Yellow flies are back!

April 7, 2023

It’s that time of year again, and those nasty yellow flies are biting… here are some tips for armoring yourself

In Florida, the name “yellow fly” is used to describe about a dozen different species of yellow-bodied biting flies. “Yellow flies” readily attack humans and are usually abundant in Florida with peak annoyance occurring in May and June. “Yellow flies” are in the family known as Tabanidae. All tabanids go through an egg, larva, pupa and adult stage, referred to as “complete metamorphosis,” the same development process that mosquitoes go through. Tabanids lay egg masses containing 50 to several hundred eggs. Most species deposit their eggs around ponds, streams or swamps on overhanging vegetation such as grasses or cattails.

Yellow flies congregate in shaded, humid areas on the edges of forests, rivers and creeks, avoiding large, open, sunny areas. Some species are active in the early morning while other species are more active in the late afternoon.

However, depending upon conditions such as heavy tree canopy, cloudy days or when an animal is moving through an area, yellow flies can become active and bothersome throughout the day. “Yellow flies” prefer to attack man about the head, neck or shoulders, however, any exposed part of the body may be attacked.

Their persistence to obtain a bloodmeal, once a host is found, can make 5 or 6 flies unbearable. Sometimes the use of the old-fashioned fly swatter will give relief by taking out the few flies in an area.

Learn more from South Walton Mosquito Control District here.

What to do

A trapping method homeowners can use, which does not involve the use of pesticides, is called the “sticky black ball” trap. Basically it is a beach ball, (milk jugs work just as well and are easier to hang) painted black and coated with a sticky substance. The sticky substance is called Tangle-Trap and comes in a spray or liquid applicator. It can be found at local Ace Hardware and Frank’s Cash and Carry stores.

These devices are hung from a tree limb using string, in a shaded area, about 4 feet above the ground. Movement of the ball by the wind attracts the flies, thinking it is an animal, they land, get stuck, and die on the ball. Several of these balls will reduce the local adult populations.

A black beach ball coated with Tangle-Trap. The yellow flies are attracted to the heat and motion.
A black beach ball coated with Tangle-Trap. The yellow flies are attracted to the heat and motion.

Birds are not attracted to the ball nor can be “stuck” as the adhesive is only strong enough for insects.

CLICK HERE FOR VISUAL INSTRUCTIONS

South Walton Mosquito Control District offers a black ball kit, with a string and Tangle-Trap supply for free to residents in south Walton County that live south of the Choctawhatchee Bay only. Available for pick up only with proof of residency such as a utility bill with address. For more information, call (850) 267-2112. Limit one kit per household. Kits can be picked up at the SWCMCD headquarters located at 774 N. Hwy 393 Santa Rosa Beach, Monday through Friday from 8:00 am until 3:00 pm.

You can also create your own “ball” using a milk jug, spray paint it a dark color and apply a sticky substance.

Vegetation management
By removing underbrush around a residence, helps to eliminate resting sites for the flies and increases light levels making the area less attractive.

 

 

Bite and sting relief
Here is a general purpose sting relief for yellow flies. It is also helpful for mosquito, chigger and jellyfish bites.
1 tsp. baking soda
1/3 cup ammonia (Windex is mostly ammonia)
1/3 tsp. papain (meat tenderizer)
1 crushed aspirin
Mix thoroughly and store in refrigerator (be sure to label container). When needed, shake well and apply with cotton swab, and rub briskly.

Cactus juice, a non-toxic protectant has shown to be effective against yellow flies. Available at Ace Hardware in Santa Rosa Beach.
Cactus juice, a non-toxic protectant has shown to be effective against yellow flies. Available at Ace Hardware in Santa Rosa Beach.

Vinegar wipe/bath: When you first notice the bite, try applying a small amount of vinegar directly to the bump. If you have many bites, you may want to take a very hot bath in a tub filled with water and 2 1/2 cups of apple cider vinegar.

Other methods locals have used with some success: Witchazel, Preparation H with aloe if put on bite immediately helps relieve itching and swelling, Cortisone cream.

Protection:
Personal protective measures include the use of repellents containing DEET (diethyl metatoluamide) applied to exposed skin. Wearing physical barriers such as a head net, long sleeve shirts and long pants are effective protection if you must be out in areas where “yellow fly” populations are high. Permethrin containing products labeled for application to clothing only, can also be effective in repelling and killing “yellow flies.” Thankfully, “yellow fly” season is relatively short, one maybe two months, and then mosquitoes become our major pest.

Non-toxic repellents such as “Cactus Juice” is available at Ace Hardware, and Modica Market in Seaside, also “Swamp Gator” available at Frank’s Cash and Carry.