So, what can you do if your trees are showing symptoms? Pruning is one method of reducing the source of future infections. Anything that promotes rapid and soft, succulent growth will make that tissue more susceptible to infection. The bacterium can also be spread by hard, driving rain, and it will infect plants through wounds caused by hail, insects, and fresh pruning cuts.īesides rainfall, other environmental conditions and cultural practices that can promote fire blight development include excess moisture, high rates of nitrogen, and excessive pruning. These insects carry the bacterium to blooms, and then honeybees visiting the flowers pick up the bacterium and pass it to other blooms, continuing the spread of the disease. In the spring, the bacteria in the cankers become active and an ooze containing bacteria will emerge which attracts various types of insects. The bacterium overwinters in cankers, or dead areas, on twigs and limbs. However, I’ve seen lots of ornamental pears around town that appear to be fine. It appears environmental conditions were just right this year during the pear blooming season. Each bacterium is capable of causing an infection! At 70 degrees, bacterial numbers double every 20 minutes, becoming billions in less than a day. When conditions are favorable for bacterial growth, populations can develop rapidly. This includes a warm period prior to and during bloom, and rain during bloom. Fire blight, like all diseases, requires a certain set of circumstances to occur in order for the disease to take place. Most years, fire blight is not a problem on ornamental pear. Certain varieties, like Aristocrat, are more susceptible than Bradford, one of the more common varieties of ornamental pear. Most ornamental pears are resistant, but they are not immune to fire blight. In 1999, we saw more fire blight on ornamental pears than normal, and it looks like it may be a repeat this year. Instead of blackened leaves and shoots, apple leaves turn brown. The symptoms on apples and crabapples are slightly different than on pears. Many ornamental plants are also attacked, including ornamental or flowering pear, crabapple, quince, pyracantha, cotoneaster and hawthorn. Many edible pears and apples are very susceptible to fire blight and easily contract the disease, and is thus one of the factors limiting their production in our area. These are the classic symptoms of fire blight.įire blight is a bacterial disease, and is one of the worst diseases of pears and apples, since it is capable of killing trees of susceptible varieties. The blackened leaves cling to the blighted twigs. The ends of tender new growth curls, looking like the crook of a shepherd’s staff. The twigs look like they have been scorched with a blow torch. In early April, many people began noticing dead twigs in their flowering pear trees. With full acknowledgement of the fine work done by Extension employees like Keith, we offer his report to you here:īy Keith C. Keith Hansen, Smith County horticulturist with the Texas AgriLife Extension has prepared great information that should prove of help to you. This spring has been especially noteworthy for it. If you’re seeing blackened or browned branch tips on your apples and pears, your trees have been struck by the fire blight bacterium.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |