From paths and backyards along the L.A. River in Atwater Village and Elysian Valley to the hills of Elysian Park and the ball field at Dodger Stadium, swarms of Black Flies – or Buffalo Gnats – have been once again buzzing, bothering and biting people as well as animals. It’s not clear if this year’s infestation is worse than previous years, but the Greater Los Angeles County Vector Control District, the agency that deals with mosquitoes and other insects that pose public health problems, has been treating the L.A. River and areas near Dodger Stadium for Black Flies, said agency spokesman Truc Devor.
“We began seeing more activity near the Dodger Stadium area in mid-March and have been treating on a weekly basis,” Dever said in an email. “The full length of the river is monitored regularly by our Vector Control Specialist and Vector Ecologist. We believe that with the current control activities we’re conducting and with trends we’ve seen in black fly development over the years, residents should be seeing relief soon.”
The flies do not spread disease. But the bites by the females, which suck blood from people as well as animals, can be painful and also cause swelling and itching. Even Dodger players are not immune, with some team members over the years using Avon’s Skin So Soft lotion and other remedies to fight off the flies and other insects.
To deal with the problem, property owners within two miles of a section of the L.A. River and the Arroyo Seco pay an additional 15 cents to finance Black Fly treatment programs.
Workers with the agency treat the river on a weekly basis with Bacillus thuringiensis israelensis (Bti), a pesticide used to control black flies, mosquitoes, and other insects that breed along rivers. “It affects the mid-gut of the larvae once ingested and interferes with normal digestion,” said Dever “This triggers the insect to stop feeding. Bti is applied directly to the water in very low doses. Bti has very low toxicity and is one of the safest control products on the market.”