Scorpions: A Serious Public Health Threat

Residual control of scorpions has been added to the Talstar Lawn & Tree Flowable Insecticide/Miticide label, according to FMC Corporation. In a recent study completed by the University of Arizona, Talstar provided 83% control of bark scorpions, Centruroides exilicauda, within hours of exposure to soil treated with a standard 0.06% label rate.

The study results are significant because scorpions are notoriously difficult to control with a residual insecticide treatment, says Dr. Dave Langston, a University of Arizona entomologist and director of the study. "Most insecticides will control scorpions when applied directly to them," he says. "Talstar Lawn & Tree Flowable provided 100% control of bark scorpions within 24 hours after a label rate was applied to them. Talstar was also very effective when applied as a soil treatment."

Langston says the University of Arizona Extension Service recommends direct treatment as the most effective method of control. However, direct treatment requires use of a black light at night to find active scorpions — their bodies naturally fluoresce — or the use of a flushing agent during the day. Since either method is not always practical or totally effective, the ability to establish a residual barrier of protection can be an important option around homes.

PUBLIC HEALTH CONCERNS. Langston selected bark scorpions for his study because they are responsible for many human stinging incidents. They are also the only scorpion species in the United States with potentially lethal venom.

Additional research is needed on scorpion control, Langston says. Scorpions have become a public health issue in Arizona and other parts of the Southwest. Last year, poison control centers in Arizona received more than 8,000 calls reporting scorpion stinging incidents and seeking medical advice.

If all stinging incidents in Arizona were reported, it is believed that the total number of annual stingings could be two to three times higher. Bark scorpions are also being found in Palm Springs, Las Vegas and other metropolitan areas in the Southwest.