29 January 2009 –A United Nations official has warned today that a UN-led team of experts is in a race against time in its attempt to halt a vast plague of caterpillars, known as armyworms, which has already swarmed across northern Liberia and threatens to march into neighbouring West African countries, destroying all crops and water supplies in its path.
The enormous infestation of tens of millions of armyworms, one of the most destructive of insect pests, has forced the Liberian President, Ellen Johnson-Sirleaf, to call a national emergency in a country where access to food is already precarious.
“The millions-strong caterpillar hordes devour all vegetation in their path and pollute wells and streams with their excrements wherever they go,” said Representative of the UN Food and Agriculture Organization (FAO) in Liberia, Winfred Hammond.
Some 100 villages in northern and central Liberia have now been affected and six communities in neighbouring Guinea to the north had also been struck, in some cases overrunning buildings and sending residents fleeing in panic. According to Liberian authorities, the emergency involves about 500,000 villagers.
Mr. Hammond warned that much worse could be in store as many of the caterpillars had bored into the ground, out of reach of pesticides, and formed protective cocoons around themselves, waiting to re-emerge as moths in a week or so.
“Each moth can fly up to 1,000 kilometers and lay 1,000 eggs,” explained Mr. Hammond, who is an entomologist, stressing that “potentially, that's a recipe for disaster.”
Setting pheromone traps against male moths to avert the pending catastrophe is one of the possibilities the FAO team, comprising of experts from Ghana, Sierra Leone and Liberia, is considering. The traps would be baited with the scent females use to lure males into mating.
Meanwhile, the Agriculture Ministry is using powerful pesticide sprayers to reach armyworms in the foliage of tall Dahoma trees, where they tend to congregate.
“That's a very strange way for them to behave. Normally they like to stay much closer to the ground,” said Mr. Hammond, offering climate change as a possible explanation for the abnormal behaviour.
For its part, the UN peacekeeping mission in Liberia (UNMIL) is providing logistical support and security to government officials and experts as they carry out fact-finding visits to some of the difficult to access remote areas of the country affected by plague.
FAO has established a task force which has drafted an immediate response plan and has begun developing medium and short-term measures aimed at reducing the impact of the emergency, and the Government has set up three emergency committees to tackle planning, resource mobilization and communication strategies.