Augmentative 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 population 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-effective production to meet increasing demands; and ii) fine-tune parasitoid releases for effective control of the MHM. Our findings lay basis for standardize production of parasitoids for industrial use in the Sahel.

1. 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.
1ICRISAT, 2UoM, 3INERA, 4INRAN, 5Virginia Tech,
Acknowledgements: The feed the future InnovaKon
Lab for CollaboraKve Research On sorghum and Millet;
and the Mcknight FoundaKon
Ba1 M., Baoua2 I., Kabore3 A., Amadou4 L., Karimoune1 L., 5Muniappan R.,.
On-farm augmentative releases of
parasitoid wasps for biological control of
the millet head miner WCA
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