Heavy rain and flooding after a severe drought can lead to an increase in mosquito populations and a higher risk of mosquito-borne disease. With your help, we can work together to reduce mosquito populations and keep our communities safe and healthy.

Although different species and life stages come out at different times of the year, in Marin and Sonoma counties, ticks can be found year-round. We often say that November 1st is the start of the adult season for the western black-legged tick, which usually corresponds with the first rain of the season. The nymphs of this species (Ixodes pacificus) start to emerge more in the spring. However, it…

Composting is a great way to manage your waste. Not only will you be sustainably recycling the food scraps and yard trimmings you generate all year long, but you will also have nutrient-rich soil for your garden. If not done properly, however, composting can result in major rodent issues in and around your home.

Rats aren’t necessarily picky about where they take up residence. If they have water, shelter and food, rats will survive. However, they are more likely to enter your home during the winter months as they are seeking protection from the inclement weather. So, how do you know if you are sharing your home with rats? 

Nearly 10 years ago, two invasive mosquito species (Aedes albopictus, the Asian tiger mosquito, and Aedes aegypti, the yellow fever mosquito) were first detected in central and Southern California. Since then, they have slowly spread throughout the state, making their way as far north as Shasta County and as close to our region as Contra Costa County. These invasive mosquitoes are not native to…

Lack of rain does not necessarily mean a lack of mosquitoes. In residential areas, utility vaults and the catch basins that allow rainwater to drain into sewer systems have long been recognized as problematic sources of mosquitoes. Landscape irrigation often flows into these vaults and catch basins because of over-irrigation or incorrect placement of sprinkler head nozzles. Because they are shaded…

Mosquitoes are more than just a nuisance. Not only can their bites cause severe allergic reactions, but they can also spread debilitating diseases that can sometimes be fatal. In fact, mosquitoes are responsible for more than one million deaths per year worldwide.

​It’s spring, and that means many people are starting their yearly process of planting their gardens. A garden can be a smorgasbord for rodents, attracting them from near and far. Some rodents may take a meal and move on, while others may decide to take up residence in and around your home. While it can be difficult to completely rid your garden of rats, there are ways to make it less inviting to…

Humans aren’t the only ones that can get diseases from mosquitoes and ticks—your pets can too! Pets are important members of your family and rely on you to help keep them happy and healthy. Here are a few ways you can protect your pets from diseases transmitted by mosquitoes and ticks.

Have you ever thought about your own backyard when it comes to protecting yourself and your pets from ticks? Most backyards aren’t prime habitat for ticks, but if your property backs up to open space or you have a large parcel that is overgrown or allows access to wild animals, you may encounter ticks. Ticks prefer to live in shady, humid areas such as leaf litter, tall grass and overgrown…

Ixodes pacificus, the western black-legged tick, is not deterred by the cold weather we have been experiencing lately in the North Bay. In fact, last week our Scientific Programs Manager came across several of these ticks while conducting tick surveillance in 44 degrees temperatures! As long as it’s not below freezing and there is no snow on the ground, these ticks will be active.

Each year we receive hundreds of calls seeking advice on how to control or prevent rodent issues in and around homes. Here are answers to the five most common questions to help you navigate your way to a rodent-free property.

In our last newsletter we discussed how yellowjackets have a knack for ruining backyard barbeques, so we would be remiss if we didn’t mention another party crasher - the mosquito.

Nothing ruins a relaxing backyard barbecue more than an army of yellowjackets trying to get a bite of your juicy, protein-packed meal. Well, nothing except for mosquitoes looking for a blood meal—but that is a topic for another time!

Mosquitofish (Gambusia affinis) were first introduced into California for the control of mosquito larvae in the 1920’s and continue to be an important biological control measure to this day. These fish are routinely used by our vector control technicians to control mosquito larvae in backyard water sources, water troughs, neglected swimming pools and other artificial containers that are at least…

The Marin/Sonoma Mosquito and Vector Control District (the District) maintains a multifaceted surveillance program for viruses transmitted by mosquitoes, including West Nile virus, St. Louis encephalitis virus, and western equine encephalitis virus. Both active and passive surveillance techniques are used to detect and measure the density of mosquito populations and estimate the intensity of virus…

Are your water conservation methods producing mosquitoes?

Throughout the year, District laboratory staff collect ticks of different species and life stages from trails in state, regional, and local parks and recreation areas around Marin and Sonoma counties. Collected specimens are identified and separated by species, sex and life stages to be tested for pathogens when appropriate. The three main species collected by the District are Dermacentor…

Meet Dr. Kelly Liebman, Scientific Programs Manager at the District! Kelly has been studying and working with vector-borne diseases for more than 15 years. With an educational and professional background in public health and entomology, she joined the District in April 2018 after working as a biologist with the California Department of Public Health, Vector-borne Disease Section.

Spring is the prime time for the emergence of the western treehole mosquito, also known as Aedes sierrensis. As the name suggests, these mosquitoes lay their eggs in the cavities of oak, bay, and several other types of trees. Treehole mosquito larvae can also be found in discarded tires or containers where plant debris and water has accumulated. Residents living in areas with dense populations of…

Rodents aren’t picky about where they take up residence. They can be found in well-maintained homes, yards with overgrown vegetation, and homes with cluttered living spaces. As long as they have water, shelter and food, rats will survive.

You are cozy and warm in your bed, having just dozed off to sleep, when you are suddenly awakened by the buzzing sound of a mosquito in your ear. You jump out of bed and turn on the lights, only to realize that the mosquito has disappeared! You weren’t imagining it--there was a mosquito buzzing in your ear, but because of its tendency to feed in the dark, it hides when the lights are on.

Rain barrels that are not screened or are improperly maintained can become a major source of mosquito production. One rain barrel has the potential to produce thousands of mosquitoes, causing major issues not just for you, but also for your neighbors.

November 2020-Ticks are active year-round in Marin and Sonoma counties. Ticks are blood-sucking arthropods that can transmit a variety of diseases such as Lyme disease, Rocky Mountain spotted fever, tick-borne relapsing fever, tularemia, anaplasmosis and ehrlichiosis. Not all tick species are created equal, so let’s take a look at the differences between the three most commonly encountered tick…

September 2020-The primary mission of the Marin/Sonoma Mosquito and Vector Control District is to protect public health from mosquitoes and vector-borne disease through education, source reduction, performing surveillance, and directly managing mosquito populations so they don’t present a significant health risk. However, we cannot do this alone. We need your help.

August 2020 - Most people associate rodent infestations with dilapidated homes covered in overgrown vegetation and junk strewn all over the yard, but the truth is that rats aren’t picky about where they take up residence. Rats are just as likely to be found in well-maintained homes with picture perfect yards as those that are unkempt and in disarray. As long as they can find water, shelter and…

July 2020- One of the most commonly asked questions we receive this time of year is, “How do I locate an underground yellowjacket nest?” Locating underground yellowjacket nests can be a challenge that requires time and lots of patience, but it can be done. 

June 2020-Some people may say if you have seen one mosquito you have seen them all but, mosquitoes are much more complex than people give them credit for. In Marin and Sonoma counties we have over 20 different species of mosquitoes, each with their own characteristics such as host preference, biting time, flight distance, vector competence, seasonality of emergence, and preferred habitat type.

June 2020-As we all navigate the challenges of daily life and adapt to the new normal presented to us by the COVID-19 pandemic, one thing remains the same: mosquito control continues to be essential.

May 2020- During this time of year, the District receives numerous calls from the public regarding large swarms of mosquitoes in backyards and along bike trails. Fortunately, these swarms of insects are not mosquitoes, but non-biting midges.

May 2020- The name “Asian giant hornet” (Vespa mandarinia) is pretty descriptive—it accurately reveals the insect’s origin, size and the fact that it is a “true” hornet (a member of the genus Vespa). There are definitely examples of confusing or misleading insect names that perhaps should be altered (see example below), but in this case, the perfectly descriptive (and formidable) common name was…

March 2020 - Per the California Department of Public Health and Centers for Disease Control and Prevention, the District is taking the following proactive measures to reduce the spread of COVID-19:

February 2020 -Throughout the year, District laboratory staff collect ticks of different species and life stages from trails in state, regional, and local parks and recreation areas around Marin and Sonoma counties. Ticks are collected by dragging a one meter square flannel flag on the ground and in the vegetation along trails. Collected specimens are identified and separated by species, sex, and…

With the rainfall the North Bay experienced this past month we thought it was the perfect time to start talking about rainwater harvesting.

The last thing on people's minds during the winter is mosquitoes. In fact, most people think that mosquitoes just disappear this time of year. The truth is that mosquitoes can be found year round in Marin and Sonoma counties, and there is even one whose common name is the winter mosquito.

Rodents aren’t picky about where they take up residence. They can be found in well-maintained homes, as well as in yards with overgrown vegetation and homes with cluttered living spaces. As long as they have water, shelter and food, rats will survive.

Heavy rain and flooding can lead to increased mosquito production. With more water comes more mosquitoes and a higher risk of mosquito-borne disease. Early prevention can reduce mosquito numbers as the weather gets warmer.

Februry 2019-This year’s tick season is in full swing. With the heavy rains over the past few months, the adult ticks have been hiding out and staying dry, waiting for the sun to shine and their hosts to walk by!