In south Georgia, we are never more than a few days from a drought. Although we had plenty of rain in April, it can become very dry, very quickly. A pest that causes problems in turfgrass and seems to enjoy the drought like conditions is the chinch bug.
Although they may attack other grasses, most people have only seen them damage St. Augustine lawns. Young chinch bugs are red to pink with a white band across their back. As they age, chinch bugs turn gray to black with a white band or patch on their back. Adults are one-eighth to one-10th inch long — about the size of a large ant.
These bugs are hard to catch. To find them, search in the green grass at the edge of a dead patch. Part the grass quickly and pull back the thatch. You can also look inside the leaf sheaths where the grass blades come together at the bottom of the plant.
Another method is to cut out both ends of a coffee can. Sink one end into the ground several inches in the green grass at the edge of the dead turf. Fill the can with water and keep the water level up for five minutes. Watch the top of the water for floating chinch bugs. Whatever method you use, check several areas if you do not see them at first.
For chinch bug remediation, first, use cultural practices. Heavily fertilized St. Augustine lawns are more susceptible to chinch bugs. Use slow-release fertilizers in the summer and reduce fertilizer rates by half.
Because stronger roots help resist insect attack, mow St. Augustine grass three inches tall and often enough so that you do not remove more than one-third of the leaf blade at any one time. Sharp mowing blades give a cleaner cut and reduce stress on the grass and make the lawn more resistant to chinch bug injury.
Chinch bugs begin their attack in hot, dry areas and live in the thatch layer of the lawn. Over watering and over fertilization can increase amount of thatch. Wait until the grass wilts slightly to water and put out three-quarters to one inch of water. Place an empty pie pan, tuna can or similar pan under your irrigation system and run and time it until it applies this much water.
If the thatch layer is thicker than one inch on St. Augustine lawns, it is probably too thick. De-thatching is generally recommended and performed in the summer months.
Chinch bugs are one of the few lawn pests that require insecticide treatment. Chinch bugs can quickly destroy a St. Augustine lawn. You will probably need one or more insecticide treatments two to three weeks apart to reduce the problem. Read and follow all label directions when using pesticides. No insecticide does a good job of killing the eggs. You are likely to need more than one application for serious chinch bug problems. Select chemicals from differing classes of chemicals for repeat treatments which reduce the chance of insects developing resistance.
Many different insecticide chemical classes are effective in controlling chinch bugs.
In summary, chinch bugs also become significant based on environmental situations. They are a dry weather pest. During cool, moist periods, chinch bugs are susceptible to infections from naturally occurring fungi. For that reason, watering regularly during the time that chinch bugs are active will help fight them.
For additional questions contact Effingham County Extension Agent Sam Ingram at 754-8040 or firstname.lastname@example.org.