April 24, 2014

Small insect could cause large problems for Nebraska fruit growers

A very tiny bug is raising big alarms for Nebraska producers.

Its name is the spotted wing drosophila and it closely resembles a common fruit fly. It’s only an eighth of an inch long, but infestations are now confirmed next-door in Iowa and in 19 other states.

Entomologist Laura Jesse says the invasive insect could be a serious threat to certain Nebraska crops.

“The spotted wing drosophila is going to be a big problem primarily for small fruit growers, growers of small fruits like raspberries, strawberries, blueberries,” Jesse says. “It can reportedly attack apples but not really fruits with harder skins.” Blackberries, cherries and grapes could also be at risk.

This red-eyed pest is difficult to tell from a regular fruit fly, even for an expert on wee winged creatures like Jesse. She needs a microscope to accurately distinguish the drosophila from the more common variety.

“Those fruit flies, that we’re used to, attack rotting fruit,” Jesse says. “You always know when you’ve got a bunch of ‘em in your kitchen, you know there’s a banana that you forgot somewhere and it’s rotten. Our normal native fruit fly can’t attack fruit that’s not damaged where as we’re concerned about this fruit fly because it can attack healthy fruit.”

The female fly can slice into the skin of fresh fruit to lay eggs and producers in other states report a serious yield impact with maggots in the produce.

Unfortunately, the fruit flies shouldn’t have a problem over-wintering in the region.

“When it first came into the U.S, it was picked up in California, Washington and Oregon and there was some hopes that maybe it wouldn’t survive in the Midwest,” Jesse says. “It’s actually been in Michigan the past few years and done just fine there so we suspect it will be able to survive our winters.”

The pest is native to Asia and was first found in the U.S. in 2008 and quickly spread. It’s confirmed in at least 20 states, including Iowa, Wisconsin, Illinois and Minnesota.

Jesse has some advice for producers with concerns about this pest: Pick all fruit when harvesting and remove and destroy any fallen, damaged and overripe fruit. Also, there are insecticides available but options are limited.