Management of Fall Armyworm (Spodoptera frugiperda)
The Fall Armyworm (FAW) is native to America and was first reported on the African continent in January 2016. FAW spreads quickly across large geographic areas. The moths have both a migratory habit and a more localized dispersal habit. In the migratory habit, moths can migrate over 500 km before oviposition (laying of eggs). When the wind
pattern is right, moths can move much larger distances.
Control of Fall Armyworm:
• Use of Pesticides:
Control using pesticides is most effective when the larva is still small and young. Older larvae are difficult to control because of the “frass plug” that deters insecticide penetration into the larva. Some of the pesticides found to be more efficient and eco-friendlier include Ecoterex, Emamectin benzoate, Super dash, Ampligo, and Lambda‐cyhalothrin among others.
• Cultural agronomic practices:
Some cultural practices used in managing and controlling FAW infestation include handpicking and killing larvae, placing sand or wood‐ash in whorls of maize plants, drenching plants with tobacco extracts, deep plowing to kill pupae, early planting, destruction of ratoon host plants, burning infested crop residues after harvesting, intercropping with non‐host plants, use of multiple cultivars, and rotation with non‐host crops.
• Biological Control Practices:
The FAW has several natural enemies, such as predators, parasitoids, and pathogens that regulate its population levels. In some cases, intercropping creates an environment that favors the development and growth of a population of natural enemies, large enough to control FAW. This has popularized the “push-pull technology” (PPT) currently being recommended for FAW control. The PPT method was developed for the control of stem borers in maize and is now being promoted and used in the control FAW. The PPT is based on intercropping maize with Greenleaf desmodium (Desmodium intortum) and bordering the intercrop with Brachiaria ‘Mulato II’. The Desmodium protects the maize by emitting semiochemicals that repel (push) the moths that are concurrently attracted (pulled) by semiochemicals released by the border crop.
• Integrated Pest Management (IPM) strategies:
An IPM strategy aims at controlling a pest using a combination of methods while causing the minimum possible damage to the environment, animals, and people. Thus, it combines cultural, biological, host‐plant resistance, and safe pesticide control methods. The IPM targeted at controlling FAW includes routine monitoring, scouting, and early detection to identify and respond to infestations. Pheromone traps are used to monitor the pest’s presence and abundance in and around the field, and this can be used to forecast the pest’s movements. The traps attract, trap, and kill male moths, but do not sufficiently reduce the male moth population to disrupt mating, hence they should not be used for FAW control purposes but only for monitoring and forecasting.