This table shows the number of acres treated with larvicide during September and October. The number of acres treated is drastically lower in October compared to September, largely from the marshes and impounds category. Helicopter treatments were not conducted during the month of October, which is a large part of summer acreage treated. Also, after a dry summer and mostly dry autumn thus far, there is less standing water throughout the county. Creeks and catch basins are continuously treated in summer.
This table contains the number of each type of service request in October 2018 compared to the three-year average in October. Total number of service requests are above average, mainly because of yellow jacket and wasp requests. Dead birds were also somewhat higher than average this October.
The table and graphs below show the average number of mosquitoes collected per CO2 trap per night during the month of October, compared to the five-year average for the six most common mosquito species in San Mateo County. Counts for all species are averaging below ten per trap, which is consistent with the five-year average. Although Culex pipiens had a late peak in September, it has returned to normal levels, and we expect it to further decrease through the colder months.
Every year the District collects ticks from recreational areas in the county to assess the risk of tick-borne disease. One way to measure this is by determining the minimum infection prevalence (MIP), which estimates what percentage of these ticks are expected to be carrying a given disease agent in a population. The laboratory has completed testing for two vector-borne diseases from ticks collected from November 2017 to May 2018.