zed larvae H. hebetor releases villages Control (no releases)
  10. Completely damaged panicles Saved panicles Up to 30% grain yield gain (Baoua et al. 2013 How effec=ve it is?
  11. Why another project? •  There have been some failures of this technology, because for unknown reasons some bags do not produce parasitoids. •  Moreover, in many cases the emerging offspring was male biased which reduces control because only females parasiHze MHM larvae. •  Parasitoids only target late instars larvae, control of eggs could enhanced the BCP
  12. Why another project? •  Finally Hmely release of H. hebetor parasitoids is challenging •  Releases of parasitoids are needed every growing season. •  High demand for parasitoid that research laboratories could not meet
  13. Overall objec=ve: significantly reduce insect pest damage to millet for improvement of crop producHvity.
  14. Specific Objec=ves •  OpHmized H. hebetor rearing technique for enhancement of numbers and longevity of emerging H. hebetor parasitoids •  OpHmized H. hebetor release techniques for beYer control of MHM •  Iden=fy/test egg parasitoids for enhancement of the BCP §  Assess the economic feasibility of establishing a coYage industry for parasitoid producHon (to make parasitoids available every year)
  15. Objec=ve 1: Op=miza=on of H. hebetor rearing techniques •  Ac=vi=es –  Evaluate performance of H. hebetor when reared on C. cephalonica feeding on different types of medium –  IdenHfy C. cephalonica opHmal larvae stage for H. hebetor parasiHsm –  Determine best H. hebetor/C. cephalonica raHo for the greatest number of parasitoid offspring –  Assess superparasiHsm of H. hebetor
  16. Objec=ve 2: Op=miza=on of H. hebetor release techniques •  Ac=vi=es –  Test direct release of H. hebetor adults using different numbers of parasitoids per area of pearl millet –  Determine beYer millet growing stage (panicle exerHon, flowering) for releases of H. hebetor –  Determine beYer Hme for release of H. hebetor aXer first appearance of MHM moths/eggs.
  17. Objec=ve 3: Assess effec=veness of egg parasitoids for controlling MHM •  Ac=vi=es –  Assess seasonal occurrence of MHM egg parasitoids in Senegal and Niger –  Construct life table and assess demographic parameters of egg parasitoids –  Assess interspecific/intraspecific compeHHon among the egg parasitoid species –  Develop mass rearing technique for egg parasitoids
  18. Objec=ve 4: Assessing the economic feasibility of establishing parasitoid coYage industry •  Ac=vi=es –  Conduct baseline survey to characterized pearl millet growers –  Conduct ex-ante studies to assess the kind of business model to be develop (individual enterprise, cooperaHve…) –  Assess the cost/benefits of mass rearing and releases of H. hebetor
  19. TOC: Causal pathway from ac=vi=es to impacts Ac=vi=es Intermediate outputs Final outputs Impacts Test effecHveness of MHM egg parasitoids Life tables and demographic parameters of parasitoids assessed Approaches for release of egg parasitoids tested 1 Ph.D. student completed Knowledge obtained of opHmal approach to release parasitoids OpHmize H.hebetor rearing and release techniques -Learn effects of C. cephalonica rearing medium on H. hebetor development -BeYer Hming for releases of H. hebetor assessed Protocol for opHmal H. hebetor rearing and release; 1 Ph.D. student completed Knowledge of opHmal Hming of releases, number of parasitoids to release per ha Assess economic feasibility of H. hebetor industry IniHal baseline survey -economic benefits of the parasitoid releases. Design of the coYage industry for parasitoid release; 1 MS student completed -Reduced losses due to MHM; higher incomes for farmers and those producing parasitoids;
  20. Thank you! ICRISAT is a member of the CGIAR Consortium Thank you!
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