Fireblight

In last Thursday's posting of the Garden Checklist, it mentioned to watch for, and cut away, fireblight. I saw this pear tree, plus an apple tree that was close by, that are infected with fireblight. It is a bacterial infection that attacks apple trees, including crab apples; and pear trees, including fruitless pears. It can also infect pyracantha and roses. It will completely kill a tree if not contained.

The symptoms start usually with the blossoms or flowers, and moves up the twigs and then the branches. The flowers turn brown and wilt; twigs shrivel and blacken, with the ends often curling. The affected portions of the tree look like they have been burned by fire, hence the name fireblight. If not pruned out, the infection will create cankers, discolored oozing patches, which form on branches. The ooze contains masses of bacteria. Insects, birds, squirrels, splashing rain/sprinklers, and gardeners can spread the bacteria even before there area cankers.

There is no prevention, cure or spray for fireblight, but there are things that can be done to eradicate it. First and foremost--in the spring and fall cut out infected twigs and branches at least 12 inches below any evidence of the disease. If there aren't 12 inches between the tree trunk and the infection, cut the branch off just above the branch collar (this is at the base of all branches and is an area of wrinkled wood). Discard cuttings, do not compost. Make sure to use clean pruners after cutting out each branch by dipping in an alcohol solution (three parts denatured alcohol to one part water), or in diluted bleach (one part bleach to nine parts water). With the diluted bleach, pruners need to be wiped dry to prevent corrosion. When pruning is completed and pruners dried, wiping with an oily rag will help protect the metal.