New pest poses threat to Britain's fruit farms

Fruit farmers and garden growers in the region are being urged to be vigilant and help monitor the spread of a devastating Asian fruit fly first identified in the UK last year

Caroline Dickinson, who runs the Brockbushes Farm Shop and Tea Room
Caroline Dickinson, who runs the Brockbushes Farm Shop and Tea Room

Fruit farmers and garden growers in the region are being urged to be vigilant and help monitor the spread of a devastating Asian fruit fly first identified in the UK last year.

The pest, known as Drosophila suzukii, has already spread through the USA as well as Italy, and the state of California lost $500m-worth of crops, including $300m-worth of strawberries alone, when the insect was first detected in the US in 2008.

The insect differs from common fruit flies, which only lay eggs in rotten fruit, as Drosophila suzukii has a powerful saw-like ovipositor capable of breaking through the skins of ripe fruit, to lay its eggs.

The maggots subsequently hatch and eat through the fruit, causing rapid rot from the inside.

The pest is known to spoil whole crops of soft fruits including strawberries, raspberries and blueberries. The fly has already caused huge economic impact with some areas in the US experiencing 80% crop loss.

Caroline Dickinson, who runs the Brockbushes Farm Shop and Tea Room at Corbridge, Northumberland, said: “I hadn’t heard of this pest, thank goodness, as its effects sound absolutely awful.

“I dread to think what would happen if we were affected, especially as we’ve been so busy recently, with a great fruit crop.

“We’ve finished our main crop of strawberries and are waiting for the final batch to ripen. They should be ready for this weekend and we’re hoping the blackberries will be ready too.”

Drosophila suzukii is slightly larger than the normal fruit fly being 2.6-2.9mm long and male species has dark spots on each wing; females are slightly larger being 3.2-3.4mm. The insect, also known as the spotted wing Drosophila, originates from South East Asia.

University of Leicester scientists are researching ways to prevent the pest from causing devastating UK losses, by finding a biological solution to the problem. They are also appealing to farmers and members of the public to help monitor the spread.

Researchers at the University’s Department of Genetics plan to genetically modify male fruit flies and “switch off” the genes essential for the development of the maggot by a natural process of gene regulation. The process does not involve toxic substances or foreign genes.

When modified male flies are released and mate with females, the resulting offspring will not develop into larvae. The method will remove the need to use crop pesticides or introduce new predators to kill the insects.

The university is asking for the public to help by setting fly traps around the country in order to monitor spread. By using a recycled plastic bottle and cutting small holes in the sides and introducing a small amount of cider vinegar into the bottle, the trap can then be hung from a tree or in a garden.

Farmers and members of the public can send the liquid back to the university to check if any Drosophila suzukii are present. More than 50 people have already agreed to take part according to the university.

Dr Ezio Rosato said: “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 introduce new predators.

“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.”

Journalists

David Whetstone
Culture Editor
Graeme Whitfield
Business Editor
Mark Douglas
Newcastle United Editor
Stuart Rayner
Sports Writer