rtg:

Your description of the leaf problem does not exactly match that of fireblight, but it could be. FB usually blackens the leaves more than browning them, and the leaves droop rather than curl. So you could also have something like an aphid or mite problem (Have you looked under the leaves?) or too little/too much moisture.

It might be worthwhile to Google "fireblight" to see if you can find photos that match your problem. If not, you will have to take a closer look for aphids and mites.

When problems like this occur on old or new growth, the best thing to do is usually to prune it off. Please state your location when asking a question of this nature. It makes it easier for the diagnostician. It's already hard enough to make these guesses from long-distance.

Don Yellman, Great Falls, VA

Thanks Don,

I thought the zone was enough location info - I live in Southeast Ontario (30 miles east of Toronto). I looked at some pictures of fire blight and they don't look similar unless my tree is only in the very early stages. How long until the blight would manifest in a more obvious way?

I have examined the leaves and seen no evidence of mites or aphids but I did notice a few ladybugs (I think they eat aphids?).

If it is a water issue how do I know if it is too much or too little? I water the tree 1-2 times per week max unless it rains alot. We have had a decent amount of rain this ummer so far but my grass (which I rarely water) is starting to turn brown in some areas.

Thanks for your help!

Rob

Red Delicious usually don't get fireblight, but if you're watering heavily, ::shrug::.

Fireblight in pears produces black leaves. Fireblight in apples produces dark brown leaves. Sure sounds to me like that's what you've got. If it progresses slowly toward the center of the tree, I would be quite confident that's what it is.

Some authorities suggest pruning it out while others suggest waiting until dormancy to remove it. I generally prune it out right away. YMMV. Sanitize tools with bleach, alcohol, or iodine before and after the cut, leave an ugly stub to cut out during dormancy, and cut at least 6" below any visible blight.

In the future you want to prevent vigorous shoot growth this late in the season by fertilizing less and avoiding irrigation unless the tree would otherwise be stressed.

Hi rtg35-
People may be able to give you a more definitive diagnosis if you post a picture.
If it is fireblight, I would expect that you'd see it progress to a burnt looking tip within a matter of a day or two. If it doesn't do that, it may be something else?
-Glenn

Your description could also hint at symptoms of herbicide damage. Or fertilizer burn.

(Zone 9)Southern California: Newly planted apple tree. When in container as purchased leaves looked green & healthy. Its been in the ground approx. 3 weeks and some leaves are turning brown on the edges. Weather has been cool with some light rain (more than normal for this time of year). I deep soak the tree once a week. Also other newly planted plants (hibiscus shrub/tree) in the same area have some leaves that are turning yellow. Could they be getting to much water or do you suspect something else? The other existing plants in the yard are doing great.