By Andrea Lucia

DENTON (CBSDFW.COM)  – Low flying planes swept the sky over Denton County Saturday evening, dropping  a second round of pesticide over much of the area.

Weather conditions forced flights to be cancelled on Thursday and be cut short on Friday.

The biggest factor has been the wind.  There has been either too much or too little to carry the droplets of pesticide to their target.

“They’re 30 microns. They’re a third of the size of a human hair. So, they’re extremely light, and they basically float.  If you have wind, that pushes them toward the ground in the area they need to be,” explained Laura McGowan, of Dynamic Aviation.

Ten cities in Denton County opted out of the aerial spraying, including the city of Denton itself.

Some residents in Denton County, though, have been eager for it.

“I think if we can take precautions, we should do it,” said Candice Harris, of Krum.

Dallas County leaders Thursday released a report by the US Centers for Disease Control and Prevention showing aerial spraying there may have killed as many as 93 percent of the mosquitoes that carry West Nile.

“That should be the proof in the pudding, if it’s working there,” said Coia Sneed, a football coach in Krum.