Senegal: Farmers make natural pesticides from local plants

| November 23, 2020

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Farmers in the Kolda region of Senegal are finding success using local plant leaves, like neem, to make organic pesticides. Penda Traoré manages termites and nematodes using Icacina senegalensis or mankasnasso leaves. She also uses cailcedrat leaves, neem leaves, leaves of the silk tree, together with a layer of ash, to treat her soil. Souleymane Diao, another farmer in the Kolda region, uses a neem mixture to spray plant leaves to control other pests. He sprays in the evening after watering once or twice a week until three or four days before harvest.

Penda Traoré is a farmer from Dianabo, a village seven kilometres from Kolda, Senegal.

In 2013, Mrs. Traoré received training on how to make and use organic pesticides. To protect her onions, peppers, chili peppers, cabbage, and okra, she applies a natural mixture to the soil before planting her crops. She combines a local plant called mankanasso in Mandingo or Icacina senegalensis with ash and the bark of cailcedrat, also known as Khaya senegalensis.

Farming is the main income-generating activity in Kolda, an area in the farming region of Casamance, in southwestern Senegal. This is the wettest part of the country, with an annual rainfall of more than 1,000 mm.

While there’s good rainfall in this area, termites, nematodes, locusts, and other pests sometimes infest the soil or invade fields and destroy crops and plants. To cope, some farmers in Kolda make organic pesticides. The pesticides are accessible and affordable for farmers, and are less dangerous to human health and the environment than chemical pesticides.

Mrs. Traoré is a member of a women’s group in her village. In 2014, her group visited farmers in Thies, 70 kilometres from Dakar, so that the groups could learn from each other. The visit focused on organic farming practices, composting, and organic pesticides.

Mrs. Traoré explains the techniques she learned during her stay in Thies. In order to treat a 10 square metre area, she thoroughly tills the soil to be planted. Then she gathers two kilograms of fresh mankanasso leaves or one kilogram of dried and crushed mankanasso leaves, and sprinkles them on the area. The leaves are dried in the shade to maintain their properties.

She also crushes 500 grams of fresh cailcedrat leaves, a few handfuls of neem leaves, and a few leaves of the silk tree, also called Sodom apple. She pours the entire mixture on the field and spreads it, then adds a layer of ash. She rakes the soil so that it absorbs the mixture. Finally, she thoroughly waters the area for five to eight days before planting. Mrs. Traoré explains, “This kills termites and nematodes.”

The mankanasso mixture manages soilborne pests. But farmers in Kolda use several other organic pesticides to protect their crops. One of them is a neem-based solution.

Souleymane Diao has been a farmer for 20 years. He sings the praises of neem, which he calls a 100% natural insecticide: “All the parts of neem can be used.”

According to experts, neem seeds have the highest concentration of the active ingredients that manage pests, including azadirachtin, which is active against more than 200 insects.

But Mr. Diao makes his mixture from neem leaves. To treat one 2,500 square metre field—about a quarter of a hectare—he thoroughly crushes 10 kg of neem leaves, puts them in a large container, and adds 40 litres of water. He closes the airtight container and leaves it for three or four days. Then he removes the leaves and filters the mixture, adding either pepper powder or milk. To apply the solution, Mr. Diao uses a sprayer or watering can.

Mr. Diao explains: “For five litres, I add the contents of a matchbox of pepper. This serves as a pest repellent. If it’s milk, I use a half-litre per five litres. Milk is not a poison, but it helps the solution stick to the plants.”

The advantage of using neem leaves is that, unlike neem seeds which are only available seasonally, the leaves are available all year round and can be obtained free of charge.

Mr. Diao treats his field in the evening after watering because the effectiveness of the solution decreases with exposure to sunlight. In heavily infested areas, it is recommended to apply the solution twice a week. Otherwise, one application every seven to 10 days is enough. As the neem spray is very bitter, it is recommended to stop the treatment three or four days before harvest.

These organic pesticides are easily accessible and inexpensive for farmers in Kolda, making them a popular method for controlling pests.

Photo: Souleymane Diao’s groundnut field.

This article was produced with the support of the Belgian Development Cooperation, Enabel, and the Wehubit program.