Penn State says it takes several days just above freezing to kill them. Yuk...no way would I eat a fly or it's larvae.

Here's something from Oregon State Univ. cckw.

OSU is also investigating the impact of cold weather on the insect's survival. Early data suggest that some adults can survive fluctuating conditions and can live for 150 days in the winter. Low humidity appears to negatively impact the fly's survival and reproduction, but tests are still ongoing to confirm these findings.

OSU is also advising growers to monitor for the fly by hanging homemade traps containing apple cider vinegar in plastic cups punctured with small holes that lure in the insect. Amy Dreves, an entomologist with OSU Extension, explains how to make them in a video. Researchers are working to develop better baits and traps that catch the spotted wing drosophila earlier in the ripening season to help growers determine when to treat for the pest.

Yes, you should put out a fresh trap or examine the fruit rather than rely on cool weather for non-infested donated fruit.

The trap would have to be clean for several days; as the fly larvae take time to develop to a visible size.

Overnight refrigerated or frozen berries will have obvious larva on the berry or container surface. A clean batch of those berries are lower risk for containing larva.

Hi cckw,

I've read optimum laying temps for the SWD are b/t 70 and 90F, so if your temps have been as cool as ours, I doubt you have much, if any, egg laying going on.

Larry is right though, if you want to make sure you have no larva in the fruit, check the fruit with the salt water test.

I hate this pest. I trapped for it this year and it showed up before blackberries were even ripe. I had to bag all the cull fruit (vs. leaving it on the ground) and keep everything well sprayed.