Spotted wing drosophila

The spotted wing drosophila was not seen in Britain for the first time until 2012. This exotic species, native to Southeast Asia, is a threat to fruit production.

recognize Spotted wing drosophila (SWD)
Spotted wing drosophila (SWD) - female, photo: Phycus
recognize Spotted wing drosophila (SWD)
Spotted wing drosophila (SWD) - male, photo: Judy Gallagher - CC BY-SA 2.0

The spotted wing drosophila (SWD) (Drosophila suzukii) is very similar to several species of vinegar fly. The female measures about 3 mm; the male is slightly smaller. This fruit fly has red eyes.

The spotted wing drosophila was not seen in Britain for the first time until 2012. This exotic species, native to Southeast Asia, is a threat to fruit production because the females lay eggs in ripe and ripening (soft) fruit.

The spotted wing drosophila lays eggs in near-ripe fruit: soft, red fruits (e.g. strawberry, raspberry, red currant, cherry). The larvae eat the flesh and the fruit rots away. This exotic pest can survive mild winters; in true frost, the spotted wing drosophila dies.

Affected plants

Remedy

Remove affected fruit and pick fallen fruit from the ground. Do not put the collected fruit in the compost heap – the ideal breeding ground for this fruit fly; put it in a plastic bag and put this in a garbage container.

Presence of natural enemies (parasitic wasp species, predatory bugs and mites) reduce the numbers of the spotted wing drosophila. Control is evolving: experiments are being made with nematodes and fungi.

Prevention

Clear up tarnished fruit and fallen fruit. A natural form of to control is to establish flower strips between fruit trees and berry bushes. This attracts the predators of the spotted wing drosophila: earwigs, damsel bugs, spiders and ants.