Pest Information: Mosquitoes

Mosquito feeding on a humanMosquitoes are one of the most common and important bloodsucking insects. The adult female mosquito feeds on the warm blood of mammals (including man) and birds and on the cold blood of fish, reptiles and amphibians. Mosquitoes are one of the most important public health pests due to vectoring of disease-causing pathogens. These mosquito-borne pathogens cause diseases like the West Nile virus, malaria, yellow fever, dengue and encephalitis. Worldwide these diseases afflict tens of millions people per year and kill millions per year as well. In the US, West Nile Virus is spreading westward by way of infected birds and encephalitis outbreaks occur frequently.

Mosquitoes undergo a complete life cycle, which means they go through four stages: eggs, larvae, pupae, and adults. All mosquitoes complete their life-cycle in about 10 - 14 days in summer months. Female adult mosquitoes usually are the only ones that feed on blood. They have piercing-sucking mouthparts (needle with suction tube) from which to extract blood from a victim. For normal metabolic function, plant juices and nectar provide the required nutrients. A blood meal is required for egg development from which protein is extracted. It is during this feeding process that pathogens are introduced into victim’s blood stream. Eggs are laid singularly or in tight clusters called rafts.

Many species of mosquitoes occur worldwide. Culex, Aedes and Anopheles are general genus groupings.

Common Culex species include C. pipiens (Northern House), C. p. quinquefaciatus and C. tarsalis. Culex pipiens and C. p. quinquefaciatus are plain brown and lay eggs in rafts in rain barrels, flower pots and any other waterholding vessel high in organic pollution. C.tarsalis is dark brown with white bands on legs and on proboscis and may lay eggs in clear water. Larvae develop into pupae while still in water.

Common Aedes species include salt marsh species like A. taeniorhynchus (Black Salt Marsh), A. sollicitans and A. dorsalis. These species typically breed in salt water marshes along the coast. They lay eggs singularly on water or on mud surfaces. Aedes species also include the floodwater species that breed in riverine flood plains and in water seepage areas. Aedes species such as Ae. sierrensis, Ae. triseriatus and Ae. aegypti most often breed in water-filled tree hole cavities. Common Anopheles species include An. freeborni, An. quadrimaculatus, An. earlei, An. occidentalis and An. aztecus. Eggs are laid in clean still water. Anopheles quadrimaculatus is common vector for malaria in USA. Life cycle in this species on average may take about 3 weeks to a month, and the egg stage is very prone to desiccation.

Pest Best Management Practices