The Pennsylvania Department of Environmental Protection plans to control the adult mosquito populations by spraying at the Stoneboro Fairgrounds.

Mosquito sampling at the fairgrounds has shown unusually large numbers of mosquitoes that may carry the West Nile virus.

The fairgrounds are the site of the Great Stoneboro Fair, which begins Wednesday.

Weather permitting, spraying will occur during the afternoon and evening hours Tuesday. The Mercer County and DEP West Nile virus staff will direct sprays onto vegetation and in wooded areas using backpacks and handheld equipment.