maize |
It was first
detected in Africa barely a year ago, yet the fall armyworm, a type of
caterpillar whose name derives from its tendency to maraud in vast
numbers, has already infested hundreds of thousands of hectares of maize
across more than a dozen countries on the continent, presenting a
serious threat to food security.
Spodoptera
frugiperda is a formidable foe. Pesticides only work when the larvae are
very small and before they have begun to cause visible damage to the
crop. After that, there are no quick fixes.
The pest can cause crop losses of more than 70 percent.
In Zimbabwe, El
NiƱo-induced droughts left four million people needing food aid during
the 2015/2016 agricultural season. This year, good rains had raised
hopes of a decent harvest, but now the fall armyworm is dashing them for
many farmers.
Vavariro Mashamba,
51, hoped to harvest 10 tonnes of maize from each of the 20 hectares he
planted in his farm in the Karoi district, in north-central Zimbabwe.
But when he started to see ragged holes on the foliage of his crop and
sawdust-like frass near the whorl and upper leaves of the plants, he
knew he was in trouble. His best hope now is a yield of six or seven
tonnes per hectare.
"At first I thought
it was the African armyworm (Spodoptera exempta) that was damaging my
crops. I bought Cabaryl pesticide and sprayed on the plants. There was
no change. Instead, the worms continued to multiply in my field,"
Mashamba told IRIN.
Experts from the
Ministry of Agriculture visited his farm, but by then it was too late to
eradicate the fall armyworm (The "fall" part of the name comes from the
caterpillar's feeding habits: In its native Americas, it does most
damage in late summer and early autumn - or "fall" in US English. See
here for more details).Mashamba experimented with different pesticides, but to no avail.
Widespread problem
According to the
UN's Food and Agriculture Organization, which held an emergency meeting
on the pest in Harare in February, up to 130,000 hectares of maize and
corn could already infested by fall armyworm in Zimbabwe, 90,000 in
Zambia, and 50,000 in Namibia. It was first detected in Africa in
Nigeria in January 2016 and its presence has also been confirmed in
Botswana, Congo, Ghana, Kenya, Malawi, South Africa, Swaziland, Togo,
and Uganda.
Shingirayi
Nyamutukwa, acting head of plant protection at the government's
Department of Research and Specialist Services, said all of Zimbabwe's
10 provinces had reported being affected by the caterpillar but it was
difficult to ascertain the extent of the damage to yields now as crops
were at varying stages of growth.
"We started
receiving reports that there was a pest causing damage on crops in
October last year in Matabeleland North," said Nyamutukwa, warning that
most of the country's 1.3 million hectares of land under maize
cultivation was potentially at risk.
Zimbabwe Farmers Union Director Paul Zacariya said the country was ill-prepared for the arrival of fall armyworm.
"No information or
warnings were given to notify farmers of the pest. As such, many farmers
could not identify the pest and lacked the knowledge and requisite
skills on how to contain the damages caused," he told IRIN.
Food security threatened
Noting its stubborn
resistance to available control methods, FAO Sub-regional Coordinator
for Southern Africa David Phiri said he was worried "the pest could be
here to stay".
"The costs and
implication of such a scenario are very serious indeed, as seen in
places where the pest is endemic, like in Brazil where the government
incurs control costs in excess of $600 million per annum," he warned.
"The implications for livelihoods and food security are also too serious
to contemplate, and assessments have to be done to ascertain the damage
caused."
At the emergency
meeting, the FAO advocated a countrywide response as part of a regional
programme of integrated management of fall armyworm.
"Already, we are
working in collaboration with other partners. We are ready to assist
countries with the necessary assessment activities aimed at improving
understanding on the extent and intensity of the fall armyworm threat to
the region," said Phiri.
But he warned that it could take several years to develop effective methods to control the pest.
"Planting
quick-maturing crop varieties and early planting may lessen infestation
and damage caused by the fall armyworms," he said. "And no single method
or product has been found to completely eradicate the fall armyworm."
Additional measures
proposed at the meeting included the deployment of other insects such
as lacewing, ladybirds, minute pirate bugs, parasitic wasps, and flies -
all of which feed on armyworm eggs.
Prompt action
Nyamutukwa said
farmers should treat their crops before armyworm larvae burrow deep into
the whorl or enter ears of more mature plants.
If applied early
enough, insecticide applications by ground rig using at least 30 gallons
per acre (340 litres per hectare) and high pressure are believed to
give the best results.
"It is also
advisable to apply pesticides early or late in the day, because fall
armyworm larvae are most active at these times," said Nyamutukwa, adding
that ministry experts who directly advise farmers, known as extension
workers, were now better placed to respond to the infestation.
"So far, 479
[extension] officers and task force teams have been trained in all 10
provinces in the country and procured chemicals, which were distributed
for free in all provinces for the management of the fall armyworm," he
said.
In addition, the
Zimbabwean government is preparing for the winter wheat season by
putting in place community-based armyworm forecasting systems and
intends to put plant clinics in rural communities.
"If farmers do not
control the pest and it attacks the cobs and developing grain, then
farmers lose by a percentage yet to be determined because crops are
still in the field. Fall armyworm infestation impacts negatively on
yield, [so] a reduction in yield is a threat to food security and
nutrition," he explained.
Zacariya, the
director of the farmers' union, noted how critical food security is to
Zimbabwe's rural development and the need for assistance given the
armyworm invasion.
"The fall armyworm
has the effect of drastically reducing the yields of rural farmers," he
said. "As such, the gap created will need to be covered through local
safety nets or government and food aid agencies will have to step in
with food aid programmes to avert any shortages that may rise."
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