Fire Blight

Erwinia amylovora

Apple tree with fire blight
Apple tree infected with fire blight. Photo courtesy of I, Paethon. Licensed under CC BY-SA 3.0.
Fire blight is a bacterial disease which infects apples and pears resulting in a characteristic burnt appearance and significant loss of fruit. Severe infections can lead to death of the tree.
Infection leads to a characteristic burnt appearance on leaves.
Severe fire blight infection
Gala apple tree with a severe infection. Photo courtesy of the Agricultural Research Service.
Fire blight infects blossoms and leaves resulting in the loss of fruit. It can also systemically infect susceptible trees resulting in disfigurement or death of the tree.
Fire blight can be controlled through antibiotics if applied shortly prior to or immediately after infection. Once the infection is established and symptoms appear, it is not possible to stop it. Always read and follow all label directions.