Natural mosquito control calls for a multi-pronged approach to fight these disease-carrying pests. Smart landscaping that limits their breeding opportunities may be your best defense in this battle. At the same time, you will want to resist the temptation to use chemical bug sprays as repellents. Many people feel that using such sprays poses just as much of a health risk as allowing yourself to be bitten by mosquitoes.
Stating the Problem: When Neither Chemical Sprays nor Mosquito Bites Are Acceptable
Do you spend a lot of time landscaping the yard in summer? Then you know that mosquito control of some sort is a necessity. Such awareness could well save your life in this age of the West Nile, Eastern equine encephalitis, and Zika viruses. Giving in and allowing yourself to be bitten by mosquitoes can be deadly. But if you are concerned about the long-term health effects of applying chemical bug sprays to your skin, then you must seek alternatives. Restricting yourself to the use of safe bug repellents is part of natural mosquito control.
What is so bad about chemical bug sprays? The U.S. National Library of Medicine (NLM) discusses two different and widely-used ingredients in bug sprays:
- DEET (N,N-diethyl-m-toluamide)
According to NLM, using very high concentrations of DEET (over 50%) over a long period of time may cause not only severe skin reactions, but also insomnia and mood changes.
The same source states that the use of pyrethrin-based sprays can lead to breathing problems if large quantities are inhaled (even though the general consensus is that they are not, technically, toxic). While these facts may not be especially alarming (in and of themselves), remember that not everybody's body responds to substances in precisely the same way.
When erring on the side of caution, assume that a chemical spray that might not bother the general public much might cause you great harm.
If we take "natural mosquito control" in the broadest sense (that is, any mosquito control measures that save you from applying chemical bug sprays), a number of options present themselves.
Examples of Natural Mosquito Control Methods and Safe Repellents:
- Plant oils that can be applied to the skin as natural repellents; for example, those that come from citronella, castor bean plants, or catnip plants.
- Certain bath oils with repellent qualities. Many people swear by Avon's Skin So Soft, although it is specifically Avon’s "Skin So Soft Bug Guard Plus" that is marketed as the true mosquito repellent.
- Devices such as the Mosquito Magnet.
- How you dress: Avoid dark clothing.
- Attacking the problem at the source: mosquito-larvae control.
- Staying organic in your landscape maintenance so as to avoid killing mosquito predators.
You have probably heard of high tech's answer to the problem: the Mosquito Magnet (and similar products). It is a device that gives off a gas that mimics natural human breath, whereby it lures mosquitoes into its death chamber.
Even how you dress can influence whether you suffer mosquito bites. Mosquitoes are drawn to dark-colored clothing, so do your gardening in light-colored clothes.
A Tale of Two Citronellas
Before we can discuss citronella properly, we must specify exactly what we mean by that term. The oils, etc. with which you are probably familiar are derived from the tropical grass, Cymbopogon nardus. Do not confuse the latter with a plant named Pelargonium citrosa, which is variously dubbed "mosquito plant," "citronella plant," etc. Its fragrance may remind people of citronella, but it is not related to Cymbopogon. More importantly (and in spite of the hype), most experts now agree that it simply does not work. That is, it is not effective at repelling mosquitoes, regardless of whether you stand next to the plant while you are out in the yard or crush its leaves and spread the juice on your skin.
As for the effectiveness of Cymbopogon nardus, itself, the jury is still out. Some swear by it, while others are skeptical.
Citronella products made from Cymbopogon nardus are widely used in natural mosquito control. Some people burn citronella in a candle, while others apply it to the skin as a protective oil. In the latter case, citronella is sometimes mixed with other oils, derived from plants such as castor bean or catnip.
Landscaping Measures You Can Take Against Mosquitoes
Besides using mosquito repellents to protect your skin against insect bites, you can also take measures to control mosquitoes naturally by making changes to your landscape. Since the deadly illnesses mentioned above are transmitted to humans via mosquitoes, and since the larvae of mosquitoes are found in standing water, it is a no-brainer to try to get rid of sources of standing water in your landscaping. But just what those sources consist of can be far from obvious. We need to identify the nooks and crannies holding up "Welcome" signs to breeding mosquitoes and either get rid of them or make them less welcoming.
We know that fish eat bugs. So perhaps you have thought, "Too bad there isn't a 'mosquitofish' I could put in my water garden to eat mosquito larvae." Well, believe it or not, the mosquitofish is not a mythical beast. There really is such a thing as mosquitofish, and their presence makes a water feature much less welcoming to mosquitoes.
You will learn more about the mosquitofish below. But first, let's consider ways to stop mosquitoes from breeding simply by adjusting our landscaping efforts.
A simple yet important observation to remember is that when mosquitoes become adults, they rule the skies. Locating and killing winged bugs is difficult. Let's face it: The bugs are small, and the sky is big. It is like trying to find a needle in a haystack.
So mosquito control that focuses instead on killing mosquito larvae or depriving mosquitoes of breeding grounds in the first place makes a lot of sense. If you can eliminate sources of standing water in your yard (in which mosquito larvae are born), you are hitting mosquitoes where it really hurts.
Or else you can kill the mosquito larvae while they are still confined to the water. They are sitting ducks while they remain wingless, swimming in an artificial pond, say, or a swimming pool. Why? Because they are in a medium (water) that is contained in a finite, easily-managed area. This is the time to kill them. And you can even do so without resorting to chemicals, if you prefer; for instance:
- By using Bt bacteria (Bacillus thuringiensis), which attack mosquito larvae but pose no threat to other life forms. There are different strains of Bt bacteria; for an example of one used to fight mosquitoes, see below.
- Or by acquiring the eaters of mosquito larvae mentioned above, the aptly named "mosquitofish."
But before considering ways to kill the larvae in areas of your landscaping where you intentionally keep standing water, let's look at some of the sources of standing water that you might not immediately think of:
- Water buckets and rain barrels.
- Bottles and cans.
- Empty plastic pots from the nursery and other concave odds and ends you threw in a pile behind the garage.
- Old car tires (notorious rain-catchers).
- That wheelbarrow you have been meaning to bring inside, as soon as you fix its flat tire.
- Boat tarps or pool covers in which water can puddle.
- Uneven areas in lawns or gardens where irrigation water can collect.
- Clogged rain gutters and clogged drains.
- Birdbaths and water bowls for pets.
- Seepage from septic tanks.
But that still leaves the standing water that you wish to keep, such as that in swimming pools and garden ponds. How can you control or kill the mosquito larvae which may be lurking in these places?
- Keep swimming pools clean, aerated and chlorinated.
- A bacteria called "Bti" (a strain of the Bacillus thuringiensis mentioned above) is often used for mosquito larvae control in standing water.
- Aerate artificial ponds. The idea is to keep the water moving, using a pump. Mosquitoes will breed only in stagnant water.
- Avoid the temptation to mass aquatic plants together in artificial ponds (mosquito larvae can hide from the fish if plants are growing closely together).
- Stock artificial ponds with fish that eat mosquito larvae.
But which fish are the best eaters of mosquito larvae? Minnows and goldfish are commonly used in artificial ponds, and they do a fine job of eating mosquito larvae. But another fish, Gambusia affinis (and the related G. holbrooki), has acquired such a reputation as an eater of mosquito larvae that it has been given the nickname already mentioned: "mosquitofish." This fish is, however, an invasive species, so do not release any into the wild. Use them in small, contained water features only.