June 27, 2008

Grass Mites Tough to Control

By David Clement

My lawn was green last fall and when the snow melted this spring, the grass is dead. What happened to my lawn?

Many lawns in Douglas County have been devastated by the Banks grass mite. This tiny beast feeds when lawns are blanketed by snow. Populations increase during the winter months. Usually mites are found on south- or southwest-facing lawns.

Banks grass mites are yellowish- green, eight-legged, and about the size of a pen tip. The damage has a characteristic stippling appearance, with whitish flecking on leaf blades. Mites can be observed with a hand lens, but not normally with the naked eye.

Fall and winter watering is the most important form of control. If mites are feeding in your lawn now, you may want to spray a pesticide, although chemical control of this mite is difficult.

For help identifying mite damage, call your local CSU Extension Office. The CSU Fact Sheet on clover and Banks grass mites is 5.505, which you can access at www.ext.colostate.edu/PUBS/INSECT/ 05505.html.

How can my trees die from being planted too deep?

Eighty percent of all woody plant problems in the Front Range are caused by non-living sources like early or late freezes or planting holes that are too deep. The science behind planting seems simple, but trees throughout our communities are dying prematurely, often because of improper planting.

Tree-planting techniques have changed a lot in 10 years. Unlike many improvements, planting techniques have gotten easier on your back. Dig the planting hole at least 2 inches above grade. If your root ball is 10 inches deep, dig the hole 8 inches or less. Remove the soil from around the trunk while in the root ball until you find the "root flare," which is the area of the trunk that extends outward where the root crown begins. Many times the root flare is inches too deep in the root ball and when planted at two inches above grade, the tree is still too deep.

Information on proper planting of trees and shrubs is available at www.ext.colostate.edu. Adjust the techniques recommended for midsummer planting by avoiding the hottest parts of the day.

Is my drip system the proper way to water my new trees and shrubs?

Water with a drip system, sprinklers, hose ends or buckets. What matters is not the method of irrigation but rather the plant's needs as it strives to regenerate its root system. The two essential "rules of (green) thumb" to keep in mind are: First, do not water a new tree or shrub unless it needs it. Second, always water in the winter. Your trees and shrubs will need a good soaking at least once per month in the winter. Winter watering is perhaps the most underrated factor for the long-term success of our trees and shrubs.

Establishing root systems need oxygen as much as they need water. We need to let them "breathe" in between very thorough soakings. Think "drench-then-dry." The only way to know for sure if your transplant needs water is to check the soil. You can do this by hand, digging down 6 inches or so outside the root ball.

You will need to monitor your midsummer transplants very closely, as they can transpire water very quickly. Do not confuse a little wilt with a need to water. Sometimes a cool night is all it takes to restore the vigor of foliage. Once again, before you water, check the soil.

Originally published by David Clement, Special to the Rocky.

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