Tiny Asian Fruit Fly Threatens UK Fruit Crops

Strawberries and other soft fruits being grown in the UK are at risk of destruction by a tiny Asian fruit fly known as Drosophila suzukii, researchers report.

Despite its diminutive 2 millimeter size, the fly has powerful, saw-like jaws that can use to break through the skin of ripe fruit to lay its eggs inside.

Drosophila suzukii already has a reputation in the United States for damaging crops, and now a team of scientists at the University of Leicester are trying to determine how widespread the flies are in the UK and have called upon the public to assist in the research.

The tiny flies, also known as spotted wing Drosophila, can devastate fruit crops. When first discovered in California in 2008, the state lost $300 million worth of strawberry crops due to the flies.

Unlike a common fruit fly, which lays eggs in rotting fruit, the Drosophila suzukii prefers ripe, soft frutis like strawberries, blueberries or raspberries to lay its eggs inside. Once hatched, the maggots eat through the flesh of the fruit.

"Drosophila suzukii are different from the common fruit flies found in the UK. They are able to use their enormous ovipositor to break into fresh fruit and lay their eggs," said Ezio Rosato, of the Department of Genetics at University of Leicester.

"This creates trouble. If you are a fruit grower and have little maggots growing in your fruit, it won't be marketable. The animal has already had a huge effect on the soft fruit market in the USA and Italy."

To that effect, Rosato and his colleagues are calling upon local "citizen scientists" to track populations of Drosophila suzukii around the UK by setting simple traps to catch the flies. A little bit of cider vinegar in a recycled plastic bottle with some holes poked into it will attract the flies, which will then drown in the vinegar. The scientists ask that the liquid is shipped back to them so they can analyze its contents and check for any Drosophila.

This will help them in creating a map of the fly's location around the nation.

"We want to limit the impact the animal will have in the UK. We want to develop a genetic system to control the spread of the animal -- rather than relying on pesticides or introducing new predators," Rosato said.

"Having the public involved in this project is really useful - as it will help us have an idea of where the animal already is in the country. It is also a really good way of involving people in science - and I think people really appreciate having the chance to take part."