AgroPages-The impact of Africa's tomato Tuta absoluta pest problem-Agricultural news

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Nigeria's tomato supply has been ravaged by the crop pest Tuta absoluta. Prices have soared to around 15 times higher than before the outbreak; but this provides no consolation for farmers, who have lost most of their crops and cannot afford to plant the corn and rice they usually do after harvesting tomatoes.

Since arriving from South America via Spain in 2008, Tuta absoluta has spread across at least 15 African countries. The moth landed in Nigeria, the continent’s biggest economy, in 2015. The main tomato-producing region’s government declared a state of emergency, and the Africa’s richest man, Aliko Dangote, had to halt output at a $20 million processing plant due to lack of supply.

Africa exported almost $800 million of tomatoes in 2015, or about 10% of the world’s total, according to the Geneva-based International Trade Centre. The continent produced $6.9 billion of the fruit in 2013, the Food and Agriculture Organisation estimates.

Tuta absoluta broke out in Zambia last month, raising the threat of infestation in surrounding countries. While the pest is yet to be detected in South Africa, the risk rises as it spreads, Jan Hendrik Venter, a plant health early-warnings scientist at the nation’s Agriculture Ministry, said by e-mail.

“Tuta has the potential to effectively eliminate tomato from the agricultural cycle,” Richard Hopkins, head of pest behaviour at the London-based University of Greenwich’s Natural Resources Institute, said by e-mail.

Cause havoc

“This is going to cause havoc but nobody cares until it hits,” said Shakir Al-Zaidi, managing director at Russell IPM, a U.K.-based pest-management company that’s been fighting Tuta absoluta for 10 years.

Farmers usually increase the amount and frequency of pesticide applications after an outbreak, said Rangaswamy Muniappan, director of integrated pest management at Virginia Polytechnic Institute and State University’s Office of International Research, Education, and Development in Blacksburg, Virginia. Growers in developing countries often use formulations banned elsewhere because it’s all that’s available, increasing risks of cancer and damage to the nervous systems of consumers, he said.

Using more expensive pesticides also raises production costs, he said by phone. Spanish farmers spent 450 euros ($512) more per hectare of tomato when the country in 2006 became the first outside South America to be invaded. Managing the pest cost farmers an extra $500 million annually once it spreads globally, Muniappan said.

Since arriving in Europe, Tuta absoluta spread throughout the Mediterranean and north Africa. The Sahara desert created a buffer zone, but when it got to Senegal and Sudan in 2012, its move to surrounding nations was rapid. Asia too is under threat, with the tomato-leaf miners invading India in 2014, and expected to arrive in Nepal and Bangladesh this year. It spreads through infected seedlings, contaminated fruit or reused crates and boxes.

Pesticide resistance

Farmers have tried controlling Tuta by rotating pesticides so the insects don’t get the chance to develop resistance, and by using pheromone traps, where scents mimicking a female ready to mate attract males, which then stick to glue-covered paper. While helpful to detect the arrival of Tuta absoluta, the devices are “totally useless” as a mass trapping method because they catch a few dozen out of thousands of moths, Al-Zaidi said.

He recommends a combined solution of farmer education, and applying the metarhizium anisopliae fungus to the soil which kills the insects in their pupal stages. Trials in Tanzania last year showed this to be effective, and Russell IPM is selling the fungus commercially there. Next month, Al-Zaidi will demonstrate it in Nigeria. There are no side effects to humans, he said.

“It will not go away but we need learn how live with it and how to keep it under control,” Al-Zaidi said.