@mayhaw9999
There are different strains of fireblight as your likely aware. Fortunately the one we have in this area is not the worst type. I grow several Eldorado here with no problems yet. It has not bloomed until this year. Menie has had dozens of strikes. Some pears are not at all vulnerable until they bloom. Some constantly have problems. Menie is a rapid growing pear and anytime cells divide quickly they provoke fireblight. The other trees in great danger bloom a long time. Blooms are rapid cell division. That’s why fireblight attacks no tree in the winter in cold climates. Many of you know of the 65/65 rule which refers to ideal temperature and humidity for fireblight. So you might wonder how do I know there are worse types? I have received scion wood from various places and it looks perfect however after I graft it the tree grows rapidly and dies to the rootstock. It’s clear it was that scion that harbored the illness. At first i thought the rapid growth was the cause but all scions had rapid growth. Then i believed it was chance which was partially true but why only scions from 1 area? I might make 5 grafts and 3 die 2 dont and never had any other problems. It was then i realized the wood came infected even with a bleach bath.Had i bathed it with copper i might have been wiser since copper inhibits the growth of bacteria. Why did the new strain of bacteria not escape and thrive here? I don’t have the answer to that. Some trees are fireblight magnets Eldorado is not that tree in my location. I might suggest in other locations that are very warm with high humidity e.g… southern United States, Australia even a kieffer is a fireblight susceptible tree. @rayrose and i had this conversation years ago it’s not the same strain of fireblight it’s a more aggressive form in the south and ideal humid conditions exist nearly all the time. That’s why @coolmantoole started a thread specifically on Southern pears. Like with any observation It’s not fact It’s a hypothesis I think is true about fireblight. Fireblight is still a very mysterious illness picking some years to be worse than others for reasons I can’t understand at times. My belief is that insect and bird numbers / migration are a factor in severe fireblight years. Cicada damage brought on the worst fireblight I ever saw 17 year cicada's woke up hungry. 2015 was a bad year here for fireblight Late season Fireblight