Have you ever noticed tiny little black insects in your grass? If so, these could be chinch bugs—and they love to chow down on St. Augustinegrass.
One of the hardest things to distinguish between are the differences between drought damage, disease damage or insect damage. In fact, chinch bug damage looks very similar to drought. So, how do we properly diagnose a chinch bug problem, and, more importantly, how do we treat an infestation? Below are a few answers to those questions. Although there are several different types of chinch bugs, most of this article will focus on the southern chinch bug.
What are chinch bugs?
Chinch bugs are little, tiny black insects commonly found in lawns and gardens throughout North America. There are several different types of chinch bugs including the common chinch bug, the hairy chinch bug, the southern chinch bug and the western chinch bug.
Chinch bugs can be spotted in other grass types like centipede grass, but they tend to love St. Augustinegrass the most.
What do chinch bugs look like?
The southern chinch bug is usually dark red, black or brown in color with a white band across the middle of its body. Some species of adult chinch bugs feature two distinctive white spots on their backs. They typically measure to about four millimeters in length (about 1/10th of an inch), which is about the equivalent of the tip of a pen. The immatures are either bright red or grayish with white line across their back.
What do chinch bugs feed on?
Chinch bugs enjoy eating plants in the grass family (mainly St. Augustinegrass); however, you can also spot them in other grasses like zoysiagrass, bermudagrass and others or agricultural crops like wheat, sorghum, rye, barley, oats and corn.
Although chinch bugs are a type of beetle, there is not a grub or larvae stage or a pupa/cocoon stage during the chinch bug lifecycle. Chinch bugs love lush, heavily fertilized grass and prefer grass that boasts a heavy thatch layer. They are not big fans of moisture.
Chinch bug damage often looks like drought stress, so it's important to take a sample of a given area of turf.Sod Solutions
How do chinch bugs damage grass?
Chinch bugs eat grass blades as a food source. They suck on the blades of grass and then inject the grass blades with poison in their saliva that stops water movement within the blade. This causes the grass blade to turn yellow and die. As a result, the chinch bug moves on to another nearby grass blade.
Over time, they move outward, forming a perimeter of large, dead patches in your lawn. Chinch bugs go through a gradual metamorphosis beginning as an egg, hatching as nymphs without wings and then transforming into adults with the addition of wings.
What time of year do chinch bugs damage lawns?
Depending on the area you’re located in and the type of climate your area has, chinch bugs begin to become active in the early spring, but they are the most active and destructive during late June to September when weather is warmest. Most people start to see visible damage around the beginning of August.
How do I identify a chinch bug infestation?
Chinch bug damage is easy to identify. At first, you’ll see a general yellowing of the turf, but the grass eventually dies, and they can kill the entire lawn. Other symptoms include thin, bare spots that’s not very good looking even at a low infestation level. Damage looks very similar to drought damage, so if you know your area has received a lot of water or you’ve kept up with proper irrigation practices and can rule out drought, you may have chinch bugs.
Diseases like brown patch, which St. Augustine is prone to, appear in circular patterns whereas chinch bug damage has irregular patchy areas of damage. This can make diagnosis difficult. However, the best thing to do is take samples and send to your local extension office for diagnosis.
You may be able to spot chinch bugs toward the edges of your lawn where you can see further into the grass canopy. Chinch bugs are really small, so you may need a magnifying glass.
You can also detect chinch bugs by conducting a soap flush test. Take an empty coffee canister or any can that may closely resemble this and make sure it is open on both sides so that it does not have a top or a bottom. You should be able to remove the top and the bottom of the can with a can opener the same way you would open a can of beans in the kitchen.
Once you have removed the top and the bottom, stick the can 3 inches deep into the soil. You may have to force the end of the can into your lawn or dig a small hole prior to setting the can up.
Fill up 3/4 of the can with water and let it sit for 10 minutes. After the 10 minutes are up, stir the water so that you agitate everything inside and see if any chinch bugs float to the top. You can also do this with PBC pipe with a sharpened edge, as Dr. J.C. Chong explains in the above video, that you can push 2 or 3 inches into the soil.
Where can I find chinch bugs in my lawn?
If you want to try and look for chinch bugs, be sure to bring a magnifying lens with you as you spread the turf near the soil with your hand. They are harmless to humans, so don’t worry about being bitten. It may be easier to spot chinch bugs if you look toward the ends of your lawn where you may typically edge so that you can see part of the soil and where the grass is growing.
How do I treat chinch bugs?
Cultural control
There are a few things you can do to prevent and control chinch bugs without insecticides. However, these are not always the most effective treatments and chinch bug damage may continue to ensue. As previously mentioned, chinch bugs like hot, dry conditions for optimum feeding. This is why it’s helpful to irrigate your lawn during hot, dry weather periods. One inch of rainfall or irrigation a week is sufficient.
Another step you can make is thatch removal. Chinch bugs move into hibernation during the winter and occupy the soil’s surface. Use a rake to remove thatch from the top layer of your lawn to destroy hibernation sites or locations where eggs and nymphs may live.
Chemical control
If your lawn’s damage is severe and the chinch bugs are not manageable with cultural methods, you can use a chemical treatment. Insecticide treatments are usually required when populations reach 15 to 20 square feet in a yard. There is an abundance of insecticides you can apply on your lawn for chinch bug treatment—granular or liquid.
The chemicals you will need to look for are trichlorfon (use it in extreme infestations), bifenthrin and carbaryl. Be sure to read the label carefully before purchasing or applying the insecticide on your lawn.
How do I prevent chinch bugs?
The absolute best treatment strategy for chinch bugs is preventing them before an infestation gets out of hand. Damage typically doesn’t show up until August, but it can still appear at different times of the year. Preventing beforehand will save you a lot of time and money. Start with doing this in late June and early July.
Earwigs are insects that are actually good for your lawn and garden. Earwigs feed on other damaging lawn insects such as chinch bugs, sod webworms and smaller sized mole crickets. In fact, earwigs can eat up to 50 chinch bugs in a day.
Are there chinch bug-resistant turfgrasses?
Perennial ryegrass, fine fescues and tall fescues are highly resistant to chinch bugs. Although fertilizer doesn’t treat infestations, a proper fertilizer schedule will help your lawn remain strong and endure stress a little better.
