Yellowjacket nest treatment is a popular service during the summer months. If you know where the nest is, District staff can treat the nest.

Culex erythrothorax, a mosquito that breeds in lakes and ponds with tules, was the most frequently collected mosquito in July. The high number of tule mosquitoes this month reflects a large, seasonal emergence of this species in Pacifica. Adults of this species are usually present from around April through October. Seasonal helicopter treatments for this mosquito began in July, which modestly reduced total abundance since June, but counts remain high. Culex pipiens, the northern house mosquito and typically the most abundant mosquito in San Mateo County, increased in numbers during July, but abundance remains below average for this time of year, likely because of dry weather and cool nighttime temperatures in San Mateo County.

The total number of service requests is close to average for July (527 compared to an average of 540). Yellowjacket and other wasp requests increased dramatically for the second month in a row, from 34 in May to 174 in June to 367 in July. Yellowjacket and wasp requests are common in the summer and will likely remain numerous until the weather cools in autumn. The number of mosquito service requests is lower than average, likely because of a low abundance of Culex pipiens, which usually prompts the most mosquito requests. Dead bird requests have increased as well, from nine in June to sixteen in July, as West Nile virus has become more seasonally active in California. Fortunately, West Nile virus has not been detected in San Mateo County or any neighboring counties this year through the month of July. The category of “other” included a variety of request types, such as bumblebees, fleas, cockroaches, flies, mites, and ticks.