One briquette last about 30 days and treats 100 square feet of surface water. You can find them in pet stores or stores that sell pond supplies. Clean and chlorinate swimming pools that are not in use. Mosquitoes can breed in the water that collects on swimming pool covers. Use landscaping to eliminate standing water that collects on your property.
Mosquitoes can breed in any puddle that lasts more than four days.
You may want to fill tree stumps with sand to prevent pools of water from forming in them. Clean livestock-watering troughs monthly. Also keeping vegetation trimmed low can eliminate resting sites for mosquitoes in the daytime. Decrease your animals' exposure to adult mosquitoes as well as reducing your personal exposure. Housing animals in structures with well-maintained insect screening can reduce exposure to adult mosquitoes.