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Winter annual lawn weeds and Fire Blight prevention
By John Fulton

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[April 05, 2016]  Winter Annual Lawn Weeds - Each year, the winter annual weeds chickweed and henbit run number one and two in the early spring. This year, it seems like numbers are about equal. The henbit is also making a flashy show in area farm fields, with large purple areas from the blooms.

Winter annual weeds can actually germinate in the fall, carry through the winter, and get going very early in the spring. They also are done by the heat of the summer, leaving seed to germinate again later in the fall. Right now chickweed stands out in yards because it is quite abundant, and has a lighter green color than grass and most other weeds. It is also beginning to set seed. There are two types: common chickweed and mouse-ear chickweed. Henbit is easier to identify since it has purple flowers and smells like mint. As for control, that gets a bit easier.


Chickweed

 

The straight 2,4-D that is used on dandelions seems to act like a fertilizer for chickweed and other problem weeds. 2-4D is a growth regulator, and if it doesnít actually kill a weed it does make it grow faster. Combinations that contain 2,4-D, MCPP, and dicamba are rated very effective on chickweed, henbit, red sorrel, purslane, white clover, and others. Just remember the control time for most broadleaf weeds is early May, but the winter annuals are going strong now. These combinations are sold under several different trade names. You can find these at most hardware, discount, and lawn and garden stores. Just check the label under active ingredients and check for two long chemical names and dicamba. Some of the newer formulations also contain triclopyr to help control the hardest group of weeds such as violets. These mixtures will also be effective. You can also check to see that it says it will control chickweed and henbit. This group of chemicals is effective in the 50 degree range and up. It just takes a lot longer for control with very cool temperatures. As with any chemical control, read and follow label instructions very carefully. There will be some cautions on these product labels concerning injury to sensitive plants that you should be aware of. This is because dicamba can drift as a vapor for a few weeks after you apply it if the weather gets hot and sunny.

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 Many ask what happens if you donít control these weeds. The short answer is: not much since you will just keep mowing them. These weeds will die out in the summer months, then come back in the fall or spring from seed which was dropped. Of course, you get to look at them for the three months or so they are aggressively growing.

Fire Blight Prevention

We have had several years of increasing problems with fire blight in both pears and apples. Fire blight often shows as the newest year growth looking like you took a torch to it. As a reminder, fire blight is caused by a bacterium. This means fungicide sprays are not effective for management of the disease. Copper is an effective bactericide and almost any copper material is effective in reducing the primary inoculum at bloom time. Examples of copper containing compounds would include Bordeaux mix, Kocide, and Copper Count-N. The timing for this treatment would be at tight cluster to early pink stage, which means just before blooms open. Applying right now is a bit premature in most areas, but the application time is coming right up. Knowing that, you can begin to locate a source if you are wanting to Ė or needing to spray.

This program wonít completely control fire blight, especially if you have had moderate or severe problems in the past. There are additional treatments with streptomycin antibiotic for commercial growers to help control blossom infections recommended. The same goes for shoot tip infections and timing is very critical, and really beyond a home orchard or ornamental program.

[By JOHN FULTON, COUNTY EXTENSION DIRECTOR SERVING LOGAN, MENARD, AND SANGAMON COUNTIES]

 

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