Feature: Scientists defeat stubborn weed impoverishing rural Kenyan farmers

Elizabeth Auma, a farmer in Siaya, Western Kenya, is a happy woman as her maize crop, which she planted two months ago, are now flourishing.

Her joy is understandable since for the past four years, Auma would plant but not reap anything because of striga, a stubborn weed prevalent in the region.

She has, however, now embraced a new farming practice introduced by International Center of Insect Physiology and Ecology (ICIPE), which has helped her eliminate the weed.

The technology, identified as push-pull system, is a form of ecological farming used to control parasitic weeds and insects that damage crops.

Professor Zeyaur Khan, the project director at ICIPE, said Friday that push-pull technology involves the use of napier grass and desmodium, a leguminous herb, which is intercropped with other food crops such as maize, sorghum or rice.

"This is a simple innovation that is currently being adopted by farmers in Western Kenya where striga weed is rampant,"said Khan.

Striga, popularly known as witch weed, affects cereal crops in many parts of Africa. Agriculturists estimate that the weed can reduce crop production by 100 percent and the dormancy can last for over 15 years.

As striga germinates, its roots grow towards the host crop, penetrate the crop roots and start to draw nutrients from there. This causes severe stunting of the host crop and yield loss.

According to Khan, when a farm is infested with striga, the affected plants hardly grow more than one foot tall.

In the push-pull system, the napier grass is planted on the edges of the farm, trapping the stem borer moth and preventing it from completing the lifecycle.

The scientists said that when desmodium is intercropped with maize, it repels the striga pest from the crop (push). Many farmers have been trained on the technology and are now embracing it.

Auma, who hails from Usonga village, has been grappling with low yields because of striga weed that invaded her farm in 2012. She was trained by ICIPE last year and since then, her crop yield has increased tremendously.

"It is only last harvesting season that I found the solution to striga weed after attending training," the 49-year-old farmer told Xinhua in an interview.

Joseph Kibagendi, a maize farmer in Kisii County, is now able to harvest 15 90kg bags of maize . "The weed has denied me abundant harvest in the previous years, but I'm glad that I have managed to fight to the end," he said.

Khan explained that desmodium is planted in between rows of maize. The crop produces a smell that stem borers do not like pushing them away from the maize plants.

According to Khan, the stem borer moths lay eggs in napier grass but since the grass does not allow the larvae to develop into adults, they end up dying.

He said chemicals released by desmodium roots also control the parasitic weed, striga hermonthica, by inducing abortive germination, and providing very effective control of the noxious weed.

Maize is the main staple in Kenya, with the country producing an average of 35 million bags annually and consuming 3.6 million every month. The persistence of striga in Western Kenya has become a threat to food security as farmers are losing tonnes of maize to the weed. Endi