An international team of experts is "racing against time" to contain a vast plague of voracious armyworm caterpillars in Liberia, the Rome-based UN Food and Agriculture Organization (FAO) said Thursday.
The plague which threatens food crops could spread to much of West Africa unless resolved soon, the Rome-based FAO said.
On Monday, Liberian President Ellen Johnson-Sirleaf declared a state of national emergency and appealed to the country's international partners for help, reported dpa.
Some 100 villages in northern and central Liberia were now affected and that six communities in neighbouring Guinea had also been struck, according to FAO's Permanent Representative in Liberia, Winfred Hammond.
The millions-strong caterpillar hordes devour all vegetation in their path and pollute wells and streams with their excrements.
In some cases they overrun homes and buildings, sending inhabitants fleeing in panic.
According to Liberian authorities, the emergency involves about 500,000 villagers.
It was not immediately clear whether the plague was rapidly spreading - first reports last week said 45 villages were infested - or whether pre-existing hotspots are only now being reported, FAO said.
Hammond voiced concern that many of the armyworms had now bored into the ground, out of reach of pesticides, and formed protective cocoons around themselves.
When they re-emerge, after a week to 12 days, it will be as moths which through their ability to fly are much more mobile.
"Each moth can fly up to 1,000 kilometers - and lay 1,000 eggs," Hammond, an entomologist explained. "Potentially, that's a recipe for disaster."
One of the possibilities being investigated is to set pheromone traps against male moths. These are baited with the scent females use to lure them into mating - but which would now send them to their doom.
FAO's international team includes experts from Ghana, Sierra Leone and Liberia.
