Fruit Fly Control on Cherry Trees

My cherry tree is plagued by fruit flies. I have been trying to control it using netting without too much success. I also applied spinosad spray with limited success. Could someone help me with a more effective way to deal with this problem?

Thank you!


You have to apply the Spinosad frequently, as it doesn’t last long. Hummingbird feeders might help, too.


I’m betting big on hummers. I’ve already planted a whole bunch of their favorite flowers all over my property, and I’m adding more every year for more quantity and for better coverage throughout the season. I know the hummingbirds won’t eliminate the problem, but I’m hoping they’ll keep it at tolerable levels. Worst case scenario I have lots of pretty flowers.


If you use netting you have to use an insect netting. Also Mosquito netting will work.
Powdered DE helps kill them, it’s not toxic to us if consumed. It washes right off, and you need to spray almost daily and certainly after it rains. Bad news is the dust is very dangerous a N-95 or high end pesticide mask should be worn. It is Organic, but being organic does not mean it’s not toxic. Use a dry powder sprayer with DE.
Some good news but won’t help for some time is the parasite wasp to SWD is approved for release. Trials are going on now.

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I am thinking of using Spinosad. Literature use a “degree model” to calculate the time for the first application, which I find hard to follow. Is there an easier way to do it? Right now, the fruits are about 1/2 inch. I would not be able to recognize a cherry fruit fly, but the fruits are full of worms year after year :(.

My issue has been with the SWD - took out a whole crop two years ago. UC Davis says SWD start attacking cherries when they turn straw colored. I used traps to monitor and then sprayed Spinosad 2-3 times and got worm free fruit last year.

I don’t know which kind of worms were getting in my cherries, but last year I sprayed with Spinosad about once a week starting as soon as petals dropped. I stopped when they were getting red and nearly ripe. I picked them for first time, about 12-15 gallons in all. I also have netted them from birds for the last three years.

SWD are a nightmare to control because they are not necessarily around the fruit at the time of spraying. Since the egg laying is the issue, they may be off elsewhere and only come to the fruit to lay an egg. Since they do not ingest any spinosad in this process it won’t kill them. I’d like to try Grandevo and Venerate this year as these seem to also provide partial control. Both combined with Spinosad, may be able to provide adequate control while avoiding resistance build up. They’re also advertised as a deterrent, but I do not know if this is the case for SWD. They are also pretty cheaply available to home growers as well.

Another option for a home grower would be to make a huge vinegar trap, you can read about these in most SWD literature, but I’m thinking a 5 gallon bucket instead of a solo cup. This may provide enough trapping to protect a few trees. Fruit flies are attracted to rotting fruit so if you know anything about fermentation you could also make a batch of wine vinegar by just mixing some store bought grape juice and some raw vinegar.

I had this bug on my black gold cherry tree two days ago.

Now I have these dots on some of my cherries.

I had these bumps on most of my cherries last year too. I didn’t know to check for swd inside though and then the birds got them.

I was wondering if this is swd or something else. I ask because my cherries are pretty hard and not at all close to ripening. From what I’ve read, they like fruit as it ripens. I’ve also recently seen reports that swd is out and about now.

Thanks for any advice you can give me.