Researchers turn to biological methods for Armyworm control

________________

Fall armyworm is a deadly pest capable of causing up to 100% yield loss in maize if not controlled early.

Farmers have long relied on chemicals to control armyworms.

However, misuse is common, leading to chemical residues in food, soil and the human body. Civil society groups have long criticised reliance on agrochemicals.

In response, researchers at the National Agriculture Research Laboratories in Kawanda, Wakiso district, working with the International Centre of Insect Physiology and Ecology (ICIPE), have developed four environmentally-friendly technologies under the Ecological Pest Management and IPM Project.

They rolled out the technologies at Kawanda on November 12.

“These methods were tested with farmers and have been embraced because they protect crops while safeguarding the environment,” ICIPE country representative Girma Hailu said while handing over information packs to the agriculture ministry.

These innovations mark a turning point in pest management. Moses Echeku Okello, the Soroti district agriculture officer, recalled that when the fall armyworm first appeared, farmers used all kinds of concoctions, which were sometimes unsuccessful, to manage them.

“Over the last three years, those who tried the chemical-free technologies have seen yields increase,” he said.

Biological vs chemical

A study published last year in the Journal of Environmental Management compared the costs of chemical-free initiatives between 2020 and 2021 in Kenya and Uganda.

The findings show that the pest management practices above achieved a combined net present value of $500m (sh1.8 trillion).

The study also noted that the technologies improved food security for 641,000 people and lifted 445,349 people above the poverty line, representing 2% of the poor population in both countries.

The technologies also generated an average income increase of $5 per capita annually and reduced pesticide use by more than 526,000 litres between 2007 and 2021.

Policy integration

Ephrance Tumuboine, the assistant commissioner in the phytosanitary and quarantine division of the agriculture ministry, said the technologies will be mainstreamed in the country’s agriculture extension system.

This will enable extension workers to spread their use to farmers in districts that are not yet using them.

The project was piloted in eight eastern and northern Uganda districts, chosen for their commercial maize production and high infestation levels, Dr Jimmy Adriko said.

He is a director of the National Agricultural Research Organisation and Eco-PM Project co-ordinator.

“This project leaves behind practical knowledge to raise parasitoids to manage the fall armyworm, which should be utilised in raising other biological control agents for other pests in the country,” Adriko said.

While the initiatives are effective, they are threatened by climate change, where higher temperatures affect the reproduction of parasitoids, limited equipment and a shortage of skilled people to implement them further.

Beneficiary testimony

Scovia Acana, a farmer and trainer with the Oyam District Farmers Association, has adopted the push-pull technology.

“We used to harvest very little maize whenever the gardens were attacked. Since applying this method three years ago, yields have improved, and we now have pasture for our cows and goats,” she explained.

From her two acres, Acana used to harvest six to seven tonnes of maize per season, but today, that same field yields 12-14 tonnes. Earnings from the maize are being used to improve her home.

“I help my husband to pay school fees for my children,” Acana said.

Chemical-free ways to combat armyworms

• Pheromone traps to monitor biological control agent populations.
• Push-pull technology, intercropping maize with Desmodium legumes (which repels worms and stem borers) and surrounding fields with Brachiaria grass (which traps them). For dairy farmers, push-pull also has significant benefits, since Desmodium or Brachiaria grass are high-quality fodder plants that can be fed to livestock as pasture.
• Natural enemies (parasitoids) — tiny wasps that feed on armyworms.
• Biopesticides, naturally occurring organisms that disrupt the development of larvae or eggs.