Dead spots caused by turf mites
Author: Stefan Palm Date Posted: 25 September 2018
Turf mites have become a significant problem in Adelaide over the past few years. Turf mites literally suck the life out of your lawn leaving it lifeless and patchy. The good news is that once identified and treated, lawns rebound very quickly.
While turf mite infestation is not super common in domestic lawns, I have seen it more this year than any other. Experts say that this is due to the drought conditions we have experienced over the past few years. Turf Mites are microscopic organisms that come from the arachnid class (the same class as spiders and scorpions). They breed quickly, have a short life span and occur in their millions. Mite damage is most common in couch and kikuyu lawns and can have a number of effects on your lawn.
The first noticeable damage often happens in spring when the lawn fails to begin its normal growth in spite of plenty of water and fertiliser. The mites sit at the base of the blades of the grass where they attach to the runner (called the stolon) and suck the life from the grass. This results in the lawn failing to thrive. The turf noticeably loses its colour in patches and takes on what’s called a “witches broom” effect (see the photo below where you can see the yellow stunted shoots of lawn that resemble witches brooms). For those who are technically minded, “mites cause a shortening of the internodes and the apparent stimulation of abnormally excessive plant growth. The mites remain hidden under the leaf sheaths and vary in number from a few to a hundred or more under a single sheath. With heavy infestations the grass will turn brown and die.” Eventually the grass, in infested lawns, thins out leaving the lawn susceptible to weed and diseases attack.
Conditions that favour mites are dry warm weather during spring & summer. Turf under stress from irrigation, fertility and heat will recover slower from damage.
So…. “How do I control Turf Mites” I hear you say. One of the best ways is to create an environment that they don’t like. This includes:
- Making sure your grass is adequately fertilised (ideally 3 times per year)
- Making sure your grass is adequately watered
- Making sure you don’t leave clippings on your lawn where mites are a problem
If you are doing all this and still manage to get an outbreak, then chemical control is your only option. Off the shelf chemicals that contain pyrethroids or diazinon are not particularly good at controlling turf mites. The best control method is with products containing an active ingredient called abermectin such as Thumper.
If you think you have a turf mite problem or any other problem resulting in your lawn dying, then cut out a core sample and take it down to your lawn specialist for correct identification.