Last week, L.J. asked about the peculiar discolorations in a lawn that had been beautiful and is now mottled with lots of yellowing spots in the turf.
To me, the photo showed what looked like a fungal infection. I suggested taking a sample of the turf to a nursery for further diagnosis, and then treating the turf with a fungicidal spray to regain the lawn’s health.
But there are lots of things that can affect lawns. I’m also going to suggest that the area be inspected for insects, too. Once you cut out the 12 by 12 inch chunk of the lawn, inspect the roots. You’re looking for grubs, chinch bugs or sod webworms.
Any of these creatures, in mass, could be part of the cause of your lawn looking so terrible. Grubs are the larval stage of a myriad of different beetles that we tend to have in this neck of the woods. They are truly ugly critters, too.
In the dug up chunk, if you find plump “C”-shaped, chalky-grey colored, caterpillar-looking immobile bugs, then you have found grubs. Finding one in the sample isn’t a big deal, but if there are six or more in your sampling, then they could be the cause of the lawn looking so cruddy. They feed on the roots of the grass, causing a lot of damage leaving the lawn yellowing rather rapidly.
There are “natural” pesticides that can be applied. Milky disease spore sprayed over a deeply watered lawn, to get the grub closer to the surface, is a fairly effective way to hunt grubs.
Chinch bugs are dark-bodied, one-sixth of an inch long, winged bugs that oddly enough stink when they are disturbed or crushed. The young nymphs are bright red bugs that wear a white band across their backs. Chinch bugs tend to congregate in open, sunny parts of the lawn, which the photo seems to be showing.
To control chinch bugs, it’s recommended soaking the lawn with soapy water. Dilute two gallons of water with one ounce of liquid dish soap, then water the lawn with that mixture. You want to really soak the turf with that mixture and then lay a flannel sheet over the area.
The chinch bugs, in the effort to get out of the soapy lawn, will get trapped on the flannel. Then gather up the sheet and rinse it out in a tub of soapy water to kill the bugs.
Next, be sure to rinse off the lawn so the soap solution is well-diluted and not harming the grass. It’s recommended to keep the lawn really well-watered for three-to-four weeks, making the area less attractive to chinch bugs.
Finally, your turf could be home to sod webworms. These guys chew blades of grass, just at the thatch line, and pull the severed blades into their tunnels in the ground. The sod webworm seems to like blue grass, so they could be a culprit.
“Natural” controls for the sod webworm would be spraying the lawn, when the webworms are very young, with bacillus thuringiensis kurstaki. This liquid bacterium is very effective and very safe in the use of control against all sorts of “bad” insects in their larval stage.
So I will suggest you get out there and really inspect the lawn for any soil-dwelling pests that could be eating the roots or chewing on the grass blades themselves, making your lawn look so sad.
Also, a good raking to remove any deep thatch layer in the lawn would be a great help. With more oxygen movement, better water and fertilization absorption, and stronger, straighter growing blades of grass, the lawn will naturally be healthier.
Another tip: During the heat of the year, don’t go mowing the lawn too short. Allow the grass blades to grow longer between mowings. The longer blade will shade the ground, keeping the grass roots healthier and not so cooked by the sun.
Just keep Diggin’ In doing things the right way.
Tracey Fitzgibbon is a certified nurseryman. Send garden-related questions to Digging In, Albuquerque Journal, 7777 Jefferson NE, Albuquerque, NM 87109, or to firstname.lastname@example.org.