The fight by sub-Saharan farmers against the Fall Armyworm pest, which has devastated crops and threatened food security for 300-million people, has gone digital.

The United Nations (UN) has reported that the new weapon which was launched by the Food and Agriculture Organisation (FAO) and Pennsylvania State University, is a talking mobile phone app named Nuru which can identify the insect which is in fact a caterpillar.

“Many African farmers might have heard about Fall Army worm but are seeing it for the first time,” FAO said in a statement. “Often they are unable to recognize it or unsure of what they are facing.”

Thanks to the Nuru app, identifying a Fall Armyworm infestation is as simple as holding a mobile phone next to a sick plant.

Confirmation is immediate, FAO says, adding that the software works on a standard Android phone.

Soon, in addition to English, Nuru will be able to speak Swahili, French and Twi. New languages are also to be added and these will walk the farmers through the process of checking their crops and report back on infestation levels before giving them advice on how to fight the pest.

Another important feature of the app is that it can work offline so farmers can use it whenever they want.

Fall Armyworm ­called Spodoptera frugiperda is native to tropical and subtropical regions of the Americas.

The insect first appeared in West Africa in 2016, then spread rapidly across all countries in sub-Saharan Africa in 2017, infecting millions of hectares of maize.

The bug prefers maize, but can feed on more than 80 species of plants, including rice, sorghum, millet, sugarcane, vegetable crops and cotton.

Because of trade and the moth’s strong flying ability, it has the potential to spread further.