Once it's hot enough in Houston, it's not long before the dreaded chinch bugs come to suck the life out of our St. Augustine turfgrass. They especially like to chew up lawns that aren't taken care of very well. In other words, well-watered and well-fertilized lawns are the best way to keep chinch bugs at bay. But what if you suspect you've got chinch bugs? Is there a quick way to tell?
Unfortunately, in many cases, people make the wrong diagnosis when chinch bugs begin their damage. Quite often, when the first telltale sign pops up in the form of small yellowing spots, people either assume they have a fungal disease or iron deficiency. Then, they spray in vain with a fungicide or put out an iron supplement or fertilizer. And even when people think they have chinch bugs, they sometimes don't treat often enough to break the cycle. I'll get to that a little later.
If you start seeing a small yellowing, irregular patch in the lawn, first find out if you've got chinch bugs. You can make that determination with a regular coffee can and a water hose, while you get down on your hands and knees to do a little investigation. On the green-yellow edge of the patch, shove the coffee can (open at both ends, for my Aggie brethren out there) into the soil and fill it with water. If you see flea-like insects floating to the top, you've got chinch bugs.
While you're on your hands and knees, push the grass aside and look down near the root systems - near that yellow-green edge of the patch again. See if you can spot those flea- sized bugs with white spots on their sides or the baby ones that are orange with a white ring.
To treat for chinch bugs, you need to apply a liquid insecticide (a synthetic pyrethroid like bifenthrin, permethrin, cypermethrin or deltamethrin) three times over a 21-day period ... or once every five to seven days ... up to four applications at most. Sadly, most people who try to treat for chinch bugs use a granular insecticide or they only make one application of liquid insecticide.