Louisiana: New Pest Could Cost Blueberry Growers

ALEXANDRIA, La. – Louisiana blueberry growers have a new pest to watch for that has the potential of reducing their yield by up to 30 percent.

LSU AgCenter entomologists have confirmed that the spotted wing drosophilla, a member of the fruit fly family that has been moving across the nation since the early 1990s, is finally here, said LSU AgCenter entomologist Michael Ferro.

“This insect was originally observed in Japan and later moved in China,” Ferro said. “In the 1980s it was found in Hawaii, then in the 90s in California.”

The pest moved across the northern part of the country, then down the East Coast in recent years.

“This fruit fly is different in that normally fruit flies will only attack ripened fruit, with a wound or a bit of blemish or a problem,” Ferro said. The spotted wing drosophilla likes soft fruit like blueberries, blackberries, raspberries, but it will also attack plums and cherries.”

There are about 1,500 species of fruit flies, and they all look alike. But the one good thing about this species is the male is very distinct, he said.

“This guy has these black dots on its wings, red eyes and black bands on its front legs,” Ferro said.

Unlike other fruit flies, the spotted wing drosophilla female has a long, spike-like ovipositor, which is an egg-laying device with serrated teeth on it.

“The female will land on a fresh, not quite ripe blueberry, puncture the skin and lay her eggs inside,” he said.

Females have the ability to lay up to 350 eggs during their lifetime. And with heavy infestation, multiple females may lay eggs in the same berry.

Ferro said if you pick a berry with a fresh egg inside you won’t know there’s a problem, but after a while, the berry will become soft.

Louisiana has three varieties of blueberries that provide three picking seasons that run from late May through mid-August.



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