Santa Cruz County Mosquito and Vector Control is a division of the County Agricultural Department and has been protecting public health for 25 years. As a public health agency, we monitor and control organisms that can transmit diseases to humans (also known as “vectors”).

Vectors are living organisms that can transmit infectious pathogens between humans, or from animals to humans. Examples are mosquitoes, ticks, fleas, flies, and rodents.

We monitor mosquitoes by using specialized traps and by sampling water sources throughout the county. We control mosquitoes based on mosquito species (transmit disease) and their proximity to human populations. We try to treat mosquitoes while they are larvae (immature aquatic stage) to prevent them from developing into adults that can fly around, bite people, and spread disease.

Fish, frogs, spiders, water beetles and dragonflies are excellent mosquito predators and help control mosquito populations, especially while still in larval form in the water. However, mosquitoes often hatch in large numbers before predators like frogs can catch up and eat them—mosquitoes have a very quick lifecycle (~1 week from egg to adult in warm weather).

Bats prefer to eat larger flying insects (like moths), so public health pest managers do not believe that bats substantially contribute to mosquito control. Studies of wild bats have shown that mosquitoes make up less than one percent of their diet. More importantly, bats can transmit rabies to people and animals. In the most recent report for California, most of the rabies cases (85%) were due to exposure to bats. Promoting bat colonies increases the risk of human and bat contact, and they may leave bat boxes in winter and can nest in attics. Learn More

The California Department of Public Health recommends using insect repellents containing the ingredients DEET, picaridin, IR3535, oil of lemon eucalyptus or para-menthane-diol for long-lasting protection. If using sunscreen and insect repellent, apply sunscreen first and then the repellent. It is recommended and safe for pregnant women, and women who are breastfeeding, to use an EPA-registered insect repellent according to the product label. Do not use insect repellent on infants less than two months of age. Oil of lemon eucalyptus is the best all-natural repellant but is only for ages 3 and up. Consult the labels before use. Learn More

The Santa Cruz County Mosquito and Vector Control Department controls yellowjacket and wasp nests on public property within the county. If a nest is on private property, we can offer tips to residents for controlling at home and/or a list of certified Pest Control businesses for hire that can eliminate the nest. If it is a honeybee nest that has formed, we will contact the Santa Cruz Bee Keepers Guild to remove the nest and re-hive the queen at another location. Click Here to submit a Service Request.

We use (Environmental Protection Agency) EPA-registered products that are applied directly to the water by trained and certified technicians. The applications are localized and stay on the water source. The products we use are specific towards the aquatic, larval stages of mosquitoes and pose very little risk to people, animals or fish.

We would treat flying adults when they become a threat to public health (according to state response guidelines). Large-scale adult treatments, or foggings, would need prior approval by the County Health Officer and Board of Supervisors.

We focus on controlling mosquitoes in their immature, or larval, stages found in stagnating water before they hatch into flying adults.

Most of the larval control products we use are organic and listed by the Organic Materials Review Institute-OMRI (labeled for use on organic farms). As a public health agency, we use multiple EPA-registered pesticides to protect public health and to combat resistance to those products.

Our technicians are trained and certified to ensure the best possible use of pesticides that protect public health. We use integrated mosquito management methods to ensure the most appropriate solution to each mosquito problem, emphasizing water management, source reduction and bio-control and will do what is needed to protect the community and the environment.

You can find mosquito control products at your local garden or hardware store or online for larger water sources around the yard, such as bird baths, ponds and fountains. The active ingredient in these products is the same as what we use and are derived from natural soil bacteria, Bacillus thuringiensis israelensis (Bti). It contains spores that produce toxins that specifically target and only affect the larvae of the mosquito, blackfly and fungus gnat. EPA has concluded through numerous studies it does not pose a risk to humans.

For larger sources, like a fountain or horse trough, that cannot be emptied and refilled on a regular basis, we can offer mosquito eating fish to residents free of charge. For other containers around the yard, dump and drain once a week! Learn More

  1. Use clean, fine-tipped tweezers to grasp the tick as close to the skin's surface as possible.
  2. Pull upward with steady, even pressure. Don't twist or jerk the tick; this can cause the mouth-parts to break off and remain in the skin. If this happens, remove the mouth-parts with tweezers. If you cannot remove the mouth easily with tweezers, leave it alone and let the skin heal.
  3. After removing the tick, thoroughly clean the bite area and your hands with rubbing alcohol or soap and water.
  4. Never crush a tick with your fingers. Dispose of a live tick by:
    • Putting it in rubbing alcohol,
    • Placing it in a sealed bag/container,
    • Wrapping it tightly in tape, or
    • Flushing it down the toilet.

If you can remove the tick with most of it still in one piece and not crushed, you can send a picture of it to PestHelp@santacruzcountyca.gov, submit a service request or call (831) 454-2590 to set-up a time to drop it off at our office. We can identity if it is the species that can carry the bacteria that causes Lyme disease and consult about testing it and early symptom warnings.

Yes, ticks in Santa Cruz County can carry the bacteria that causes Lyme disease, known as Borrelia burgdorferi. Learn More

Santa Cruz county recently passed all other counties with the highest incidence rate of Lyme disease in the state at an average of 3.4 confirmed cases per 100,000 residents each year from 2014-2023.

Exclusion is key! Your home needs to be properly sealed up from the outside to ensure the rodents cannot make it to the inside. Closing gaps around the home is essential as rats only need about a hole the size of a quarter to squeeze through while mice can fit through a gap the size of a dime. Clearing clutter from around the exterior of the home will remove hiding and nesting places.

Our department provides inspections of the exteriors of homes free of charge. Our technicians are trained and certified to find nesting areas and entry points into the home and can offer recommendations to remediate the issues. Learn more about our services here, or here to make a Service Request.