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Delaware back to normal for mosquitoes this year

Lots of early rain fueled hatching of dormant larvae causing last year’s irruption
July 19, 2019

This time last year, Bill Meredith, Delaware’s mosquito control administrator, was in the midst of a mosquito irruption. This year, he said, things are back to normal.

During a recent interview, Meredith said he thinks the reason for the irruption last year was twofold – higher-than-average rain in the spring and the hatching of mosquito larvae that had been dormant. He said there are species of mosquitoes with larvae that can hatch months or even years after the eggs were laid.

All that rain last spring got places wet that hadn’t been wet in a while, he said.

In a normal year, the division receives 2,000 to 3,000 mosquito complaints. Last year, Meredith said, they received 6,000 complaints, with a significant majority of them coming in a six-to seven-week period in May and June. The division is on track for a normal number of complaints this year, he said.

According to the Accuweather forecast provided to the Cape Gazette, the amount of precipitation this year couldn’t be more normal. Through July 11, the area had received 23.31 inches of precipitation. The average amount through this time of year is 23.53 inches.

While Meredith is happy mosquitos appear to be back to normal, he warned things in Delaware can change quickly. He said Delaware’s low-lying, wetland-covered topography and dense population are ideal for mosquito breeding. Delaware is in the top 10 states for percentage of wetland coverage and for human population density, he said.

Meredith, who has been program administrator for almost two decades, said the state’s normal mosquito population is really unnatural. He said if the mosquito control division wasn’t doing its work behind the scenes, the mosquitoes would be much worse. Every spring, Delaware sprays wooded wetlands across the state with insecticides to kill mosquito larvae.

“We’re pretty good at making the unnatural seem natural,” he said.

The state also runs a sentinel program every year, which uses caged chickens in 20 stations throughout the state, testing them for indicators of disease. Meredith said, to date, since the first week of July, no positive tests for disease have been recorded.

For more information, call mosquito control’s main office at 302-739-9917. To report sick or dead birds, call mosquito control’s field offices between 8 a.m. and 4 p.m., Monday through Friday. The Glasgow office’s number is 302-836-2555, which serves New Castle County and Kent County from Dover north. The Milford office’s number is 302-422-1512, serving the remainder of Kent County and Sussex County.

For more information about West Nile virus in horses, Eastern equine encephalitis, or vaccines, call the Delaware Department of Agriculture’s Poultry and Animal Health Section at 800-282-8685 (Delaware only) or 302-698-4500.