10 May 2021
For a long time, tomato farmers have relentlessly relied on chemical control in the management of Tuta absoluta. However, this strategy has several negative effects on the health of humans, livestock, and does not discriminate natural enemies and other beneficial insects. Furthermore, the synthetic pesticides tend to be not so pocket friendly to the farmer thus increasing the cost of production.
Tuta absoluta commonly known as tomato leaf miner, is a small yet highly destructive pest that mainly affects tomatoes. Although originally from South America, it has spread to several countries in Europe, Asia and almost all countries in Africa within a short time, causing huge losses to tomato farmers. The tiny T. absoluta larvae tunnel into the leaves, eating the green part of the leaf, causing the leaves to dry out. They also tunnel into tomatoes causing deformities and rotting due to secondary infection.
As ravaging impact of T. absoluta continues to be felt by most tomato farmers in Kenya, David Irungu Mwangi, a farmer who hails from Gatitika in Mwea district, Kirinyaga county, attests to losing half of his crop last season. According to Mr. Irungu, although he had invested Kshs.250,000 in his three acres where he planted tomatoes, his proceeds were only Ksh. 120,000; a loss he attributes to the adverse destruction of the pest. “Tomato farmers can relate to the pain I felt,” he said with a tone of sadness. Nevertheless, he decided to use his meagre savings to establish another farm, only that this time he planted tomato on a smaller piece of land.
In addition to tomato, Mr. Irungu also grows bell and chili pepper for commercial use. He explained that he has used different pesticides from several companies manufacturing farm chemicals, with little or no success. “I have tried a variety of pesticides on my tomato and pepper farm. Various experts have visited my farm and recommended a ‘ton of the best-bet chemicals’ to rid my tomato crop of Tuta absoluta, but none has worked well,” he said. He even opted to increase the frequency of spraying the tomatoes to at least thrice a week, but the results were still disappointing. He noted that T. absoluta is a menace right from when the crop is still in the nursery through the entire crop season.
Determined to salvage his crop, Mr. Irungu sought help from Kenya Agriculture and Livestock Research Organization (KALRO) office in Kimbimbi, Mwea county. He was then introduced to the icipe Tuta Integrated Pest Management team who agreed to visit his farm to ascertain the gravity of the problem. The team identified the damage caused by T. absoluta and proposed to do a demonstration on management of the pest on Mr. Irungu’s farm. The farmer quickly accepted the proposal and thus the icipe group organized for the release of the natural enemy for the management of the pest. “I felt that I had nothing to lose by trying one more option, since everything else had failed. They told me they would bring another insect that destroys the pest and its eggs,” Mr. Irungu said.
icipe and national partners including Kenya Agriculture and Livestock Research Organization (KALRO), Kenya Plant Heath Inspectorate Services (KEPHIS), Pest Control Products Board (PCPB) and the Ministry of Agriculture in Kirinyaga county participated in the release of the natural enemy, Dolichogenidea gelechiidivoris in Mr. Irungu’s farm on 29th October 2020. This was the first time the parasitoid was being released outside its native range of South America. Mr. Irungu is now eagerly waiting for the just released parasitoid to rescue the farmers from the destructive pest and halt the over reliance on chemical use. He commended icipe for the effort to address the plights of the farmers.
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