Research shortfalls are hampering attempts to increase the use of biological methods to control the fall armyworm (Spodoptera frugiperda), one of the world’s major agricultural pests.
Originating in the Americas, the moth is now present as an invasive species in 80 countries, from Africa through to Asia. It poses a major threat to cereal crops, with damage of $9.4 billion a year in Africa alone.
While there are hundreds of known pathogens, parasitoids and predators associated with fall armyworm, only around 40% have been the subject of testing by scientists to determine their effectiveness in reducing the species’ numbers, an international team of researchers reported in the journal Biological Control. The research shortfall means “we fail to effectively harness what nature has provided” to control the pest, they said.
Blind spots and biases
Despite a fast-expanding research base, the quest to improve S. frugiperda biocontrol has been hampered by geographic biases which limit species discovery, they noted, with most of the “knowledge stockpile” coming from Brazil, USA, Mexico, China and India.
It has also been affected by a predominance of ‘snapshots’ over methodical analyses of natural enemy populations, a bias towards large-bodied and day-active biocontrols and a lack of focus on how habitat conservation and ecosystem services contribute towards effective non-pesticide control.
“Despite decennia of fall armyworm research, it remains difficult to determine whether and how certain biota actually contribute to biological control,” they wrote.
“All too often, critical research shortfalls leave us ill-informed about their role as biological control agents and how such is mediated by aspects of the farming system.”
Field studies and closer ties needed
The team of experts advocated that researchers should “head back to the field” to take a deeper look at biocontrol within farming systems, with realistic control and metrics that are relevant to farmers, such as yield ands profit.
They advised biocontrol specialists to “integrate or perish”, noting a lack of engagement with other agricultural practices such as soil science and agronomy. They also noted that scientists are failing to sufficiently communicate the societal benefits of biocontrol to stakeholders, resulting in the continued overwhelming emphasis on pesticides.
“Throughout the tropics and subtropics, the fall armyworm is impacting food security, jeopardizing farmer livelihoods and triggering pesticide overuse,” they added.
“Agroecological and biodiversity-based measures such as biological control constitute safe, cost-effective and environmentally-sound alternatives to pesticidal control and offer ‘best-bet’ solutions for millions of cereal growers.”
