A natural way to control pests: the Push-Pull method in Ethiopia
The main sources of income for small-scale farmers in the Tolay region in the southwest of Ethiopia are cereal growing and livestock production. However, many farmers are facing numerous problems presently. Alongside depleted soils, they also have to wage a fight against two dangerous enemies: the stem borer moth and the striga weed. The stem borer moth lays its eggs on maize and sorghum plants; the larvae then bore into the plant’s stem, eating it from the inside. Striga is a parasitic weed that penetrates the maize roots, drawing nutrients and water from the plant. If stem borers and striga occur together, they can cause huge crop losses – with fatal consequences for a region such as Tolay, where many live below the poverty line.
The Push-Pull method helps to defeat both enemies. The leguminous plant desmodium is planted in between the rows of maize or sorghum. It then suppresses the growth of the striga weed by natural means – as opposed to the patented alternative of chemical company BASF, which offers hybrid maize varieties resistant to Imazapyr, a herbicide (StrigAway®) that kills the striga seed as it germinates. The smell of desmodium repels the stem borer moths and drives them away from the main crop (push). Around the fields, the farmers plant napier grass, which attracts female stem borer moths (pull). They place their eggs in the grass where, once they try to bore into the grass, the hatched larvae die in the sticky substance the grass produces. Soils and livestock also benefit from Push-Pull. Like other leguminous plants, desmodium fixes nitrogen from the air with its root nodules. Its organic matter and the animals’ manure can then be composted and used to boost soil fertility. The napier grass serves as a highly nutritious extra fodder for the cattle that increases milk production. Farmers can also generate an additional income by selling the remaining grass.