140,000 African farmers have introduced push-pull technology to protect their crops from fall armyworms © CABI
In the 2 years since the invasive species, fall armyworm, arrived in Africa it has spread to 43 countries and up to 35 million ha of maize is currently suffering from infection or at risk of being infected. Push-pull technology is being implemented across the continent in an attempt to combat the non-native pest, which originates from South America.
Believed to have been introduced to the continent through imported produce, fall armyworm moths can fly 100 km in one night and lay 1,000 hungry larvae in 10 days. The devastating speed with which the fall armyworm operates is overwhelming smallholders. However, the introduction of foliage around crop fields to distract, or pull, fall armyworms away from produce, and the practice of intercropping repellent plants into the field to ward off, or push, fall armyworms away from crops is showing early signs of promise. Greenleaf desmodium has proven to be an effective repellent and Napier grass is used as foliage to entrap fall armyworm eggs in this ‘push-pull’ technique.
Fall armyworms are different to the native African armyworm, so different resistance techniques to the ones previously used on the continent are needed to stop the moths boring into farmers’ crops. Mary-Lucy Oronje, an agricultural researcher from the Centre for Agriculture and Bioscience International (CABI), acknowledges that getting the seeds of the push and pull plants to farmers is proving difficult. Equally, in drier environments, some farmers find that the push-pull plants can’t survive unless they are using climate adapted seeds. Those who have successfully introduced the technology in Kenya, Tanzania and Uganda, however, are reporting 86% reductions in crop damage and on average 82.7% less fall armyworm larvae per plant.
Other suggested solutions include spraying biological pesticides and encouraging natural predators, but “The push-pull technology is proving to be one of the most reliable methods of controlling the [fall] armyworm, as it uses natural methods,” says Dr Saliou Niassy from the International Centre of Insect Physiology and Ecology. Across Africa, 140,000 farmers have already embraced the push-pull technology and a further 150,000 farmers have been trained in how to start planting push-pull seeds correctly.
Trevor Nicholls, CEO of CABI, argues that, “Experience shows that this is a controllable pest.” Delegations from Brazil have been to Africa to share their experiences on how to tackle fall armyworms and CABI has recently launched a new project, which takes a three pronged, ‘defend, detect and defeat,’ approach to combatting the pest. The push-pull technology embodies the ‘defeat’ part of that strategy and although it won’t, “Immediately fix the problem,” according to Nicholls it, “…provides long-term protection,” and will help to take back control.
For more information about protecting against fall armyworm, see a new technical guide by the International Maize and Wheat Improvement Center: Fall Armyworm in Africa: A Guide for Integrated Pest Management.