Fall Armyworm (Spodoptera frugiperda): A Comprehensive Scientific Review of Insect Damage, Lifecycle, and Integrated Pest Management in Maize

The fall armyworm (FAW), Spodoptera frugiperda, is a polyphagous pest native to the American continent that was first detected in Africa in 2016 and has since become a major constraint to global agriculture Togola 2025. This species severely damages staple crops like maize, sorghum, and rice, threatening food security and the livelihoods of millions of smallholder farmers Togola 2025. Maize is the most vulnerable crop in sub-Saharan Africa, suffering significant annual losses due to the destructive impact of FAW, which affects agricultural productivity and overall rural economies Togola 2025.

The fall armyworm belongs to the order Lepidoptera and the family Noctuidae Kenis 2022 Joshi 2025. It was originally described by J. E. Smith in 1797 and is regarded as a serious pest of several crops, particularly maize and other cereals Kenis 2022. FAW comprises two genetic strains: the "rice strain," which prefers rice and other grass species, and the "maize strain," which feeds upon maize and sorghum Abbas 2022. However, recent genomic analyses show that FAW is much more diverse than previously assumed, and reference to host strains is uninformative in invasive populations because multidirectional introduction events likely underpinned its rapid global spread Tay 2022.

FAW has a wide host range of over 353 plants from 76 families, primarily from the Poaceae, Asteraceae, and Fabaceae Rajashekhar 2024. The pest is capable of causing up to 100% yield loss due to its unforeseen occurrence from the seedling to the cob formation stage Kumar 2022. Infestations of FAW have been shown to reduce maize yields by 15–73% Rajashekhar 2024. The larval stage is the most devastating in nature, affecting the production of 353 species of crops with up to 70 percent yield loss in the overall economy Sagar 2020.

The FAW lifecycle encompasses four stages and its presence can be discerned through both phenotypic characteristics and damage patterns, with genetic analysis also playing a crucial role in its identification Razzaq 2024. Under favorable conditions, FAW's holometabolous metamorphosis takes about 30 days to complete; however, longer cycles occur at lower temperatures, potentially extending up to 60–90 days Joshi 2025 Deshmukh 2021. The pest generally spreads quickly due to its nocturnal, long-distance migration, which affects maize by causing defoliation, structural damage, and decreased yields Joshi 2025. The inherently superior biological characteristics of FAW, including its strong migration ability, high fecundity, and rapid development of resistance to insecticides and viruses, contribute to its invasiveness Wan 2021.

The pests are found to thrive in temperatures above 10 degrees Celsius, and the wings of moths are deformed above 30 degrees Celsius Sagar 2020. The pest displays complex biological and ecological patterns that are highly dependent on environmental factors, host plant availability, and natural enemy diversity, making control efforts challenging Togola 2025. The pre-adult development of S. frugiperda is fastest on popcorn (28.02 days), maize (28.04 days), and sweet corn (28.31 days) but slowest on soybean (34.83 days) Sharma 2024. The highest net reproductive rate, intrinsic rate of increase, and finite rate of increase were observed on maize, and the feeding potential of S. frugiperda was also highest on maize Sharma 2024. The maximum consumption of the sixth larval instar was observed on maize (19,470.47 mm²) while the lowest was on soybean (9,033.67 mm²) Sharma 2024.

The fall armyworm causes considerable economic losses to countless crops worldwide, totaling up to billions of dollars annually Abdulqader 2024. Coming from the Americas, the pest has quickly distributed to Africa, Asia, and Australia, triggering extensive damage to maize and other economically significant plants including rice, sorghum, and cotton Abdulqader 2024. Due to the high consumption of cereal crops, mainly maize, in smallholder diets, FAW could substantially impact global food security Rajashekhar 2024. Furthermore, damage to maize may aggravate dependent industries like bio-ethanol, poultry, and animal husbandry Rajashekhar 2024. While leaf damage at specific plant developmental stages has a significant negative linear effect on grain yield, in all three maize maturity varieties tested, leaf damage explained less than 3% of the variation in yield at the plant level Chisonga 2022.

Integrated Pest Management (IPM) is crucial for reducing pesticide reliance and ensuring stable agricultural production against FAW Togola 2025. IPM includes cultural practices, biological control, mechanical/physical methods, host plant resistance, and judicious application of chemicals Togola 2025. Regular crop monitoring and surveillance principles are also discussed as prevention and early detection measures to mitigate FAW damage Togola 2025. Over three consecutive years, field demonstrations testing a four-component IPM approach (pheromone traps, microbial agents, botanicals, and ETL-based insecticide applications) led to substantial reductions in FAW infestation and increased maize yields by 12.62–24.87% over control Rajashekhar 2024.

Biological control is widely considered one of the most important options for insect pest management, especially given the adverse effects of pesticides on ecosystems and human health Abbas 2022. A comprehensive review of biological control covers predators, parasitoids, entomopathogenic fungi, viruses, nematodes, bacteria, and biopesticides, with a special focus on their effectiveness against FAW Abbas 2022. Egg parasitoids such as Trichogramma pretiosum and Trichogramma atopovirilia, larval parasitoids including Chelonus insularis and Cotesia marginiventris, and predators like Doru lineare and Podisus nigrispinus are effective natural enemies Wan 2021. Biopesticides include viruses (SfGV and SfMNPV), fungi (Metarhizium anisopliae, Beauveria bassiana), bacteria (Bacillus thuringiensis), and nematodes (Heterorhabditis bacteriophora) Wan 2021. A biocontrol-based IPM strategy comprising pheromone traps, Trichogramma pretiosum releases, neem oil, Bacillus thuringiensis, and Metarhizium anisopliae resulted in 71–76% egg mass reduction and 74–80% larval population reduction, with a 38–42% gain in cob yield Varshney 2020.

Maize growers tend to apply high dosages of pesticides to manage this serious pest, and this indiscriminate usage has resulted in unacceptable insect resurgence, harming maize production and consumption Kumar 2022. The insect's propensity to withstand traditional pesticides has demanded intricate monitoring methods, leading to the appearance of integrated pest management approaches Abdulqader 2024. Spinosad has demonstrated 90% larval mortality, while chlorpyrifos mixed with sawdust controls 20% of the pest Sagar 2020. The combined application of entomopathogenic fungi (Beauveria bassiana), nematodes (Heterorhabditis bacteriophora), and the chemical insecticide chlorantraniliprole significantly increased mortality rates in both third and fifth instar larvae, with the highest mortality observed in the triple-combination group (100% by day 7) Razzaq 2024.

Sustainable control of FAW requires implementation of effective IPM strategies, with host plant resistance as a key component Prasanna 2022. Significant strides have been made in breeding elite maize lines and hybrids with native genetic resistance to FAW in Africa, based on the strong foundation of insect-resistant tropical germplasm developed at the International Maize and Wheat Improvement Center in Mexico Prasanna 2022. Genetically modified Bt maize with resistance to FAW is already commercialized in South Africa and in a few countries in Asia, while efforts are being made to commercialize Bt maize events in additional countries Prasanna 2022. Combinations of native genetic resistance and Bt maize also need to be explored as a path to more effective and sustainable host plant resistance options Prasanna 2022. In countries where Bt maize is commercialized, implementing a robust insect resistance management strategy is essential Prasanna 2022.

Pesticidal plants provide an effective and established approach to pest management in African smallholder farming, and recent research has shown that their use can be cost-beneficial and sustainable Phambala 2020. In contact toxicity tests, the highest larval mortality was obtained from Nicotiana tabacum (66%) and Lippia javanica (66%) Phambala 2020. In a feeding bioassay, L. javanica (62%) and N. tabacum (60%) exhibited high larval mortality at the highest concentration evaluated Phambala 2020. Feeding deterrence evaluations showed that Cymbopogon citratus (36%) and Azadirachta indica (20%) were the most potent feeding deterrents among the pesticidal plants evaluated Phambala 2020. Agro-ecological techniques and botanical extracts provide affordable, sustainable solutions for smallholder farmers Joshi 2025. IPM strategies should focus on interventions aimed at improving plant vigor through integrated soil fertility management and the role of natural enemies, as these are likely to result in greater yield gains at lower cost than a focus on FAW control alone Chisonga 2022.

Advances in control strategies against S. frugiperda have been developing over the past four decades; however, insecticide resistance and the remarkable adaptability of this insect have hindered success Paredes-Sánchez 2021. Recent research highlights the analysis of chemical compounds, plant extract metabolites with antifeedant and repellent effects, biological control agents, and sex pheromones for monitoring Paredes-Sánchez 2021. Given that natural selection forces likely differ geographically, region-specific approaches will be needed to control this global pest Tay 2022. Simulations based on age-stage, two-sex life tables could be helpful in predicting the most appropriate time for pesticide application as well as augmentative releases of egg and larval parasitoids Sharma 2024. Knowledge gaps remain in understanding the invasive mechanisms of S. frugiperda, preventing its further spread, and providing better management strategies Wan 2021. Collective efforts, such as community-based monitoring and early warning systems, are essential in addressing the hazards posed by Spodoptera frugiperda Abdulqader 2024. An awareness program through advisory services regarding pest identification, damage symptoms, and control measures can reduce the incidence of the pest Sagar 2020.

Conclusion: Efficient and sustainable IPM strategies, combining biological, chemical, botanical, and genetic tools, remain vital to managing the global threat of Fall Armyworm in maize production.