The best way to get rid of mosquitoes is to get rid of all water sources they can use to breed. If you have pond, however, it can be impossible – not to mention undesirable – to eliminate the pond altogether. Instead, you’ll want to take measures to control mosquito growth in the pond. There are several methods discussed here, some of which are more environmentally friendly than others.
The nature of the pond is the first thing to consider. Is there a way to get the water moving? The mosquito needs still water to develop, so if you can get the water moving, that will make the water inhospitable to mosquitoes. Ways to get the water moving in a pond include putting in an overflow or adding a fountain feature if the pond is small.
Next, consider what else is living in the pond. A living, non-stagnant pond can support several varieties of aquaculture, including many fish and insects who love to dine on mosquito larvae. A conversation with your local agriculture extension service can help you find out what kinds of animals can help make your pond a viable aquaculture inhospitable to mosquitoes. Not only that, but your local extension service may be able to provide you with stock free of charge.
Depending on the size of the pond, you may be able to treat the water with the bacteria bacillus thuringiensis which destroys the mosquito larvae. If you have a large pond, however, this may be cost prohibitive. Still, it’s an effective natural option to consider.
Depending on the level of problem you have and the size and utility of the pond, destruction of the pond is something you may have to face. After all, elimination of habitat is the only absolutely certain way to eliminate mosquitoes. If your problem is serious enough and other measures haven’t been effective, it may be time to consider eliminating the pond.
If these methods aren’t effective, or if they aren’t appropriate for your situation, your remaining options are chemical. One of the most commonly used of these methods is the spreading of oil on the surface of the still water. Several commercial preparations exist and are based on mineral oil. The oil forms a barrier on the surface of the water which prevents the larvae from getting the air they need to live. The oil also kills everything else in the pond as well, so it’s certainly a last resort option. In addition, if wind and rain agitate the oil, it may need to be reapplied. This can be a messy solution, and is certainly not the most environmentally friendly choice.
Larvicides can also be used, such as the chemical methoprene. This chemical interferes with the natural growth cycle of the mosquito and prevents the larvae from becoming adults. If you plan to use any chemical preparations, follow label directions carefully and consult with a pesticide expert before applying them.
In addition to treating your pond, remove all other breeding locations and do what you can to eliminate the adult population of mosquitoes as well. It may seem like a never ending battle, but with perseverance, you can make a difference.