The rain left behind by Hurricane Harvey has created large areas where mosquitoes can lay their eggs.
To address increasing numbers of mosquitoes and the risk they pose to the recovery effort and public health, the Texas Department of State Health Services activated its contract for aerial mosquito control and requested additional mosquito control assistance from the Federal Emergency Management Agency. Aerial spraying targeting mosquitoes began early September in Aransas, Bee, Nueces, Refugio and San Patricio counties.
Last night, flight operations treated about 326,000 acres over Calhoun, Harris, Liberty, Montgomery, Polk and San Jacinto counties. Crews are planning to be up tonight spraying over portions of Galveston, Jackson, Montgomery, Polk and San Jacinto counties, conditions permitting. As those areas are completed, planes will move on to Sabine and Jasper counties and expect to conclude spraying this week.
A total of approximately 6.03 million acres has been sprayed across all areas. Flight schedules are subject to change.
Most mosquitoes that appear after floods are nuisance mosquitoes that don’t spread disease but can have a serious effect on recovery operations by preventing responders and people affected by a disaster from being outside. Areas of standing water can also increase the number of mosquitoes capable of spreading diseases like West Nile virus and Zika.
Aerial application of insecticide, when applied according to label instructions by a licensed professional, is the most effective way to rapidly reduce the number of mosquitoes in a large area and does not present a risk to people, pets or other animals.
A small amount of insecticide, one to two tablespoons per acre, is dispersed by airplanes equipped with nozzles that create ultra-low volume droplets just the right size to kill mosquitoes. The tiny droplets are calibrated to float in the air for a period of time and kill adult mosquitoes on contact while limiting exposure to other animals and people. Once any remaining droplets settle to the ground, they quickly break down on surfaces, in water and in sunlight.
The small amount of insecticide used does not pose a health risk to people, pets or the environment in the area. According to the Environmental Protection Agency, people may prefer to stay inside and close windows and doors when spraying takes place, but it is not necessary.
Spraying is also done to minimize any effects on beneficial insects like bees. Applications will be done starting around dusk when mosquitoes are most active and after bees have returned to their hives for the night. The insecticides dissipate and break down quickly in the environment, and when bees emerge in daylight, they are not affected. Although this type of application will not cause a significant exposure for bees, beekeepers may choose to cover their colonies and prevent bees from exiting during treatment.
Flights will be conducted by Clarke, Texas’ environmental services contractor, using three twin-engine Beechcraft King Air planes. Crews will be working from dusk to dawn beginning Thursday night with Refugio and Bee counties, areas identified as priorities. Texas is also expecting additional support from the U.S. Air Force Reserve’s 910th Airlift Wing flying two specially equipped C-130H cargo planes in the coming days in areas over the upper Texas coast. DSHS will continue to work with local governments that have requested aerial mosquito spraying and will update information as flight plans are finalized.
People can help control mosquitoes during the recovery effort by dumping out standing water around their homes and businesses and applying a commercially available larvicide in water that can’t be drained. People should also avoid mosquito bites by using an EPA-registered mosquito repellent every time they go outside and making sure their window and door screens are in good repair after the storm to keep mosquitoes out of homes.