If you see wilted and dead blossoms on your apple tree, you might have blight. Fire blight affects rose bushes and apple and pear trees, and is caused by the bacteria Erwinia amylovora. The bacteria attacks the flowers first, and then moves on to the stems and branches. Fire blight gets its name from the "scorched" appearance of the infected blossoms and stems. Although bactericides are available to fend off fire blight, you can treat your apple trees naturally for this infection with heavy and diligent pruning.
Diagnose blight on your apple trees by looking for withered and dead blossoms. You'll see reddish lesions or cankers on the bark that ooze an orange-brown liquid. The infected shoots on the apple tree will turn black or brown and look "scorched."
Prune back infected branches 2 to 3 inches below the visible lesions. Remove branches only in the winter.
Scrape away the diseased areas from branches and limbs that are too large to remove. Seal the scraped areas with tree paint.
Cut off any blackened leaves, stems or apples 12 inches below any signs of disease. Do this throughout the summer months.
Disinfect your pruning shears and other tools that have contact with the infected trees. After each cut, hold your pruning shears for at least two seconds submerged in a bleach solution that is one part household bleach and four parts water.