On Friday, Santa Clara County plans to soar over the Palo Alto Flood Basin – an area known as a breeding ground for mosquitoes this time of year – to release certain bacteria in the soil that inhibit mosquito maturation.
The county’s Vector Control District, established to fight diseases transmitted to humans from parasites and other wildlife, is scheduled to fly low in a helicopter at around 7:30 a.m. on Friday to spray the area. According to the district, the process is expected to take a few hours.
“We follow the best practices recommended by the Environmental Protection Agency for mosquito management,” said Dr. Nayer Zahiri, district vector control manager, in a district press release on Wednesday. “These efforts have been shown to be safe and effective for over 25 years.”
The target of interest is the winter salt mosquito (Aedes squamiger), one of more than 50 species of mosquitoes that inhabit California. These particular mosquitoes are known as the vicious day-biters and are more than 15 miles away from their breeding grounds. From mid-February to mid-March they become full adults. To do this, however, they feed on the microorganisms that occur in the swamp areas, hence their common name, the winter salt swamp.
This is where people from the vector control district will step in to treat the area with a bacterium found in the soil known as Bacillus thuringiensis var. Israelensis (also known as Bti) and methoprene, a common ingredient in sprays for domestic insects that regulates their growth. As soon as mosquito larvae feed on the bacteria, they are prevented from growing up.