Many different species of this insect pest occur throughout the world. In addition to having an annoying bite, they transmit encephalitis and West Nile virus within the United States and other serious diseases, such as yellow fever and malaria, in other parts of the world. Adults emerge from hibernation with warm spring weather. The males feed on nectar, honeydew, and plant sap; the females require a blood meal in order to produce their eggs. Larval development takes place exclusively in water. Typically, eggs are laid in shallow accumulations of fresh, stagnant, or salty water. The larvae may mature within 5 days or may take months to mature.
Maintain door and window screens in good repair. Drain any standing water near the house and replenish water in birdbaths every day.