Scientists in Britain are hoping to find a sustainable way to stop the march of the voracious fall armyworm caterpillar that has infested Africa. Anna Bevan reports.

It's blighted crops from Mali to Zambia, but the end may be in sight for the fall armyworm: a voracious caterpillar that's threatening the food security of more than 300 million people in Africa.

Causing damage to an estimated 20 to 50 percent of the maize harvest, which much of the region relies on for food.

Malawi recently reported maize output declined by 28 percent last year due to the crop-eating fall armyworm and drought.

But now British scientists are trialing new ways of combating the pest, without using expensive and harmful pesticides.

"First of all, we're looking at the crop variety seeing if we can get more resistant crops. Then secondly, we're looking for repellent inter-crops that can be used as a kind of push to push the pest away and then we're also looking for attractive trap crops, that's the third thing, so that you can divert the insect to another area away from the crop," says Professor Toby Bruce of Keele University.

In other words, driving away the fall armyworm using plants they find unappetizing or luring them away with plants they view as more tasty.

The team is also trialing a novel bait station designed to use natural alternatives to chemical killing agents.

Dr Joe Roberts of Keele University says the ultimate aim would be, if this system is a success, to roll it out to other crops in other countries.

"Not just beans and peas but beetle pests of those crops but as many different crops, as sort of almost an alternative to pesticides is how we would envisage it, or complementary to pesticides."

Almost all sub-Saharan countries have reported infestations, affecting millions of hectares of crops.

With the fall armyworm recently spotted in Asia, a solution can't come soon enough.