Wilting and browning grass often indicates drought conditions, but a chinch bug infestation mimics this same turf stress. At around 1/5 inch long chinch bugs pierce grass blades to access the nutritious fluids. As their saliva enters the grass, root moisture cannot move throughout the turf's internal vessels, causing widespread damage. Grass can only grow back if the infestation is not severe.
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Preferring sunny and dry turfs, a light infestation is typically less than 15 chinch bugs in 1 square foot. They work in groups for protection and successful feeding. Their damage is still apparent as dead patches of lawn appear like puddles in your green turf -- blades takes on a yellow to brown hue. Once you've treated a light infestation, the grass can typically fill in the damaged area through stolons and rhizomes. Because of the chinch bugs' toxic saliva running through the damaged grass, it may take several weeks to see turf recovery.
You have a heavy infestation when approximately 20 to 25 chinch bugs are spotted in 1 square foot. Your grass takes on a widespread yellow to brown color as the turf slowly dies back. Typically, your turf cannot recover from this damage because the grass blades can no longer function as energy producers. Without photosynthesis, no new growth is possible at the root or blade level. If you successfully treat the grass to eradicate the pests, you should sod the damaged area to create a lush lawn.
Patchy Areas and Weeds
Regardless of the damage, those patchy areas are often filled in by weeds after successful chinch bug treatment. Because these pests prefer sunny spots, damaged areas are prime targets for weed seed germination -- they can grow seedlings faster than the grass can recover. Instead of waiting for your grass to spread into the damaged area, fill the area with sod to prevent weeds. Although sodding is more expensive than seeding, you are only filling in patches rather than covering the entire yard.
Proper cultural controls keep chinch bugs from infesting your lawn again. Do not over-water your lawn -- a deep watering once a week is enough for most grass species. Inspect your thatch layer periodically. You should dethatch the lawn with a vertical mower if your thatch is thicker than 1 inch -- this barrier to moisture and pesticides makes it easy for chinch bugs to move into your lawn. Mow your lawn once a week during the growing season and keep the mower's blades sharp. Remove approximately one-third of the grass' height during each mowing session.