Plague of armyworms on the march
Southern African crops decimated
SOUTHERN Africa has been struck by a pestilence so severe that farmers have invoked plagues of biblical proportions. Hungry caterpillars called fall armyworms are on the move across the continent from Zambia southward.
Early this month, South Africa’s Agricultural Department issued a report noting that, for the first time, this unfamiliar pest had been spotted in the Limpopo province.
“Little is known on how this particular pest entered southern Africa,” said the report.
“Since this pest is very new in Africa, very little is known on its long-term effects.” It was positively identified as the fall armyworm a few days later.
“It has come in like one of the 10 plagues of the Bible,” Ben Freeth, who operates a commercial farm in Zimbabwe, said.
“It is widespread and seems to be spreading rapidly. It can lay up to 2 000 eggs and its life cycle is very quick.”
Armyworms – which grow into moths and are not, technically speaking, worms – are so named for their ability to destroy massive amounts of crops, in the manner of troops trampling over a countryside.
Kenneth Wilson, who is studying the use of biological parasites to battle crop pests at England’s Lancaster University, described the havoc as the combination of two species: a surge in the population of the native African armyworm, plus the fall armyworm, an invader from the Americas.
African armyworms eat in hordes as dense as 1 000 caterpillars per square metre, Wilson noted, stripping maize plants bare.
The newcomers may be no less destructive.
“The impact of the fall armyworm is likely to be devastating because it eats the leaves of the plant as well as its reproductive parts,” Wilson wrote.
“This damages or destroys the maize cob itself.”
He cited an estimate that put Zambia’s possible losses of maize, an important grain staple, as high as 40%.
“The situation remains fluid. Preliminary reports indicate the possible presence (of the pest) in Malawi, Mozambique, Namibia, South Africa, Zambia and Zimbabwe.
Zimbabwe has positively identified the presence of the pest while the rest are expected to release test results soon,” said David Phiri, the UN Food and Agriculture Organisation’s southern Africa regional co-ordinator.
The Food and Agriculture Organisation has set up an emergency meeting to discuss plans to combat the pests.
The Zambian government acquired insecticides and has begun stockpiling seeds to help farmers replenish consumed crops.
Meanwhile, South Africa plans to import pheromone traps to catch and identify the extent of the pests’ spread.
Pesticides have shown to be effective against armyworms in the past, Wilson noted.
But it is not yet known if the current caterpillar outbreak has developed a resistance to the usual chemicals that kill them.
What’s more, as moths, armyworms are known to fly great distances
In 2012, US Agriculture Department entomologists tracked fall armyworm populations travelling from southern Texas to Minnesota.
“Only time will tell,” Wilson wrote, “what the full impact of this armyworm invasion will be.”
A crop-eating armyworm on a sorghum plant.