FCPH has built their mosquito program based on principals of integrated pest management (IPM).  IPM is a comprehensive approach to pest management that focuses on prevention, education, and controlling pests at their most vulnerable stage while minimizing hazards to the environment.

Central to IPM is pest identification.  FCPH has an extensive surveillance network to monitor numbers and species of mosquitoes in its service areas.  We set over 150 mosquito traps per week (3 different types of traps) from mid-May through the end of September.  We then test mosquitoes from each of our 63 zones each week for West Nile virus. Find our trap data here.

FCPH educates residents about the diseases that mosquitoes can spread.  We also promote ways they public can protect themselves from bites and reduce mosquito numbers in their own yard.  Preventing mosquitoes from laying eggs in standing water in the first place is the most effective way to control mosquitoes.  Find more prevention tips and resources here.

FCPH routinely monitors and inspects hundreds of sites where we know mosquitoes breed.  We apply larvicides to standing water which control mosquitoes at their most vulnerable development stage.  We also encourage the public to alert us to areas of stagnant water through our service request form.

Responsible pesticide application does have a role within IPM.  FCPH will make decisions to spray an area by truck based on surveillance data collected from our mosquito traps.  In accordance with IPM, we have set action thresholds that must be met before we will consider spraying an area.  These action thresholds include presence of West Nile infected mosquitoes and high numbers of mosquitoes.  We do not spray whole areas by truck based on complaints alone.

FCPH and its service contractor Clarke Environmental Mosquito Management began expanding the use of Organic Material Review Institute (OMRI) listed products in 2019.  OMRI listed products are approved to be used on organic gardens and farms as they contain no synthetic active ingredients.  Find out more about OMRI here.

For each class of product we use we make sure to have a variety that contain different active ingredients.  It is important to rotate the active ingredients we use to prevent our local mosquito population from developing resistance to them.  Each year we test our mosquito population for pesticide resistance using the CDC developed bottle bioassay.  We test for resistance for all active ingredients that our program uses as well as others that we know other industries apply that may impact mosquitoes in our area.

Larvicides are applied to standing water to prevent mosquito larvae from developing into flying and biting adult mosquitoes.  Most larvicides are very specific to only harm mosquitoes and come in a variety of formulations for different mosquito larval habitats such as temporary floodwaters, roadside ditches, rain barrels, and catch basins.  Different formulations have varying residual effects from a one time application to 180 days of continuous mosquito control. Here is a list of all the larvicides we may potentially use in our program.

*Indicates the product is OMRI listed.

Natular G*

Natular G30*

Natular DT


VectoBac WDG*

VectoLex FG

FourStar Briquet-180

Adulticides are designed to kill flying adult mosquitoes and are applied using a ULV (ultra-low volume) truck mounted sprayer. We use electric sprayers that are quieter and produce less emissions than traditional gas-powered sprayers. They are calibrated monthly to ensure that the flow rate and droplet size are within the range indicated on the product label. In addition to the low application rate and tiny droplet size, we only apply after sunset to minimize our impact on insects other than mosquitoes. All mosquito adulticides we use are required to have minimal residual effect to further protect beneficial insects such as pollinators that will be out the next day. The active ingredients for all adulticides below are natural pyrethrum derived from chrysanthemum flowers or a synthetic version of that active ingredient called pyrethroids.

*Indicates the product is OMRI listed.

Merus 3.0*


Biomist 3+15

We occasionally apply barrier treatments to vegetation in yards during service requests to reduce the number of adult mosquitoes when deemed necessary. We apply these products using backpack sprayers and take care to avoid any blooming plants to protect pollinators. Barrier treatments provide residual control for up to 2-3 weeks.

Flit 13.3

Talstar P