It's No Cinch, but your lawn might have Chinch... Bugs
This July has seen record rainfall (10"+ so far) in Chicago's northern suburbs. With animals pairing up and heading for the ark you may not have been paying attention to your lawn. I should have been, wasn't, and now part of my lawn is breakfast, lunch and dinner for hairy Chinch bugs (henceforth known as CB). See typical damage. Yep, my lawn, my photos.
It' been a long time since my college turf classes so I needed review, and a Q & A chat with Chalet's Soil & Turf manager Tony Kacinas. I guess CB snookered me as I know them to be happiest when it's hot and dry. Evidently when it got dry the first two weeks in June they got busy reproducing. Why is this important? The nymphs and adults feed on grass blades by sucking out fluids AND injecting a toxin that affects the vascular system causing the grass to yellow and die. This shouldn't be confused with grub damage which appears later in the summer.
So, garden readers, take a moment and really assess your lawn. CB symptoms could be confused with drought stress or fungal diseases. Is your lawn thick, green and lush right now? No dying areas? Probably safe. If your turf is dying in ever-increasing, straw-colored patches in sunny, hot areas and doesn't respond to additional moisture, perhaps you should check for CB. Look first at areas adjacent to reflective surfaces like driveways and patios where the soil heats up and dries out first. CB also loves lawns with heavy thatch buildup.
How to check for CB is a fair question. Get a large coffee can (Keurig users look for other alternatives) and cut the top and bottom out. Go to the edge of areas where dead meets green, and punch the end of the can an 1" or more into the ground. Fill with water, refilling if it soaks in. Stir the clippings and thatch at the bottom of the "pool" to bring them to the surface. Watch this soup for 10 minutes or so before counting. A commonly agreed-upon threshold suggesting control is 25+ per square foot (that includes nymphs and adults, as they will be found feeding at the same time).
When deciding whether to use a control or not, understand this turf is very probably dead, and dead will spread. Whereas, with grubs if the 12-or- more-per-square foot threshold hasn't been met the turf will try to stage a comeback. When choosing a control make sure CB is on the label as certain active ingredients may not kill them.
It's natural to wonder what prompts CB to dine on some lawns and pass on others. Lawns with thick thatch are particularly CB-irresistible. Understand, please, thatch isn't grass clippings. Thatch is the compressed, spongy layer of undecomposed stems, crowns and surface roots just above the soil surface. Doesn't that sound like a swell place to spend the winter? CB thinks so. The late spring-laid eggs incubate for 20-30 days, or as little as a week based on temperatures above 80 degrees F. That means two generations per year, even this far north. Great...
Don't try to cut corners and reseed into "thatchy", dead turf. You won't get a good, deep-rooted result. If the areas to be reseeded are large you may want to consider using a slit-seeder. They are wondrous machines that slice through heavy thatch and drop the seed directly in contact with the soil. Slit-seeders are heavy, and are like trying to push an elephant around. I speak from experience. Consider hiring turf professionals to do it. It's so-o-o-o-o worth it.