Pest Profile: Southern Chinch Bugs

Along with mowers and sprayers, you might want to add a vacuum to your equipment room.

Yes, that's one way to find out if your customer has a problem with Southern chinch bugs. But we'll get to that later.

These pests can cause major damage to a lawn, mainly St. Augustine grass, in Georgia, South Carolina, Florida, Southern Alabama and Texas, and the signs of damage are often misdiagnosed.

In addition, Southern chinch bugs have built a resistance to some chemicals.

Lawn & Landscape spoke with Eileen Buss, associate professor of turfgrass entomology at the University of Florida, about dealing with Southern chinch bugs.
 

Diagnosis. Here's where that vacuum comes into play. Buss says using a dust buster or a reverse intake leaf blower to vacuum around the damaged area is a quick and easy way to find out if chinch bugs are attacking your client's lawn.

"With the smaller vacuums, it's useful to have a pre-made filter inside and you just vacuum around the damage. Vacuuming right in the middle of the damage might not be as useful as on the edge or somewhere where it's turning yellow because dead grass is not a great thing for bugs to be feeding on," Buss says.

"So, you vacuum around the damaged areas, and then you take the filter out and dump the contents into a bucket, gallon bag or just on the sidewalk. It's a great teaching tool for the homeowners or the client."

Southern chinch bugs develop from egg to adult in about four to six weeks in the summer and depending on temperature, adults can live up to two months.

"It takes about a week for some maturation to occur after they become adults, and then you get three to five eggs or so being laid every day by each female over the course of that two-month period," Buss says.
 

Control. Because Southern chinch bugs cause a growth decline and turn turf yellow, eventually causing it to die, it's easy to misdiagnose the symptoms.

"They're a lot of things that people think are chinch bug problems, that are not," Buss says. "If the grass is dry, people think that chinch bugs are to blame, when they really should be looking at whether their irrigation system is working. That misdiagnosis is very common."

Buss says that an insecticide that kills at least 80 percent is considered acceptable when dealing with insects.

"Most applicators don't want to hear that even one survived," she says.

"When it comes to doing research trials, we prefer to have products that provide more than 90 percent chinch bug mortality."

Buss says the chemicals that are most effective for controlling Southern chinch bugs are: neonicotinoids, pyrethroids, clothianidin, thiamethoxam, and clothianidin and bifenthrin.
 

Resistance. A major problem with Southern chinch bugs is their ability to develop a resistance to chemicals.

This is similar to the way in which bacteria sometimes becomes resistant to antibiotics used by humans.

If an LCO keeps using pyrethroids, they will only kill the non-resistant individuals, while the resistant bugs keep breeding. Buss says LCOs need to rotate the products on an as needed basis. Only start using chemicals if you start to see damage as opposed to sticking to a calendar rotation.

"You want to avoid building up resistance to more than one compound or chemistry within one generation," Buss says.

"So, knock that generation back with one product and then if possible, follow-up with a different mode of action or a different chemical class and treat the next generation separately."

The author is an associate editor at Lawn & Landscape. He can be reached at bhorn@gie.net.