LEWISTON – Last month’s unrelenting rain may yield a bumper crop of black flies and mosquitoes.

Many communities across Maine recorded double the average rainfall for April, according to the National Weather Service.

All of that rain in addition to a deep snowpack has caused standing water and heavy flows on rivers and streams.

“Mosquitoes breed in standing water. Black flies breed in moving water,” said Dave Struble, the state entomologist.

“We’ve had plenty of both.”

Struble, along with Jim Dill of the University of Maine Cooperative Extension, said Mainers should take precautions to avoid being bitten by mosquitoes, which are known carriers of a variety of diseases, most recently the West Nile virus.

Dill suggested that people initiate a spring dumping of water from old tires, buckets left outside, rain gutters and elsewhere. “Birdbaths should be flushed once a week, too,” he noted.

The U.S. Centers for Disease Control and Prevention is recommending the use of repellents containing the chemical picaridin or the oil of lemon eucalyptus for “long-lasting protection against mosquito bites.”

Picaridin and the oil join DEET-based repellents as those considered the best protection against pesky insects.

New lines of “bug-be-gone” clothing sold by L.L. Bean and other retailers are proving effective, Struble and Dill said. The clothing has been sprayed or soaked with Permanone, an insecticide consisting of the chemical permethrim.

Dill said the jury is still out on black flies. The heavy winter snowfall may not have a big impact since they mature in swift running rivers and streams. “Snow melt and rain will not affect their populations too much,” he said.

As for mosquitoes, “it might be a good year, or a bad year, depending on if you are an entomologist or a consumer, or being consumed,” he said.