Biological weapon against fall armyworm found in Africa

[LAGOS] Scientists have identified a biological weapon that could end the devastating effect of the fall armyworm in Sub-Saharan Africa.

According to the FAO, fall armyworm has already spread across Sub-Saharan Africa since its detection in the region in 2016, affecting millions of hectares of maize and sorghum. Fall armyworm threatens the food security of about 200 million people in Africa.

The biological weapon, known as Telenomus remus, is a parasitoid — an insect that completes its larval development within the body of another insect leading to the death of its host. It is being used to augment control of fall armyworm in the Americas, experts say.

“We hope that by using this parasitoid or other biological control agents, the quantity of synthetic insecticides used against fall armyworm will diminish.”

Marc Kenis, CABI

T. remus has now been identified through DNA analysis in Benin, Cote d’Ivoire, Kenya, Niger and South Africa, according to a study published in the journal Insects last week (29 March).

“T. remus is a vital tool that can fight against the fall armyworm, a pest that has the ability to cause yield losses of up to 20.6 million tonnes per annum in 12 of Africa’s maize-producing countries,” says Marc Kenis, lead author of the study and head of risk analysis at the Centre for Agriculture and Biosciences International (CABI, the parent organisation of SciDev.Net).

Kenis tells SciDev.Net that at the moment, control methods include mainly the massive use of broad-spectrum insecticides, which has serious economic, environmental and health impacts.

The use of natural enemies to control a pest, an approach called biological control, is environmentally more sustainable and has no negative impact on human health.

“Many teams in Africa are looking for natural enemies of fall armyworm in several African countries. Of particular interest are parasitoids,” says Kenis. “Our discovery showed that the parasitoid is already in West, East and Southern Africa and can readily be used as biological control agent.”

But according to Kenis, biological control agents do not eradicate pests.

“They just lower their populations and impact below a tolerance threshold. We hope that by using this parasitoid or other biological control agents, the quantity of synthetic insecticides used against fall armyworm will diminish,” Kenis explains, adding that the main challenge will be to develop a production method specific for the African context that will be economically viable for farmers.

African policymakers should begin to facilitate the use of T. remus as biological control agent through facilitating its registration Kenis says.

Tony Wemton the director of Wemton Agricultural Development and Advisory Services in Nigeria, tells SciDev.Net that Nigerian farmers have been using insecticides to fight fall armyworm, which can cause great harm to farmers and end users of their products.

“With this new biological weapon that can fight fall armyworm, African governments can help local farmers by making funds available through grants or subsidies so that they can have access to it,” Wemton says.

This piece was produced by SciDev.Net’s Sub-Saharan Africa English desk.