How to Kill Mosquito Larvae in Standing Water With Household Products

It's easier to control insects in the larval stage than it is to control adults. Mosquito larvae are relatively helpless, and although they are too small to see, their breeding grounds aren't hard to find because they are always located in standing water. Unfortunately, you can't always use chemicals to kill the larvae; the water may be part of a municipal water supply, and it often harbors other types of life that could be harmed by the chemicals. For this reason, most control strategies involve disruption of the breeding grounds or introduction of natural predators, but there are safe chemicals you can use.

The most effective strategy for controlling mosquito larvae, according to the University of Kentucky College of Agriculture, is to disrupt their breeding grounds.

Empty rainwater from all buckets and other vessels in your yard -- especially old tires, which are a favorite breeding ground. 

Pick up drink containers and old plastic bags, which effectively trap and hold rainwater.  Drain standing water in your yard by digging a trench to divert it a lower elevation where it can soak into the ground. 

Circulate water in your pond by creating feature, such as a fountain or a waterfall. Disturb the water around the edges of the pond by walking around the pond and stirring things up with a stick.

Introduce natural predators to your backyard pond, such as goldfish (Carassius auratus), koi (Cyprinus carpio) or mosquitofish (Gambusia affinis).

Oils, such as mineral oil or motor oil, leave a thin film on the surface of standing water, effectively robbing the larvae of oxygen and killing them. While this may be a safe treatment for an area of poor drainage in your yard, it could be harmful for other creatures inhabiting a pond, and it's definitely a no-no for a water that flows into a public reservoir. In lieu of potentially harmful oils, consider the following alternatives:

An enzyme-based household cleaner. When introduced into standing water, such as a birdbath -- in a low concentration of enzyme-based cleaner, such as 1 part cleaner to 50,000 parts water, or about a hundredth of a teaspoon per gallon of water -- alters the surface tension of the water. That prevents the larvae from staying above the surface and getting the oxygen they need. In such low concentrations, enzyme cleaners are harmless to animals and fish.

Neem seed oil.  You may not have this around the house, but it's easy to obtain from a garden store. At a concentration of 1/2 teaspoon per gallon of water it has been shown to kill 100 percent of mosquito larvae.

Dawn dish soap. A concentration of 0.125 milliliter (four-thousandths of an ounce) per gallon kills 100 percent of mosquito larvae.

Shaving cream. At a concentration of 0.0625 milliliter (two-thousandths of an ounce) per gallon, shaving cream kills 100 percent of mosquito larvae.

Available at most hardware stores, mosquito dunks contain a bacterium -- Bacillus thuringiensis israelensis, or Bti -- that selectively kills mosquito larvae and a few other related insects. Mosquito dunks are doughnut-shaped, and you use one by tossing it onto the surface of the water and forgetting about it. Products vary, and you should always read the instructions, but mosquito dunks typically keep working for 30 days.