UK strawberry growers should encourage more hoverflies into their crops as they act as both pollinators and natural aphid predators, says horticultural researchers NIAB EMR.
Some of the UK’s native hoverfly (Syrphidae) species not only visits strawberry flowers as adults, but also, during the larval stage, offer the added bonus of eating aphids. However, whether aphid-eating hoverflies were able to effectively pollinate strawberry flowers had remained largely unknown until now.
NIAB EMR research, part of a PhD project funded by East Malling Trust and Royal Holloway University London, showed that strawberry plants in cages visited by syrphine hoverflies produced over 70% more strawberries than cages without the insects. In addition, twice as many of those berries were of supermarket quality.
With concerns over a decline in numbers of wild pollinator insects, the results could pave the way for new crop management practices that benefit hoverflies and commercial strawberry growers.
Dr Michelle Fountain, Deputy Head of Pest and Pathogen Ecology at NIAB EMR, said, “This is the first time that the pollination role of hoverflies in strawberries has been quantified. We also compared two hoverfly species, and found that one species (Eupeodes latifasciatus) was nearly twice as effective at producing marketable fruit as the other (Episyrphus balteatus), demonstrating that hoverfly species may also differ in their pollination efficacy. Using these results we can look in more detail at the ecological requirements of the key hoverfly species and potentially implement specific wild flower strips that will help boost their numbers in strawberry crops.”
The research project was part of a PhD project by Dylan Hodgkiss, funded by the East Malling Trust and Royal Holloway University London. The project results are published in the Journal of Pollination Ecology in the paper ‘Syrphine hoverflies are effective pollinators of commercial strawberry’ by D Hodgkiss, M Brown and MT Fountain (2018).