With fireblight, you must wait for dry weather when you remove damaged tissue.

You don't need to wait for dry weather if it's too cold for fireblight to spread, I would think. I would want to be sure canker was FB. It's hard to imagine a nursery shipping a tree with a huge canker like that. Usually FB strikes mature trees through the flowers supposedly, although the FB I've been seeing lately seems to enter through shoots. Still, it tends to strike older trees. In all my years, I've never gotten FB from a nursery tree.

Hmm. The canker was not on the tree when I bought it (I wouldn't have bought it like that). It was simply a pruning cut when I bought it. The canker has developed over the past month or two around the pruning cut. It isn't nearly cold here (90 yesterday), but it is extremely dry.

Maybe I should see if I can get someone more experienced than I am to have a look at it...

There are many grafted Tennosui branches growing on several varieties of pear trees, as well as pear rootstocks, at this Houston area place. Other than a tiny experience with fireblight, they have been very healthy. Many of the 2 year old grafts have resulted in 6 to 8 foot long verticle branches, and I can't find any discolored, diseased,or disfigured bark on these. I do have several below-the-graft young branches with tan bark that were discolored from disease when I did those T-buds a year ago. It was a choice that I made to do T-buds in the flexible tan bark where there was some splotchy discoloration rather than bark grafts farther down the tree where the older, thicker gray bark looked very healthy. I was running out of scions to graft with, so I tried a few buds. The white wood below this ugly bark was beautiful, and the buds grew out well. There is no disease on these new branches, but the remaining tan stubs still show their discolored, ugly bark. I suppose that these young, healthy Tennosui branches will continue their skyward blastoff despite having an imperfect launchpad.........Is the diseased part of your tree below the Tennosui graft? Are their branches growing and look healthy? Was this a bare root tree, and if so, did you prune away 30-50% of the branches when you planted it? There are a zillion ways that real pear growers could provide professional guidance on rehabbing/boosting your tree. As a semi-hack at this stuff, I might invest $5 in a bag of Black Kow cow manure at Lowes and spread it thinly around the planting site. That, a layer of mulch on top, and regular watering ......who knows....maybe the Tennosui will grow well anyway. Point of interest: Some local plant sales offered Tennosui grafted onto slow growing, "dwarfing" rootstocks. Impatience can be alleviated somewhat by buying and planting the biggest Bradford pear tree that you can and afterwards graft Tennosui buds or scions from your young tree onto the Bradford branches. Fast forwarding is fun.

Hi - thanks copingwithclay. The spot with the canker is well above the graft union - I would say a good 30" - 36" up the tree from the graft. I purchased the tree in a container in February - it was dormant, but not bare root. I didn't prune it at all myself after purchase because it already had a nice double leader form and I had read that the lush growth that can occur after heavily pruning a pear in the Houston area can encourage fireblight.

The tree actually looks very healthy other than this one spot. Both the couple of branches below the spot and all the branches above the spot look fine. There is minor singeing of the newest leaf tips, but nothing worse than I've seen on every single pear tree I've looked at in every yard and nursery I've been to - better than most.

I think this weekend I may head back to the nursery where I bought it and see what they have to say. Maybe pick up a fireblight spray. I'll try your compost suggestion too - it's already been mulched and appropriately watered.

Thanks again.