BACKYARD SOLUTIONS FOR MOSQUITOES

• Set up large fans for home barbeques or other outdoor gatherings.
• Use citronella candles or yellow outdoor light bulbs to repel mosquitoes.
• Some botanicals such as garlic or pepper are used as barriers around property.
• Encourage natural predators - stock closed, ornamental ponds with mosquito-eating fish (Gambusia holbrooki). Do not allow ornamental ponds to enter waterways, G. holbrooki are not native to all parts of the U.S. Whenever possible, nurture natural mosquito predators such as bats, birds, dragonflies, beetles, frogs and snails (pesticide use adversely effects predators).
• Carbon dioxide mosquito traps and attractants 
• Fill holes or depressions in trees with sand or mortar, or drain after each rain.
• Microbial Insecticides (Bti - Bacillus thuringiensis israelensis) (Cinnamon Oil) to kill larvae.
• Botanical Yard Repellents (Scented Geranium, citrusy or lemon-scented plants such as Lemon Grass, and herbs like Oregano, Catnip, or sweet and holy basil [see Dave's Garden plant database], Garlic barriers, Dr. T's Nature Products);
  (Any mention of product names is for informational purposes and does not constitute an endorsement.)

http://www.beyondpesticides.org/mosquito/activist/index.htm#factsheets