Expert Says Mosquito Populations Low But Precautions Still Necessary

Wayne L. Kramer, Blanchard, Tobie M.  |  6/21/2006 9:25:08 PM

News Release Distributed 06/21/06

There is one good thing about the drier-than-normal weather conditions around Louisiana so far this year. That’s fewer mosquitoes, according to an expert with the LSU AgCenter, who stressed precautions still are needed to prevent mosquito-borne diseases.

LSU AgCenter entomologist and mosquito expert Dr. Wayne Kramer said there is a direct relationship between the amount of water in the environment and the overall mosquito population. But dry weather still doesn’t mean there aren’t any mosquitoes – and the dangers they pose – out there.

"We have over 60 species or varieties of mosquitoes in Louisiana, and they really take advantage of almost every aquatic habitat out there," Kramer said.

These days people have to worry about more than just an itchy, irritated bite when it comes to mosquitoes. They also have to worry about the risk of mosquito-borne diseases such as West Nile virus. These diseases still are active even when the weather is dry, according to experts.

While Kramer said Louisiana has not reached the major part of its West Nile season yet – the virus peaks in July and August – it’s still not too early to take precautions against these potentially dangerous pests.

"The key message we want to tell everybody is that they should make sure they are not raising mosquitoes on their own property or in their own yards," Kramer said.

To eliminate all possible mosquito habitats, Kramer advises keeping yards clear of standing water. This includes emptying flower pots, bird baths, tires and toys.

Homeowners also can use other control methods to keep mosquito populations down – such as keeping fish in aquatic ponds or using mosquito dunks in ditches. Dunks release bacteria into the water that helps to eliminate them.

"The mosquitoes ingest the bacteria as part of the feeding process," Kramer explained. "It is toxic to them and it kills them."

Mosquito dunks are safe to use, according to Kramer, who says the product targets mosquitoes and does not harm anything else in the water.

Kramer is studying mosquitoes to develop other products that also could control them.

"One of the things we are starting to look at is the egg-laying behavior of female mosquitoes."

Kramer is looking at ways to attract female mosquitoes to lay their eggs or to repel them from laying their eggs in certain waters. This would allow for products that could control the eggs before they hatch.

Another part of his research involves studying the cycle of West Nile virus and learning more about the birds and mosquitoes that carry and transmit the virus. He also is looking at what birds mosquitoes that transmit the virus are feeding on.

"The birds that the mosquitoes have a preference to feed on may be different from the birds that are the most abundant," the LSU AgCenter researcher said.

According to Kramer, some birds are better at manufacturing the virus in their bloodstreams and making it available to mosquitoes that feed on them. In addition, Kramer is looking at the cycle of West Nile virus and how it moves from mosquitoes and birds early in summer and shows up in humans and horses later in the season.

Humans and horses are dead-end hosts of the virus, Kramer explained.

"What that means is that while humans and horses can get sick, we don’t develop enough virus in our blood so that mosquitoes can bite us and then transmit the virus to other humans and horses."


Contact: Wayne Kramer at (225) 578-1835 or
Writer: Tobie Blanchard at (225) 578-5649 or

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