April 8, 2009
Vol. 39, No. 133

For more information, contact William Meredith, Mosquito Control, 302-739-9917, or Joanna Wilson, Public Affairs, 302-739-9902.

Spring Mosquito Spraying of Wooded Wetlands Continues

            DNREC’s Mosquito Control Section is nearing the end of its annual spring woodland pool spraying, treating wooded wetlands in New Castle, Kent and Sussex counties. Areas where early season woodland pool mosquitoes breed in quantity are being treated by helicopter or aircraft, with the focus on woodlands near cities, towns and large developments. Areas too small to warrant aerial insecticide application will be treated by Mosquito Control staff using backpack sprayers.

Control efforts target the immature (larval) stages of early-season woodland pool mosquitoes. Aerial spraying of woodland pools must be completed before the forest canopy fills in with leaves, usually around mid-April, because leaves will prevent the insecticide from reaching pools and other wet spots containing larvae on the forest floor.

If larval stages of these early season mosquitoes are not successfully controlled, an intolerable number of biting adult mosquitoes could take wing by early to mid-May and remain through late June, becoming particularly troublesome for residents within one to two miles of their woodland pool origins. Mosquito Control uses a bacterially-produced insecticide, Bti, in accordance with all EPA-approved instructions as required by federal law.

The amount of spraying needed is determined by the location of the wooded wetlands, the amount of mosquito larvae present, and how wet areas are, which can vary depending on the location and amount of precipitation over the past autumn, winter and early spring. Woodland pool levels have increased over the past two weeks due to increased rainfall, although overall levels are still running slightly below average, according to Mosquito Control staff.

Even though it may seem early in the season, the public is encouraged to do its part to reduce mosquito-rearing habitat by cleaning clogged rain gutters, keeping fresh water in birdbaths, draining abandoned swimming pools and emptying standing water from such containers as scrap tires, cans, flower pot liners, unused water cisterns, upright wheelbarrows, uncovered trash cans, depressions in tarps covering boats or other objects stored outside.