Deer flies, members of the Tabanidae family, are notorious for their aggressive pursuit and painful bite, making outdoor activities a challenge during peak season. Unlike mosquitoes, which use chemosensors, female deer flies are primarily visual hunters, attracted to movement, heat, and dark objects. This reliance on visual cues explains why traditional personal repellents often fail to deter them. Effective strategies combine chemical barriers on clothing with behavioral modifications and physical area control methods to minimize contact.
Effective Topical Chemical Solutions
While deer flies are less sensitive to chemical deterrents than other biting insects, certain active ingredients can still play a role in defense. Repellents like DEET and Picaridin are standard for personal protection, though their effectiveness against deer flies is limited since the flies are not easily repelled by odor alone. For skin application, Picaridin (often used at 20% concentration) is sometimes cited as having slightly greater efficacy against flies than DEET. DEET concentrations between 20% and 30% are common, but these primarily work by confusing the fly’s sensory input.
A stronger chemical defense involves treating clothing and gear with Permethrin, a contact insecticide. Permethrin is applied only to fabric, never directly to the skin, and works by killing the fly when it lands on the treated surface. Once dry, the treatment is odorless and remains effective through multiple wash cycles, creating a lasting chemical barrier. This clothing treatment should be paired with a skin-applied repellent to cover exposed areas.
Behavioral and Clothing Strategies
Since deer flies hunt by sight, personal apparel and movement patterns are powerful tools for avoidance. Minimizing rapid motion in heavily infested areas can reduce attention, as deer flies are strongly attracted to moving objects. Wearing light-colored clothing, particularly white or khaki, is recommended because it makes a person less visually appealing. This contrasts sharply with the flies’ attraction to dark colors, especially shades of blue and black.
Physical barriers provide an immediate defense against their painful mouthparts. Wearing thick, loose-fitting clothing makes it difficult for the fly to penetrate to the skin. Because deer flies frequently target the highest point of a host, a wide-brimmed hat or a mesh head net is useful for protecting the head and neck area.
Trapping Methods for Area Control
For managing localized populations, such as around a campsite or yard, trapping systems that exploit the fly’s visual hunting instincts offer the most direct control. The most common design involves a dark, movable object coated in a high-tack adhesive, such as Tanglefoot. Deer flies are attracted to the dark sphere, mistaking it for a host, and become permanently stuck upon landing. The traps often utilize a blue or black ball suspended from a rope to allow slight movement, which mimics a moving host and increases attraction.
Optimal placement for these traps is in sunny areas, positioned four to six feet above the ground, and near known deer fly habitats like wooded edges or wetlands. Regular maintenance, involving reapplying the sticky adhesive, is required to maintain effectiveness as the traps fill up. While non-chemical options, such as essential oils or Oil of Lemon Eucalyptus (OLE), are sometimes explored, they generally provide only a short-term, mild repellent effect. OLE is an EPA-registered repellent, but it is often less effective at deterring the visually-driven deer fly than a purpose-built, sticky trap.