Southern Chinch Bugs

Does your lawn have yellow patches that turn brown and die? It may be southern chinch bugs.

Chinch bug damage

Southern chinch bugs (Blissus insularis) love to eat your lawn, especially St. Augustinegrass. They gather in large groups and feed voraciously, draining the sap from your grass plants, causing them to wither and die. Damaged areas can be irregular or circular in shape, similar to masked chafer damage. Unlike many other insects, chinch bugs thrive in hot weather, becoming especially active when temperatures are above 90°F, when your grass plants are already stressed.

Beneficial big-eyed bug (Jack Dykinga)

(Agriculture for beginners, 1914) Public Domain

Southern chinch bug description
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These pests look a lot like beneficial big-eyed bugs. Both have a dark body and light wings that fold over the back in a similar shield-like pattern. The only difference is that big-eyed bugs have a wide head and bulging eyes. Chinch bugs do not. These pests can be seen on grass blades and near the crown. Chinch bugs can be purple, black, brown, or reddish, but they tend to be black and are usually around 1/5 inch long.

​Expose pests with a drench test

If you are not sure what is causing your lawn damage, you can conduct a drench test. Follow these steps to force underground pests to the surface:

1. Add 2 to 4 tablespoons of liquid dish soap to a gallon of water. If your soil is particularly dry, double the recipe. Place this mixture in a watering can.
2. Mark off one square yard of lawn that includes both healthy and unhealthy turf with a rope, cord, or hose.
3. Slowly saturate the marked off area with the soapy water.
4. Over the next 10 minutes, document the type and number of insects that emerge.

If more than 135 bugs, or 15 nymphs are found, you will need to treat the area with an insecticide.

Chinch bug management

You can reduce the damage done by southern chinch bugs with these handy tips:

• reduce thatch
• irrigate properly and regularly (chinch bugs don’t care for moisture)
• use the lowest amount of nitrogen necessary

Personally, I find that my chickens do an excellent job of eradicating bugs from my lawn!