dying pyracantha

Hello. We have three adjacent pyracanthas at rear of house (northeast US), that have been very large and hardy for at least 7 years. Grew like weeds. Some branches 15 feet high. Now a few major limbs are dying. All three plants. No apparent scale, no evidence of borers on bark or in soil beneath. The only possible factor I can think of is that we did some aggressive pruning last spring without "sealing" the cuts. Garden supply guy says that should not have caused it - not necessary to seal pruning cuts.
Garden supply guy says to prune dead limbs, sterilizing shears in alcohol between cuts (is that neessary?), then use a growth supplement for soil that supposedly strengthens the plants defenses against fungus, etc. (The product is called Messenger. Active ingredient listed as "Harpin Protein".)
I'd appreciate any other insights.
Thanks, Ron
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On Tue, 27 Sep 2005 10:10:07 -0400, Ron wrote:

Sounds like fire blight. Google "disease pyracantha". Plant something resistant. daveA
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Thanks for the reply. After additional research, fire blight is my guess also, although I don't see the (supposedly) characteristic curling of the leaf shoots that I saw in one picture on the web. Not ready to give up on these plants, though. There are still several healthy major branches. Gonna prune deadwood, with sterile rinse between cuts, and use that Messenger product in the spring.
I'd been googling on "dying pyracantha". Your string is much more productive. Thx again, Ron
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