Wednesday evening the first of five twin-engine Beechcraft planes arrived at Dallas’ Executive airport. From there they’ll fly 200 to 400 feet above the rooftops of 11 North Texas cities, spraying a fine mist of the insecticide Duet.
Duet is a synthetic pyrethroid is in the same class of chemicals Dallas has used to spray for mosquitoes from the ground.
Laura McGowan is a spokesperson for Clarke Mosquito Control, the manufacturer. She says Duet contains an ingredient that excites mosquitoes.
“It’s called “benign agitation,” McGowan said . “What that does is flush mosquitoes out of hedges and overhangs and things like that so more mosquitoes come in contact with the spray.”
McGowan says the insecticide droplets are very fine and the planes so quiet residents in the path of the spray may not know it’s being applied. The EPA has approved Duet for mosquito control and State Health Commissioner David Lakey says the chemicals are safe though people and pets should go inside during the spraying.
But many residents have expressed concern. The product label for Duet says it is toxic to aquatic organisms including fish. It can kill honey bees and contaminate exposed drinking water.
McGowan claims that shouldn’t happen because the chemical will be diluted and the spraying will take place after dark.
“Any other insects that might be affected are typically harboring at this time of night. That’s why it’s so important that we go up after sunset when mosquitoes are most active and bees have gone back into their hives,” she said.
Dallas County Health and Human Services Director Zachary Thompson says his team should be able to tell fairly quickly whether the aerial spraying has worked.
“They’re mapping the area. They are looking at spots for setting up pre-traps. After the spraying those traps will be picked up to look at the effectiveness of the spraying,” Thompson said..
It is likely there will be at least two aerial applications of the insecticide because Duet only kills adults. County officials have said they many need to spray again after the larvae have hatched.