L.A. Battles Year-Round Mosquitoes With Sterile Male Releases

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To curb the invasive Aedes aegypti mosquito that can carry dengue fever, officials in Los Angeles County are releasing sterilized male mosquitoes in a process called the sterile insect technique. The approach has shown promising results, with female mosquito populations dropping by over 80% in test neighborhoods. However, funding to expand the program across the entire county is uncertain as business owners have been reluctant to pay higher fees to support the effort.

Why it matters

The Aedes aegypti mosquito is a growing problem in Los Angeles, as it can transmit dangerous diseases like dengue, Zika, and chikungunya. The sterile insect technique offers a pesticide-free way to control the mosquito population, but securing the necessary funding from property owners has proven challenging, threatening the ability to scale the program and protect more communities.

The details

The Greater Los Angeles County Vector Control District is preparing to release its third round of sterilized male Aedes aegypti mosquitoes in the Sunland-Tujunga neighborhoods this May. The district uses X-rays to sterilize the male mosquitoes, which are then released to mate with wild females, producing eggs that don't hatch. The last two years of the pilot program saw an average 82% drop in female mosquito populations in the treated areas. However, expanding the program to the district's full service area of 36 cities and unincorporated communities would require a new fee of up to $20 per single-family home, on top of the existing $18.97 fee. A recent ballot measure to approve the new fee was only supported by 47% of respondents, with business owners in particular opposing the additional cost.

• The Greater Los Angeles County Vector Control District is set to release sterilized male mosquitoes for the third year in a row this May.
• In 2024, the district launched its initial pilot program, releasing nearly 600,000 sterilized male mosquitoes over about five months.
• Last year, the pilot program saw similar success in reducing female mosquito populations, though there was also a natural drop in activity districtwide.

What they’re saying

What’s next

The Greater Los Angeles County Vector Control District plans to send out another round of sample ballots next year to property owners, seeking approval for a new fee to expand the sterile male mosquito release program across the entire county.