Wasp support in war on whitefly
16 November 2009
A wasp that feeds on whitefly has been found in the UK for the first time, offering hope to beleaguered gardeners battling the common pest outdoors on brassicas and other edible and ornamental plants.
Wasp expert Dr Andrew Polaszek, of the Natural History Museum, was collecting specimens for his research on parasitoid wasps when he spotted the 1mm-long Encarsia aleurochitonis emerging from an adult whitefly. It is the first time the wasp, native to mainland Europe, has been recorded in the UK, though it's believed it may have been here for some time but overlooked because of its miniscule size.
“There are dozens of parasitoid wasps right under our noses keeping a lot of pests under control without us knowing they're there,” said Dr Polaszek. “They provide an ecosystem service, and it's not until things get out of balance that we're aware of what they're doing.”
E. aleurochitonis itself is of limited use to gardeners as it feeds mainly on wild whitefly, although a close relative, E. formosa, has been used for some time as a biological control for whitefly in the greenhouse. However, the confirmation of the wasp's presence in the UK leads Dr Polaszek to believe there may be an army of closely-related parasitoid wasps keeping the many dozens of whitefly species that live here under control.