Fire Blight

(May 2012)

My wife and I have tried to find a solution to a pyracantha problem.  The plant has developed black leaves and white chalky spots.  She has applied a fungicide twice and there has been no real change.  What can she do to fix this problem?

The problem could be several things at once.  Pyracantha can get fireblight which will start on the tips and look like the plant was burned.  The disease is spread during bloom by honeybees, and no control other than cutting it out can be done once you see the problem.  Spider mites are also common problems on pyracantha and can cause the leaves to look white or mottled.  They tend to be worse when it is dry--and so far this spring, it has been dry.  I would suggest taking a plant sample in to your local county extension office to get a proper diagnosis so that you use the correct control measures.

(June 2006)

We planted a few young apple trees last year. They leafed out well, even had a few flowers and now small fruit--they have been growing great, but a few weeks ago I noticed some of the leaves looked black and wilty. I at first thought it was just because it was because they were still young but it doesn’t seem to be outgrowing it. Can you tell me what is wrong by this sample? What can I do to save the tree?

The plant sample you sent has fireblight--a bacterial disease. Generally succulent, rapidly growing twigs and shoots are most susceptible. There is no sprayable cure, but the disease pressure should stop now that hot weather is here. This has been an extremely prolific fireblight year. Just cut out the damage 6-8 inches beneath where it is visible. Sterilize your pruning shears after each cut with rubbing alcohol or a Clorox solution. Be sure to clean and oil your shears when you are done pruning.

(May 2006)

Our Bradford pear trees bloomed beautifully and greened up this spring. Now there are numerous dark brown leaves on the trees. They are in clusters all over the tree. It does not appear to have insects or anything else causing the problem that is visible to the naked eye. What can I do to save the tree?

This has been a fire blight year. We are seeing many fruiting and ornamental pear trees with black leaves on the tips of the branches. Fire blight is a bacterial disease that is spread during flowering. Once the weather heats up and stays in the 80's it usually stops spreading. That doesn’t mean the disease goes away, it just stays put. At this point there is no spray schedule. For now simply cut out the damaged branches--6-8 inches beneath visible damage. Sterilize your pruning shears with either alcohol or a bleach solution in between cuts. This prevents you from transmitting the bacteria from one cut to another should you cut into damaged tissue. Be sure to clean and oil your pruners before storing them.

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