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Help me ID these apple problems

Posted by steve333 z5 CO Mountains (My Page) on
Mon, Sep 9, 13 at 0:59

I generally do not spray my apples trees much, unless a specific problem is present. And until this year it has worked out quite well, getting mostly pest/blemish free fruit. This year however, I am seeing two very common problems on the Lodi apples I just harvested, which I'd like help identifying:

The first problem is a coarse grey/brown patch on the apple skin, surrounding where the stem attaches to the apple. It varies in size from 1/4" across up to an inch or more, irregular in shape. On some of the larger patches there are also cracks in the skin down through the flesh. I don't notice any signs of insect eating inside the apple under these patches, so I think they maybe due to fungi/bacteria, or perhaps some bug chewing from the outside?

The second problem is numerous tiny tunnels in the apple flesh. These tunnels are almost thread-like in size, and would not be noticeable at all except that the flesh is brown colored along the thread/tunnel, like when you leave a cut apple exposed to air for a while. The tunnels seem to wander around under the flesh, and do not have a particular destination (like out to the skin so whomever can escape). Whatever insect did these, they must be very tiny. I did not see any "worms" present in these tunnels in any of the cut apples, although plenty of these tunnels/threads. Any thoughts about what these might be from and how to combat them?

I might add, that our high elevation, cold temps, and dry climate generally cut way down on the number of insect and bacterial/fungi problems compared to most growing areas. However this past season has been unusually warm and wet, so perhaps I am starting to see some of the common fruit problems.


Follow-Up Postings:

RE: Help me ID these apple problems


The first issue may be russeting caused by climatic conditions or possibly spring frost. If so that's cosmetic.

The tunnels may be apple maggot. Look that up and compare.

I'm surprised you don't have coddling moth. Those make big tunnels and eat out the core.

RE: Help me ID these apple problems

Thanks fruitnut. Took a look at the pics of apple maggot damage, and I am not sure that's it. Might be but most of the pics showed considerably larger tunnels and active maggots in the fruit from the apple maggot. The "tunnels" in my apples are literally thread-like. With no visible open space, just the thin brown line in the apple flesh.

I suppose it is possible that the apple maggots I have were just very tiny, but I think it odd that I did not find any of the maggots still in the fruit. And I did not see any of their dimples on the skin from where the female inserted the egg.

I do have some coddling moths, I think I found one in the 100-200 apples we've processed so far. They just have not been a major problem, so far at least.

I'll keep searching for the exact cause. In the mean time I am planning on putting out sticky red sphere traps and doing some more spraying next year... Oh well, it was good while it lasted ;)

RE: Help me ID these apple problems

Very thin brown lines in the flesh could indicate they were harvested when post-mature.

If not, then I agree with the apple maggot thought. In this case, the skin is often somewhat dimpled and has suggestions of the trails in the flesh.

Any chance of images?

RE: Help me ID these apple problems

Thanks Jean. Over-ripe is a possibility.

The tree flowered in waves this spring, some flowering several weeks later than the first. And I did not pick as things ripened, but when the majority seemed ripe; so some were a bit under ripe, some over. I had not noticed if it was the riper apples that have these lines in them, but will look for that when I am next processing these apples.

Will get some pics up then too.

RE: Help me ID these apple problems

I agree with fruitnut, its russeting by the stem and apple maggot in the fruit. Very often there is no bug to be found. Keep looking and look at different times of the season, eventually you will find one.


RE: Help me ID these apple problems

I used to get apple maggot damage before I started bagging the fruit. The tunnels were visible in the flesh, but I never did see a maggot.

That sounds like the best guess on the problem to me.

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