In a quiet persimmon orchard nestled in northern Greece, a team of scientists meticulously opens paper bags, releasing thousands of tiny flies. This crucial experiment is designed to significantly reduce the devastating impact of aggressive new invasive species.
These particular insects are sterile male Mediterranean fruit flies (Ceratitis capitata), a notorious pest responsible for extensive annual crop damage in Naousa, a region renowned for its considerable peach exports.
However, this project has a more ambitious goal: to counter the escalating threat posed by fruit fly species originating from Asia, which are increasingly appearing in southeastern Europe as local temperatures rise due to climate change.
This vital four-year initiative, an EU-funded project known as REACT, unites researchers from a dozen different nations, including the UK, Israel, and South Africa.
The program operates with a substantial budget of 6.65 million euros (approximately $7.8 million).
A Potent Bacterial Supplement
George Tsiamis, director of the University of Patras’s Laboratory of Microbiology Systems, explained during a media tour in Naousa that these male flies are specially cultivated. They receive a bacterial supplement designed to enhance their activity, resilience, and competitive edge.
He further elaborated, “This augmentation makes them more likely to survive in their natural habitat, travel greater distances, live longer, and most crucially, successfully mate with wild female flies.”
“Because these male flies are sterile,” he continued, “their matings yield no offspring, leading to a gradual reduction and eventual elimination of the harmful wild populations.”
According to Tsiamis, this innovative Enhanced Sterile Insect Technique (Enhanced-SIT) is completely free of pesticides, environmentally conscious, and perfectly suited for organic farming methods.
Savvas Pastopoulos, an agronomist and local orchard owner, has enthusiastically embraced the project and is now tasked with garnering support from other fruit growers in Naousa.
“Initially, there was some skepticism when they first saw the bags of insects,” the 40-year-old shared with AFP, “but once the process was explained, they quickly understood its value.”
He recounted, “In some seasons, the Mediterranean fruit fly alone caused us to lose our entire production in as little as two weeks.”
Experts emphasize that invasive fruit flies represent one of the most destructive challenges facing global food production today.
Specifically, two species – Bactrocera dorsalis (the oriental fruit fly) and Bactrocera zonata (the peach fruit fly) – have already inflicted colossal economic damage across the globe.
Though originally from Southeast Asia, these relentless pests now pose a significant threat of invasion to Europe.
Nikos Papadopoulos confirmed that the oriental fruit fly has been sighted multiple times throughout Europe. Annual reports indicate several occurrences near Naples, with records also noting its presence in France and Belgium.
The Growing Threat from Climate Change
Vasilis Rodovitis, a doctoral candidate at the University of Thessaly’s Laboratory of Entomology and Agricultural Zoology, warned that climate change is exacerbating the problem, as both invasive species flourish in warmer temperatures.
He explained, “Research has revealed that these two destructive insects are capable of surviving winter in Europe’s warmer regions, including Crete and Valencia.”
“Even in more temperate areas such as Naples and Thessaloniki,” he added, “we’ve observed a small but sufficient survival rate that allows them to establish new populations by early spring, following the winter.”
The team strategically selected Naousa as their testing ground because the local Mediterranean fruit fly population is relatively low, mirroring the conditions found during the initial phases of a new species invasion.
Marc F. Schetelig, the project’s coordinator, stated, “This represents Europe’s inaugural field trial for releasing sterile insects on such a precise, small scale, utilizing our specially enhanced sterile flies.”
“Our preliminary results are exceptionally promising,” he noted, “the releases have already led to a quantifiable decrease in the local pest population, a trend we will continue to monitor closely this year and next.”
Schetelig, who is also a professor of Insect Biotechnology in Plant Protection at the University of Giessen in Germany, highlighted the strong support from the local community for this approach, particularly its avoidance of extensive pesticide use.
He concluded, “This focused, small-scale trial is intended to serve as a benchmark for all of Europe, demonstrating how intelligent, localized actions can bring widespread benefits across the entire continent.”