Aerial mosquito larvicide treatments

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About
Aerial treatment schedule
Products used
Treatment locations
More information

About

The Vector Control Program routinely uses a helicopter to drop small grains of mosquito larvicide into areas of standing water know to breed mosquitoes.

We treat most areas by hand or by truck (about 1600 sites countywide), but use a helicopter for hard-to-reach areas of standing water that can't be treated from the ground.

These treatments protect our communities by lowering mosquito numbers, which helps to decrease the risk of West Nile virus in San Diego County.

Aerial mosquito larvicide drops occur every three to four weeks during the mosquito breeding season, generally April to October. Signs will be posted at treatment locations. Vector Control Program staff are on site before, during, and right after the treatments to answer questions and track progress.

If you would like to sign up for e-mail reminders of scheduled aerial treatments, subscribe here.

Aerial treatment schedule - 2025

April 23 (and 24 if needed)
May 14 and 15
June 4 and 5
June 25 and 26
July 16 and 17
August 6 and 7
August 27 and 28
Sept 17 and 18
October 8 and 9 (if needed)

Treatment dates are subject to change depending on conditions.

Products used

Bacterial larvicides are made of different natural bacteria and natural substances made by bacteria that kill mosquito larvae but don't harm people, pets, plants, or wildlife. Small grains of the larvicides are used to precisely target areas of standing water and prevent drift.

Product details

Product Name	Active Ingredient(s)	Product Label and Safety data sheet (SDS)
VectoMax	Bacillus sphaericus, Bacillus thuringiensis subsp. israelensis	Label
		SDS
VectoBac GR	Bacillus thuringiensis subsp. israelensis	Label
		SDS
Natular	Spinosad (Saccharopolyspora spinosa products)	Label
		SDS

Treatment locations

The map and table below show potential locations for aerial mosquito larvicide drops. We decide which sites to treat with the helicopter based on mosquito trap counts, environmental conditions, and other factors. Many more sites throughout the county are treated from the ground.

City	Name of Site	Acres
Carlsbad	Las Olas, East Rancho Santa Fe Rd	8
Carlsbad	Las Olas, West Rancho Santa Fe Rd	8
Carlsbad	Laguna Riviera City Park	44
Carlsbad	Evan's Point	8
Chula Vista / San Diego	Salt Creek	8
Chula Vista / San Diego	Otay River, Broadway / Beyer	34
Chula Vista / San Diego	Chula Vista - Hollister Street	48
Chula Vista / San Diego	Otay River, West Hwy 805	44
Chula Vista / San Diego	Otay River, East Hwy 805	36
Encinitas / Solana Beach	San Elijo Lagoon, East	92
Encinitas / Solana Beach	San Elijo Lagoon, West	16
Escondido	Kit Carson Park	8
Escondido	Lake Hodges	20
Fallbrook	Lake Rancho Viejo	12
Lakeside	Lindo Lake	4
Lakeside	Cactus County Park	8
Lakeside	Willowbrook	40
Oceanside	San Luis Rey River, West Capistrano Pk	3
Oceanside	San Luis Rey River, East Capistrano Pk	1
Oceanside	San Luis Rey River, West Douglas Dr	42
Oceanside	Huula Dr.	3
Oceanside	Foss Lake	38
Oceanside	Libby Lake	2
Oceanside	Talone Lake	24
Oceanside	Guajome County Park	34
Oceanside	Antique Gas	10
Oceanside / Carlsbad	Buena Vista Lagoon	112
Rancho Bernardo	Rancho Bernardo Inn Golf Course	4
Rancho Bernardo	Rancho Bernardo Lakes, Salviatia	2
Rancho Bernardo	Rancho Bernardo Lakes, Bel Etage	8
Rancho Bernardo	The Landing	2
Rancho Santa Fe	Goldentop Road	2
Rancho Santa Fe	San Dieguito River - Bing Crosby	4
Rancho Santa Fe	Lusardi Pond	38
San Diego	Watson Ranch	5
San Diego	Sabre Springs	16
San Diego	Lake Kumeyaay	32
San Diego	San Diego River - near Home Depot	12
San Diego	San Diego River - Qualcomm Way	20
San Diego	Dairy Mart Road	70
San Diego	Monument Rd	100
San Diego	Swap Meet	16
San Diego	Tijuana River, Hollister	52
San Diego	Carmel Creek	52
San Diego	Peñasquitos Lagoon	112
San Diego	San Diego Polo Grounds	50
San Diego	Derby Downs	20
San Diego/4S Ranch	Rainsford's Pond/Old Course Rd	5
Santee	San Diego River - Town Center	24
Santee	Carlton Oaks	16
Santee	Sycamore Creek	8
Santee	Chubb Lane	20