By John Geiger
What are chinch Bugs?
Chinch bugs are tiny creatures measuring about 1/5 inch in length when they reach adulthood. They feed on the sap of grasses using their sharp mouthparts and can do significant damage if left untreated. Because chinch bugs proliferate during hot and dry times of the year, many folks confuse the issue with drought and respond with heavy watering. Unfortunately, you cannot water your way out of a chinch bug infestation. In fact, overwatering will worsen the issue.
How to tell if it's drought stress or chinch bugs?
Drought stress tends to show up broadly or in areas your sprinklers miss and bounces back after a good watering – chinch bug damage doesn’t, because the bugs disrupt the plant’s water-conducting system as they feed. Location matters too: chinch bug damage shows up as expanding, irregular patches in hot, sunny spots near driveways and sidewalks, while drought stress usually appears wherever sprinklers miss. Try parting the grass at the edge of a dying patch and look for small black insects with white wings — if there are enough to cause damage, you’ll easily spot them moving around. To be certain, take a coffee can, cut out the bottom of it, and insert it a couple of inches into the ground where dead grass and live grass meet. Fill it with water. The chinch bugs will float to the top.
How to avoid chinch bugs in the first place?
Avoid overwatering
This keeps roots at the surface where they are more susceptible to pests and creates saturated, oxygen-deprived soils that cannot sustain essential microbes.
Mow properly
Set your mower at or near its highest setting (4 inches high), mow regularly so the leaves don’t get too long, and leave the clippings on the lawn. This reduces thatch and returns important nutrients to the soil, strengthening the grass.
Aerate and top dress with ½ inch of organic compost
Doing this at least once a year (twice is better) builds healthy soil which is essential for healthy grass – grass capable of staving off pests and disease.
Lay off the fertilizer
Excessive fertilizer enhances thatch formation and makes the grass more attractive as a food source. Reduce fertilizer use and apply a balanced, organic, slow-release product.
How to deal with a chinch bug infestation?
Water properly
Stick with the tried-and-true standard: 1 inch a week including rain, applied deeply through a cycle-and-soak method.
Use organic methods
Apply insecticidal soap or oil. These natural treatments can be used to control chinch bugs without harming the environment or beneficial insects. Apply the soap or oil directly to the affected areas according to the manufacturer’s instructions.
Products that contain Beauvaria bassonia, a fungus, are highly effective against chinch bugs and a long list of other insect pests. Scientists consider the fungus to be harmless to beneficial insects, although they recommend not spraying in areas where honeybees are foraging. The bees themselves won’t become contaminated, but they may carry spores back and infect the brood.
Another organic method contains terpene – entirely harmless to mammals, birds, and fish but deadly to chinch bugs.
Biological control
Beneficial insects, such as ladybugs, parasitic wasps, and big eyed bugs help keep chinch bug populations in check. Big-eyed bugs are often mistaken for chinch bugs. These bugs are beneficial predators that kill chinch bugs and other pests. Chinch bugs and big-eyed bugs are similar in size, but big-eyed bugs have a head as wide (or wider) than their thorax along with large, protruding eyes. Big-eyed bugs also do not have black and white wings like chinch bugs. Chinch bugs have smaller heads and eyes as well as more slender bodies.
A note about chemical insecticides
Avoid applying broad spectrum insecticides. If you do, you’ll make your life harder by eliminating a major source of control. If you’ve tried everything else and feel you must, be very targeted where you apply it. Bifenthrin (synthetic Pyrethrin) is effective. Its also highly toxic to fish and beneficial insects like bees and butterflies. Follow label instructions very carefully and avoid applying them near water sources.
More about chinch bugs in St Augustine lawns
Find out more through Texas A&M Agrilife Extension Entomology.
