Mosquitoes can breed in any puddle that lasts more than four days. The type of standing water in which they choose to lay their eggs depends upon the species. The presence of beneficial predators such as fish and dragonfly nymphs in permanent ponds, lakes, and streams usually keeps these bodies of water relatively free of mosquito larvae. However, portions of marshes, swamps, clogged ditches, and temporary pools and puddles are all prolific breeding sites.
Other sites in which some species lay their eggs include tree holes and containers such as old tires, buckets, toys, potted plant trays and saucers, and plastic covers or tarpaulins. Some of the most annoying and potentially dangerous species, such as the Asian tiger mosquito, come from these sites.
Mosquitoes can spread certain diseases to humans. In some cases, these diseases can be life-threatening.
Some mosquito-borne illnesses include:
- West Nile virus
- Dengue fever
- Yellow fever
- Japanese encephalitis virus
- Eastern equine encephalitis
- La Crosse encephalitis
- St. Louis encephalitis
- Western equine encephalitis.
Controlling these insects, and exposure to diseases they may carry, can be done by chemical and nonchemical methods. Public activities, such as surveillance, are one part of mosquito control. Areas are occasionally sprayed to prevent disease and nuisance caused by large mosquito numbers. The typical pesticides sprayed for mosquito control are either larvicides or adulticides.
Activities in and around the home are another important part of the strategy. Suggestions for preventing bites include:
- Using insect repellent
- Wearing protective clothing
- Being aware of peak mosquito hours
- Mosquito-proofing one's home
- Helping the community.