Delaware’s mosquito season now in full buzz

With a truck-mounted sprayer an ultra-low volume ground application for adult mosquito control is made. (Submitted photo/DNREC)

With a truck-mounted sprayer an ultra-low volume ground application for adult mosquito control is made. (Submitted photos/DNREC)


DOVER — Guess what?

It’s the middle of mosquito control season in Delaware.

Who knew?

While there’s no count of how many mosquitoes are now flitting around — state program administrator Bill Meredith described a population in the “zillions” — officials described their impact as fairly consistent with past years.

The Mosquito Control section, however, can report that just 19 species of the approximate 57 species in Delaware are categorized as bothersome to humans or domestic animals.

That’s comforting.

The season often begins in late March or early April, depending on temperatures, when spraying for the woodland-pool-breeding species begins, and can run through the end of October. Control needs can stretch until Thanksgiving at times when it stays warm, Mr. Meredith said.

“From early April to late October, we have a lot of challenges,” Mr. Meredith said. “There’s always something popping up.”
Delaware is among the top 10 percent in states nationally for both wetlands coverage and population density, meaning a lot of people are in close proximity to prime mosquito breeding grounds, Mr. Meredith said.

Half-jokingly, Mr. Meredith quipped, “We’re one state agency that doesn’t mind getting yelled at. We want people to tell us when they’re having problems with mosquitoes so we can respond to it.”

A New Jersey light trap is used for monitoring mosquitoes in consistent locations throughout the summer,

A New Jersey light trap is used for monitoring mosquitoes in consistent locations throughout the summer,

The state’s Mosquito Control Division is currently running one or two fog trucks a night, covering five to six areas at a time. Aerial drops are also part of the action.

Residents can be notified of spray announcements through an email contact list (go to in the mosquito section to register) or by calling a toll-free hot line at (800) 338-8181

Initially, operations to thwart the hatching of larvae in ditches, stormwater ponds, wet woodlands and the haven coastal salt marshes are enacted in early spring. Inspectors first go out in the field to sample water and determine where the mosquitoes are arising the most, Mr. Meredith said.

From the salt marshes, Mr. Meredith said, mosquitoes can fly five to six miles inland.

Administered insecticides — larvicides and adulticides — are registered with the U.S. Environmental Protection agency and deemed to bring no unusual danger to humans, wildlife, or the environment if applied properly, The treatment is part of the state’s Integrated Pest Management program.

Whenever possible, other non-insecticide measures are used to control mosquitoes, preferably eliminating habitats favorable to breeding and controlling mosquitoes in their pre-emergence larval stages, according to the Mosquito Control Section’s website.

Methods of elimination

“These methods include water sanitation and elimination of container breeding habitats, Open Marsh Water Management, management of tidal flows and marsh water levels, and stocking of mosquito fish,” an online entry in the Mosquito Control Section at explained.

“When source reduction is not possible, or practicable, insecticides are used.”

Also, there’s a public information push to educate citizens the value of eliminating standing water areas whenever possible, which cuts down on available breeding locations.

Seventeen full-time employees administer the program with a $2 million annual budget, with 10 seasonal hires working three months in the summer.

The numbers are smaller than other states in proportion to the work done, Mr. Meredith said.

So far this year, there’s been two cases of the mosquito-borne West Nile Virus, including a 6-year-old Sussex County girl in late June who was briefly hospitalized in the first reported human case since 2013. Also a crow with the virus was located in the Milford area last week.

For more information on mosquito control, call the state’s administrative headquarters in Dover at 739-9917, or field offices in Glasgow at 836-2555 or Milford at 422-1512.

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