Do not apply sealant to the pruned or scraped area, as this will just trap any remaining bacteria. The fire blight bacteria lives in the tissue outside of the visibly affected area, and only by removing enough extra tissue can you actually remove the infection. While it may seem extreme to remove so much healthy tissue beyond the diseased area, this is very important for disease management. It is also advisable to remove trees where more than half the canopy is diseased. If the trunk becomes girdled, you will need to remove the tree entirely. If this causes a branch to become girdled (completely stripped for more than half of the circumference), the branch will need to be entirely removed. Keep scraping off the bark around the canker until all discolored tissue is removed, and then remove an additional 6 to 8 inches in every direction. If possible, remove the whole infected branch and the branch to which it is attached all the way to the collar (for information on making good pruning cuts, watch Pruning 101).įor branches that are too large to prune, or to remove cankers on the trunk itself, scrape off the outer and the inner bark entirely during the dormant season. Remove diseased branches 8 to 12 inches beyond the visible infection. Most disease control pruning is done in the summer and the winter, when the infection is not actively spreading through the tree. No matter what other products or methods you use to treat fire blight, pruning for disease management is essential. The most important of these is mechanical disease control with pruning. If your tree becomes infected with fire blight, there are several courses of treatment that are recommended by the University of California Cooperative Extension. There are many options to combat these pesky bugs read this article for the best solutions. Controlling sucking insects such as aphids and leafhoppers, which can carry this disease to new places, is another good prevention idea. To determine how much nitrogen you actually need to add, test your soil annually. To check if your tree is growing at a healthy rate, use the handy chart in this article. Over fertilization leads to rapid growth, and this abundant new growth is most at risk of becoming infected. Proper fertilization is also important to reduce the risk of fire blight. Trees that are planted too close together, too deeply, or in too much shade will become stressed and this will increase their susceptibility to disease. When planting your trees, select a site that receives at least 6 hours of sunlight, and plant your trees at the proper spacing and depth. A thorough list of varieties that are resistant and susceptible can be found on the Purdue University Extension website. Also select varieties that are grafted onto disease resistant rootstock, as are all of our trees. Select varieties that are resistant to fire blight, such as Seckel, Potomac and Warren pears, Hosui Asian pears, and Cox Orange Pippin apples. Good management begins before you even plant your trees. Keeping your trees healthy in the first place is the best solution when it comes to fire blight. This bacteria-laden liquid is then moved to other parts of the tree by insects, birds and other vectors, thus spreading the infection. In the spring, these cankers may ooze as the tree and the bacteria begin their new growth for the year. During the winter months, the bacteria in the canker will go into a state of dormancy along with the tree. These cankers are visible by their discoloration, often with red-brown streaking, and the edges of the canker may be blistered and raised. The bacteria lives inside the bark, festering in spots called cankers. These areas are easy to spot in the summer against the bright green of neighboring healthy growth. The dead leaves and fruit remain attached and can be brown or black. Affected branches often curl back in a “shepherd’s crook” or J-shape. Depending on the severity of the infection, leaves can be patchy with dead spots, or entire sections of new growth and even whole limbs can be killed off. Is Your Tree Infected?įire blight is named for the scorched appearance of infected leaves and branches. However, it can be kept under control using organic methods to prevent the disease from spreading and killing the tree. Once a tree is infected, it is nearly impossible to eliminate. It is caused by the bacteria Erwinia amylovora. Fire Blight Is A Common Disease For Roses, Pears and Applesįire blight is a common and potentially fatal disease among trees in the rose family, especially pears and apples.
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