Will the pests that caused so much trouble for berry growers be back in 2014?

There is good news and bad news on that subject. The two viruses that together took a big chunk of the strawberries in Virginia and the Carolinas are unlikely to be a significant problem again.

But the fruit fly spotted wing drosophila (SWD) is an issue that appears to be here to stay, said Hannah Burrack, North Carolina State University Extension entomologist.

“It can be a problem on any soft-skinned fruit. In North Carolina, it has been found on strawberries, blueberries, blackberries, raspberries and cherries. In some nearby states, it has also been found on peaches and grapes. SWD preys on soft and sweet fruits, and if you are growing any, you need to be prepared to manage it.”

In the South, SWD was first spotted in Florida in 2009, in Mississippi and both the Carolinas in 2010, and most other Southern states in 2011 and 2012. It is now in 41 states.

“Everywhere it is found, it is likely to require management, and you need a plan to manage it,” said Burrack. “There aren’t a lot of tools for dealing with SWD, so we need to optimize the tools we have.”

Here are some tips to get the best control:

  • Harvest as frequently as possible and get as good post-harvest quality control as you can get.
  • Keep the fruit cold after your harvest it. “Immature SWD don’t develop in temperatures colder than 41 degrees F, although they may not actually die,” she said.
  • Take steps to make sure the canopy is open.
  • Use insecticides if needed. One new insecticide may be available for use on blueberries this season, Burrack said, but she can't yet reveal the name.
  • Don’t let any berries stay on the ground after harvest, since the insect can use them to reproduce.
  • It may be less important to aggressively protect strawberries during the first weeks of harvest. SWD are likely to be most significant in strawberries later in the season.
  • SWD are also likely to be a bigger issue in day-neutral strawberries. “That is one of the crops where we found the first reproducing population of SWD in North Carolina in 2010,” Burrack said.
  • SWD populations may be higher as they move into later crops, such as rabbiteye blueberries, blackberries and raspberries.