There Are Worms In The Blackberries You Just Picked | KUOW News and Information

There Are Worms In The Blackberries You Just Picked

Aug 14, 2015

You know those blackberries you just picked?

There are worms in them.

Tiny white worms, almost transparent, that will ultimately blossom into fruit flies -- unless you eat them first. Scientists know them as Drosophila suzukii.

Before we go on, we should tell you to stop gagging, because they are safe to eat. (Also, protein.)

This particular fly arrived in the Northwest six years ago. Warm weather has made it particularly pervasive this year.

“We had such a mild winter; basically we didn't get that winter kill,” said Doug Walsh, an entomologist at Washington State University. “Likewise we've had such a warm summer; the flies have really done very well this year. The best hope for the future is a cold winter.”

(Hmmm.)

How the fly baby came to nest inside Northwest blackberries is a story of rekindled friendship.

In Southeast Asia, the fly and Himalayan blackberry evolved together. In 1885, botanist Luther Burbank reportedly brought the Himalayan blackberry to the U.S.

More than a century later, in late 2008, commerce brought the Drosophila suzukii to California. Since then, the fly has colonized all of North America. In Seattle, it found its old friend the Himalayan blackberry bush in vacant lots, on rusty fences and along old railroad lines.

If you look closely, you'll suddenly see them all. Drosophila suzukii is a pest that has colonized all of North America since arriving in 2008. The female injects her larvae directly into the fruit.
Credit KUOW Photo/Ann Dornfeld

The fly also made other friends along the way, burrowing into raspberries and cherries. Its larvae has even been found in huckleberries on the high slopes of Mount Adams.

It is a close relative of the vinegar fly, currently swarming the bananas on your counter.

But this fly is more ruthless than the traditional fruit fly, because it strikes fruit earlier in the ripening process. The female, unlike a regular fruit fly, can insert her larvae into fruit.

She does this by piercing fruit with her needle-like ovipositor – think stinger – and laying the larvae. In a wild blackberry, she injects between six and 10 eggs. In summer conditions, the eggs will hatch in about a day.

As the fruit disintegrates, the worm crawls out and drops into the soil. It forms a pupa and later emerges as an adult.

Commercial growers hate these pests, as the fly has claimed lots of the softer-skinned fruits.

But the casual berry picker has nothing to fear, Walsh said: “People have been eating these insects for time immemorial.” 

His tips for avoiding the worms: Pick fruit before they're overripe and place them in the fridge. We've also heard that soaking the berries in salty water can encourage the worms to emerge and float to the top.