Midge Flies, chironomids are commonly found in man made lakes, wastewater facilities and streams with high nutrient content. These flies are similar in appearance to mosquitos, yet do not bite. The midge fly larvae (known as blood worms) feed on the organic debris at the bottom of the body of water and provide a food source for fish and predatory insects. (Apperson ¹)

These flies are a nuisance to people who live and work near man-made lakes and in Gilbert, recharge facilities. The warm winter temperatures this year created an early midge fly season. Under normal circumstances, staff is able to dry up the basins as the weather warms up. Unfortunately, the nights were warm enough during the winter to allow the midges to hatch before our water demands increased at the customer sites (which reduces flow to the recharge basins). So, Gilbert has been out of balance at the South Recharge Facility.

Gilbert's Efforts to Mitigate Midge Flies:

Gilbert is making every effort to prevent and treat midge flies and mosquitoes, especially at the South Recharge Facility where they are most evident. We are actively treating the South Recharge Facility with larvicide, fish that prey on larvae, application of dish-soap spray to vegetation and night-time fogging three times per week, which is the maximum based on EPA standards for the product being used.

Gilbert is also redirecting a portion of the reclaimed water towards the north side of town to other customers and recharge facilities in order to minimize the amount of water going to the South Recharge Facility. To help prevent midge flies and mosquitoes long-term, Gilbert is planning to perform some enhancements this summer when the basins are accessible at the South Recharge Facility. 

How You can Prevent Midge Flies and Mosquitoes:

• Eliminate standing water from your property 

• Keep swimming pools treated and circulating 

• Keep fountains operating or drain the water 

• Repair leaky pipes and outside faucets and sprinklers 

• Replace your outdoor lights with yellow “bug lights” 

• White or Apple Cider Vinegar mixed 1:1 with water can also be an effective, natural insect repellent.

Apperson, Charles. “Biology and Control of Non-Biting Aquatic Midges.” Residential, Structural and Community Pests. North Carolina State University, July 2006.Insect Notes.5/8/2014. www.ces.ncsu.edu/depts/ent/notes/Urban/midges.htm