Try the GF-120. I think it is widely used commercially and since it's a bait, it's organic. But have heard it doesn't help much with the new pest, the spotted wing Drosophila. Are you sure that isn't what you have? Could be both.

There is some spotted fruit-fly information on this webpage
(scroll down a ways)

http://oregonstate.edu/dept/NWREC/archive.php?id=27

The NWREC deals mostly with berry crops, but fruit fly controls would apply to most fruits.
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The spotted fly is a late-season problem in the Northwest (later than most cherries)

So I assume you have already seen webpages like this specifically for the cherry fly:

http://www.coopext.colostate.edu/TRA/PLANTS/WesternCherryFruitFly.pdf

I have been told that the cherry fruit fly can be controlled by removing *every* cherry from the area, including those fallen on the ground. With them go the fruit flies. At the very least I would think their numbers would be reduced. Here is a quote from someone more knowledgeable at:

Western Cherry Fruit Fly Management

Pest populations can be suppressed or eliminated by careful attention to harvest. Few cherry fruit flies will complete their life cycle if all fruit is picked and removed from the orchard each season early in the traditional harvest period. If they are not controlled early in the fruit ripening period, some of the most advanced larvae will emerge and drop to the soil by mid-harvest. The author determined that from 10,000 to 20,000 fruit/acre remain in the average well-picked orchard after harvest. These fruit are sufficient to maintain endemic populations of this pest in the orchard, unless control is continued post-harvest. If all of the fruit is removed from an isolated tree or orchard prior to the time larvae emerge from the fruit, the trees become free of the pest until reintroduction. This re-establishment may occur rapidly, but often may not occur for several years. If fruit is abandoned due to rain cracking, and post harvest pest management is neglected, cherry fruit fly populations often greatly increase and control is more difficult the next several seasons.

Bump

Fruit flies - in general, can be a problem. Although, I'm not familiar with cherry types, we have them in great numbers from the prolific orange and citrus type fruits that are abundant here.

I try to keep fallen fruit, and orange/citrus peelings from encouraging fruit fly reproduction by composting the peels and fallen fruit in a large box, which I add dirt, sawdust and/or leaves. They compost well. To date, I have not added this material to my growing areas, but it becomes composted, and that is the main reason for the box method - to eliminate or lessen the fruit fly invasion.

In the future, I may try to utilize this material in and around my plants, but I still am not sure if the compost is completely clear of molds, disease, etc. It is a cold processed compost and may need further heat to completely rid it of diseases.

Just my 2 c's.

Bejay