Fall Armyworm

Spodoptera frugiperda — the fall armyworm — is one of the most economically destructive AGRICULTURAL PESTS to emerge globally in the past decade and one of about 35,000 species in family Noctuidae. The species is native to the Americas (especially the southern US, Central America, Caribbean, and South America) where it has been a major NA agricultural pest for centuries. Fall armyworm INVADED AFRICA IN 2016 (first detected in Nigeria — almost certainly introduced via accidental international shipping) and rapidly spread across most of sub-Saharan Africa over the following 2 years (now established in over 40 African countries). The species INVADED ASIA IN 2018-19 (first detected in India in 2018, then China in 2019), AUSTRALIA IN 2020, and continues to spread. The global invasion has been one of the most rapid documented insect range expansions in modern history. Adults are 3-4 cm wingspan, gray-brown moths with two distinct dark forewing bands. Larvae are 3-4 cm long when fully grown, color-polymorphic (light green to dark brown variants) with longitudinal stripes and a distinctive INVERTED 'Y'-SHAPED MARKING on the head capsule (the diagnostic field-ID feature for fall armyworm vs. other Spodoptera and similar caterpillars). The species' major significance comes from the EXTREME POLYPHAGY — fall armyworm attacks OVER 350 PLANT SPECIES, with major impact on most commercial CROPS: MAIZE (the most cited crop and the focus of African food-security concerns; fall armyworm can completely defoliate maize fields in outbreak years), RICE, SORGHUM, COTTON, SOYBEAN, SUGARCANE, ALFALFA, and many other crops. The species causes massive economic damage in subtropical and tropical regions where multiple generations occur per year. AFRICAN CROP LOSSES to fall armyworm have been estimated at $2-6 BILLION ANNUALLY in maize alone — a devastating impact on a continent where maize is the staple food crop for hundreds of millions of people. The species is now a major threat to global food security in tropical and subtropical regions and is the focus of major FAO, USAID, CGIAR, and other international food-security control programs. Modern control approaches include: traditional insecticides (with rapid resistance evolution problems), Bt CROPS (Bt corn provides good control of fall armyworm in countries that allow GMO adoption — a major contrast between the protected US/Argentina maize sectors and the vulnerable African and Asian sectors that lack widespread Bt corn adoption), biological control with introduced parasitoid wasps and microbial pesticides, pheromone monitoring and disruption, and farmer-education programs in newly-invaded regions. The species is harmless to humans (no venom, no bite) but is the single greatest emerging threat to global food security in modern agricultural entomology.