Caption
Aphids are pesky green bugs that can wreak havoc on your garden.
Identification
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.
Still not sure? Use our Plant Problem ID tool to easily diagnose pests and diseases.
Control and Prevention
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!
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Comments
We would advise washing the soil with a soapy solution, avoiding overfertilization, and using insecticidal soaps or horticultural oils (neem oil) on the soil. If you'd like to plant right away, we'd also recommend perhaps planting garlic with your new plants so that the aphids will stay away. Good luck!
Given this is an edible, we don't recommend chemical applications. See if you can identify the insect that is chomping on your leaves. It may very well be something that will be gone in a few weeks and your peppers will be none the worse for wear. Often, insect pests feed at dusk and nightfall. It's a good time to go out there to see what you are dealing with. Sometimes a simple solution of warm water and dish soap is enough to deter pesky feeders.
It appears that you might have aphids based on the distortion and color of your lime leaves. The brown undersides could be a collection of brown aphids or sooty mold caused by the honeydew that aphids secrete. In order to be sure, use our tips to identify the small bugs. Good luck!
Curling tomato leaves can mean several things. There are some viruses that produce this effect, but it can also be signs of stress due to cold temperatures and rain, irregular watering, too much water, heat and drought, improper pruning, herbicides, transplant shock, mites . . . If it is aphids, they would be fairly easy to see -- check under the leaves and along stems and junctions for small, pear-shape insects -- usually moving very slowly or staying still. Color ranges from dark gray to green to orange, depending on species.
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Hi Michelle,
How strange! Pentas are rarely bothered by pests or disease. It' wonderful of you to want to protect the bees! Not knowing what the pests are, I suggest two things: 1. Rub the leaves with warm soapy water to get them off of the plant. 2. If possible, take a few photos of the insects and the damage they cause and visit a local plant nursery (not Home Depot). Ask the staff if they are familiar with the pest--that is the only way to choose the right product for treatment. The spray you applied may be effective only at a certain stage of the pest's life cycle. In order to treat, you must know thy enemy! Hope that is of some help.