It's be a hard stressful summer/year for most of us in the eastern US this year, but even more so for our plants. Here locally, we have had to most extreme weather I've ever seen in one year. From February to August there was a temperature range of 135 degrees for me locally. Went from 27" rain in five weeks, immediately to drought and no rain for months with temps near, equally, or even exceeding all time highs (after near all time lows in February. As a consequence I am having more disease problems this year than previous five years put together.
Which brings me to the subject of my post. I recently removed and disposed of a crabapple that had black sunken lesions on the trunk. Now I have two more crabapples with very similar lesions. In both cases seemly originating near the ground, and especially near the graft union. At first I thought Fire Blight, but now I don't think so. About 10 days ago, I noticed yellow leaves in our Oklahoma Redbud, while everything else was green. Suspecting a canker, I removed the branch, and sure enough there was a canker at a crotch. I split the crotch, and there was black penetrating necrosis just under the bark. After a bit or searching, I decided it was likely Botryosphaeria canker. It is more prevalent during drought years, or which we are currently. Unfortunately I did not take any pictures. Well today, on a small (less than 1" caliper) Autumn Blaze Maple, I found a similar sunken lesion. I removed the tree from the rooting pruning pot (very impressive result BTW from just a few months), and looked for clues. This time I got a couple of pictures of the small lesion, and though one of you may have seen it before, and perhaps confirm that it is likely to be the culprit. Sorry for the small size of the lesion, as I caught it early. Also the wetness is due to using Isopropyl alcohol to increase contrast, and to kill any surface spores that may try to spread.
Now I'm not too broken up over the ABM, or the branch of the Redbud. I'm simply trying to get a handle on if it is in fact the same disease I am dealing with on multiple host. The lesions certainly look similar, and I have talked to others that seem to be having similar issues. So anyone got any input?
Thanks in advance,