10 Natural & Organic Aphid Control Methods
Get rid of aphids in your garden – and keep them away – with these simple natural & organic aphid control methods…
Aphids can be a real pest in the garden. They often appear seemingly out of nowhere, and suddenly your perfectly healthy plants have curling, shriveled, or yellowing leaves as the aphids start sucking the life out of them. What can be done, and how can you keep your garden safe from aphids – especially as an organic gardener? Read on to learn more about this common garden pest, and how to control it using natural and organic aphid control methods.
How Can You Spot Aphids?
Aphids – also commonly known as plant lice – are soft-bodied insects that feed on soft stems, buds, and leaves, preferring tender new growth to established, tougher foliage, so they are often found towards the tips of your growing plants. There are many different species of aphids (over 4,400, in fact, although only about 250 of them are destructive to garden plants and trees) that feed on different types of plants and trees, and a heavy infestation can cause severe damage to your plants. They are usually found in groups feeding together, and range in color from white to black, gray, green, pink, yellow and even orange. Aphids secrete a sticky substance called honeydew that attracts ants, so if you see ants on your plants, check for the presence of aphids.
Controlling aphids can be a challenge, and not all common organic control methods are up to the task. For example, I regularly have aphids show up on plants that are covered with netting, so even barrier methods don’t always do the trick. Aphids seem to be particularly fond of the fall garden, and once they show up, they can be difficult to get rid of. In most cases, aphids won’t entirely kill a plant – unless it’s small, weak, or a new seedling – but they can damage and stress your plants, leaving them more prone to disease, and they can also ruin edible greens. Fortunately, there are a number of effective organic aphid control methods that you can use to help clear these pests out of your garden.
Different methods may work better in some gardens than others, so if the first method you try doesn’t work, just move on to the next! Below I have listed 10 methods to help control aphids in your garden using natural, organic, and sustainable means. The first few methods are the most sustainable and require little intervention from you. However, if you have a severe infestation, you may need to move on to one of the more aggressive treatments.
1.) Natural Predators
One of the best ways to control aphids in your garden (and other pests as well, for that matter) is to attract predatory insects to your garden. Ladybugs are one of the best natural predators for aphids, so create an environment where your ladybugs will want to stick around. Ladybugs often enjoy lacy plants like carrots and dill, and cilantro or other blooming herbs are also great for attracting them. You can buy live ladybugs online or from some garden center stores, but the best way is usually to use companion planting and plant things that attract ladybugs naturally so they’ll happily make a home in your garden and gobble up your aphid pests. (Green lacewings are another good option.)
It’s amazing how quickly ladybugs can work! A few summers ago, I noticed a growing infestation of aphids on my okra plants. I tried a soap spray (see below for more on this method), and while it did kill some of them, there were still plenty of live aphids on my plants a few days later. I was going to spray again, but before I did so, I noticed some little crawly things on a few of the okra leaves. Upon closer inspection, I determined them to be lions (ladybug larvae), so I decided to hold off on the spraying, and relocated a few of the larvae to the plants with the heaviest aphid infestation. Within less than a week, every single aphid was gone! That’s when I realized that letting predator insects do the work for you is the absolute best method of pest control! 🙂
2.) Companion Planting
Growing a diverse garden filled with many different species of plants is the best way to attract and maintain good populations of beneficial insects, and it also helps to reduce habitat for pests that prefer certain types of crops – such as aphids. Interplanting species that aphids love together with other plants that they don’t care much for will not only make it harder for aphids to find their preferred foods in your garden, but will also limit the amount of food available to them.
Good companion plants that may help to repel aphids include onions, garlic, chives, leeks, marigolds, dill, fennel, and cilantro. Try planting these between or surrounding your aphid-prone crops such as brassicas, chard, tomatoes, and okra.
3.) Trap Crops
Besides companion planting, another sustainable method of aphid control is to plant a “trap crop.” These are designed to attract aphids (or other unwanted insect pests), and keep them on the trap plants instead of on your veggies. Nasturtiums are a great example – aphids absolutely LOVE them! Other good trap crops for aphids include asters, mums, cosmos, hollyhock, larkspur, verbena, dahlia, and zinnia. However, while these may look lovely in your garden, be prepared to pull out and remove your trap plants once they are full of aphids in order to prevent your garden from becoming an aphid metropolis!
Personally, I have never found trap crops to be all that effective, and I worry that they are actually attracting more pests to the garden so I don’t use them that often, but I know other gardeners that swear by them.
4.) Hand Pruning
If you only have a few aphids on a small, localized area of a plant, you may be able to get rid of your aphids before they reproduce further by pinching or pruning off any infested leaves and shoots. However, this will quickly become problematic if you have a larger infestation, as of course, you don’t want to cut too much off of your garden crops. This method works best for small, new, and localized infestations that haven’t gotten out of control yet, so it is important to always keep a close eye on your garden and watch for signs of aphids so you can get a handle on them before they get out of control.
5.) Water Spray
Probably the most common method of organic aphid control that you’ll run across is the recommendation to spray your affected plants with a hard blast of water. The theory is that aphids aren’t avid travelers, and if you can knock them off the plants, they won’t be able to climb back up. I have tried this method without a lot of success – mostly because our garden is watered via a gravity feed, so we don’t have a lot of water pressure to blast the plants.
In many cases, I’ve also found that the aphids are feeding on tender or delicate plants that don’t hold up well under strong water blasts. If you have aphids on your tougher plants like established brassicas, this method may work, but you’ll need quite a bit of water pressure, and a lot of dedicated spraying to get them all off. If you don’t get them all, they’ll just reproduce again and you’ll soon be back where you started, which is why many people recommend following this method up with another aphid control tactic like the ones that follow.
6.) Soap Spray
One of the most common natural aphid killers is a simple soap spray. Soap can help kill aphids by dissolving the waxy coating on their soft bodies, thereby causing them to shrivel up and die. This method can and does work, but you’ll want to be careful not to make your spray too strong, as too much soap can actually harm sensitive plants. All you need for this is water and some natural dishwashing liquid or a pure castile soap (don’t use detergents or the harsh chemical stuff that has weird colors like blue or orange – you just want an all-natural kind like 7th Generation, although generic brands are fine too).
A basic recipe is 1-2 tsp of soap per 1 quart of water. Mix it up in a spray bottle. Before you spray the whole plant, it is recommended to spray, dip, or dab just one leaf with the mixture and wait 24 hours to make sure your plant doesn’t have an adverse reaction. If it looks fine the next day, you can spray liberally over (and under) the affected areas of your plants. Be sure to get the stems and the undersides of the leaves where aphids like to hide and feed.
To reduce stress on the plants, you’ll want to spray this preferably in the evening or on a cloudy day, as sunlight may cause the plants to burn. To catch the next generation when it hatches, you will want to repeat the spraying again about a week later, and keep an eye on your plants to make sure the aphids don’t return.
7.) DIY Natural Aphid Spray
Another homemade aphid spray option is to mix up a tincture of spicy things that aphids don’t like (raw garlic, onions, hot peppers), and spray this on the plants. To do this, you’ll want to chop or mince your ingredients, add them to a quart of water, and let them sit overnight. Then strain out the solids and put the liquid in a spray bottle. Apply according to the same instructions above – and don’t forget to test it on a small area of the plant first! Even though these ingredients are all-natural, some sensitive plants can still be burned. This method is great to use after you’ve mostly got your infestation under control, as it repels aphids from your plants and keeps them from coming back.
8.) Neem Oil Spray
Neem oil is another substance that can be used to treat aphids. It works by stopping their reproduction cycle, so it can take a week or two to see results. To make a simple neem oil aphid spray, see this homemade aphid spray recipe. (Make sure to use cold-pressed organic 100% neem oil). Mix in a pump sprayer, shake well and spray liberally on all sides of the affected plants, making sure to get under the leaves and up and down the stem. Spray it on the soil around the plants as well for full coverage. Repeat in 2 weeks to make sure you got them all.
When used properly, neem oil is not toxic to bees or most other beneficial insects in the garden. Still, you will always want to spray in the evening to minimize stress to the plants, and try to avoid spraying on any bees or other beneficial insects that may be in the vicinity.
9.) Diatomaceous Earth
Diatomaceous earth is a powder made of ground fossils, and it is a mechanical deterrent for aphids and many other garden pests. It can both repel aphids, and also help to kill them by creating tiny cuts in their soft bodies and then desiccating them. Be sure to use food-grade DE, and as it can be irritating to the skin and mucous membranes, you may wish to wear gloves and a mask and/or goggles when applying. Avoid applying when windy or wet, as diatomaceous earth has to be dry for it to work. The downsides of using DE are that it can be tricky to apply to plants with frilly or lacy leaves, and it also may not stick well to the undersides of leaves. You’ll also need to reapply after a rain. (I have also read that flour can work similarly to repel aphids, but have not tested this for myself.) DE can harm bees and some other beneficials, so don’t apply to plants that are blooming.
10.) Plant Purple & Red Veggies
Lastly, odd as it may sound, many pests (including aphids) seem to be less attracted to plant varieties with red or purple colors. This may be because the insects are more visible to predators and have more trouble blending in than on green crops. Or it could be because red and purple varieties of vegetables have higher levels of an antioxidant called anthocyanin – which is especially good for humans, but not so good for pests! In fact, it may be mildly toxic to some insects, so many of them, including aphids, much prefer the green varieties. If you have an aphid problem in your garden, it may be worth adding some red and purple veggies to your lineup – not only will they be less of a target for aphids, but they’re better for you too!
As you can see, there are many different organic aphid control methods available, so if your garden is plagued by this tiny menace, don’t despair! Give some of these methods a try, and remember, the best method of controlling any pest is to keep it from gaining a foothold in your garden in the first place. After you get your infestation under control, follow some of the sustainable methods listed above to attract more beneficial insects and repel the unwanted ones from your garden.