What is in this article?:
- Southern berries bedeviled by spotted wing drosophila
- Soft skinned fruit susceptible
• Ripening and ripe fruit are susceptible to attack by spotted wing drosophila attack, but the insects do not appear to be attracted to unripe fruit.
TWO SPOTTED wing drosophila flies light on a raspberry in North Carolina.
Soft skinned fruit susceptible
Peaches and nectarines could be vulnerable as well, he added. “Any fruit with soft skin can be susceptible.”
Because of the life cycle of SWD, there is a danger of resistance developing to any specific insecticide. “So managing to avoid resistance is very important,” said Pfeiffer. “Insecticides with different mode of actions should be rotated.”
And pay special attention to pre-harvest intervals. They can range widely from one type of berry to another. “It will be critical to check the label of alternative products for PHI for the crop needing protection,” he said.
As in North Carolina, intense sanitation is strongly recommended in Virginia.
“Harvest fruit promptly to eliminate breeding sites,” Pfeiffer said. “Any over-ripe or rotten fruit nearby should be destroyed. If a crop is found to be infested with SWD, especially if not established in the area, it should be destroyed after samples are taken for proper identification.”
SWD is still a relative newcomer in the southeastern states. After its first discovery in the continental United States in California in 2008, it was found in Florida in 2009, in the Carolinas in 2010 and in Virginia in 2011.
As if flies with spotted wings weren’t bad enough, Tar Heel strawberry growers had to deal this season with the strawberry “clipper,” a small weevil that lays its eggs in developing flower buds.
The small, snout-nosed beetles most often appear in fields with wooded edges, where they spend the summer and the winter.
“They are not great dispersers,” said Burrack. “Damage is worse in rows bordering the woods, and it decreases as you move inward.”
Should you treat for this insect? Strawberry clipper activity typically lasts for only a few weeks, and strawberries seem able to compensate for clipper damage, at least in matted row plantings.
“So I often don’t recommend aggressive management for strawberry clippers,” said Burrack. “The materials that are effective against them are broad-spectrum insecticides that can be detrimental to bees.”
If you apply any pesticide to plants during bloom, be sure to avoid bee exposure, she said. Treat at dusk or dark, when bees are not foraging, and you allow for maximum “dry time.”
“Also, wait to treat your plants until after bloom is complete,” she added. “The latter is not an option for strawberries, but can be employed for some caneberries and crops.”
Select the least toxic material to bees that is effective against the target pest, she said.
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