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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. Augustine grass! 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 some of the most frequently asked questions, a video and an infographic about chinch bugs. Although there are several different types of chinch bugs, the majority of this article will focus on the southern chinch bug. Take a look at the informational video on Clemson University Entomologist Dr. J.C. Chong who discusses the appropriate ways to identify, prevent and treat an infestation.
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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.
In the southeast, the southern chinch bug is a problem for residential and commercial lawns. The hairy chinch bug is a larger issue in the midwest. The majority of this article will discuss the southern chinch bug, which can be found throughout the entire southeastern United States and in some areas of California.
Chinch bugs can be spotted in other grass types like centipede grass, but they tend to love St. Augustine grass the most.
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.
Photo credit: https://aggieturf.tamu.edu/wp-content/uploads/ESC-031_soChinchBugs.pdf
Chinch bugs enjoy eating plants in the grass family (mainly St. Augustine grass), however, you can also spot them in other grasses like zoysia grass, bermuda grass 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 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.
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–September when weather is warmest. Most people start to see visible damage around the beginning of August.
Chinch bug damage is fairly 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.
Pictured above from left to right: Patchy chinch bug damage contrasting the appearance of drought damage.
You may be able to spot chinch bugs towards 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 three 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 3/4s of the can with water and let it sit for ten minutes. After the ten 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 two or three inches into the soil.
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 towards 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.
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.
Photo credit: https://iloveturf.com/library/articles/thatch-st-augustine-lawns
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 15–20 sq. ft. in a yard. There are 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 (this can be kind of harsh, so use it in extreme infestations), bifenthrin, and carbaryl. Bifenthrin is the most recommended chemical for homeowner usage. Be sure to read the label carefully before purchasing or applying the insecticide on your lawn. Check out some of our recommended chinch bug insecticides below.
A few applications a year keeps them away. If you prefer not to treat yourself, learn more about how to hire a professional here.
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. Take a look at the image below to see what one looks like.
Pictured above: An earwig.
Perennial ryegrass, fine fescues and tall fescues are highly resistant to chinch bugs. However, perennial ryegrass, fine fescues and tall fescues do not flourish well in the south as they are bred for the northern climates.
If you are looking to potentially replace your lawn or even use grass plugs to patch up damaged areas, we recommend EMPIRE® Zoysia. EMPIRE has rhizomes, meaning the turf continues to branch off under the soil’s surface—chinch bugs are not able to access it. Even if the chinch bugs damage your lawn above the soil’s surface, the grass will continue to survive and grow. You will just need to invest in an insecticide to get rid of chinch bugs and prevent them in the future. Read more about EMPIRE’s chinch bug resistance here.
Although fertilizer doesn’t treat infestations, a proper fertilizer schedule will help your lawn remain strong and endure stress a little better. You might want to consider a fertility program such as Lawnifi®. Lawnifi is a fertilizer program designed to give your lawn the nutrients it needs when it needs them. Subscribe to receive seasonal Lawnifi fertilizer boxes throughout the year, or purchase each seasonal box individually. You can learn more about Lawnifi at lawnifi.com or by reading Why Use Lawnifi Fertilizer?.