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Managing Fall Armyworm: The (Suspected) Stowaway That Won’t Go Away

fall armyworm (Spodoptera frugiperda)

A new guide in the open-access Journal of Integrated Pest Management outlines the key strategies for managing the invasive fall armyworm (Spodotera frugiperda), which is currently ravaging crops on the African continent. (Photo via Clemson University – USDA Cooperative Extension Slide Series, Bugwood.org)

By Dennis Ndolo, Ph.D.

Dennis Ndolo, Ph.D.

Dennis Ndolo, Ph.D.

Tucked away in the luggage compartment of an airplane, just possibly, may be a stowaway. The stowaway could be an insect such as the fall armyworm (Spodotera frugiperda), which is currently ravaging crops on the African continent. This may or may not have been the true mode of transport that brought S. frugiperda from its native home in the Americas; regardless, it made its way to Africa.

This uninvited guest quickly became a burden, causing untold havoc to crop production in the region. Panic set in and African farmers began the practice of extensive spraying of insecticides to help control the pest. Insecticides were readily provided by governments, and often used without regard for best practice. This large-scale use of insecticides may pose a risk to human health and the environment, and it also increases costs to resource-constrained smallholder farmers.

However, we cannot do without insecticides. As a tool in pest management, they have resulted in huge increases in agricultural productivity over the years, but judicious use must be prioritized. We can use an comprehensive approach that limits the use of these chemicals by integrating various control methods.

In a new paper published in February in the Journal of Integrated Pest Management, my co-authors (Elizabeth Njuguna, Phophi Nethononda, Karim Maredia, Ruth Mbabazi, Paul Kachapulula, and Arielle Rowe) and I highlight new technologies and lessons learned so far from the fall armyworm outbreaks in sub-Saharan Africa, as well as current and potential integrated management strategies for this pest.

Phophi Nethonond

One of the authors of a new paper in the Journal of Integrated Pest Management, Phophi Nethononda, a Ph.D. student in entomology at the University of Pretoria, collects fall armyworm samples from a maize field in Thohoyandou, Limpopo Province, South Africa.  (Photo by Dennis Ndolo, Ph.D.)

The following are the suggested strategies for developing an integrated pest management (IPM) program for the fall armyworm in sub-Saharan Africa:

  • Know your enemy. Train extension workers and local farmers about the importance of pest identification and understanding the life cycle of the fall armyworm.
  • Find your enemy. Monitor adult populations by using pheromone traps, light traps, and sampling or scouting for both egg masses and neonate larvae. Area-wide monitoring and scouting are more desirable in the smallholders’ situation. Given the overlap of cropping systems and crop growth stages, continuous monitoring of fall armyworm population throughout the season is very important.
  • Prevention is better than cure. Seed treatment with suitable biopesticides or chemical insecticides can greatly help prevent damage after the germination of maize and the early stages of growth, when plants are most vulnerable to fall armyworm.
  • Clean cultivation. Given that the pest is polyphagous and feeds on both crops and wild plants, farmers should keep their fields cleared of grasses and weeds that may harbor fall armyworm populations.
  • Integrated pest management. Based on the results of scouting and monitoring, control methods should be selected using the available tools, resources, and pest management practices (e.g. biopesticides, chemical insecticides, and other locally available techniques). Chemical insecticides should be used as a last resort and applied properly to achieve effective control of the pest. Insecticide management is critical to reduce the overuse, misuse, and mismanagement of chemical insecticides and prevent the development of resistance.

Overall, the authors suggest that the ability of farmers to adopt recommended approaches should be given significant consideration in developing and promoting sustainable integrated management strategies to control fall armyworm.

Dennis Ndolo, Ph.D., is the group leader for biopesticides at the International Centre for Genetic Engineering and Biotechnology in Cape Town, South Africa. Email: ndolo@icgeb.org.

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