В Южной Африке тестируют ос-опылителей как альтернативу пчелам для повышения урожайности

At a recent hoverfly pollination field day near Simondium in South Africa's Western Cape, Bee-Tech Group director Michiel Bruggeman outlined the results emerging from local trials assessing commercially reared hoverflies as pollinators for protected and open-field crops. Two hoverfly species, Queenfly® ( Eristalis tenax ) and Goldfly® ( Eristalinus aeneus ) from Spanish company Polyfly, have been introduced in the trials. The trials are aimed at establishing whether hoverflies can improve fruit set and ultimately deliver measurable production benefits under South African conditions. Early observations are positive, although Michiel stresses that yield data is still being generated. Protected cultivation can also create specific management challenges for honeybees. He notes that bees may escape through tunnel or greenhouse netting and then struggle to return, sometimes becoming trapped on the structure. Hoverflies offer a different management model. The insects used in the trials are sustainably reared rather than collected from wild populations, and are supplied in batches that can be replaced as their working period ends. "They're sustainably bred, and just get replaced. They're not being taken from the wild, so you're not actually killing the wild swarms, stressing them or potentially the wild bee populations." The work is particularly relevant in South Africa because bumblebees, widely used for greenhouse pollination internationally, cannot currently be imported, creating interest in alternative pollination strategies. © Bee-Tech Potential across protected crops Initial observations suggest that crop characteristics will be important in determining where hoverflies provide the greatest value. He identifies blueberries as a promising crop because of their relatively large flowers, while peppers have also shown potential in tunnel production. "They work in pepper greenhouses. In crops where there are fewer flowers, you can put a smaller amount of hoverflies and still get the same amount of visits. Other tunnel-grown crops requiring insect pollination, including zucchini, could also warrant investigation." Environmental conditions are another consideration. In the trials, hoverflies were active in the morning and appeared to maintain activity under cooler conditions. "They definitely work clearly in the morning. They work better under cold conditions than the bees." © Bee-Tech Working alongside bees The objective is not necessarily to replace honeybees. Instead, hoverflies could potentially form part of a multi-pollinator strategy, providing activity under conditions or in production systems where conventional pollinators may be less effective. According to Michiel, the two types of pollinators can operate together without significant territorial interaction. "They don't bother each other because they're not territorial. The hoverflies do that thing alongside the bees, and they work quite nicely together." © Bee-Tech Release rates and crop protection Commercial data from Polyfly are available to inform hoverfly release rates and timing. However, release recommendations continue to be refined for individual crops, taking into account factors such as crop density, flowering intensity and the duration of the flowering period. "Developing and validating crop-specific release rates is an ongoing project." Crop-protection programmes will also influence deployment. As insects, hoverflies can be affected by insecticides, but their use in replaceable batches could provide flexibility around spray applications. © Bee-Tech Measuring the commercial return For growers, however, biological activity is only the first step. The ongoing trials are intended to establish whether improved pollination translates into higher yields and sufficient economic returns. "Right now, the basic data is that they work, and they work to sustain the crop. But assessing the yield, the yield improvement, is an ongoing project." Further trials across strawberries, blueberries, peppers and tomatoes are intended to help compare pollination costs with production returns. Work is also being conducted on crops including avocado and mango. For more information: Bee-Tech Group Michiel Bruggeman [email protected] https://bee-techgroup.com/