Value-Added Food and Processes: Biocontrol Opens New Prospects in the Sahel

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Integrated Pest Management Innovation Lab

In Niger, the sun is ablaze. The earth below is orange, dry, cracked, and not a drop of water pinches the sky. The West African nation possesses a distinctive climate with extremely high temperatures and short rainy seasons that result in the dependence on drought-resistant crops, namely, millet. Niger is the largest producer of millet, with 6.9 million hectares of the protein- and iron-rich crop that can be made into food, fodder and more. Millet is an incredibly resilient grain, but its match is met in a one-inch worm called the millet head miner.

The millet head miner is a major threat to food security in Niger, destroying nearly 85 percent of yields; the pest deposits eggs in the heads of millet and the caterpillars leave long, winding tunnels around the panicle. When the pest matures, it drops to the ground and pupates in the soil, returning the following season. While the millet head miner is difficult to control, researchers funded by the Feed the Future Innovation Lab for Collaborative Research on Sorghum and Millet are working to fully develop and scale-up a biocontrol program that is helping to restore access to food and form a new market for producers.

Ibrahim Baoua is a professor of entomology at the University of Maradi in Niger and a collaborator on the project. “Millet is a cereal that is well adapted to the environment and the arid Sahelian climate,” he said. “It provides most of the food for Niger. Any increase in millet production will impact at least 90 percent of Nigeriens. In a village of 2,000 people, an increase in production of 500 tons of millet will contribute majorly to food security.”

The Sorghum and Millet team and collaborators mass-multiply and release Habrobracon hebetor, a parasitic wasp local to the Sahel, to control the millet head miner. The wasp already naturally parasitizes the pest but too late in the season when significant damage to millet has already taken place. Mass-multiplying and releasing the natural enemy early in the growing season when the crop begins producing spikes has shown an increase in millet yields up to 34 percent.

While the release of natural enemies against the head miner could seriously improve food security in Niger, where 20 percent of the population cannot meet their food needs, it’s the sale of H. hebetor that has elevated an entirely new market in the Sahel. H. hebetor is not sold to individual farmers but to farmer cooperatives. Sets of 15 small jute bags — filled with enough wasps to cover a whole village’s fields, along with a mixture of grains, flour and the larvae the wasps are reared on — are sold to the cooperatives, who then disperse the natural enemies on a village-wide basis.

In the Sahel so far, sales have reached up to 6,133 parasitoid bags a year.

Laouali Amadou, a PhD student working on the biocontrol of the millet head miner, said that a market that targets a collective group over an individual ensures a greater outcome for farmers who earn a very low income. Buying in groups, he said, will help the cottage industries to produce more and earn more profit.

“The production and sale of parasitoids in Niger is carried out by eight farmer cottage industries including one agribusiness…The money from the natural enemies business belongs to community cottage industries with 10 percent from the amount used to pay labor,” he said.

Further, a series of trials has greatly improved the process of developing the natural enemy, increasingly adding value to the sale of H. hebetor as a whole:

  • H. hebetor is reared on an alternative host, the rice moth Corcyra cephalonica, instead of the millet head miner, which cuts production costs.

  • The addition of 50 percent cowpea flour in the jute bags harvests the best quality and quantity of rice moth larvae for the production of H. hebetor.

  • While H. hebetor is released in the fields through a jute bag, the size of the bag has significantly decreased over time to save on the amount of grain that is being used inside.

In the future, Baoua said that there are a number of ways he wants to add even more value to releasing the natural enemy, like helping farmers to collectively face other constraints on cowpea or garden crops.

Muni Muniappan, director of the Feed the Future Innovation Lab for Integrated Pest Management and a sub-awardee on the project, said that biocontrol naturally reduces the use of pesticides, which threaten human and animal life and are expensive to buy, but that isn’t the only step to improving the livelihoods of smallholder farmers.

“We don’t just want to increase the amount of food people have but their ability to earn income from the many channels in which they have it,” he said.

In Niger, you might come across women sitting in a circle, harvesting okra in the shape of bulky stars. You might see people milling around, on their way to the market, to the farm, a jug of water or corn on the cob in hand as evidence. Hopefully you’ll also see the swaying stalks of millet, growing abundantly, healthily, and pointing upward toward the fierce but luminous sky.

By Sara Hendery