Products used to control mosquito larvae are called larvicides.
The District mainly uses three different types of larvicide, plus
one mosquito predator:
BVA-2 Oil: A refined petroleum
distillate that breaks down in a few days. It is applied to the
surface of standing water and causes mosquito larvae to drown.
Mosquito larvae are only found in standing water, so mosquito
larval control products are applied to water. These products are
often applied by hand to small areas, such as backyard ponds and
catch basins.
The District uses a helicopter to apply solid granular larvicide
to larger areas where there is dense vegetation or where applying
the product on foot might harm sensitive wildlife and habitats.
Currently, a helicopter is used at Annex Lake, Mills Field, and
Sharp Park golf course.
Even very small amounts of water can provide enough space for
mosquito larvae. Some mosquito species need as little as a bottle
cap full of water to reproduce!
How long does it take for mosquitoes to breed?
Under the right conditions, it can take as little as a week for
mosquito larvae to emerge as adults. In general, warmer weather
means faster development.
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.
When do helicopter treatments occur?
Helicopter treatments are scheduled as needed. You can find
upcoming treatments listed on our
calendar. We conduct an average of four treatments per year.
