Global crop impacts, yield losses and action thresholds for fall armyworm (Spodoptera frugiperda): A review

Authors: OVERTON, KATHY - Wagga Wagga Agricultural Institute; MAINO, JAMES - Wagga Wagga Agricultural Institute; DAY, ROGER - Commonwealth Agricultural Bureau International (CABI); UMINA, PAUL - University Of Melbourne; BETT, BOSIBORI - Department Of Agriculture - Australia; CARNOVALE, DANIELA - Department Of Agriculture - Australia; EKESI, SUNDAY - African Insect Science For Food And Health (ICIPE); Meagher, Robert - Rob; REYNOLDS, OLIVIA - Wagga Wagga Agricultural Institute

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/24/2021
Publication Date: 3/30/2021
Citation: Overton, K., Maino, J.L., Day, R., Umina, P.A., Bett, B., Carnovale, D., Ekesi, S., Meagher Jr, R.L., Reynolds, O.L. 2021. Global crop impacts, yield losses and action thresholds for fall armyworm (Spodoptera frugiperda): A review. Crop Protection Journal. 145.Article 105641. https://doi.org/10.1016/j.cropro.21.105641.
DOI: https://doi.org/10.1016/j.cropro.2021.105641

Interpretive Summary: The fall armyworm (FAW) is a plant pest that can severely impact yields of several agricultural crops including corn, sorghum, soybeans, and pasture grasses. It is native to the Western Hemisphere, but since 2017 has invaded Africa, Asia, and now Australia. Understanding the economic impact and management thresholds for FAW across a variety of crops is crucial for effective management. Researchers from various institutions in Australia, in collaboration with a scientist from USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Florida, evaluated information from across the world on: (1) yield losses reported as a result of FAW infestations, (2) the relationship between FAW density and reported yield loss, and (3) current known economic injury levels, economic thresholds and action thresholds. For example with corn, there were differences between experimentally derived yield losses (17.3%), and those obtained through farmer surveys (35.6%). Yield loss also varied with management strategies, with genetically modified and/or insecticide treated crops typically retaining higher yields. The available management thresholds for FAW illustrated that the reporting of economic injury levels and action thresholds varied significantly both between and within crops, highlighting the need for a standardized approach when measuring FAW numbers in a crop.

Technical Abstract: The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a highly polyphagous plant pest that can severely impact yields of several agricultural crops. Understanding the economic impact and management thresholds for FAW across a variety of crop commodities is crucial for effective management. Evaluating the peer-reviewed and grey literature, we compiled global data on: (1) yield losses reported as a result of FAW infestations, (2) the relationship between FAW pressure/density and reported yield loss, and (3) current known economic injury levels, economic thresholds and action thresholds. We identified 71 references that reported yield losses from FAW infestation, with a total of 888 separate yield loss entries. The majority of research quantifying yield losses and the relationship between pest pressure and yield has focused on maize, sorghum, and cotton, with some evidence for sweet corn, bermudagrass, and rice. For maize, there are differences between experimentally derived yield losses (17.31 ± 0.90%), and those obtained through farmer surveys (35.57 ± 2.45%). Yield loss also varied with management strategies, with genetically modified and/or insecticide treated crops typically retaining higher yields. Most studies investigating the relationship between FAW density and yield loss across different crops have focused on early and mid FAW larval instars and on vegetative to reproductive plant growth stages, with minimal research on both late larval instars and on seedlings. The available management thresholds for FAW illustrated that the reporting of economic injury levels and action thresholds varied significantly both between and within crops, highlighting the need for a standardised approach when measuring FAW pressures or densities that should elicit management responses.