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Mosquito Control

The Orange County Mosquito and Vector Control District utilizes many different methods to control mosquitoes. District programs are based on scientifically planned management tactics and control strategies to reduce the abundance of vectors in a timely manner. This method is referred to as Integrated Vector Management (IVM). To learn more about the District's IVM program, click here.

Biorational and chemical control 

The District routinely applies biorational pesticides to control mosquitoes. The term biorational relates to the application of naturally occurring mosquito pathogens and predators in a manner that provides effective mosquito control with the least amount of environmental impact. Currently, the District uses biorationals which include two microorganisms, Bascillus thuringiensis israelensis (Bti) and Bascillus sphaericus, in addition to methoprene, an insect growth regulator.

To learn more about what the District uses, please click here.

Biological Control


The District uses mosquitofish (Gambusia affinis) as biological control agents in water sources that can sustain immature mosquitoes. These fish are not native to California, so they are only used in water sources that do not connect or drain to natural water bodies. Sources that would fall under this category would be unused swimming pools and or spas, ornamental ponds, water troughs, etc.

 To learn more about mosquitofish and to download fish pick-up forms, please click here. 

Physical Control

Physical control or manipulating the environment to reduce mosquito breeding sites is a very effective method of mosquito control. A few examples of physical control include: promoting effective drainage, controlling vegetation and reducing backyard breeding sources.

Source Reduction

Manipulating or eliminating potential mosquito breeding sources can provide a dramatic reduction in mosquito populations. District staff educate property owners as to ways in which they can remove these sources like by emptying containers holding water. Staff also works with large land managers to restore and maintain water flow or circulation in systems that become clogged with sediment and debris or over run with vegetation.

To learn the various ways you can eliminate breeding sources around your home, please click here.