New pest threatens berry crops

Blueberries litter the ground in Linda Boyd’s orchard near Oxford. Boyd estimates 80 percent of her crop was lost to damage from spotted wing drosophila. (Courtesy)

Blueberries litter the ground in Linda Boyd’s orchard near Oxford.
Boyd estimates 80 percent of her crop was lost to damage from
spotted wing drosophila. (Courtesy)

By Errol Castens
Daily Journal

OXFORD – Linda Boyd’s orchard is carpeted in blue after her 500 blueberry bushes have jettisoned much of their fruit.

Boyd is among the first growers in north Mississippi with an infestation of spotted wing drosophila, a tiny but devastating fruit fly.

“They lay their eggs into the berries, and then the larvae eat the insides of the berries,” she said. The affected fruits leak juice, become soft, can develop a vinegary smell and eventually fall to the ground.

Even of Boyd’s picked berries, washed and left to dry overnight, many were leaking the next morning and had to be discarded. She estimates an 80 percent loss.

“We were expecting this to be one of our best crops,” she said.

The spotted wing drosophila, or SWD, was found in south Mississippi in 2010, but only last year posed significant problems there.

“We didn’t have a lot this year until late in the season,” said John Braswell, a retired Extension horticulturist. “Last year we started seeing it early, so this year everybody pretty much was geared up.” He noted both conventional and organic

SWD controls are available, but require a heavy schedule of spraying.

“One of the reasons blueberries, blackberries and figs are such popular backyard fruit is that they have few insect pests and can usually be grown without spraying,” Extension entomologist Blake Layton wrote last year. “SWD will change this.”

Boyd still hopes Extension will focus on more long-lasting organic controls, citing dependence on honeybees, native bees and butterflies for pollination.

Extension horticulturist Eric Stafne said SWD is a threat to blackberries, cherries, strawberries and even tomatoes as well.

“Believe it or not, blueberries are not one of its favorite hosts,” he said. “It affects anything with a real thin skin and high sugar content.”

Despite Boyd’s losses, SWD appears to be an isolated problem in north Mississippi so far. Anne McCullough of Pumpkin Creek Farm near Oxford said a cold, late spring threatened their blueberries, “but it turned out to be a nice-sized crop. We haven’t seen a bit of berry drop.”

Billy Rico of Panola County reported a good berry season as well.

“I had a big crop,” he said. “I don’t spray anything to keep something like that out, but I haven’t seen any damage.”

Still, it’s something the region’s growers may need to monitor. Layton wrote last year of SWD, “This little fly has already caused millions of dollars in economic loss in U.S. fruit, and it appears that it is just getting started.”

errol.castens@journalinc.com