COLLEGE STATION Abundant rainfall during fall and winter may have helped ease the drought situation in Texas, but it is bringing the expectation of high mosquito populations during the spring and summer.
Dr. Jim Olson, Texas Agricultural Experiment Station entomologist said, “The mild winter we had, coupled with the moisture, has probably allowed the overwintering egg populations…to get through in fairly good shape.
“Likewise, those that waited out the winter as adults probably did about as well.
“We’re looking at having a fairly decent if you want to look at it from my vantage point mosquito season if and when the temperatures rise above and stay above 60 to 65 degrees. That’s the thing right now that’s been holding off any major mosquito problems statewide.”
Mosquitos tend to stay in hibernation in temperatures below 60 degrees Fahrenheit.
“The temperatures have been on our side up to this point.”
As the weather warms into spring, however, the mosquito eggs which overwintered will hatch, creating a potential for exploding populations of some species.
“We’ve had a few local bursts of mosquitos, and of course we have those species that are most active during the winter, particularly along the (Gulf) Coast, that have caused some local problems, but we haven’t had a statewide problem. If we start getting these temperatures above 65 degrees, a little drying off, and then some serious floods, we’re going to have some tremendous mosquito problems, wherever that occurs, whether it be in El Paso or be in Texarkana, Lubbock or the lower Rio Grande Valley.”
With 84 species, Texas never has a complete absence of mosquito activity, particularly in the coastal areas, he said. “We just change species with the seasons.”
There are at least a half-dozen to a dozen species active at any one time.
Olson estimated the first major burst of mosquito activity in the southern and central regions of Texas will occur in mid-April.
The state health department is already coordinating a surveillance program for the West Nile virus that focuses primarily on the migratory waterfowl and birds migration patterns along the Gulf Coast. So far, there has been no detection of any virus activity, he said. The primary vector of West Nile virus is the Culex pipiens species of mosquito.
West Nile virus is closely related to St. Louis encephalitis, which has been in the United States for at least a century. A major outbreak of West Nile disease was found among birds in New York State in1999, the first documented appearance of this virus into the United States, according to the Dutchess County, N.Y., Department of Health. Last year, the virus spread into surrounding states.
Olson said, “The prognosticators are saying (West Nile disease) should make a significant move to the west, and likewise to the south, within the next year. It looks like it is established; the question is how far will it go.”
Another public health problem officials are monitoring is Eastern Equine Encephalitis (EEE). A rare viral disease, it is spread by mosquitos. With the warmer-than-normal temperatures, the activity of the species, Culiseta melanura, that carries the disease virus has not necessarily been shut down.
There is no reason for undue alarm, though, the entomologist said. “The main things protecting us (as Americans) are screen wire, air-conditioning and prime time television. That’s taken us out of harm’s way when mosquitos are most active.”
To help reduce mosquito populations around homes, dispose of prime breeding habitats, he said. Any type of container, natural or human made, that can hold water for up to three days, is a potential breeding ground for mosquitos. This can include flower pots, bird baths, dog dishes, old tires or rain gutters.
“If you don’t need the article, get rid of it; if you need the article, put it under cover or turn it over so it won’t collect rain, or at least dump the water out of the container every three days,” he urged.
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