Southern California: heat halves mosquito breeding cycles; Altadena and Monterey Park get emergency treatments on 7–8 October 2026 to cut West Nile virus risk

ABC7 Los Angeles (KABC) reported on 7 October 2026 that mosquito control treatments would be carried out on Wednesday and Thursday (7 and 8 October 2026) in Altadena and Monterey Park, Southern California, to reduce mosquito numbers that have surged during an intense heat wave and to lower the risk of West Nile virus.

Main points

• Crews use ultra-low volume (ULV) adulticide and low volume larvicide applications to target mosquitoes at several stages of their life cycle.
• According to the report, the extreme heat has cut breeding cycles in half. Mosquitoes stay very active in a heat wave even without rain, because they need only a spoonful of water to lay eggs.
• Anais Medina Diaz, communications director of the San Gabriel Valley Mosquito & Vector Control District, said bug zappers “do not work” and kill many beneficial insects; it is much easier to kill hundreds of larvae in the water than one mosquito that is already flying, which is why the district focuses on tipping and tossing standing water.
• Health officials advise removing standing water from rain gutters, old tyres, buckets and anything that holds water for more than a week, including pet dishes, bird baths and drip trays under indoor and outdoor plants; keeping pools, spas and ponds maintained; and using repellent outdoors.

VPMA’s note

A real example of combining adult mosquito control with larval control when the weather favours a mosquito surge. The message that “killing larvae is easier than killing flying mosquitoes” and the advice not to rely on electric bug zappers are also useful when members advise household customers in Vietnam.

Source: ABC7 Los Angeles – Extreme heat accelerates mosquito breeding, prompts emergency spraying amid health concerns (summarised in English by VPMA). Read the Vietnamese page.

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