AMPA, Fla. – About 150 lawn care operators from the Tampa and Orlando Fla., areas received, courtesy of Valent Professional Products, a rundown on Southern chinch bugs and how to delay or overcome pyrethroid resistance among chinch bug populations.
Chinch bugs are developing resistance to pyrethroid-based insecticides due to the chronic overuse of such products.
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 populations, while the resistant bugs keep breeding.
Dr. Eileen Buss, associate professor of turfgrass entomology at the University of Florida, says it’s important to first make sure you have chinch bugs, since damage caused by that pest can be misdiagnosed as scalping damage, herbicide damage, drought stress or even a dog “toilet” area.
To avoid a misdiagnosis, vacuum the affected area and, if chinch bugs are present, you’ll know it. “They’ll get caught in the filter and you can dump them in a bag,” Buss says.
Getting rid of 80 percent of the bugs is considered acceptable in research testing, Buss added, but less control may be achieved where the bugs have become resistant to pyrethroids.
While pyrethroid-resistant chinch bugs are sometimes responsible for unsightly damage to St. Augustine grass, chemical resistance isn’t the only threat to a healthy lawn. Lawns need to be kept at the proper height and thatch has to be managed correctly in order for pesticides to get good coverage.
In addition, lawns have to be irrigated properly, because if grass is stressed from lack of water, it won’t be able to handle additional stress like that caused by Southern chinch bugs.
Todd Mayhew, regional field development managers for Valent Professional Products, says it is becoming more and more difficult for researchers to introduce new products, and consistently using one product until it doesn’t work anymore isn’t a good practice.
That includes overusing Valent’s Arena Insecticide, which controls pyrethroid-resistant Southern chinch bugs.
“We need to find a way to use all available tools,” says Mayhew, who encourages LCOs to rotate products with different modes of action as part of a resistance management program.
Joe Chamberlin, also a regional field development manager for Valent, says everyone has to learn from the past mistakes and not overuse the product.
Chamberlin says Arena should be applied in April or May, and then a pyrethroid can be applied in late summer, making chinch bugs more susceptible to treatments.
“If we overuse Arena like we did the pyrethroids, it will stop working,” Chamberlin says. L&L
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