Crane Flies & Fire Blight

Karen Cambre, Sharpe, Kenneth W.

News article for February 19, 2018

What a difference a week makes! Last week I was anticipating the early arrival of warm temperatures and now we have had them long enough for many trees to start flowering and to begin putting on leaves.

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Another indicator of spring is the massive number of “giant mosquitoes” that are hovering near the ground in your lawn. Actually, they are not mosquitoes at all, but I cannot convince my youngest granddaughter. These large flying bugs are known as crane flies and they do not bite. Crane flies are very harmless.

The larvae form of crane flies live in the organic layer of the soil and adult flies normally emerge at the end of winter or early spring in large numbers. I see thousands of them in my yard. They are attracted to light and will hang out around the door, waiting to sneak in when the door is opened. Then, they find their way to the nearest lamp and you will hear that constant tapping as they keep hitting the lamp shade. You might want to consider changing your doorway light bulbs to yellow, which will reduce the light attraction.


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Every year I get a lot of complaints about fire blight, especially in pear trees and the ornamental flowering pear trees. Fire blight is a bacterial disease that infects the trees and the symptoms are leaves that turn black and die back on the end of the branches. This die back will occur when it warms up during the growing season. A unique feature of the disease is that the black leaves will not fall off, but cling to the branches and not readily fall to the ground.

Fire blight bacteria overwinter in the wounds of branches left from last year’s infection. So if you had fire blight previously, you are probably going to have it again this year. Once you see the black leaves, it is too late to treat. Your opportunity to treat for fire blight is in the bloom stage.

As the trees flower, the bacteria will ooze from the previous wounds and mix with the sugars. Honeybees are very attracted to the sugars this time of year and they get both pollen and bacteria on them. Bees will fly from tree to tree pollinating flowers and spreading the bacteria at the same time. Bacteria are also spread by splashing rain.

There is no sure cure for fire blight, but spraying with a spray during blooming will help and will reduce the spread to other susceptible plants. Those plants that are susceptible to fire blight would include pear, apple, crabapple, quince, mayhaw, loquat, hawthorn, Indian Hawthorne and pyracantha.

You can spray with either streptomycin or a copper fungicide. There are lots of copper fungicides, but some examples would be Tri-Basic Copper Sulfate and Kocide. Streptomycin can be purchased in products such as Agri-Mycin and Bonide Fire Blight Spray.

Start your spray when 10% of the pear blooms are open. If more than 10% are already open, start today. Repeat your spray every 4-7 days until all the flowers have opened, but follow the directions on the product label for the number of applications and intervals between sprays.

For more information on these or related topics contact Kenny at 225-686-3020 or visit our website at

5/9/2018 4:10:41 PM
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