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Skip Navigation LinksDNREC : News : 2015 Mosquito Control season begins with spraying wooded wetlands

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Contact: Joanna Wilson, DNREC Public Affairs, 302-739-9902

2015 Mosquito Control season begins
with spraying wooded wetlands

DOVER (March 23, 2015) – DNREC’s Mosquito Control Section begins its annual spring woodland-pool spraying today, treating wooded wetlands near select populated areas in New Castle, Kent and Sussex counties. About 8,000 forested acres that produce large numbers of early season mosquitoes will be strategically sprayed to treat immature aquatic larval stages, using larvicides applied by helicopter and possibly aircraft.

The colder weather this year has somewhat delayed development of larvae for these species,” said Mosquito Control Administrator Dr. William Meredith, “But it won’t much affect the numbers of adult mosquitoes that will eventually emerge. With woodland flooding conditions upstate running about normal so far but well above normal downstate, potential exists for lots of mosquitoes to emerge.”

Aerial spraying of woodland pools must be completed before the forest canopy fills in with leaves, usually around mid-April, because leaves prevent the insecticide from reaching pools and other wet spots on the forest floor containing larvae. The spring campaign marks the beginning of Delaware’s annual mosquito season, which in most years continues until sometime between mid-October and early November, depending upon when the first killing frost occurs.

If larval stages of early season mosquitoes are not successfully controlled, an intolerable number of biting adult mosquitoes would take wing in late April and remain through late June, becoming particularly troublesome within one to two miles of their woodland pool origins, and significantly affecting quality of life and human health for residents and visitors alike, said Dr. Meredith.  

“Delaware has about 100,000 acres of wet woodlands during most springs, and its not possible for logistical or budgetary reasons to larvicide all woodland mosquito-producing habitats,” Dr. Meredith continued. “Targeting the pools near populated areas is the best return-on-investment in providing mosquito relief to the most people.”

Over the next few weeks, Mosquito Control will apply a bacterially-produced insecticide, Bti. “Like all insecticides used by Mosquito Control, the U.S. Environmental Protection Agency has determined that Bti, when used in accordance with all EPA-approved instructions as required by federal law, can be applied without posing unreasonable risk to human health, wildlife or the environment,” said Dr. Meredith.  

The amount of spraying needed is determined by where and how wet the woodlands are, and can vary from year to year depending on the location and amount of precipitation that has occurred over the past autumn, winter and early spring.

As in the past, advance public notice of when and where spraying will occur this year will be given daily via radio announcements, by calling 800-338-8181 toll-free, or by visiting Interested parties may also subscribe to receive email notices of mosquito control spray announcements by visiting DNREC’s homepage, On the left-hand column under Services, click “email list subscription,” choose “DNREC Mosquito Control Spraying,” and send a blank email to start receiving notices.

During mosquito season, the public is encouraged to do its part to reduce mosquito-producing 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.  

To request local mosquito control, call Mosquito Control’s field offices:

·        Glasgow Office, 302-836-2555, serving New Castle County and the northern half of Kent County, including Dover.

·        Milford Office, 302-422-1512, serving the southern half of Kent County south of Dover and all of Sussex County.

For more information about Delaware’s Mosquito Control program, call the Dover office at 302-739-9917.

DNREC’s Delaware Mosquito Control Section provides statewide services to about 926,000 Delaware residents and 7.5 million visitors annually to maintain quality-of-life and protect public health by reducing the possibility of mosquito-borne illnesses such as West Nile virus or eastern equine encephalitis, along with a new concern for chikungunya. Throughout the warmer months, Mosquito Control monitors and treats mosquito populations that emerge from wetland areas found throughout the state, including ditches, stormwater ponds, wet woodlands and coastal salt marshes. The Section also works year-round on water and marsh management projects designed to reduce mosquito populations, and provides the public with information on dealing with mosquitoes, from reducing backyard mosquito production to avoiding mosquito bites.

Vol. 45, No. 73
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