Regional governments are to hold a crisis meeting in Johannesburg next month following signs that a virulent pest attacking maize crops may have found its way to South Africa.
The possible outbreak threatens food supply, with one government official warning of a possible hike in food prices.
The meeting to discuss the fall armyworm outbreak will be convened by the UN's Food and Agriculture Organisation. It will be the first time regional governments have come together since the outbreak was detected in Zambia last year.
Food shortages, higher food prices and an increase in people with an insecure food supply are among the potential consequences . This will not bode well for the region, which already has 40 million food-insecure people, due largely to the drought that decimated crops and livestock last season.
The meeting would let the countries share knowledge and assess the extent of damage, said Chimimba David Phiri, the FAO subregional co-ordinator for Southern Africa. "This exchange of information must take place as soon as possible," he said.
Fall armyworm has mostly affected maize - the region's staple grain - hitting Zambia, Zimbabwe, Malawi, Namibia, Mozambique and South Africa with varying degrees of severity.
But it is the spread to South Africa - the largest maize producer in the region - that could prove most devastating for regional food security. South Africa is the single largest producer, contributing 42% of the 30 million tons of maize the Southern African Development Community produces.
Wandile Sihlobo, an agricultural economist at the Agricultural Business Chamber, said South Africa would produce between 11.7 million and 13 million tons of maize this season, with domestic requirements of about 10.5 million tons.
"All of that was under the assumption we would get good rains until the end of February. The million-plus surplus of maize would assist the region, but there has been an outbreak of fall armyworm in Limpopo, North West and the Free State. An assessment of whether this is indeed new fall armyworm is also under way by the ministry of agriculture," Sihlobo said.
Grain South Africa said "initial indications" showed that specimens collected from the affected provinces were fall armyworm. "However, until specimens ... that have been collected by the Agricultural Research Council and North-West University are identified by a taxonomist, it cannot be confirmed."
Bomikazi Molapo, spokeswoman for the Department of Agriculture, Forestry and Fisheries, said test results were expected at the end of this week. "This [potential] outbreak poses a great risk to our food security and has a link to food prices. The implications would be very negative for us as a country," she said.
The department would co-operate fully with the rest of the region on a response .
"Once we have the identification, we would then know how to proceed further and consider all options, which include talking to Brazil," Molapo said. Brazil, the world's third-largest maize producer, spends more than $400-million (about R5.4-billion) annually to contain the pest, according to the International Institute of Tropical Agriculture.
Originating in South America, fall armyworm burrows inside the stem of young maize plants, unlike the African armyworm, which is usually found on leaves.
"Severe outbreaks usually coincide with the onset of the wet season, especially when the new cropping season follows a long period of drought," said Georg Goergen, co-author of a paper on fall armyworm outbreaks in West and Central Africa.
Quantifying the damage was difficult. Sihlobo said: "We can only quantify the cost when the extent of the damage is known. As of now, the damage is not really there; the insect has been detected and, if we are fast enough, we may be able to contain it. The success of any pesticide is not known yet and we remain optimistic we can get a good crop."
John Robertson, head of Robertson Economics in Harare, said: " We have to wait until March, when the harvest of the crop takes place, to see the actual extent of damage and the impact this will have on food prices."
In Zimbabwe, the devastation has been severe, with most provinces hit by fall armyworm. The outbreak could derail a command agriculture programme which President Robert Mugabe's administration launched in July last year, aimed at putting 500,000ha under tillage. The aim is to produce 2 million tons of maize. Last year, Zimbabwe imported most of its 700,000 tons of maize, mainly from South Africa and Zambia, costing about $256-million.
Ben Freeth, a former commercial farmer in Zimbabwe, said the fall armyworm had a rapid life cycle which made it difficult to contain. "It's widespread and seems to be spreading rapidly. It can lay up to 2,000 eggs and its life cycle is very quick. As there are no registered chemicals in Zimbabwe to deal with it, farmers are trying to spray using different mixes put together. It has come in like one of the 10 plagues of the Bible."
Freeth said given that the fall armyworm was a pest never dealt with before, it was too early to predict its impact on the government's command agriculture programme.
The military in Zambia, where the fall armyworm outbreak originated, has been trying to contain it. About 124,000ha of land has been hit by the pest. Zambia contributes about 9% of regional maize output.
In Malawi, officials said more than 2,000ha of tilled land had been affected.
The International Institute of Tropical Agriculture said early detection was essential as insecticides were effective only in the pest's early larval stages.