Vinegar flies hit Swiss cherry crop

Vinegar flies lay their eggs in fruit just before the harvest and the larvae eat the cherries from the inside. © Keystone / Michael Buholzer

Despite trees full of fruit, this year’s cherry harvest will be much lower than expected because of the cherry vinegar fly, reports Swiss public broadcaster SRF.

“We assume that we will not reach the estimated 2,500 tonnes of eating cherries,” says Beatrice Rüttimann, spokesperson for the Swiss Fruit Association. “And also with distilling cherries – where we estimated 3,000 tonnes before the harvest – we will not reach that figure.” The association does not yet have exact figures for the whole of Switzerland, as harvesting is still going on in eastern Switzerland.

The cherry vinegar fly, a native of Asia which arrived in Switzerland about 15 years ago, comes when the cherries are ripe, bites into the skin and lays eggs in the fruit. The larvae then begin to eat the fruit from the inside, making it inedible. These flies reproduce very quickly, and so can rapidly infect many trees.

SRF quotes Aurelia Jud, who trains farmers in Lucerne, as saying the best way to protect crops is with close-meshed nets, but it is hard to do this without leaving gaps on high-trunk trees, which can grow up to 20 metres high.

The Swiss Fruit Association is hoping that a natural opponent of the vinegar fly will emerge, such as the parasitic wasp.