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Armies against armies July 15th, 2018 by

Some battles are harder to win than others. Last year farmers in much of Africa were faced for the first time with a new species of armyworm and saw their maize crops attacked. The fall armyworm had come from Latin America and was unknown to farmers, extension workers and governments. Responses across the continent differed, but quite some governments attempted to stem the tide of fall armyworms with pesticides. In Zambia, the government used the army, deploying soldiers across the country to spray farmers’ maize fields.

But the pest is not easily killed by pesticides and the worry is that this approach will cause more harm than good. The fall armyworm begins life as a caterpillar before becomimg an adult moth. The moth is nocturnal and lives for about two weeks during which it lays its eggs in batches of 100-300 tiny eggs. The small, whitish fluffy spots are mostly found on the underside of maize leaves. When the tiny caterpillars emerge en masse they look like an army, ready to invade the plant. Some armyworms drop off the leaves, hanging on a fragile thread and then carried by the wind to attack neighbouring maize plants. After feeding just a few days on the surface of leaves, the young armyworms hide inside the leaf whorl of young plants. On mature maize plants they tunnel through the husk and chew on soft maize kernels. Either way, the armyworms are protected from pesticide sprays.

Last week, Marcella and I were in Embu County in Kenya, making two farmer training videos on how best to manage the fall armyworm. I was particularly curious to find out if farmers had come up with their own solutions. After all, they have not had a lot of time to experiment. But necessity is the mother of invention, and when livelihoods are at stake farmers can be quick and inventive in finding effective ways to manage damaging pests.

John Fundi, a young farmer in Ugweri village, told us how he merged two independent observations to come up with a life-saving solution. “When my wife cooks in the kitchen, I have seen that when some of the cooking fat is spoiled on the floor, these tiny black ants come and feed on it. And when we dry our maize after harvest, I have seen that some of these ants also carry caterpillars from the maize ears. So I thought that perhaps these ants can help me control the fall armyworm.”

John with his wife and young son now go to their field when the maize is just a few weeks old. With their fingers they smear a little bit of solid cooking fat to the base of the maize stalk. With a small pack of cooking fat, they can easily cover half a hectare. “In no time, the tiny black ants will come to feed on the oil and while they are on the maize they also find any armyworms. Even when we cannot see the tiny caterpillars inside the whorl, the ants will find and kill them,” John says with a satisfying smile. When the maize plant starts to develop maize ears, John and his wife repeat the treatment, smearing the fat at the base of the stalk and one metre high on the stalk.

Neighbours who had sprayed pesticides in vain found it difficult to believe that John’s innovation would work. But as they have seen the results of using cooking fat with their own eyes all have started to copy John’s method. With the videos we hope that examples of innovative farmers like John will inspire farmers and governments across Africa to try out low-cost and simple methods.

In agriculture, armies of ants can do the job of national armies for free – and without the costly and damaging effects of spraying pesticides.

Related blogs

Agro-Insight has written many blog stories on Local innovation and Pest management

Related videos

Scouting for fall armyworms

Killing fall armyworms naturally

Other videos we made that relate to ants used in pest control are:

Weaver ants against fruit flies

Promoting weaver ants in your orchard

Acknowledgement

The videos on fall armyworm are developed in collaboration with the Food and Agriculture Organization of the United Nations (FAO) with funding from the McKnight Foundation’s Collaborative Crop Research Program (CCRP).

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