After losing a fifth of his maize crop to Fall armyworm last year, Sipho Mpofu fears the worst for the new growing season, which starts in November. Mr. Mpofu grows sorghum and millet as well as maize in Mashonaland West Province, in southwestern Zimbabwe. Fall armyworm caught him by surprise last year, and he worries that he won’t know what to do if it attacks again.
The Fall armyworm is originally from Latin America. It was first detected in Africa in January 2016. One year later, it had spread to at least 26 African countries.
Fall armyworm eats more than 80 plant species, including maize, wheat, rice, sorghum, millet, and cotton. If left untreated, the caterpillars can eat through a hectare in three days.
Like other farmers in his province, Mr. Mpofu has seen occasional outbreaks of African armyworm. It’s a cousin to the Fall armyworm, and also likes to eat maize. But farmers have seen it for many years, and they know how to deal with it.
Mr. Mpofu encountered Fall armyworm last year for the first time. He assumed it was the usual armyworm — but the difference is in the markings. Mr. Mpofu fought the caterpillars with the pesticides recommended for African armyworm. To his dismay, they didn’t work.
The government recognized the new threat and recommended alternative pesticides. Mr. Mpofu says, “That saved many farmers from certain ruin.”
But he still lost about 20% of his maize. He says, “There was a significant percentage [of armyworm] which was not affected by the pesticides,” possibly because heavy rains prevented follow-up applications, or because the caterpillars had burrowed deep into the plant.
The Centre for Agriculture and Biosciences International, or CABI, says Africa stands to lose $3 billion worth of maize this coming year because of Fall armyworm. This will be a dramatic setback for the small-scale farmers who grow the bulk of Africa’s maize.
Fall armyworm moths can travel 100 kilometres in a night. They multiply quickly: a female lays around 2,000 eggs during her two weeks as a moth.
Climate change may also be contributing to the spread of Fall armyworm. Drought, followed by lots of rain—as southern Africa experienced last year—stresses the plants, making them more susceptible to damage.
David Phiri is the UN Food and Agriculture Organization’s coordinator for southern Africa. He says, “Fall armyworm has come to stay and it must be managed.” But farmers and agricultural extension officers in Africa are still learning how to identify and understand the pest in order to manage it.
Mr. Mpofu has done his own research and is not optimistic. He says, “I am worried by several issues. The first one is that it is difficult to eliminate Fall armyworm, even using the recommended pesticides.”
The best chance to destroy the caterpillars with regular contact insecticides is when they are young, between the third and sixth day of their four-week lifecycle. But even then, they can be difficult to reach, hiding on the underside of leaves.
Older and larger caterpillars are even harder to kill. They bore into the stem or cobs, which protects them from chemical sprays. Feeding in the whorl and on stems can also kill the plant.
Brazil spends up to $600 million a year on containing Fall armyworm. Mr. Mpofu says, “Africa cannot afford that,”—another reason for his pessimism.
Nigeria is spending about $8 million on its Fall armyworm response. Zambia, with 130,000 hectares of land affected last year, is spending $3 million. Uganda is spending $1.2 million.
Experts and farmers don’t yet know which insecticides are the most effective against the strain of Fall armyworm now present in Africa. Testing and development take time.
In Latin America, Fall armyworm may be developing resistance to chemical pesticides. FAO advises minimizing the use of chemical insecticides in Africa to prevent a build up of resistance, and to avoid poisoning the environment.
Farmers are on the lookout for early signs of the pest. Experts advise farmers to plough deeply to bring young pupae to the surface, sow early to avoid the period of heavy infestation later in the season, and burn all crop residues to reduce food and shelter for the caterpillar.
Biopesticides made from viruses, fungi, and bacteria could be a safer alternative to traditional chemical approaches. Botanical insecticides such as neem may also be effective.
Although FAO has pledged to help fast track their introduction and local production, biopesticide research, registration, and commercialization are both costly and time-consuming.
Farmers in Zimbabwe have spotted Fall armyworm in their irrigated winter maize—which grows from June to August—despite the fact that the caterpillar hates the cold. That means Mr. Mpofu and his fellow farmers almost certainly face a difficult season ahead.
This story was adapted from an article titled “The foreign invader costing African farmers $3 billion” published by IRIN. To read the original article, please see: http://www.irinnews.org/news/2017/09/14/foreign-invader-costing-african-farmers-3-billion