How to thwart the cherry fruit fly

By Sandra Frangiadakis

KFPC Gleaning Abundance Program

Cherry season should be a welcome time of year, as the first of the tree fruits heralds in the beginning of the harvest season in our part of the world. But each year, I find myself filled with a sense of dread about cherry time, for sadly, cherry season is also Cherry Fruit Fly season, and unless you spray your cherry tree with some form of toxic pesticide, each of those lovely, juicy morsels will be home to a little, white, wiggly worm. As the coordinator of the Gleaning Abundance Program (GAP), I am charged with doing as much as possible to see that no local fruit goes to waste, but I can’t expect people to spend their time and energy picking worm-riddled cherries (although many of our volunteers are committed to organic agriculture and will put up with anything to avoid pesticides) and I can’t expect recipient agencies like the food bank or the Boys and Girls Club to welcome bins of wormy cherries either. The best we can do is try to pick unsprayed trees before the fruit is completely ripe so the worms are still minute and undetectable. Not the best scenario.

There are, however, a couple of alternatives. Spinosad, an organic-approved product which has shown to be effective against the Cherry Fruit Fly, is available commercially, and a small group of homeowners could potentially get together and share a 3.8 litre jug (approx $230). Of course, as with any pesticide, timing and thorough application are crucial to its effectiveness - it is easy to get it wrong.

A more attractive option to me, is something called a Kootenay Cover. It’s basically a fine nylon mesh bag big enough to fit over a cherry tree. Developed by Marilyn Roberts, a resourceful retired teacher from the Kootenays (thus the name), it has been around for about ten years and has proven to keep out not only the Western Cherry Fruit Fly, but also the dreaded spotted-wing drosophila, another cherry pest which is slowly making its way into the Southern Interior. Once the cover is on the tree, there’s nothing to do but wait until the cherries ripen. It lets in rain and light, but keeps out the birds and bugs. Last year, I got to witness a Kootenay Cover in action when the GAP was invited to pick a beautiful Rainier cherry tree that had been under cover all season. It was quite an impressive sight - this very large, stately cherry tree completely covered by a white shroud. I was quite surprised at the size of the tree and couldn’t imagine how they managed to get the cover on it, but there is an efficient system to do that and videos on the website show how. The results were undeniable. We picked over 300 lbs of perfectly ripe, organic cherries and didn’t find a wormy one in the lot. The tree had been partially uncovered to allow us to harvest and we did spot a few Cherry Fruit Flies, but they had been kept out long enough to save the fruit from damage.

It is initially a big expense, but to me, the Kootenay Cover seems like the best alternative to the annual distress of what to do about the cherries. For those people who are already spending money on expensive spray programs, it could even save money over time. The added bonus of keeping away the birds makes it even more of a bargain.

I, for one, plan to bite the bullet and invest in this remarkable invention. For the first time in years, I’ll be able to eat my organic cherries without having to take a second look for that ever-present little white wiggler.

Contact the Gleaning Abundance Program at or 250-851-6111,

© Kamloops This Week