DALLAS - Five planes will complete a second round of aerial spraying overnight in the city of Dallas and the surrounding suburbs that opted for West Nile spraying via air, according to county officials.
Weather permitting, more than 360,000 acres across Dallas County will be sprayed Monday night, starting at 9 p.m. and ending around 1 a.m. Officials said that larger spray zone is actually easier for the pilots.
"Our planes actually spend a lot of time making turns, [during] which they turn off the spray," said Laura McGowan, a spokeswoman with Clarke Dynamic Aviation, the contractor hired to spray. "They make a circle and come back. So, when you have a larger spray block, you're able to cover more of the area with fewer turns -- much more efficient."
The second round of spraying will take place to kill new mosquitoes born since the last round. Experts say the second pass is necessary because mosquitoes breed every five to seven days, laying 200 to 300 eggs at a time.
"So we want to make sure that we not only get the mosquitoes that are flying today, but also any ones that have hatched off since Thursday," McGowan said.
Preliminary tests are showing the mosquito population as a whole is on the decline, though studies are still being done to determine if West Nile-virus carrying mosquitoes specifically are dropping in numbers.
"What our preliminary data is showing is that these planes are going up and knocking down mosquitoes," said Dallas County Health and Human Services director Zachary Thompson. "We also see our ground approach is knocking down mosquitoes."
Crews with the Centers for Disease Control are in Dallas County to observe and learn from the spraying operation. So far, the county is expecting additional information from trapped mosquitoes within the next 24 hours.
County, state health and CDC officials will determine if two rounds of aerial spraying is enough or if a third is needed.
Because of widespread public concern about the possible health effects of aerial mosquito spraying, county health officials have also been closely following hospital admissions since the spraying began last Thursday. There have been no admissions to North Texas hospitals, nor has there been an uptick in asthma cases.
But bees and fish remain at risk. On Monday, the race is on to protect them. Bee keeper Brandon Pollard has just a few hours to cover 100 hives at some 20 locations with boxes to protect his clients' bees.
"Because we're dealing with much larger swaths and we've just found out this morning that we're going to be doing everything that has already been sprayed, which, for us, means that we need beekeeping boots on the ground," Pollard said.
As he approached the hives Monday afternoon, he saw a troublesome sign on one client's roof.
"It is really interesting to see all these June bugs," he said. "That's not normal."
Dozens of dead June bugs left Pollard wondering if the Duet pesticide used to kill mosquitoes on contact are also wiping out the June bug population.
All the more reason, Pollard said, to be proactive about covering bee hives.
Not far away, Trey Denton, who builds and maintains water gardens and ponds, was also working to cover some areas. Many of his residential clients stock fish and don't want them harmed by the spraying.
"I've got different customers in different parts of town so to get everybody done ... I can start probably at about six o'clock this afternoon and I need to be done before spray time," Denton said.
Residents can get updates where and when the plane will be spraying by following live Twitter updates from Dynamic Aviation here. For updates from WFAA, text SPRAY to 48411.