Provided there are no more weather delays, aerial mosquito spraying in Denton County will begin tonight.
County officials delayed the spraying that was scheduled for Thursday night because of a forecast of high winds.
County officials are hoping for calmer conditions tonight and Saturday so spraying can take place as planned.
“The issue is that, in order for the product to be as effective as it can be, they need a wind under 10 mph,” said Jamie Moore, Denton County emergency services spokesman.
Spraying is now set to begin at 9 p.m. and continue until 2 a.m. Saturday.
A second dose is planned between 9 p.m. Saturday and 2 a.m. Sunday.
Moore said the county is working with the National Weather Service to monitor wind speed, which was forecast to be gusting between 5 to 15 mph through the prime time for spraying.
“We said earlier in the week we don’t know the effect Isaac may have,” he said. “We don’t know if this is necessarily an effect, but [we knew] weather could change plans.”
Another factor in the delay is protecting cities that chose to opt out of being sprayed.
“We want to ensure the correct drift and make sure we don’t spray an area that did not want to be sprayed,” he said.
Laura McGowan with Clarke/Dynamic Aviation, the company that will distribute the pesticide, said ideal weather conditions are expected tonight and Saturday.
“We’re very flexible, so if there’s [unsuitable] weather [conditions] one night, we can still quickly adjust and move to another night,” she said. “We had to do that with Dallas County through the rain storms and cancellations, but we’re very capable of staying here until the job is done.
“We’d want to get things done as soon as possible. We want to be able to come in here and make a difference to the health and residents of Denton County. However, Mother Nature, we’re at her mercy, so whenever we have to move an operation so that we have greater control on another date, we’re going to do that.”
Although Denton opted out of being sprayed, planes to be used in the process will fly out of Denton Airport.
Four to five planes will apply the insecticide while flying about 300 feet above the ground. The planes spray a swath 1,000 feet wide. Droplets come out at 30 microns, about the quarter of the size of human hair, county officials said.
Eight-tenths of an ounce will be sprayed per acre. That equates to about two tablespoons of active ingredient for an area the size of a football field.
Moore said the chemical degrades quickly and has little lasting effect.
The city of Denton has been using the same chemical in its ground spraying over the last several weeks. The city has recommended that people stay inside and keep their pets inside during those times.
Moore said people may want to take those precautions, but they aren’t required.
“It’s safe for humans, it’s safe for pets and you can be outside when it’s spraying,” Moore said. “Certainly, there are those who are not going to want to be outside and maybe want to take extra precautions just because it makes them feel comfortable, and we would encourage that. But it’s not necessary and it’s not recommended by the EPA, who regulates those chemicals.”
County officials have said they would avoid spraying in areas where there are large outdoor gatherings, such as high school football games.
So far this year, the county health department has reported 141 cases of West Nile virus — 98 cases diagnosed as West Nile Fever and 43 diagnosed as the more serious neuro-invasive disease.
Staff writer Britney Tabor contributed to this report.
BJ LEWIS can be reached at 940-566-6875. His e-mail address is firstname.lastname@example.org .
Health experts recommend taking these steps during aerial or truck spraying:
• Stay indoors if possible and close windows.
• Consider keeping pets inside while spraying occurs.
• If outside or in a vehicle, be alert for the spraying truck and maintain a safe distance.
• If skin or clothes are exposed, wash them with soap and water.
• Rinse homegrown fruits and vegetables with water as a precaution.
• Cover small ornamental fish ponds.
• Because the chemical breaks down quickly in sunlight and water, no special precautions are suggested for outdoor swimming areas.
HOW AERIAL SPRAY WORKS
Beechcraft King Air twin-engine planes will fly predetermined grids at a height of about 300 feet at 170 mph. From two 100-gallon tanks mounted inside the plane, the Duet pesticide flows into tubes mounted in the airplane’s wings. An atomizer smashes the pesticide into droplets 30 microns wide, tiny enough to penetrate the tree canopy. The spray system is computer-guided, distributing the chemicals in 1,000-foot swaths at a rate of about 0.8 ounces, or about 2 tablespoons of active ingredient per acre.
SOURCE: Denton County Emergency Services