This post is written by Sara Hendery, communications coordinator for the Integrated Pest Management Innovation Lab.

In Kenya, farmers have observed a loss of at least half of their maize yields due to the fall armyworm. In Africa alone, the pest has caused an estimated $10 billion in damage. While the pest prefers maize, it attacks hundreds of plant species, significantly impacting food security across the region and beyond.

Virginia Polytechnic Institute and State University’s Integrated Pest Management Innovation Lab (IPM IL) and the International Centre of Insect Physiology and Ecology (ICIPE) initiated biocontrol, or the release of natural enemies, to combat fall armyworm in East Africa. Specifically in Kenya’s Embu and Kirinyaga counties, the teams released the parasitic wasp Telenomus remus in farmer demonstration plots. T. remus naturally occurs in Kenya, and after mass production in the lab, can be released to attack the eggs of fall armyworm with parasitism ranging from 78-100%.

Kenyan farmers observed improved farming conditions after release of the natural enemies, including significantly increased maize yields and reduced labor time in the field.

"After the release of the parasitoids, there was drastic reduction of fall armyworm infestation," remarked one of the farmers. "They reduced leaf damage and [we] did not observe any dead heart in the field where parasitoids were released. It saved labor and time to do other things in the farm because we had stopped spraying [pesticides]."

After the initial release of T. remus, maize yields in the Kenyan farmers’ fields generally increased from two bags to five bags per quarter acre. Farmers noted that this increase was significant given the fall armyworm’s dramatic impact over the last several years, including decreased quality and quantity of maize, increased production costs and increased fodder expenses for livestock (due to limited dependence on maize).

Before implementing biocontrol, Kenyan farmers remarked that they were lucky if they could harvest any maize at all, but even if they could, the grains didn’t always acquire good prices at the market.  

"Due to fall armyworm infestation, we started experiencing food insecurity and struggling to pay school fees for our children, which is very unusual for the area," said one of the farmers, detailing the impact of the pest. "We started spending more money in trying to control the insect pest using chemicals and in return got very little, if any yield."

Since the pest is most destructive in its larval stage, reducing populations as much as possible at the egg stage is vital. While many solutions to combat the pest exist — including genetically modified crops, chemical pesticides and mechanical control — fall armyworm adapts to new conditions rapidly and thrives in harsh conditions. Having established itself in most of Africa, as well as many areas of Asia, the fall armyworm has also been reported in Australia and other parts of Oceania. More than 70 countries have been impacted by its spread.  

In addition to Kenya, ICIPE and IPM IL have trained researchers on biocontrol of fall armyworm in Ethiopia, Tanzania and a range of other countries in Africa and Asia, with hopes of initiating biocontrol "satellite" sites throughout both continents.  

"Farmer demand to control fall armyworm is a high priority," said Tadele Tefera, country head of ICIPE in Ethiopia. "The release of biocontrol agents initiated by IPM IL and ICIPE should and can be fast-tracked and expanded to reach several maize-growing communities; any delay could lead to substantial yield loss that could affect farmer livelihoods."

"Augmentative biological control," Tefera added, "where natural enemies are periodically introduced to control the fall armyworm, is an effective, environmentally-friendly approach. After witnessing the effectiveness of natural enemies on their own farms, farmers are motivated to use this form of biological control to reduce environmental impacts of pesticides."

For more information on biocontrol of fall armyworm, contact Sara Hendery at [email protected].