Invisible to the naked eye, mosquito larvae live in standing water and eventually grow into pesky, blood-sucking adults. The larvae require only minimal amounts of water, and even something as small as a puddle of water on a discarded plastic bag can house them. Whenever possible, it is better to prevent mosquito larvae than to try to deal with the problem after the fact. There are, however, several household items you can use to safely kill any larvae that may be lurking in standing water outside your home.
The best way to deal with mosquito larvae is to avoid them. To do so, remove full buckets, barrels, toys, plastic bags and other clutter from your property. Anything that can hold water can host mosquito larvae, so examine your surroundings closely for potential breeding sites. Consider cleaning your gutters, as well, if they overflow when it rains. Clogged gutters may hold standing water in a location safely above predators where larvae can thrive. If you have a backyard pond, keep the water well-aerated and stock it with goldfish varieties that eat mosquito larvae. It is also helpful to grow plants that naturally repel mosquitoes throughout your landscape. Some suggestions include lime basil, catnip and thyme. Change the water in birdbaths regularly and stay on top of pool maintenance.
If you find standing water on your property that may already be hosting mosquito larvae, you can use household items to kill them safely. Pay attention to the environment around you, and use control methods that are safe for children, pets and other wildlife. Some methods work better on some mosquito species than others, so feel free to experiment with multiple methods to see which works best for you.
A thin coating of oil on top of water suffocates mosquito larvae, killing them quickly. Use natural oils, such as olive oil or vegetable oil, for this control method. You also can use cinnamon oil. You only need 1 teaspoon of oil per gallon of water. Do not use this method on ponds and other bodies of water that contain fish.
Apple Cider Vinegar
Adding apple cider vinegar to standing water effectively kills mosquito larvae but requires about 18 hours to get the job done. Completely non-toxic, vinegar kills mosquito larvae at a ratio of 15 percent vinegar to 85 percent water. Make sure you use enough vinegar; lower concentrations don't kill the larvae. Vinegar is environmentally safe, so use more than necessary when in doubt. Vinegar also can be used as a mosquito repellent.
Although not environmentally friendly, household bleach is an effective mosquito larvae killer. Use bleach only as a last resort and only if you are sure a runoff can't enter a water source or harm wildlife. Most often used to clean larvae from rain gutters, a tablespoon of bleach per gallon of standing water will kill larvae. For ongoing protection, consider wiping your gutters with a 1-to-1 solution of bleach and water.
Though not a household item, mosquito dunks are an excellent way to safely kill mosquito larvae. These doughnut-shaped rings contain bacteria (Bacillus thuringiensis israelensis) that are toxic only to mosquito larvae. Each dunk treats a water surface up to 100 square feet and lasts about a month. Although deadly to mosquito larvae, these bacteria are harmless to pets and wildlife. Simply drop the dunk in the water you wish to treat, and you're finished. The same bacteria are available in pellet form to treat smaller areas of standing water.