Tanzania: Farmers use traditional and chemical methods to manage maize pests

| May 26, 2019

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It’s the rainy season in Karagwe District, and 58-year-old farmer Jane Joseph is standing in her maize farm, wondering why her maize is not growing well. She bends over to observe some maize leaves and notices a caterpillar on the plant.

Mrs. Joseph says: “These insect pests are the result of climate change. Drought and heat have caused them to multiply. We farm lots of maize, but they damage most of our maize, which leads to huge losses.” She says that Fall armyworm eats the stems of the maize plant, and burrows inside the stems and hides.

Karagwe is one of the parts of Tanzania that produces a lot of maize. The area was recently attacked by Fall armyworm, which resulted in reduced harvests and hunger in 2016 and 2017. Farmers in this area have turned to many methods to manage Fall armyworm and other pests, including traditional techniques and chemical pesticides. But both options have downsides. Neither is guaranteed to be effective, and both can be difficult to procure in the right quantities or for the right price.

Protas Patrice is the chairman of Katanda village. When asked which insect pests he knows about, he says: “I know them by their names in the local language, Nyambo. They are called mtobere and kamshokweine. These are small insects that crawl and puncture the stems. They have caused so much damage in the village that about three hundred farmers have given up farming maize.”

Mr. Patrice says he has never used chemical pesticides because they are too expensive. “I cannot spend 50,000 shillings ($22 US) to buy pesticides—and even that wouldn’t be enough to spray the whole farm.”

Catherine Kaungya lives in Kihanga ward, and has been farming her whole life. She grows maize, beans, bananas, and coffee on one acre of land. Mrs. Kaungya says that, nowadays, most farmers use ash and soil to fight insect pests. She herself mixes ash and soil together and pours the mixture on the plant stem. She says it helps, but it’s difficult to make enough to apply to the whole farm.

Cleophace Kanjagaile is an extension officer in Karagwe District. He says the increased number of insect pests that feed on maize is a result of higher temperatures. He confirms that some insect pests eat through the maize stem and create a protective coat around the hole that prevents insecticides from reaching the insects and killing them.

He recommends that farmers use chemical insecticides to manage the pests. He explains: “Lots of farmers use ashes and soil to fight insect pests, but this method is not effective. Farmers should use insecticides. They are a bit expensive, but they are effective and they help famers get a good harvest by preventing insect pests from infesting the crops.”

However, like natural remedies, chemical pesticides are only effective if applied correctly—and even if applied correctly, they may not kill all pests. Avit Theophil is another farmer in Karagwe district. He says that many who have used chemical insecticides complain that their plants wilt and rust forms on the stems and branches, even if the farmer follows the label directions.

He suggests, “Researchers need to find other types of pesticides that work.”

Magdalena William is a plant and seed pathologist with the Agriculture Research Institute in Maruku, Tanzania. She says that it’s important to remember that success in using insecticides—to manage Fall armyworm or any other pest—depends on four factors. First, the specific chemical used. Particular chemicals are effective for specific pests, but do not manage others. Second, the time of application. It is best to use pesticides to manage Fall armyworm early in the morning, or in the late afternoon or evening. Third, the concentration used. Farmers should always follow the directions on the container for what concentration to use. And finally, insecticides are more effective against some life stages of Fall armyworm than others. It is much easier to control smaller rather than larger, older caterpillars.

Farmers in western Tanzania are not accustomed to taking pest management seriously in their maize fields. So, until they and the experts figure out how to manage Fall armyworm and other pests, growing maize may be more complicated and uncertain than it used to be.

This work was created with the support of AGRA, the Alliance for a Green Revolution in Africa, as part of the project, “Integrated project to increase income and improve food security and livelihood among smallholder farmers in the Western Tanzania/ Karagwe region.” The views expressed in this article do not necessarily reflect those of AGRA or any other organization.