by Dr. John Paige III, Principal Scientist, Envu
Chinch bugs can become serious pests in southern lawns, and PMPs who perform outdoor perimeter services often encounter damaging populations of these pests.
There are many products labeled for the control or suppression of chinch bugs, but many PMPs rely on tank-mixes of insecticides with differing modes of action.
A recent trial was conducted on a sod farm in Brevard County, Florida. The St. Augustine grass on the sod farm was infested with damaging levels of chinch bugs. The trial used Barricor SP (a solid particle deltamethrin formulation) in a tank-mix with Merit 2F (a liquid imidacloprid). These two classes of insecticides together are known to provide potentiating effects on pests due to differing modes of action.
All treatments were applied at 2 gallons of water per 1,000 square feet and the rate of Merit 2F was held constant at 0.60 oz./1,000 square feet. Barricor SP was applied at 0.25 and 0.5 oz./1,000 square feet.
Pre- and post-treatment counts were taken by a suction device that vacuumed the bugs out of the plots so they could be counted and identified.
The results show that the tank-mix treatments were highly efficacious at controlling chinch bugs. Mortality rates early in the trial ranged from 97-100% mortality, and by the end of the 28-day trial the range was from 99-100%.
CNIs and pyrethroids provide potentiation together. The result is improved efficacy as the CNI overstimulates the nerve, and the pyrethroid preferentially binds to these open Na+ channels, causing depolarization and death in the target insect.
Test results clearly demonstrate that PMPs need not fear the arrival of chinch bugs as they now have tools to control these pests. Additional trials will continue to be conducted.