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Black Flies

Educational poster about black flies, with a close-up image of a fly and a natural background.

What You Need to Know About Black Flies 🔊

The are naturally occurring in flowing water 💦 THINK: fountains, rivers, ponds, streams, cascades, & irrigation ditches

They fly in great numbers 😲

They bite around the eyes 👀 & neckline of humans & domestic animals 🐕🐈

Their bites are painful😖, but they do NOT transmit diseases in LA County 

May contain: invertebrate, animal, and insect

What You Can Do 🙌🏽

Wear repellent on exposed skin to stop the bites 👍🏾

Turn OFF personal water features for 24 hours once a week 🚫💦

** Don't forget to turn water back on to prevent mosquitoes 🦟using the stagnant water .

What We Do 🦸‍♀️🦸‍♂️

Our agency monitors and controls known sources of black flies in rivers, streams, and any other areas that's accessible to our staff. New breeding sites can develop when a new source of running water is introduced. This can occur if there's new water releases from the local dam or there's an unmaintained fountain or man-made waterfall in a yard.

What Does a Black Fly Look Like? 🤔💭

May contain: insect, invertebrate, and animal
Closeup image of an adult black fly.
bug lifecycle
  1. EGGS - The female deposits 200-500 fertilized eggs in or on flowing water.
  2. LARVAE - Larvae emerge and attach themselves to rocks or foliage under the water and feed on organic debris that flow by.
  3. PUPAE - In 7-10 days the larvae will pupate under water. 
  4. ADULT - Adults will emerge from the pupal case and float to the surface inside a bubble of air.
May contain: water, nature, outdoors, river, and stream
Take a closer look at actual larvae attached to rocks in flowing water.