The best solution to this problem is to plant varieties that are resistant to fire blight in the first place. Dr. Ethan Natelson and the Gulf Coast Fruit Study Group (GCFSG) have spent many years researching the best pears varieties for Houston, and I am very grateful to Yvonne Gibbs for taking so much time to share her knowledge with me. You can meet and learn from extremely knowledgeable and experienced fruit growers at GCFSG meetings, and I would recommend that anyone interested in planting a fruit tree attend one. Their research has identified Southern King, Southern Queen, Southern Bartlett, Tennessee, and Acres Home as fire-blight resistant varieties for Houston. Unfortunately these varieties are resistant to fire blight, but not immune to it.
I have Acres Home, Tennhosui, and Southern King pear trees, and this year I grafted on Southern Queen, Southern Bartlett, Tennessee, and Meadows. During one of my routine walks around the yard, I noticed some fire blight on the Acres Home and the Tennhosui. There was no sign of it on any of the other varieties. I immediately grabbed my pruning shrears, sterilized them with alcohol, and pruned out the infected areas. As recommended, I made the pruning cut at least 6-inches below the infection, and sterilized my pruning shears after each cut. According to Urban Harvest, Acres Home tends to get a little fire blight, but it typically doesn't travel down the branches to kill the tree. I cut it out anyway just to be safe, and to get it out of my yard to reduce the chance of re-infection. Sadly, my neighbor has a big neglected pear tree that I'm afraid will always harbor fire blight that can spread to my trees.
While taking the diseased wood over to the trash pile, I noticed more fire blight on my apple trees! The Dorsett Golden and the Anna both had small areas of infection, and one of my Honeycrisp grafts was burned. I again pruned out the affected areas several inches below the infection. With more rain and warm temperatures in the forecast, I decided to be proactive. I swung by Plants for All Seasons, and picked up some Fertilome Fire Blight Spray (it's organic). This spray is 21% streptomycin sulfate, an antibiotic also used to treat tuberculosis and other infections. After the rain last week, Boy #1 and I mixed up a batch and sprayed all the pear and apple trees. Hopefully removing all of the diseased wood and spraying the trees with antibiotic will help protect all of our growing grafts until they get a little bit bigger, and help reduce the chances of fire blight infection.