Aug. 16, 2012

By Julie Thibodeaux

As more people forego using chemicals on their lawns and gardens and seek organic produce, many in the local green community were outraged that cities in the Dallas-Fort Worth area were ramping up efforts to combat mosquitos carrying West Nile virus by spraying pesticides in urban neighborhoods.

This summer, North Texas has been at the center of a West Nile virus outbreak with the most confirmed cases reported in the U.S. The Centers for Disease Control and Prevention said there have been almost 700 cases of confirmed West Nile virus in the U.S. and 26 deaths this year. Texas reported the most cases with the majority concentrated in Dallas, Tarrant and Denton counties, which combined have had almost 500 confirmed cases and 13 deaths. (mosquito photo: shutterstock)

As a result, Metroplex cities are escalating efforts to combat mosquitos, which carry the disease. Dallas has opted to use aerial spraying to kill adult mosquitos for the first time since 1966. Meanwhile, Fort Worth is beginning ground spraying this week for the first time in almost 20 years. As many as 15 smaller municipalities will also be enacting ground-level or aerial spraying. (photo: Clarke Mosquito Control)

As cities across the Metroplex braced for pesticide coverage by land and air, many were worried about the effects on people, animals and beneficial insects. Concerned Dallas residents, including organic gardening guru Howard Garrett, appeared before the Dallas City Council on Wednesday to protest the spraying. “I think it’s really foolish,” said Garrett, later by phone. “[The pesticides] are much more toxic to humans, pets and fish than they say it is.”

Dallas-based entomologist Dr. Gene Helmick-Richardson also spoke out publicly against spraying in a Aug. 12 news article.  On his Facebook page, he posted that aerial spraying would only kill 30-50 percent of mosquitos, which would rebound within a few days.

Susie Marshall, Texas Organic Farmers and Gardeners Association president, said she’s received a number of calls from members worried about the effects of spraying on their gardens, crops and beehives. She said the city could do better with preventive measures, including managing water usage, rather putting residents and wildlife at risk. “If they’re telling us to keep our pets and ourselves inside, it’s got to be harmful to other things,” she said.

Carl Franklin, president of the DFW Herpetological Society and biological curator of the Amphibian and Reptile Diversity Research Center at the University of Texas at Arlington, said pesticide use could hurt the local frog and lizard populations, which are already experiencing declines. With their permeable skin, amphibians are known to have adverse reactions to pesticides. In addition, they eat mosquitos. “I don’t believe [spraying] is the best way to take care of the problem,” he said.  A petition to stop aerial spraying was also started by Vanessa Van Gliber, who had collected more than 1,600 signatures by Thursday

At a public meeting, city of Fort Worth code compliance director Brandon Bennett said that the city is using only targeted spraying in an area where multiple cases occurred within a short period of time. Bennett said the city has no plans to spray citywide by truck or air. In Fort Worth, Rid All, a local company that specializes in organic pest control was hired to do the ground-spraying. However, the contractor recommended a chemical known as permethrin be used to fog the streets, given the severity of the situation.

The EPA classified permethrin as safe for humans but toxic to both freshwater and estuarine aquatic organisms as well as honeybees and other beneficial insects. The ASPCA National Poison Control Center has also listed a permethrin-based topical flea control for dogs as being a hazard to cats, even fatal. However, Bennett said the city evaluated all the risks, including contacting the ASPCA, which confirmed that the low dosage being used would not be harmful to cats. To alleviate concerns, they recommend bringing pets indoors.

The sprayings are also being done at night to minimize the risk to beneficial insects, which are not typically flying around at night. The product being used in the Dallas area for aerial spraying is called Duet, which has two active ingredients, sumithrìn and prallethrin. The company fact sheet said, like permethrin, it breaks down quickly in the environment. Despite the city downplaying the risks, the Dallas Arboretum was covering up its koi ponds with tarp on Thursday in preparation for the aerial spraying.

Meanwhile, Garrett insisted there are number of organic solutions that work just as well as chemical products with much less risk. Removing standing water, where mosquitos breed, is the one of the most important measures homeowners can take. He also advises treating water that can’t be drained with mosquito dunks and using plant-oil based pesticides. “Garlic sprays work well to repel the insects for up to 30 days. He’s hoping city officials will see the folly of their ways. On his website he posted: “West Nile Virus is the most overblown health threat since the ‘killer bees.’”

See the EPA fact sheet on permethrin
See the EPA fact sheet on prallethrin


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Julie Thibodeaux is a Fort Worth-based writer covering environmental issues, green topics and sustainable living. Previously, she worked as an editor and writer at the Fort Worth Star-Telegram. Contact her at