Fire blight has been widespread this year and was discussed in issue no. 2 of this newsletter. The disease has continued to develop and has reached severe levels on edible fruit in neighboring states. We usually discuss fire blight on apples, crabapples, and pears. Symptoms include blighted branch tips that die very quickly and completely. Because conditions have been favorable for infection by the causal bacterium for many weeks, we have seen the disease on other susceptible ornamental hosts that normally escape. Fire blight may infect apple, crabapple, cotoneaster, hawthorn, mountain ash, pear, pyracantha, and quince.
We are long past the time when chemical sprays would help. If weather conditions remain mild and wet, further disease spread may occur. We recommend removing blighted branches as they occur. Preferably, this should be done in dry weather and tissue removed from the site. Remember to disinfect pruners before every cut and to make cuts 10 inches beyond the blighted area. Do not fertilize infected plants now. That would encourage succulent new growth, which is susceptible to infection.