By Chris Mfula
LUSAKA (Reuters) - A maize pest that has devastated crops in southern Africa is a South American species which is harder to detect and eradicate than its African counterpart, agriculture officials and experts said on Tuesday.
The fall armyworm outbreak has erupted in Zambia, Zimbabwe and Malawi and follows a crippling El Nino-triggered drought which scorched much of the region last year.
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The pest devours maize and other crops. The armyworms are caterpillars that "march" across the landscape in large groups feasting on young plants, leaving devastation in their wake.
"The tricky part with the fall armyworm is that it burrows into the plant whereas the African armyworm eats from outside," Coillard Hamusimbi, the head of agri-business at the Zambia National Farmers' Union, told Reuters.
"Because it burrows into the plant the fall armyworm will often only be seen when coming out after the damage has already been done. They can easily build resistance to chemical control because contact with the chemical is difficult."
How the pest made its way to Africa is unclear. Hamusimbi said there were suspicions it came to Nigeria through the grain trade and spread from there.
Eliot Zitsanza, the Zambia-based chief scientist at the International Red Locust Control Organisation for Central and Southern Africa, which assisted in a local study on the pest, said the South American experience suggested invaded fields could lose 30 to 40 percent of their crop.
In Zambia, an estimated 200,000 tonnes of maize have been destroyed by the fall armyworms and the military has been deployed to wage war on the bugs, which have also damaged 2,000 hectares of the staple crop in Malawi.
The outbreak in Zambia is being contained as most of the maize was attacked when it was knee-high and three-quarters of the fields that were hit were reporting the eradication of the pest, with plans to replant the crop.
Zimbabwe meanwhile was investigating, and assessing the damage caused by the pest as infestation levels varied and the crops could recover after spraying, chief entomologist in the ministry of Agriculture Godfrey Chikwenhere said.
Zambia's maize production rose to 2.87 million tonnes in the 2015/2016 crop season from 2.60 million tonnes the previous season, the one producer in the region to have experienced adequate rains during the El Nino.
(Additional reporting by MacDonald Dzirutwe in Harare; Editing by Ed Stoddard and Susan Thomas)