Courtesy of Guest Blogger, Eileen East, Master Gardener and Owner, Hill Home Forge B&B
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Last summer seemed particularly buggy. In fact, it was pretty hard to mow the lawn or even stay outside very long without being swarmed by gnats. And unlike other years, these "gnats" didn't go away in the summer heat. In fact, they got worse as summer wore on.
Usually gnats try to fly into your eyes and ears, but these guys bit. I bought a gnat hat with a net that dropped down to my shoulders and wore long sleeves and jeans tucked into my socks when I worked in the garden. My clothes were way too hot, but it was either suit up or spray myself with repellent every time I went outside.
I caught a few of the gnats to see what they looked like. They seemed to resemble fruit flies more than anything else. I decided that if they turn up again this spring I would send a sample to Penn State to find out what they are. Then, quite by accident, I did find out.
Benjamin Russell from the Pennsylvania Department of Environmental Protection contacted me. He messaged me through our Carbon County Master Gardener Facebook page in response to a question submitted by a reader who wanted to know if he had black fly in his pond. I did some research on black fly so I could answer the question, and Ben Russell happened across the exchange.
He told me about a PA-DEP program for controlling black fly as it spreads along river systems in the mid-Atlantic region, and he asked me to take a look at an informational website they set up for the benefit of educating Pennsylvania residents about black fly.
According to Russell, most species of black fly are not a problem to humans. However, one in particular is. The species Simulium jenningsi is the most common black fly pest in Pennsylvania. It breeds on fast moving river water and is multi-generational in one season.
The flies swarm their victims and bite bite bite. They get in eyes and ears and hair. The bites are itchy and painful and persist a long time. Some people are allergic to them.
Because large populations of black fly interfere with tourism and outdoor recreation, the PA-DEP has created a black fly control program that involves partnering with counties that are affected. As is the case with gypsy moth control, the county has to be willing to fund the program.
The control involves spraying the black fly larvae with a microbial insecticide called Bacillus thuringiensis subsp. israelensis or Bti. The microbe is toxic to mosquito and black fly larvae. It has to be sprayed on the larvae so they actively ingest it for it to be effective. It acts in a similar manner to the microbial spray the state uses to control gypsy moth.
Black fly is a potent pest within 20 miles from the shores of the Lehigh River. There is a potential for loss of tourism dollars, real estate sales, and fishing and hunting dollars in affected areas. Black fly can also make life difficult for outdoor workers in construction, farming and landscaping. In short, most of us will feel the bite if only in our garden.
If Carbon County elects not to spray, then what can individuals do? The PA-DEP websites recommends that we avoid infested areas during the daytime when black flies are active. Stay indoors on warm humid summer days. Wear protective clothing with long sleeves and pants tucked into socks. Use insect repellants containing DEET and re-apply every few hours. Don't use scented cosmetics. Burn citronella candles on the patio.
Remember that the source of the insects is the river, so it won't help to spray your yard. Black flies stay on the water until they are adults. Then they leave to find a blood meal so the female can reproduce. They are strong fliers and roam many miles in huge numbers when they are ready to mate. It's next to impossible to avoid being bitten unless you cover yourself up and use repellents when you go outside.
PA-DEP has a website where you can register a complaint once black fly season begins. If they get enough complaints, they will send a biologist to investigate and take samples. Then they will contact the County Commissioners about joining the program to control black fly. Right now 34 counties in Pennsylvania are participating. Neighboring counties include Luzerne, Schuylkill, Lehigh and Northampton.
An ironic fact is that black fly is a sign that our rivers are getting cleaner. When the Lehigh was polluted by old coal mine seepage, the black fly couldn't breed in the water. The same thing is true of the Susquehanna and the Delaware and other river basins in Pennsylvania.
Early Pennsylvania settlers were plagued by black fly, and then we forgot about it when we dug out the coal and our rivers ran yellow with sulfur from the mines. Now we are cleaning up the rivers and reaping huge recreational and wildlife benefits. And along with the benefits comes the black fly.
You can contact the PA-DEP Black Fly Suppression Program if you experience black fly problems. There is a button for their contact information on their home page. There is also a link that takes you to a complaint form you can fill out if you prefer.
To reach the PA-DEP website for more information, search "PA-DEP black fly", or contact your Penn State Extension office at 570-325-2788 and ask them to send you a brochure.