The fall armyworm (Spodoptera frugiperda), a highly destructive pest native to tropical regions of Central and South America, has become a major threat to global food security. Now present in more than 80 countries, this invasive species has caused extensive damage to agricultural crops, particularly corn (maize). Recent scientific findings from Australia, however, offer a potential breakthrough in the fight against this persistent pest through the discovery of native fungi capable of killing fall armyworms from within.
Characterized by their rapid spread and high reproductive capacity, fall armyworms have swiftly established themselves across Africa, Asia, Europe, and Australia. Adult moths are capable of long-distance migration, facilitated by wind currents and international trade. One of the longest recorded migrations spanned 870 miles (1,400 kilometers) from Mississippi to southern Canada in just 30 hours. A single female moth can lay between 1,000 and 2,000 eggs during her lifetime, with larvae emerging and becoming capable of significant crop damage within a week. These larvae, which resemble worms, are particularly difficult to detect due to their small size and cryptic nature, often making their presence known only after damage has begun.
While corn is their primary target, fall armyworms are highly polyphagous, meaning they can feed on a broad range of plants, including wheat, cotton, sugarcane, and various vegetables. Their adaptability and resistance to commonly used pesticides have made them an especially difficult pest to manage. As chemical treatments lose effectiveness due to resistance development, alternative biological and ecological solutions have become increasingly important.
In response to the escalating crisis, scientists from Australia’s Department of Primary Industries (DPI) have discovered five species of native fungi capable of killing fall armyworms within 24 hours of exposure. Among these is Nomuraea rileyi, a fungal species that adheres to the surface of the larva before penetrating and consuming it from the inside out. Although the DPI findings have not yet been published in a peer-reviewed journal, they were shared with stakeholders during a national meeting on fall armyworm management held in March.
In parallel, another research team from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) has been investigating additional fungal and bacterial agents. Their findings revealed that some strains of Beauveria bassiana were able to eliminate up to 75% of fall armyworm populations within 48 hours. Moreover, the bacterium Bacillus thuringiensis (Bt) — a well-known biological pesticide — was also shown to be effective. Bt functions by producing toxins that perforate the gut lining of the larvae, resulting in starvation and death.
Although the exact mechanisms by which B. bassiana eradicates the pest are still under investigation, researchers agree that these naturally occurring biological agents hold significant promise for integrated pest management (IPM). Dr. Wee Tek Tay of CSIRO emphasized the importance of strategic deployment to prevent resistance development. Since the fungi and bacteria involved are naturally present in the environment, they are less likely to cause ecological harm compared to synthetic chemicals.
The DPI team is currently pursuing regulatory approval for commercial use of N. rileyi, aiming to make this biocontrol method accessible to farmers. However, experts stress that before these fungi can be widely implemented, thorough environmental assessments are necessary to evaluate any unintended consequences.
Despite these considerations, biological control agents like fungi and bacteria offer a more environmentally sustainable approach to pest management. Compared to chemical pesticides, they pose fewer risks to ecosystems while providing an effective solution to an increasingly urgent agricultural challenge. If successfully developed and deployed, these Australian fungi could mark a turning point in global efforts to curb the spread of fall armyworm.
