IITA: Biopesticide paves comeback of cabbage in West Africa
September 24, 2009
Moth (above) and juvenile (bottom) of Plutella xylostella. IITA scientists have been successful in managing the pest using the biopesticide B bassiana. Photos from Wikimedia Commons.
Cabbage farms in West Africa ravaged by the Diamondback Moth (DBM), Plutella xylostella, are set to make a strong comeback as IITA scientists in the Benin Republic successfully develop and field test the use of a biopesticide based on Beauveria bassiana, a fungus, against the pest. For years, DBM has been devastating smallholder and commercial cabbage farms in the region, affecting farmers' incomes and market prices of the crop.
“From a disappointment, cabbage production now looks very promising with the use of B. bassiana,” says Raymond Ahinon, head of the Crop Department of the Songhai Center — a facility that specializes in training, production, and research-for-development of sustainable agricultural practices — in Porto Novo, Benin.
“We have been using B. bassiana on our cabbage farms for some time now, and it has effectively kept DBM in check,” Ahinon adds.
Cabbage, and its cousin kale, are regarded as high-value cash crops. Compared to other vegetables such as carrot and lettuce, farmers say returns are higher with cabbage cultivation.
Despite this, thousands of farmers in West Africa had to abandon cabbage production because of the destruction caused by DBM on their farms. Consequently, market prices for African cabbage have jumped because of dwindling supplies.
The situation is worsened by the high costs associated with synthetic pesticide - farmers' only recourse against DBM.
"The most common synthetic chemical pesticides used by farmers are bifenthrin and deltamethrin," says Ignace Godonou, IITA Entomologist based in Benin. "About 19 applications of these chemicals are needed within three months of the crop's growth prior to harvest. But the cost of these chemicals are oftentimes prohibitive for most farmers."
Globally, chemical control is estimated at about US$1 billion annually, not counting the costs to human health and the environment related to its use.
These past few years, farmers, like Louis Awandjinou who has been cultivating the crop since 1986, have observed that the chemical pesticides is proving ineffective against DBM. Godonou explains that this is because the pest has developed resistance to a wide range of synthetic insecticides.
Alternatively, farmers have been using botanical pesticides, mostly seed extracts of the neem tree, against DBM and a wide range of other arthropod pests, but the success of this approach has been limited.
Godonou says that when used in an integrated pest management approach, B. bassiana offers a cost-effective solution for the sustainable control of DBM.
A study by Godonou et al published in the Crop Protection Journal in 2008 indicated that B. bassiana grows naturally in soils throughout the world, generally specific to target pests, persists in the environment, ecologically-friendly and easy to mass produce.
"With the ability to remain active on the field for several months after initial application, B. bassiana will end the rigor of repetitions and high costs and risks associated with the use of chemical pesticides," Godonou adds.
A co-author of the study, C. Atcha-Ahowe, also an IITA scientist, says field trials of B. bassiana have sparked high demand for it. "Many of the farmers who abandoned cabbage cultivation because of DBM but who want to go back are requesting for B. bassiana , but the problem is the availability of the product," he says.
Like Green Muscle® which was picked up by the private sector, Godonou is hopeful that B. bassiana would go the same route and be adopted by vegetable farmers across the continent.
Jeffrey T. Oliver, o.jeffrey@cgiar.org Corporate Communications Officer (International)
Godwin Atser, g.atser@cgiar.org Corporate Communications Officer (West Africa)
Communication Office IITA - Headquarters Ibadan, Nigeria
About IITA Africa has complex problems that plague agriculture and people's lives. We develop agricultural solutions with our partners to tackle hunger and poverty. Our award winning research for development (R4D) is based on focused, authoritative thinking anchored on the development needs of sub-Saharan Africa. We work with partners in Africa and beyond to reduce producer and consumer risks, enhance crop quality and productivity, and generate wealth from agriculture. IITA is an international non-profit R4D organization since 1967, governed by a Board of Trustees, and supported primarily by the CGIAR.
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