Borrego Sun - Since 1949

San Diego County’s Vector Control program is scheduled to drop solid, granular larvicide on 48 local waterways for the fifth time this year on Wednesday to kill mosquito larvae before they can grow into biting adults.

Vector Control uses a helicopter to treat the rivers, streams and other waterways in a single day, weather permitting. The program treats the waterways roughly once a month from April or May through October to help control mosquito populations and protect the public from mosquito-borne illnesses like West Nile virus.

The solid larvicide the County uses is harmless to people and pets but deadly to the mosquito larvae that eat it. The waterways stretch from Chula Vista in the south to Fallbrook in the north and from Oceanside in the west to Lakeside in the east, totaling just over 1,000 acres.

In addition to the monthly larvicide drops, County Vector Control treats another 1,400 potential mosquito-breeding sources across the county by hand during the course of the year. It also gives out free mosquito-eating fish to the public, tracks down and treats neglected green swimming pools, tests dead birds for West Nile virus and monitors cases of other potential mosquito-borne illnesses, including Zika virus, chikungunya and dengue.

West Nile virus has become a part of the county’s environment since it first arrived here in 2003. In 2016, 22 San Diego County residents tested positive for the virus, and two people died.