'Push-Pull' strategy helps end hunger and poverty for farmers in sub-Saharan Africa

Push-Pull techniques help African farmers increase productivity, strengthen soils, and protect staple foods from pests – all without expensive chemical fertilizers or pesticides.

[Editor's note: The United Nations has declared 2014 the International Year of Family Farming (IYFF) to highlight the importance of family and smallholder farmers. Food Tank is partnering with the UN Food and Agriculture Organization (FAO) to commemorate IYFF and will feature weekly posts and other media highlighting the innovations that family farmers are using to alleviate hunger, poverty, and environmental degradation along with the campaigns and policies that support them.]

The UN Food and Agriculture Organization reports that a quarter of the world’s hungry live in sub-Saharan Africa. Supporting small-scale farmers will be critical to reducing hunger and poverty in the region. Kenya’s International Center of Insect Physiology and Ecology (icipe) has developed an intercropping strategy, called Push-Pull, that helps farmers increase productivity, strengthen soils, and protect staple foods from pests – all without expensive chemical fertilizers or pesticides.

Push-Pull was originally designed to help farmers deal with crop loss from two especially destructive pests: stemborers and striga weeds. Family farmers in sub-Saharan Africa often lose up to 80 percent of their crop to stemborers, a type of moth that lays its eggs inside the stems of corn, sorghum, and other staple crops.

Perhaps more insidious is striga, a parasitic plant, also known as witchweed, which stunts crop growth and regularly causes farmers to lose 30 to 100 percent of their crop. The combination of these pests often destroys entire harvests and costs an estimated $7 billion every year. Typical pesticides and herbicides that might solve the problem are expensive, environmentally damaging, and largely ineffective once the pests are established. 

Push-Pull offers a different solution, introducing plants that naturally repel and attract stemborers to keep them away from crops. The system adds a repellent crop to farmers’ fields, such desmodium, and then surrounds the field with a border of attractive plants, such as Napier grass.

Stemborers are then simultaneously pushed away from the maize field and pulled toward the border. In addition to protecting fields from stemborers, the intercropped desmodium plants control striga, producing a substance that causes suicidal germination—promoting striga’s initial growth and then stopping it.This eliminates striga plants from these fields, and because desmodium is a perennial plant, it keeps them free of striga between harvest seasons as well.

Desmodium also functions as a cover crop, which can be plowed back into the soil to increase soil health and nutrient content. Napier grass is also useful as a feed crop for animals, and its root system helps prevent erosion.

So far, more than 55,600 farmers in East Africa have implemented icipe’s Push-Pull system, resulting in more than triple the average maize yields achieved under previous practices. Icipe is working to expanding the practice across sub-Saharan Africa, connecting with farmers through radio, print materials, and hands-on training programs.

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