Winter mite damage is obvious if you use a hand lens

Last week I visited a lawn that was damaged by what was identified and treated as a fungus problem. While various funguses are common in many lawns this year, especially as a result of the wet cold spring, fungi were not responsible for the dead portion of this lawn. The problem was winter feeding activity of mites.


You could see where the mites had started feeding next to the sidewalk and continued to feed almost in a block-like pattern further into the lawn. The area near the sidewalk was fully exposed to the winter sun and was slightly higher than the sidewalk creating an area that dried out during late fall and winter. This is exactly what these winter-feeding mites like, dry hot turf.

Note the stippling on the leaf blade
caused by the feeding activity of the mites.



Note the purpling due to lack of adequate
nutrient movement to the tip of the blade.



Where dead grass and live grass came together, the tips of some of the grass blades were purple. This coloration is common during cold weather due to the lack of nutrient movement from the roots to the leaf tip. In this instance however, the lack of nutrient movement was due to the cellular damage caused by the mites feeding just below and in the purple region. The area of turf in the first photo is dead and will need to be removed and new sod applied. It will not come back on its own as lawns often do when infected by a disease.

Is your lawn a healthy green or a bleached white?

Turfgrass with a bleached look may be infected with Ascochyta leaf blight or may simply be responding to severe drought. Quite often the latter leads to the former.

If your lawn looks like the photo it has been suffering from inadequate water for quite some time. When I walked on this lawn the soil was hard as a rock.

Turf sprinklers need to be spaced so that water from one sprinkler reaches the neighboring sprinklers. This turf area did not appear to have adequate sprinkler coverage. I could locate only one sprinkler covering this bleached area.

If you have dry spots in your lawn, turn on your sprinklers to determine the problems. If your sprinklers are too low, not spaced properly, broken, etc., these problems must be corrected to solve the problem. If you have missing sprinklers you will need to add heads. Check out the publication at http://www.ext.colostate.edu/pubs/crops/04722.pdf for information on how to identify and correct irrigation system problems.

You could hire a "professional" but even if you do, I would suggest you know what the problem is before he/she make a house call to correct your sprinkler problems. I'm sure the irrigation system at the site shown in the photo was installed by a "professional."

Until you have the irrigation system corrected, you will need to drag a hose and water the dry spots.

Another problem at this site was high water pressure. Sprinkler efficiency is affected by water pressure. If the pressure is too high you will have misting as shown in the video. A pressure regulator should have been installed by the "professional". The owner needs to install a pressure regulator on the valve to ensure proper system pressure. You can also see several of the heads are so low the turf blocks the spray of water coming from the sprinklers. The "professional" failed to check the water pressure supplying this system. The owner of this property needs to have a pressure regulator(s) installed to correct this problem. Remember, not all "professionals" are qualified to repair your irrigation system.