A naturally occurring fungus has been found to halt the advance of the fall armyworm, a crop pest that has ravaged farms across Africa since it first appeared on the continent in 2016. Researchers in Kenya discovered the fungus in soil samples and tested it against the pest, with striking results: it killed the caterpillars within days and also stopped them from reproducing. The finding raises hopes for a biological alternative to chemical pesticides, which have proven costly and increasingly ineffective.
A silent killer in the soil
The fungus, identified as a strain of Metarhizium anisopliae, was isolated from soil in a maize field in western Kenya. In laboratory trials, it infected and killed fall armyworm larvae within five days. It also reduced egg hatching and caused deformities in surviving adults, cutting the next generation of pests. The research was led by scientists at the International Centre of Insect Physiology and Ecology (icipe) in Nairobi, working with partners from the University of Nairobi and the Kenya Agricultural and Livestock Research Organization.
Why farmers are desperate for a new weapon
The fall armyworm, native to the Americas, has spread to more than 40 African countries, feeding on maize, sorghum, and other staple crops. In Kenya, smallholder farmers have reported losses of up to half their maize harvest in severe outbreaks. Many have turned to synthetic pesticides, but the pest has developed resistance, and the chemicals are expensive and dangerous to apply without protective gear. Local agricultural officers say the fungus could be formulated into a spray or powder that farmers can use safely and cheaply, without harming beneficial insects or the environment.
A local solution with global promise
The discovery is particularly significant because the fungus is native to Africa, meaning it is already adapted to local conditions and can be mass-produced using simple methods. Researchers are now testing how to formulate it into a stable product that can survive transport and storage in tropical heat. If successful, it could be distributed across the continent, offering a sustainable tool in the fight against a pest that threatens the food supply of millions. The study was published in the journal Biological Control, and the team is seeking funding for field trials in several African countries.
This is not a silver bullet, but it is a rare piece of good news for farmers who have watched the armyworm march across their fields with few effective defenses. The fungus offers a way to fight back that is grounded in the local ecosystem, not dependent on imported chemicals. As climate change and global trade continue to spread pests to new regions, such nature-based solutions may become increasingly vital. For now, the hope is that this tiny fungus can do what pesticides have failed to do: give African farmers a real chance to protect their harvests.
