Gates Foundation funds improved cowpea storage method in central/west Africa

The Bill and Melinda Gates Foundation has awarded $11.4 million to Purdue University (Illinois, USA) Agriculture to help people in 10 African nations safely store cowpeas, an important food and cash crop, and increase their household income on average about $150 per year. With a one-time cost estimated at a little more than $3 per household, farmers in West and Central Africa will learn how to better protect the crop.

Cowpeas are marketed by an estimated 3.4 million households in those countries. Even though yields are low, the legume is one of the few grain crops that can be profitably exported by farmers in this dry, resource-poor part of Africa. Unfortunately, a pest called the cowpea weevil can consume nearly all the cowpeas stored on farms.

"Because of the storage problems, farmers are often forced to sell their cowpeas at harvest, when prices are at their lowest levels," said Joan Fulton, agricultural economist and project director. "If we teach them how to store the cowpeas properly, they can take advantage of higher prices later in the year."

Proven effective in pilot projects, the Purdue-developed hermetic storage method involves triple bagging the cowpeas in plastic and sealing them tight. It's simple and not a new idea, but most producers in the region do not know about it or have not used the method properly. Not only is the process low-cost - basically the cost of the plastic bags - it's also safer than current practices of either no protection or treating cowpeas with insecticides. "The chemicals add to the expense of storage and create health and environmental hazards," Fulton said.

Purdue will work with partners in Africa to recruit and train technicians who will travel from village to village to educate the mostly illiterate population by demonstrating the proper method for cowpea storage. In addition, the Purdue team will work with manufacturers and suppliers in the region to ensure that appropriate plastic bags are available.

"Through a simple, low-cost and environmentally-friendly technology, Purdue will work with African organizations and program managers to reach more than 3 million households with information and tools to prevent post-harvest losses, a key lever for small farmers to gain access to agricultural markets," said Dr. Rajiv Shah, director of Agricultural Development for the Gates Foundation.

Purdue entomologist and team member Larry Murdock began this work with cowpeas more than 20 years ago when, by chance, he figured out why the storage method works. A colleague experimenting with storing cowpeas in two plastic bags used a chemical in one to kill the weevils and left the other untreated as a control. "He thought that his experiment failed because there was no weevil damage in either bag," Murdock said. "I thought that interesting and started to investigate why that was so." It turns out that the pests become inactive in airtight plastic bags because they deplete the oxygen. As a result, they don't feed and can't reproduce, meaning the population doesn't grow and little or no damage occurs.

"While stored cowpeas may only contain a few insects to begin with, each female can produce 40 or more offspring about every month," Murdock said. "If they have air and are able to reproduce, within a few months you have thousands of weevils and nothing left of your crop."

Plastic bags currently used for storage in the region are often vented or thin and prone to puncture, making them ineffective.

Jess Lowenberg-Deboer, director of International Programs in Agriculture, said the project goal is that within five years 50 percent of the cowpeas stored on farms in the region will be kept in triple-layer plastic bags.

The project will combine some of the oldest teaching methods with the latest communication technology. In addition to village demonstrations, the team may try text messages and videos sent to cell phones. Purdue entomologist Barry Pittendrigh, also part of the team, said cell phones are common, even in areas where residents don't have television. "Cell phone use in Africa is rapidly expanding and may be a good way to reach remote areas," he said. "It's free to receive a cell phone message in most West African countries, so using cell phones will not impose an additional cost on the farmers."

The five-year project will cover the countries of Benin, Burkina Faso, Cameroon, Chad, Ghana, Mali, Niger, Nigeria, Senegal and Togo.

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