Push-Pull Practices 'Control Pests, Increase Maize Yields'

According to the researchers, the push-pull system uses two companion crops alongside a main crop such as maize, with the "push" plant (such as a legume) planted in rows in between maize and the "pull" plant (such as Napier grass) planted as a perimeter around the edges of the maize field.

The "push" plant repels adult female moths when they look for a place to lay their eggs. The females then travel to the edge of the field and are attracted to the "pull" plants, which attract them to lay their eggs but are poor hosts, thereby leading to at least 80 percent of the larvae dying before reaching adulthood.

"The key finding of our study is that push-pull actually gets better the longer it is established," said Tim Luttermoser, the study's lead researcher and a doctoral student at Cornell University's Department of Entomology in the United States.

He tells SciDev.Net that the push-pull combination technology led to "massive yield benefits for farmers", usually between double and triple yields compared to farms with non-push-pull technology.

"We found that pest abundance was lower and [maize] yield higher in older push-pull fields very consistently across a wide geographic and time range," says Luttermoser. "We also found some evidence that non-push-pull farms might benefit from being near older push-pull fields."

While the study period was before the fall armyworm invasion in Africa, the authors argue that push-pull remains effective even against fall armyworm as proved by other studies and expect that these results will continue to hold true even in the presence of fall armyworm.

Matilda Ouma, a lecturer in the Department of Agricultural Economics and Agribusiness Management at Jaramogi Oginga Odinga University of Science and Technology in Kenya, says that the study shows that research is evolving and the push-pull technology is getting better.