In recent years, the phytosanitary landscape of berry crops in the Mediterranean basin has been changing rapidly. Marco R. Butera of BetterBerries - an agronomic consultant specialized in blueberry cultivation and technical management, as well as in strawberries, raspberries, and blackberries in international production contexts - reports that his latest visits to southern highbush blueberry farms confirm an increasingly undeniable fact: thrips can no longer be considered a secondary issue. They are becoming a structural threat that requires continuous, proactive defence strategies.
© Marco R. Butera(Photo courtesy of Marco R. Butera)
"Frankliniella occidentalis (Western Flower Thrips, WFT) is now firmly established, with regular infestations during flowering. The real novelty is Scirtothrips dorsalis, confirmed in Spain and currently under eradication efforts in some areas, with numerous plots affected in the Valencian Community. In Turkey, it was first detected in 2020 on blueberries (Adana) and later reported in the 2021/22 season on strawberries and citrus. This indicates its presence, though not yet widespread. In Italy and Greece, it has not been officially reported or established yet. Compared with WFT, S. dorsalis poses a greater threat: it attacks flowers, shoots, leaves, and young fruits, directly reducing the commercial value of production. It is also known to vector certain viruses, though in blueberries, its main impact remains direct tissue damage," explains Butera.
The biology of these species further complicates the picture. Thrips populations are highly dependent on temperature and humidity. Under favourable conditions, they can complete a life cycle in less than two weeks, producing multiple overlapping generations in a very short time. "Scirtothrips dorsalis, for instance, develops in under three weeks at 25-27 °C, while Frankliniella occidentalis is even faster. For the latter, forecasting models already exist based on degree days, with a developmental threshold of about 8 °C and a requirement of 227-268 degree-days from egg to adult. These tools - already integrated into calculators and DSS - can be extremely useful in estimating population peaks and optimizing intervention timing," Butera notes.
Monitoring remains the cornerstone of defence, but it cannot rely solely on chromotropic adhesive traps. "These traps are useful for early detection and partial mass trapping, but relying on them alone risks creating a dangerous sense of security," the expert warns. "Too often, this results in reduced scouting frequency, leading to late interventions when populations are already above the risk threshold. This is why trap data must be combined with systematic inspections of young leaves, shoots, and flowers, and correlated with climate trends and phenological stages. In this regard, new technologies are emerging: some companies now offer automatic traps equipped with AI, able to recognize and count captures in real time and send alerts when critical thresholds are reached."
© Marco R. Butera
(Photo courtesy of Marco R. Butera)
For blueberries, the most vulnerable period is the vegetative stage, particularly in the weeks before flowering. "At this time, tissues are especially tender and attractive, and unchecked thrips pressure can compromise leaf photosynthesis and shoot elongation. The result is a weakened plant just when it should be accumulating energy and preparing for flowering, with negative consequences on vigour, yield, and flower induction," Butera continues.
Given such complexity, no single tool is sufficient; an integrated approach is essential. Butera stresses the importance of combining agronomic practices, biocontrol, and targeted chemical control. "Agronomic measures include constant monitoring, weed management, and minimizing potential inoculum sources. Biocontrol can rely on natural enemies such as Orius spp. and phytoseiid mites, which can sustainably suppress populations. Chemical protection remains a key resource, but it must be selective, restricted to products authorized for blueberries, and applied in rotation to minimize resistance risks."
The situation, however, is not uniform throughout the Mediterranean
The Mediterranean situation, however, is far from uniform. In Spain and Turkey, the established presence of Scirtothrips dorsalis calls for intensive, structured defence programs. In Italy and Greece, by contrast, Frankliniella occidentalis still predominates, usually causing more limited damage. "Officially, S. dorsalis has not yet been reported in these countries, but considering the experiences elsewhere and the rapid movement of plants and fruit in international trade, its arrival is highly likely in the near future. This makes prevention and early detection crucial in buying time and preparing effective responses," Butera explains.
Looking ahead, two distinct strategies emerge. "For Frankliniella occidentalis, the objective is to keep populations consistently below the economic damage threshold. For Scirtothrips dorsalis, however, immediate and decisive action is required at the first detection. Once established, eradication is virtually impossible. The lesson from countries already affected is clear: investment is needed in widespread monitoring systems, operator training, and ready-to-deploy defence protocols to avoid costly delays," Butera concludes.
For more information:
Marco R. Butera - Global Berry Specialist
BetterBerries
[email protected]
betterberries.it