Hello, I have a productive Schatten Morello sour cherry tree in my backyard here in Vancouver that has, for the past two summers, been completely infested by what I think is a cherry fly (pic of critter attached). I'm wondering if anyone can identify this insect and recommend a treatment that is commercially available in smaller doses (I only have the one tree) to us city dwellers . I understand there is something called spinosad that might work, but I have no idea how to acquire it. Attached are a couple of pics of last year's damaged fruit. Thanks!
The bug on the right looks like a ladybug larva to me. Adult flies usually have wings and the larvae are maggots.
Your pest looks like (is) a ladybug larva. It has nothing to do with the little white fruit fly maggots inside of your cherries. As a matter of fact it is not a pest at all, it is a beneficial insect who loves to feed on aphids destroying new growth on your plants. I am thinking, on your picture, may be it is just waiting for a little tasty maggot to emerge to have a lunch. It is only a thought though, I am not sure if ladybug larvae eat maggots. To alleviate (hopefully solve) the problem in the long run, you should pick all the cherries before they are overripe and dispose safely all the fruit you couldn't consume, before the maggots emerge.
I see from the tags on this thread that someone got the pest's name right: spotted wing drosophila. This is a recently arrived fruit fly that is infesting many fruits in the Vancouver area. Sundrop's advice is the only treatment that I'm aware of for home gardeners. Commercial fruit growers have some chemical options, but I don't think they are available for home use.
