Fight–the–Bite with Henrico’s Mosquito Division

by Gina Serge and Wes Robertson, Environmental Services Division, Department of Public Works

Did you know that Henrico County has a mosquito division as part of its Department of Public Works? That’s right, as part of the more extensive Environmental Services Division, the mosquito division uses an integrated management approach to help employees and residents combat mosquito-related issues. This time of year, our staff is gearing up to begin the mosquito season, which starts in April and lasts through the end of October. Our division consists of just three full-time employees and up to 10 seasonal and intern staff working diligently to protect public health and reduce human discomfort. Our division monitors 100 surveillance locations each season, treats up to 600 sites monthly, and participates in as many public outreach and education opportunities as time allows.

The mosquito division uses data collected from our surveillance, inspections, and treatments to keep track of mosquito species that frequent here. Henrico County has seen up to 36 unique species of mosquitoes over the years, but only about 12-15 species are considered a significant nuisance to our residents. We also test the species collected for the presence of West Nile virus (WNv). West Nile virus is the leading cause of mosquito-borne disease in the United States and is reoccurring in local mosquito populations each season. While not a reason to panic, it is essential for Henrico employees and residents to take the appropriate steps to protect themselves when spending time outside. Wearing light-colored, long pants and sleeves in combination with applying an EPA-certified repellant is one of the best ways to protect yourself from mosquito bites and disease.

So, how does the Mosquito Division protect you and your family? One of the ways is that we offer FREE mosquito inspections for all Henrico County residents. Inspections include an individual assessment where our staff visits the homeowner, inspects their property, and provides them with a consultation. With each consultation, the resident is provided with a written copy of the inspection results and is taught what they can do to reduce mosquito habitats in their yard. They are also taught how to combat future populations from moving back in. Any Henrico County employee who lives within Henrico County is eligible for this free service! This service is not exclusive to private residences. We are also available to inspect county buildings and job sites where you may be experiencing a mosquito problem.

Additionally, Henrico’s mosquito division inspects and treats standing water at over 600 county property and right-of-way areas (i.e., ditches) every 2-3 weeks. These treatments are completed using an environmentally friendly larvicide called Bacillus thuringiensis subspecies israelensis, better known as BTi. When applied in accordance with the label directions, BTi is safe for people, pets, and plants. It is “target specific,” which simply means it is only toxic to mosquitoes, black flies, and fungus gnats, all in their larval forms. This also means it is only effective when applied to those standing water areas where mosquitoes grow and develop. Because the Henrico County mosquito division relies heavily on larval and environmentally safe treatments, we do NOT do any ultra-low volume adulticide spraying and/or fogging. 

Each year, our calls, complaints, and inspections are dominated by the Asian Tiger mosquito (Aedes albopictus). The Asian Tiger mosquito is a tiny black mosquito with striped legs and a distinct white ‘racing stripe’ down its back (thorax). This mosquito is known for its aggressive biting behaviors and its ability to seek out a host any time of the day. This species is hard to manage because it only lays eggs in man-made containers, typically things left out and lying in the yard (flowerpots, corrugated pipes, trash, empty bins, tarps, etc.). Since they only need 1/10th of an inch of water (Think plastic water bottle cap!), many ‘hidden’ places can be easily missed even in the cleanest yards.

With all this said, we cannot effectively combat Henrico’s mosquito populations without the help of our fellow colleagues and residents. We want to encourage all our neighbors to Fight-the-Bite with us. Fight-the-Bite means picking one day a week, preferably the same day each week to make it a habit, walking your property or job site, and finding all the items holding water. DUMP IT! Don’t forget the very, very small hidden places like flowerpot trays, plastic trash, and those cracks and crevices in children’s toys! DUMPING IT discourages egg-laying and eliminates habitats quicker than treatments.

In addition to helping residents physically combat mosquitoes, we encourage our colleagues and neighbors to spread the word! We are happy to help here, too! The mosquito division is available to give community presentations and education sessions or provide informational flyers and pamphlets to any club, organization, group, or school within Henrico. The more neighbors we can get to join our mission, the more comfortable an outdoor experience for all of us.

For more information about group presentations or to request a mosquito inspection, email us at [email protected]!