Fireblight is a bacterial disease that affects apple trees and their relatives. Crabapple trees, quince, mountain ash, spirea, cotoneaster, pyracantha and hawthorn can also be infected with fireblight.
Fireblight can develop in early spring, encouraged by rainy weather and temperatures above 60 degrees Fahrenheit. Blossoms and twigs will show the early symptoms of wilting, shriveling and turning brown or black. The tips of young twigs will wilt and curl, while dead leaves will often remain attached to the branch. Infected twigs will appear to be water soaked and will later turn dark brown or black.
As the fireblight bacteria spreads into the main branches, the bark may crack along the edges of the infected area and produce a canker. If left untreated, the cankers become blackened, giving the appearance of scorched wood.
Fireblight bacteria overwinters in living tissue on the margins of the cankers and is then spread to other trees by insects or splashing rain.
Controlling Fireblight
If you spot symptoms that represent fireblight at any time during the season, immediately spray the tree with the biological fungicide called Actinovate. Then spray the tree every week until harvest is over.
Over The Winter - all infected twigs and cankers should be removed from the tree over winter, before the plant puts out new growth in the spring. Pruning cuts should be made at least twelve inches below any sign of infection, and the pruning tools should be disinfected between each cut. A solution of one part bleach to nine parts water will disinfect your tools and help avoid spreading the fireblight bacteria.
Next Year Just As Leaves Are Buds – Begin a bi-weekly spray program with Actinovate until harvest. If no symptoms of fireblight appear during the whole season. There is probably no need to continue the spray program next year.
