Aphids are pesky green bugs that can wreak havoc on your garden.
Preventing Aphid Infestations in Your Garden
Identifying Aphids
Aphids are tiny (adults are under 1/4 inch), and often nearly invisible to the naked eye. Various species can appear white, black, brown, gray, yellow, light green, or even pink. Some may have a waxy or woolly coating. They have pear-shaped bodies with long antennae; the nymphs (young aphids) look similar to the adults. Most species have two short tubes (called cornicles) projecting from their hind end.
Adults are usually wingless, but most species can develop a winged form when populations become crowded so that when food quality suffers, the insects can travel to other plants, reproduce, and start a new colony. Aphids usually feed in large groups, although you might occasionally see them singly or in small numbers.
While aphids in general feed on a wide variety of plants, some species of aphids can be specific to certain plants—for example: bean aphids, cabbage aphids, potato aphids, green peach aphids, melon aphids, and woolly apple aphids.
Photo credit: GrowVeg.com.
What Does Aphid Damage Look Like?
Nymphs and adults feed on plant juices, attacking leaves, stems, buds, flowers, fruit, and/or roots, depending on the species. Most aphids especially like succulent new growth. Some, such as the green peach aphid, feed on a variety of plants, while others, such as the rosy apple aphid, focus on one or just a few plant hosts.
- Look for misshapen, curling, stunted, or yellowing leaves. Be sure to check the undersides of leaves; aphids love to hide there.
- If the leaves or stems are covered with a sticky substance, that is a sign that aphids may have been sipping sap. This “honeydew,” a sugary liquid produced by the insects as waste, can attract other insects, such as ants, which gather the substance for food. When feeding on trees, aphids’ honeydew can drop onto cars, outdoor furniture, driveways, and so on.
- The honeydew can sometimes encourage a fungal growth called sooty mold, causing branches and leaves to appear black.
- Flowers or fruit can become distorted or deformed due to feeding aphids.
- Some aphid species cause galls to form on roots or leaves.
- Aphids may transmit viruses between plants.
- Aphids also attract other insects that prey on them, such as ladybugs.
Photo Credit: John Obermeyer/Purdue University.
How to Get Rid of Aphids: Killing Aphids
- Try spraying infested plants with a strong stream of water; sometimes, all aphids need is a blast to dislodge them. Typically, they are unable to find their way back to the same plant.
- Neem oil, insecticidal soaps, and horticultural oils are effective against aphids, but these substances need to come into contact with the aphids in order to work. Be sure to follow the application instructions provided on the packaging.
- You can often control aphids by wiping or spraying the leaves of the plant with a mild solution of water and a few drops of dish soap. Soapy water should be reapplied every 2-3 days for 2 weeks.
- One variation of this soap-water mix includes cayenne pepper: Stir together 1 quart water, 1 tsp liquid dish soap, and a pinch of cayenne pepper. Do not dilute before spraying on plants.
- Diatomaceous earth (DE) is a nontoxic, organic material that will dehydrate aphids.
Warning: Do not apply DE when plants are in bloom, as it will kill pollinators such as bees and butterflies if they come into contact with it.
How to Prevent Aphids
- For fruit or shade trees, spray dormant horticultural oil to kill overwintering aphid eggs.
- Beneficial insects, such as ladybugs, lacewings, and parasitic wasps, will feed on aphids. Attract these insects to your garden by providing an environment that features a range of flowers and foliage plants, as well as access to water. Supplemental populations of these insects can be ordered online and should help control the aphid populations from the start.
- Companion planting can help keep aphids away from your plants in the first place, or can draw aphids away from the plants you want to grow. For example:
- Aphids are repelled by catnip.
- Aphids are especially attracted to mustard and nasturtium. Plant these near more valuable plants as traps for the aphids. The aphids will likely go for these plants before your prized tomatoes. (Check your trap plants regularly to keep aphid populations from jumping to your valued plants.)
- Nasturtiums spoil the taste of fruit tree sap for aphids and will help keep aphids off of broccoli.
- Garlic and chives repel aphids when planted near lettuce, peas, and rose bushes.
Using Alcohol to Control Aphids
Isopropyl alcohol (also called isopropanol or rubbing alcohol) works fine and is easy to find, but be sure it doesn’t have additives. Ethanol (grain alcohol) seems to work best. Alcohol usually comes in 70 percent strength in stores (or 95 percent strength purchased commercially). To make an insecticidal alcohol solution, mix equal parts 70 percent alcohol and water (or, if using 95 percent alcohol, mix 1 part alcohol to 1 ½ parts water).
You can also add alcohol to a soapy emulsion to make it more effective. For example, in a spray bottle, combine 5 cups water, 2 cups isopropyl alcohol, and 1 tablespoon liquid dish soap.
These types of solutions should NOT be sprayed over the entire plant at once. Spray or wipe down only the infested areas. It will only kill the aphids it comes into contact with, so repeated applications may be necessary.
CAUTION: When applying an alcohol or soap spray, or a combination, always test on a small area of the plant first, and apply in the morning or evening, when the Sun is not as intense. Watch the plant for a few days for any adverse reactions before applying more. Plants can be sensitive to alcohol and dish soap. Also, some soaps have additives that can damage plants—select the purest form.
Check out this video to learn more about how to get rid of aphids:
Do you have more tips for controlling aphids? Let us know in the comments below!
Catherine Boeckmann
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I'm a new gardener and am struggling to get rid of the aphids. My kale and other leafy green veggies have had a very bad infestation. Do I need to throw away the soil? Also, though I have treated the kale, it's no longer really growing even though it's still green and edible. Do I need to get rid of the affected plants if their growth is stunted?
I've tried the dish soap and neem oil tricks but what I'm finding is that regular attention is the biggest key, one or two aphid mudering sprees don't do it. I have a spray bottle of soapy water and a spray bottle of clean water and what I'm finding pretty helpful for keeping aphid populations on my seedlings and my outdoor-become-indoor plants is a few days of spraying the plants down daily with soapy water and gently going over the leaves and stems with the fingers on my non-spraybottle hand to make sure I loosen them up and coat undersides of leaves with soapy water, wait five minutes, then use the clean water spray to wash the soapy water (and most of the aphids) off. I do this every day till I'm seeing no aphids (usually about 4 days) then I do it a few more times every other day or so just in case there are hatchlings I can't see.
My potted perpetual spinach ended up with curly deformed leaves when I left the soapy water on, and the new growth on beet greens in my bunny's indoor garden have not deformed since I've started rinsing the soap off, just make sure the soap gets a good few minutes to suffocate your aphids. For a really bad infestation, I soak the heck out of the soil too with my soapy water, to make sure any of the little buggers hiding down there also get dead. I've used this method for other kinds of pests and never had problems with just leaving mildly soapy water in any plant's soil (just enough to make suds) but if you're concerned, you can also rinse the soil after letting it be soapy for half an hour or so.
I found aphids on my pepper, eggplant and cabbage seedlings last week just as I was starting to put them outisde to harden off, so I've been giving them their bath and rinse and allowing them to dry before I put them outside to play. So far so good, every time I soap them up, there are fewer and fewer aphids. I'm a bit hesitant to use neem oil on my seedlings while I'm hardening them off (I'm also unsure how safe it is to use around my rabbit, googling it gave me conflicting information) but if the aphids are still a problem by the time I take the seedlings to the garden I will neem oil them once they're established in the garden.
Hope that helps!
or it will clog up everything in your sprayer...been there, cussed that!
YES, just save your banana peels, cut them into a few pieces, and place the peels, outside peel side UP, beneath your roses or any other plants that get aphids. The outside banana peel gives off some kind of a gas that will make your aphids get lost. I have used this for a few years and now I never have aphid troubles. And the tree next door to us is an aphid nursery. So we are really lucky with this banana trick. No pesticides, sprays or anything else needed. But you need to eat your bananas regularly.
Do aphids start multiplying in the soil? Is it best to change the soil that the plants attacked by aphids, are growing in, to successfully get rid of them ?
Most aphids live on or under the leaves of plants, but grey-white root aphids live in the soil. We highly recommend that you plant something that will repel the aphids next to the crops that have been infested. Marigold, catnip, and dill will all do the trick.
The best way to control aphids is to squash them between your thumb and forefinger. Start with the heaviest concentration of the lil buggers and squish away! Wash their nasty guts and carcasses off leaves when you're done. Be careful not to tear leaves. I have a moderate sized garden so I can manage most of it but this method might not work for larger or commercial size gardens unless you have help. It helps if while you're insecticiding them you taunt them by saying, "you're dead now!" or, "you're all going to die!" Get creative with it! Happy squashing!!
I have these pests on a Carolina reaper plant. I believe it stunted the growth of the fruit. The peppers were very small, smaller than normal and they have already turned red. Typically they grow green to full size then mature to red.
Anyways, curious to know if this type of pest infection is dangerous to the actual fruit. I washed the fruit (pepper) off but unsure if it is safe to consume.
There are a few reasons why pepper fruit can be stunted. For example, if the plant was planted too early, and the blooms were exposed to cool temperatures, then those fruit can be stunted. (Aim for 70 to 80F day temps, and above 55 night temps before planting.) Diseases such as tomato spotted wilt virus can also cause stunting of fruit. If the whole plant is stunted, then it could be cultural conditions, such as too little water or inconsistent application, not enough nutrients, etc. A heavy pest infestation, such as of aphids or whiteflies, can also stress the plant and cause sparse fruiting and stunting of fruit, as well as yellowing/wilting leaves etc. As to whether the fruit is safe to eat—it might depend on the cause of the stunting, and how far gone the fruit is. Sometimes stunting can affect taste/quality, so it would not be worth eating. If there is any doubt as to safety, it would probably be best not to eat it.
I have been told that my house is infested with insects and bugs. I have been very sick for months. At first I was secreting a sugary substance from my skin in different areas. I have undergone several different stages. I can't handle this anymore. I have tons of urine and blood tests proving that I am not on drugs. This aphids match exactly what I am going through. I have had the very tiny black ones come out in my urine. This is not a joke, and I truly need your help.
