Fungal weapon

SCIENTISTS have successfully tested a biological pesticide for the first time on grasshoppers and locusts which ravage crops across Africa. They have developed sprays containing fungal spores which are as effective as synthetic pesticides and harmless for beneficial insects.

Researchers from Benin, Niger and Britain spent the past seven years testing sprays containing spores of Metarhizium flavoviride, a fungus that infects insects and is native to Africa. They have now perfected a spray which can be effective in the harsh climatic conditions typical of sub-Saharan Africa.

When it was tested on crops in Niger that were infested with the Oedaleus senegalensis grasshopper - the most harmful insect pest in the region - its number fell by 80 per cent within three weeks. The spray was found to be equally effective against the dreaded desert locust Schistocerca gregaria and two other locust species. Though the fungal spores take longer to kill the pests, they do not have to be resprayed several times a year like a chemical pesticide, as they remain infectious throughout the swarming season and spread I from insect to insect.