|How can I control Fire-blight on my plum and apple trees, short of removing the entire tree?|
|If they are severely infected, there may be no other choice. To successfully control fire blight, all infected twigs, branches and cankers should be removed from the trees. Prune well back--6-8"--from evidence of infection. That is, if you see signs of infection on the last 6" of the branch, prune off 12-14" to be sure you are removing all infected material.
Since the bacteria that cause the disease can be spread during the pruning process, be sure to disinfect your pruning tools after each cut. Use one part household bleach to nine parts water, or dip your cutting tools in pure alcohol after each cut. After you've removed the infected plant parts you can help protect the remainder of the tree by spraying with a lime-sulfur (Bordeaux) dormant spray. Also, look around your property for infected wild trees, and prune or cut them as well.
If you need to replace your trees, choose varieties that are known to be resistant to fire blight. St. Lawrence Nurseries, located in Potsdam, New York, specializes in fruit trees for northern climates, and carry a huge variety of disease-resistant apples, as well as other fruits. The owner has a wonderful wealth of information. Their phone number is 315/265-6739; they have a web page at www.sln.potsdam.ny.us Hope this helps!