Pests and Diseases: Fire Blight

After a week talking about our Lunatic Tour at Polyface Farms, it’s time to get back to gardening. While I believe that we can learn a lot about gardening from Polyface Farms, I know that you have questions about the plants that you are growing in your backyard. If you have Bradford Pears in your yard, you may be experiencing symptoms that look like this:

fire blight

This picture shows the classic case of fire blight. Fire blight is a bacterial disease that affects Bradford pear trees as well as fruit-producing pears. Its victims can also include apples, crabapples, Pyracantha and hawthornes. Fire blight gets its name from the damage that it causes: it looks like someone has gone around and set the tips of your plants on fire. The leaves turn brown and then black and the affected areas can reach a foot or more from the terminal growth tips. This damage causes a classic shepherd’s hook appearance. Fire blight can also affect the blossoms and they end up turning brown prematurely and dying. Let’s take a closer look at the life cycle of fire blight in order to understand it better.

The bacteria that causes fire blight causes cankers that generally set up shop on the trunks of the trees. These cankers weep and ooze and allow for the bacteria to be transmitted from tree to tree by insects as well as wind driven rain. Sooty mold is often seen growing near the cankers due to their sweet exudate. With the mild winter and wet spring that the Mid-Atlantic Gardening region is experiencing, fire blight infections are a common experience in a landscape still dominated by Bradford Pears. It’s one more reason to remove Bradford Pears from your landscape…or at least vow not to plant anymore.

So what can you do if your trees are infected? If the outbreak is relatively minor, you can prune out the infected branches, ensuring that you remove an additional 8″-12″ of stem below the apparent infection. Dispose of these branches in a landfill or burn them if your local conditions permit it. You can also spray your trees with a bactericide every 7-10 days from bloom time through the spring rainy season but who wants to go through all of that trouble?

The old saying that “an ounce of prevention is worth a pound of cure” certainly applies here. There are many, many varieties of apples, pears and crabapples that are resistant to fire blight. While that doesn’t mean that these varieties will never get fire blight, it does mean that they stand a fighting chance without a lot of fussing over them by you. Resistant apple varieties include Honeycrisp, Jonagold and Winesap. Resistant pear varieties include Honeysweet, Magness and Moonglow. If crabapples are more your style, consider planting Candied Apple, Louisa or Prairie Fire. Consult your local extension agent for other varieties that work well in your gardening area.

If you have experience with combating fire blight in your landscape, please leave me a comment below or e-mail me at stacey@midatlanticgardening.com. If you enjoy being part of the Mid-Atlantic Gardening community, join our e-mail list, become a fan on Facebook and follow me at Twitter. Happy gardening!

 

May 1, 2012Permalink 2 Comments

2 thoughts on “Pests and Diseases: Fire Blight

  1. I put in a couple pear trees I think about 3 years ago. They are still young, maybe 7 feet hight, and I noticed just within this past week what I think is the fire blight the picture above and what you’ve discribed in your article. I can prune it back and burn the branches but I’m afraid I’ll have to really cut up the tree bad. The other is about 40 feet away and I don’t see anything on it yet. Should I spray it with something? I live in the Ozarks in south central Missouri and I’m telling you, fruit trees and gardening in general are very hard to accomplish. I’m trying some raised bed gardening this year and if it doesn’t produce, I think I’m going to give up untill I move somewhere else. Been here 12 years, and have planted multible peach, apricot, apple and many other items and cant seem to get them past 3 or 4 years without freezing, disease or bugs destroying everything. Very frustrating. Any suggestions. Thank you for your time

    • Hi Wesley. I’m sorry it’s taken me so long to get back to you. I hate to pass you on to someone else, but I highly recommend that you consult your local Extension agent. I am not familiar with the conditions in your area but your Extension agent surely is. BUT, don’t give up on growing fruit trees. Perhaps there are better varieties suited for your area. If you’re buying from local box stores, they are just pushing whatever is on their shelves. Build a relationship with a local nursery and they will look out for you and your gardening desires. Hope that helps!

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