The District currently uses a helicopter to treat three freshwater marshes: Annex Lake (Stanford property), Mills Field (SFO property), and Sharp Park Golf Course.

At each of these locations, only the water is treated.

Helicopter treatments are scheduled as needed. You can find upcoming treatments listed on our calendar. We conduct an average of four treatments per year.

Treatments may be cancelled or postponed on short notice due to unfavorable weather conditions

The product used is a bio-rational mosquito larvicide. It is in a solid granular form. We use this product because it affects only mosquito larvae; it does not pose any significant risk to humans, pets, wildlife, fish, or the environment.

You may see or hear a helicopter in the area of the larvicide treatment.

For Annex Lake and Mills Field, there will be no closure of public areas for the helicopter treatment.

For Sharp park, sections of the levee between Beach  Blvd. and Mori Point will be closed briefly (5-10 minutes at a time) to allow the helicopter to land safely. The beach, golf course, and Mori Point will NOT be closed during the treatment.

Treating these areas by helicopter allows the product to be dropped directly into the water in areas of dense vegetation. It also allows us to eliminate the environmental impacts created by walking or using other equipment in these sensitive aquatic environments.