I would think they'd be long since over but I've never dealt with them in the orchards I manage, which makes me grateful and puzzled at the same time as they are a common pest in my region.

I've never read about them attacking anything in storage or even apples later in the season. Here they are an issue from about mid-June to mid-July if memory serves (it doesn't always). Do you have any larvae to identify- they tunnel apples and the flies themselves are not an issue as I understand it.

my guess: theoretically there would be nothing to stop them from going to storage to attack the apples. Also, it makes sense that they will eventually find their way to your orchard.

what I know: apple maggot flies in Washington are usually mid July to mid August. The larvae are active in the apple for 20 to 30 days. This was a very, very late season in the Pacific Northwest this year, and theoretically you could have flies in late August, even September. I don't know about colder Edmonton, Canada. It is not the apple maggot that goes to the center of the apple but the codling moth larvae which is interested in the seeds.

What I suspect: What you have is not a problem from apple maggot flies as it just seems too late in the season for the flies to be active....and too short of a time frame in which to notice the problem.

Thanks HM!
I cut some open but only seen the larvae in one apple, whatever I found, [on the outside like picture shows] went into the juicer.. I'll see if there is still some around and take a better look.

The outside looked like this, the dark spot looks like the entry holes, the tunneling was mostly right under the skin, perhaps about 1/4" deep.

{{gwi:124809}}

Once again, I can only speak from what I've read but I didn't think damage would be so visible from the outside. The damage is supposed to only be visible when you bite into the apple. They also go after your earliest, reddest apples. Don't know why someone hasn't responded that's actually dealt with this pest- I'm happy to comment from memory of past reading but too lazy to look up the info. I'm in my post-harvest malaise and have no energy. And I haven't even finished harvesting.

Thanks Donnie & HM!

We see a fair bit of what I believe is apple maggot damage on the feral road trees we often use for cider. It does not look anything like this.
The entrance is usually only visible as a small dark depression. Inside the apple has tiny tunnels, you really don't see them as tunnels so much as lines of "bruising" running every which way through the flesh.

On the property we have had near complete controll with sticky spheres....although to be honest I don't see many flies AMF adults on the spheres and our control may just come from good clean up of drops. We also use Bt and Surround. But the timing on surround shouldn't help (too early)and Bt shouldn't help either (for AMF)

I am curious what caused the damage you observe. It looks similar to some leaf miner damage but I have never seen that on fruit. Do the tunnels dive away from the surface or stay just under the skin?

I'm familiar with apple maggot damage and don't recall ever seeing that visible tunneling on the skin. It's quite distinctive if you cut open the apple - brown tunnels running through the flesh of the fruit.

But if the flies are actually attacking the apples post-harvest, it might look different.

Konrad,

That definitely looks like AM to me. I never really had them here before and was always concerned more with PC, CM and OFM, or maybe because I usually continue spraying later in the season. I made my last sprays this year in late July and was prevented by all the rain from Hurricane Irene, etc. from spraying again in August. I found all my sweet fall apples got hit pretty hard by AM (especially Gala). You can easily mistakenly harvest AM infected apples as the egg oviposition sites are pretty inocuous at first, only later to find large sunken holes at the egg sites and tunnels in the apples as the larvae hatch and start tunneling. McIntosh and Macoun seemed to be spared, maybe AM doesn't like them as much (not so sweet, thicker skin, etc). But I also had a lot of AM infected drops on Baldwin (which I picked up and put out in the woods for the deer, coyote, etc.). Lesson learned, don't stop spraying until September for AM.

Jason makes some good points:

1. First of all, in my earlier post I was thinking of the idea of AM hitting the apples in the shed which didn't make sense. What he points out, though, that DOES make sense is that you might have had the eggs laid on the apples in early September, but you didn't notice at first and then the tunnels and the larvae become bigger and bigger while the apples are in storage....so that you notice 2 weeks later.

2. Also, Jason noticed that MacCoun and McIntosh seemed to be resistant. This coincides with what we have found in the PNW as well, although I recall having a difference of opinion as to the experience of others in this country from people on this thread. In the Pacific Northwest we have noted that Liberty and Spartan varieties (McIntosh or MacCoun types) seem to be resistant to apple maggot to some degree. I have had others swear that these varieties had problems, at least with codling moth, a differen pest of course.

Having said that, let me still say I don' think this is apple maggot. I am familiar with apple maggot fly and have seen its larvae in many apples.....and my experience with what I see is more in line with "ltlilton's" description. I do NOT ever see it on the outside of the apple....but I guess there is an outside chance that that particular apple has some sort of translucence that showcases the damage. A more likely scenario to me is that we are dealing with a pest I am not familiar with.

Too familiar with the little buggers.
That does not look like AM and I seriously doubt that the fly will go after anything in a shed. Never seen them anywhere except in the trees near the fruit. Here they go after the earliest ripening types first. Spraying those trees early will help control them. They seem to go after ANY apple according to it's ripeness. Look at pictures of the rascal and then next summer watch for them on your earliest ripening cultivars. You may also try the sticky balls for id purposes. I just use green pop cans covered with tangle foot. Tests showed these to be a more attractive color. Notice the commercial sticky traps are yellow! While they work I only use them now for finding when it is time to spray. Also check any wild apple trees for the trails all through the flesh. They will not be in or next to the core.I hope you do not have them since I think they are a worse pest than CM. Also the Once and Done has done a very good job on them.

Konrad, could you post a photo of one of the apples cut open?