Helicopters to spray Clearwater for mosquito larvae

Mosquito larvae in parts of Clearwater are about to get sprayed from above.

Pinellas County Mosquito Control and Lee County Mosquito Control will run aerial treatments Friday between 9 a.m. and 3 p.m. Low-flying helicopters will release a fine mist of Bacillus thuringiensis israelensis, or Bti, over the targeted areas. The county said the aircraft will fly at low altitudes in patterns, which it acknowledged will be noisy, because the approach helps the substance reach standing water. The timing, the county said, is chosen because it is easiest for people to go indoors during those hours.

Bti is a soil bacterium that the county described as specific to mosquitoes, killing only mosquito larvae and black flies. Mosquito larvae have a distinct gut pH that triggers a toxin release after they ingest the bacteria. The same active ingredient appears in the mosquito dunks and bits sold at local hardware stores for treating standing water. County materials state that Bti poses no hazard to humans, pets or pollinators.

The treatment comes amid a dengue count that has risen through the month. A Florida Department of Health report released Oct. 22 put Pinellas County at 51 confirmed dengue cases since August. Across Pinellas, Pasco and Hillsborough counties, the Tampa Bay region reached 401 confirmed cases, up 14 percent from the Oct. 15 report.

Residents can look up the treatment area at Pinellas.gov/mosquito-control-treatments/ under the aerial tab, and register for notifications of scheduled aerial larvae treatments in their area at Pinellas.gov/Alert-Pinellas.