Since 1902

Scientists outsmart fall army worm

Winfred Murithi, a farmer in Embu County demonstrates how she monitors her farm using the Delta trap technology. [David Njaaga, Standard]

John Mugambi was one of the distressed farmers who thronged a plant clinic at a market in Manyatta Sub Location, Off Embu town one drizzly morning.

Armed with a maize plant he had uprooted from his farm, Mr Mugambi wanted the plant doctors at the clinic to explain why there were transparent spots on some plants on his farm.

From a distance, the plant looked okay. But a closer observation revealed few transparent patches on the green leaves.

Paul Gitonga, one of the plant doctors at the clinic said the patches were a sign of damage done by a newly hatched fall army worm clinging beneath the leaves.

Mugambi sprung from his seat at this pronouncement. Having lost all his maize crop last year, he couldn’t imagine going through a similar situation.

“I didn’t harvest anything last year despite spending a lot of money on pesticides. I watched as the pests consumed my crops and it wasn’t a good feeling,” he said.

Mugambi is among many other small scale farmers across the country helplessly suffering as they discover the crisis too late after the pests’ invasion.

“I am trying everything I can to harvest at least two bags this year,” said Mugambi who grows coffee, macadamia, maize and carrots on his two-acre piece of farm.

Mugambi’s woes could, however, come to an end if a new plan to monitor the behaviour of the pest from space is successful.

Working with the UK Space Agency, the Centre for Agriculture and Bioscience International (CABI) has come up with Pest Risk Information Service (PRISE), a project that seeks to provide warning of pets such as the army warm.

The technology which combines real-time data from satellites and on-the-ground weather and plant growth observations alongside that of the pest’s life cycle delivers early warning systems to predict the risk of outbreaks.

Once a risk of pest outbreak is established, a warning is sent out to various categories of users including the extension staff, farmers and policy makers. The warning is sent out to plant doctors who in return send the alerts to farmers.

Cambria Finegold, CABI’s Global Director, Knowledge Management, says combined data from the satellites will provide useful predictions that will help farmers to prepare for the infestation at the right time.

“Effect on maize losses in just 12 African countries could range from 8.3 to 20.6 million tonnes per year, let alone the risks posed by other pests. It is vital therefore that we use the very latest in technology and work in partnership to bring the best insights on pest population behaviour right to the farmer’s door,” said Ms Finegold.

At the moment, the innovators are using data gathered by Meteosat, a satellite owned by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), an intergovernmental organisation responsible for launch and operation of satellites.

The researchers say data obtained from the 15-minutes update is useful in predicting manifestation of the different phases of fall army worm.

Also informing the project, are research scientists at three Kenya Agricultural & Livestock Research Organisation (KALRO) research sites in Katumani, Embu and Kitale who work on a prediction model to supply real-time observations on pest development in relation to its life cycle.

Dr Johnson Nyasani, the KALRO research scientist based in Embu says temperature is key in determining the life cycle of fall army worm.

According to research done at the University of Florida, the life cycle of the pest is completed in about 30 days during the summer.

“Fall army worm matures faster and reproduces more when it is hot. It is therefore important to examine the changes in temperature in order to determine the lifecycle of the pest,” explained Dr Nyasani.

He adds: “If we can be able to know the exact time the pest will lay eggs, then our activities of preparedness will be more focused on fighting the pest at that particular stage. At the moment, farmers fight a losing battle if they use methods to fight the larvae when dealing with eggs.”

At caterpillar stage for instance, the pest drops from the plant and burrows itself up to 8cm in the soil until populating. If the soil is too hard, the caterpillar covers itself in leaf debris and emerges about nine days later as an adult moth to restart the cycle.

“When the caterpillar is hidden in the soil, it doesn’t help to spray the plants. Better methods that target the soil are recommended but first, we must predict the particular stage in the pest’s life cycle. With reliable statistics on temperature and humidity, we can be able to predict how long the caterpillar can stay burrowed in the soil to be able to tackle it in its exact location,” says Dr Nyasani.

The information is passed to the farmers during plant clinics. Alternatively, the plant doctors organise for farm visits to scout for the pests.

At the plant clinic in Manyatta for instance, all the plant doctors had received alerts on six pests including the stage of the life cycle of each pest and the exact location on the plant.

Pauline Murithi, the plant clinic coordinator in Manyatta confesses that the alerts had made their work easier.

“At the moment, we don’t just go into people’s farms blindly. The alerts provide information on the exact location of the pest and which stage it is. As a result, we also offer more focused advice to farmers that we visit,” says Ms Murithi.

Kenya lost close to seven million bags of maize to the pest in one season last year according to the Food and Agriculture Organisation.