• Katherine Wagner-Reiss

Great Farming Ideas: PICS

Cowpeas are one of the staple foods of Burkina Faso. They are served to children in schools, served for home-cooked meals, and even used as fodder for livestock. Female farmers grow and sell the beans to make money to buy other necessities. So, an invention that would allow the beans to be stored safely, without the use of chemicals, would be a boon to the community. It would be a special aid to these entrepreneurial women, who could then sell the stored beans in seasons when the selling prices were higher.


A brilliant answer to the problem of safe, low-cost cowpea storage was designed by scientists at Purdue University. They designed PICS (Perdue Improved Cowpea Storage) bags: three-layer, airtight, plastic bags. Initially, the bags were specifically designed to kill the cowpea weevil, an insect frequently associated with cowpeas as they are harvested. If the weevils are allowed to live in stored grain, they quickly multiply and destroy the saved beans. Thus, the beauty of these bags: weevils trapped in these bags quickly die from lack of oxygen. Subsequently, the bags were marketed for foods other than cowpeas, so the acronym PICS now stands for Perdue Improved Crop Storage.


There are many advantages to the PICS bags. Their use is simple to demonstrate. Two sizes are offered, both holding manageable quantities. The bags are reusable unless visibly damaged. There is a local supply chain since the bags are manufactured in Africa and distributed throughout the Sahel.

Future studies of the bags include looking into other crops that can benefit from low-oxygen storage, designing bags with a fourth outer layer that can prevent rodent damage, and understanding the environmental impacts of creating and then disposing of worn plastic bags. A problem that governments, businesses, and NGOs must confront is the unscrupulous manufacturing and selling of counterfeit bags that are not airtight.


Sometimes the best inventions are the simplest. With PICS bags, not only can a mother save bags of cowpeas to feed her family, but she can also save them to sell when the seasonal market prices are highest.


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