Marc Fein, Kristi Nelson and Randy McIlwain, NBC 5 News
Aerial spraying is scheduled to begin at 9 p.m., weather permitting. The spraying begins an hour earlier than on Thursday because rain stopped pilots from spraying half of Thursday's targeted area.
Storms again cut short planned aerial spraying for mosquitoes in Dallas County on Friday night.
A ground stop for the four planes conducting the spraying was ordered shortly before 11 p.m. because of "deteriorating weather conditions, Dynamic Aviation tweeted. The company then tweeted at about 12:25 a.m. that the rest of the spraying was canceled because of the weather.
Clarke Mosquito Control had hoped to conduct all of the spraying Friday night, even if it meant flying until daybreak.
"We want to get this done tonight," Clarke spokeswoman Laura McGowan said.
All four planes were in the air shortly before 8:30 p.m. and navigated around the thunderstorms that developed. Two planes started in Garland, while the other two planes began their runs in Carrollton. The direction the planes flew in depended on the wind.
Chopper 5 reported seeing spraying begin over Garland at about 8:45 p.m.
Crews were only able to spray about half of the area planned for Thursday night because of the weather. The plan Friday was to spray all of the areas missed Thursday night as well as every other city that had opted for aerial spraying.
It was not immediately clear how much ground was covered Friday night. Dynamic Aviation told someone on Twitter that state officials would distribute maps in the morning.
Crews were trying to spray Dallas, Addison, Carrollton, Coppell, Farmers Branch, Garland, Grand Prairie, Mesquite and Richardson. (See a detailed map here.)
The portions of those cities that are in other counties -- such as Grand Prairie and Richardson -- would also be sprayed.
If spraying had been completed Friday, a second round of spraying was anticipated Monday and Tuesday to kill mosquitoes that hatch after the initial round of spraying.
Dallas Mayor Mike Rawlings said officials would gather data to find out if the spraying is working. They could know more by this weekend, he said.
“We're going to be putting some traps out tonight in areas that we've already sprayed," he said. "We're going to compare those traps to areas that weren't sprayed, and then we'll know the impact of it.”
Dallas residents in Thursday's spray zones said they did not notice anything different on Friday.
Some exercisers along the Katy Trail in Uptown said they heard the hum of the small planes but weren't bothered by the noise. Some said they slept through it.
"We're out running today -- didn't feel any ill effects or anything like that," David Levy said. "Everything felt fine."
Hunter Johnson, who was out walking his dog, said he was concerned about the spraying but said he didn't notice anything different about breathing outside.
NBC 5's Frank Heinz, Mark Schnyder, Amanda Guerra and Omar Villafranca contributed to this report.