Mosquito Population Four Times Higher Than Normal in the San Gabriel Valley

[UPDATED] Mosquitoes were four times higher in numbers last week in San Gabriel Valley than they were in 2018 and 2019, data from the San Gabriel Valley Mosquito and Vector Control District (SGVMVCD) showed.

The data was reported out Sunday, as Pasadena begins to observe National Mosquito Control Awareness Week, June 21-28. The SGVMVCD obtained from mosquito surveillance traps examined between June 8 and 12 at various sites within the Valley, including Pasadena.

Another local mosquito control agency, the Greater LA County Vector Control District, they have tested mosquitoes collected in Hacienda Heights, the second largest census designated place in Los Angeles County, positive for carrying West Nile virus.

In Orange County, mosquito control officials confirmed they are detecting five times the average mosquitoes in their surveillance traps compared to 2019.

To prevent the spread of mosquitoes and mosquito-borne diseases, the SGVMVCD advocates for three simple steps that residents should practice: Tip, Toss and Protect – Tip out stagnant water, Toss unused containers that can collect stagnant water, and Protect yourself from mosquito bites by using repellent.

During National Mosquito Control Awareness Week, the American Mosquito Control Association (AMCA) is putting emphasis on the three Ds to keep mosquitoes away: Drain, Dress and Defend – which means draining or emptying out water containers at least once per week; dressing in long sleeves, long pants, and light-colored, loose-fitting clothing; and defending by properly apply an approved repellent such as DEET, picaridin, IR 3535 or oil of lemon-eucalyptus.

To make your yard a mosquito-free zone, AMCA says you should dispose of any old tires that can breed thousands of mosquitoes, drill holes in the bottom of recycling containers, clear your roof gutters of debris, and clean pet water dishes regularly. You should also check and empty children’s toys of possible stagnant water, repair leaky outdoor faucets, and change the water in bird baths at least once a week.

“Encouraging your neighbors to also eliminate sources on their own property is critical to a community-wide control program,” Joseph Conlon, AMCA Technical Advisor, said. “Mosquitoes require water to complete their life cycle. If their water source is eliminated, so are their offspring.”

As to mosquito-borne diseases, West Nile virus remains to be the biggest threat to residents. Vector control officials, however, are also concerned about aggressive, day-biting Aedes mosquitoes that can transmit Zika virus, dengue fever, yellow fever and chikungunya.

No local outbreaks of these viruses have been reported in the San Gabriel Valley, but the presence of Aedes mosquitoes increases the risk, the SGVMVCD said.

For more tips on helping stop the spread of mosquitoes and mosquito-borne diseases, visit www.sgvmosquito.org.