Aphids

How to Get Rid of Aphids on Tomato Plants

Tomato plants are one of the many vegetable crops that can be taken over by aphids. These pests are drawn to the tomato blooms, and will hang around to feed on the young fruits and stems. You’ll need to eliminate the aphids on your tomato plants as soon as you spot them to protect your crop. 

To get rid of aphids on tomato plants, you can remove them manually, knock them off with a hose, or use essential oils or neem oil as an aphid repellent. Methods to kill aphids on tomato plants include using diatomaceous earth, insecticidal soap, organic pesticide, or chemical pesticide. 

What Are the Tiny Bugs on My Tomato Plants?

The tiny bugs on your tomato plants could be one of a number of common pests. These include:

  • Whiteflies
  • Spider mites
  • Thrips
  • Aphids

What Are Aphids?

Aphids are pear-shaped, soft-bodied insects that are common pests to gardens and houseplants. These tiny bugs are a vital part of the wider ecosystem; however, in high numbers, they can be highly destructive to the plants they infest. 

aphids on leaf

Being part of the insect family Aphididae, there are about 4400 different species of aphids. Roughly 250 of these species are harmful to plants. Most of these subspecies are specialist feeders, meaning they feed on specific types of plants, while other species feed indiscriminately. The colors of these insects vary greatly between species, occasionally emulating the type of the plant that the species prefers. 

Aphids tend to infest the plants that they like to feed on. Depending on the species, aphids live on most fruit and vegetable crops, some flowering plants such as roses or chrysanthemums, in bushes, and on trees. They often cluster on the underside of the leaves of these plants. Although the individuals are small and hard to see, an infestation of aphids will be easy to spot; they are easily visible when they’re clustered together in a large quantity.

Identifying Aphids on Tomatoes

Aphids are tiny bugs on tomato plants that range in size between 1/16 to ⅛ of an inch long. They have soft, pear-shaped bodies and 6 legs each. The majority of aphid species are wingless; however, some mature aphids may have wings. Immature aphids look like mature aphids but smaller in size.

Aphids come in a wide range of colors. You can encounter aphids that are green, red, black, gray, brown, or yellow. The aphids with wings tend to be darker in color than the wingless varieties. Aphids also shed their exoskeletons as they grow; you may notice the white cast skins on the leaves or around the base of affected plants.

Another identifying feature of aphids is that they have two tailpipe-like protrusions from the back end of their abdomen; these are known as cornicles. Although some may be smaller and less obvious, all varieties of aphids have these cornicles. 

Do Aphids Like Tomato Plants?

Yes, aphids do like tomato plants, and are a common pest to this crop. Like the majority of fruit and vegetable crops, aphids enjoy feeding on tomato plants. They can infest the leaves, stems, and fruits of the plant, having a particular preference for new, tender growth.

How to Get Rid of Aphids on Tomato Plants

How Do Aphids Harm Tomato Plants?

Aphids on tomato plants cause harm in three ways; they damage the tomato plant by feeding on its foliage; they release honeydew triggering issues like sooty mold and other pest infestations; and they spread viruses through their feeding process. 

1. Aphids Feeding on Tomato Plant

The primary way in which aphids cause damage to tomato plants is by feeding on the plants’ foliage. Aphids gather on parts of the tomato plant like the stems, fruits, and leaves, particularly the underside of leaves. From there, the aphids use their needle-like mouths to pierce into the plant and feed on the sap it contains. 

Upon piercing into the plant, aphids inject the foliage with a digestive enzyme that breaks down the plant matter for easier feeding. Also, as the aphids suck out the sap from the tomato plant, they rob the plant of nutrients and moisture. This causes a variety of symptoms in the tomato plant, including stunted growth, curling or yellow leaves, and deformed tomatoes.

2. Aphids Leaving Honeydew on Tomato Plant

Another harmful side effect of the aphids’ feeding process is their production of honeydew and its effect on the tomato plant. Honeydew is a sweet, sticky substance that the aphids produce as a byproduct of feeding onto the tomato plant’s sap. If you have aphids on your tomato plants, you’ll notice this substance covering the stems and leaves of the plant. 

While the honeydew itself isn’t necessarily harmful, it can trigger other issues in your tomato plants. For instance, it increases the risk of sooty mold as the honeydew can cause the plants’ leaves to stick together. On top of this, honeydew may attract other pests like ants and yellowjackets to your tomato plants. These insects enjoy feeding on the honeydew and will protect aphids on tomato plants to secure this source of food.

3. Aphids Spreading Viruses to Tomato Plant

A third issue with having aphids on your tomato plants is that these pests can spread viral diseases. When an aphid feeds on an infected tomato plant, it can become a carrier for the virus the plant is suffering from; infected aphids then transfer the virus to healthy plants when they move onto another garden. 

For example, one viral disease that aphids often spread is the cucumber mosaic virus. In tomato plants, this disease causes stunted plant growth, yellowing or mottling of the leaves, and leaves that appear shoestring-like. In severe cases, this disease will cause the tomato plant to produce few poor-quality tomatoes. 

What Does Aphid Damage on Tomato Leaves Look Like?

There are a few telltale signs that indicate there is an infestation of aphids on your tomato plants. If you notice any of these symptoms, you’re likely dealing with an aphid infestation:

  • Tomato leaves are curled, misshapen, and/or turning yellow
  • Stems and leaves of tomato plant covered in sticky residue
  • Deformation of tomatoes
  • Large number of tiny bugs on underside of tomato leaves or on stems
  • Tiny bugs at base or on roots of tomato plant

The symptoms of aphid damage are similar to those of other types of pests or plant diseases. You should determine that these are definitely the bugs on your tomato plants before proceeding with any aphid control methods

tomato plant aphid damage

How to Get Rid of Aphids on Tomato Plants

Methods to get rid of aphids on tomato plants include manual removal, washing the aphids off with a hose, or treating the tomato plants with essential oils or neem oil. 

Manually Get Rid of Aphids

For smaller infestations of aphids on tomato plants, you can get rid of the pests by hand. 

Method:

  1.  If there are very few aphids on your tomato plants, use a dry paper towel to pick the aphids off by hand. Gently crush the aphids before disposing of the paper towels. For more extensive infestations, use a wet paper towel to wipe the aphids off the tomato leaves and directly into a garbage bag.
  2. Inspect your tomato plant for any remaining aphids. Make sure you don’t leave any aphids on the plant as this leaves it vulnerable to a reinfestation.
  3. Take another wet paper towel and use it to rub any sap or honeydew off the stems and leaves of your tomato plants. This is important to avoid attracting a new infestation of ants or aphids.

Use a Hose to Get Rid of Aphids

You can remove moderate infestations of aphids on tomato plants using a hose to blast the pests off plant foliage.

Method:

  1. In the morning, use a hose to spray your tomato plants with a jet of water. Remember to focus on the underside of leaves as this is where the aphids will be in highest numbers. A low-pressure setting will be ineffective in removing the aphids; make sure your hose has enough pressure to blast off the insects without breaking the plant. 
  2.  Allow the leaves of the tomato plants to completely dry. 
  3. Once again in the evening, spray the tomato plants with a jet of water.
  4. Repeat the previous steps daily until you have eradicated the last of the aphids.

Use Essential Oil to Get Rid of Aphids

Essential oils are a natural repellent to many types of insects, including aphids. A treatment of essential oils will therefore work to get rid of aphids on tomato plants and prevent them from returning.

Method:

  1. Mix 4 to 5 drops of peppermint, rosemary, clove, and thyme essential oils with 1 cup of water.
  2. Spray the essential oil solution directly onto the infested tomato plants in the morning. You can also make an additional treatment once again in the evening. 
  3. Repeat applications daily until you get rid of all aphids on the tomato plants.

Use Neem Oil on Tomato Plants

Neem oil is another natural insect repellent that will get rid of aphids on tomato plants. This oil kills aphids by suffocating them and disturbing their reproductive cycle.

Method:

  1. Dilute 1 tablespoon of neem oil in 2 cups of water.
  2. Spray the neem oil solution all over the tomato plants, focussing on the underside of leaves.
  3. Repeat once per week until you have eliminated the last of the aphids.
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How to Kill Aphids on Tomato Plants

To kill aphids on tomato plants naturally, you can use diatomaceous earth, insecticidal soap, or an organic pesticide. Inorganic means of aphid control involve using a chemical pesticide.

Use Diatomaceous Earth to Kill Aphids

Diatomaceous earth is a natural powdery substance that will kill aphids on contact. On a molecular level, diatomaceous earth has razor sharp edges that cut into soft-bodied insects like aphids; this causes the insect to gradually dehydrate before dying.

Method:

  1. Purchase food-grade diatomaceous earth. This type of DE is non-toxic and certified as safe to use in your garden.
  2. Dust your tomato plants with the diatomaceous earth. Make sure to cover the underside of leaves and add a sprinkling around the base of the plants.
  3. Monitor your tomato plants, repeating applications of the diatomaceous earth until you have killed all of the aphids. This could take repeated applications over 2 weeks or more.
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Use Insecticidal Soap to Kill Aphids

Insecticidal soap is a low-toxicity organic pesticide that will kill aphids on tomato plants naturally. Made from potassium and fatty acids, insecticidal soap kills aphids by suffocating them. It is an excellent method of natural aphid control for larger infestations. 

Method:

  1. Purchase insecticidal soap, or make it yourself by combining 1 cup of oil with 1 tablespoon of dish soap.
  2. Mix 1 teaspoon of your insecticidal soap with 1 gallon of water. Place the mixture into a spray bottle.
  3. Spray the insecticidal soap solution on the leaves of the tomato plant and on any aphids you can see. 

Use Organic Pesticide to Kill Aphids

Before resorting to commercial treatments, you should create your own organic pesticide to kill aphids on tomato plants without chemicals. An effective DIY aphid spray is easy to make using some basic household items, such as dish soap or vinegar.

Method:

  1. Make a natural vinegar spray for aphids by combining white vinegar and water in a ratio of 1:3. 
  2. Spray your DIY aphid spray on the stems and leaves of the affected tomato plants.
  3. Repeat applications weekly until you kill the aphids.
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Use Chemical Pesticide to Kill Aphids

If your aphid infestation is severe or resistant to natural methods of control, you can use chemical pesticides as a last resort. 

Method:

  1. Purchase a systemic pesticide that contains the chemical Imidacloprid.
  2. Apply the pesticide to your tomato plants early in the morning. 
  3. Repeat applications of the pesticide as per its instructions until you kill the last aphids.

How to Prevent Aphid Infestations on Tomato Plants

Grow Companion Plants to Repel Aphids

There are certain plants that have natural aphid-repellent properties. Growing these so-called companion plants alongside your tomato plants will help to prevent infestations of aphids in your garden. 

Plants that repel aphids include basil, chives, garlic, leeks, onions, oregano, and sage. All of these plants have strong odors that aphids will avoid, keeping your nearby tomato plants free of the pests. These companion plants also work to deter other garden pests like squirrels, chipmunks, and deer. 

Avoid Overfertilizing Tomato Plants

Aphids on tomato plants almost exclusively seek out the new, tender growth that the plants produce. Applying too much fertilizer will cause an influx in new growth; this will make your tomato plants a prime breeding and feeding ground for the aphids. 

Rather than fertilizing your tomato plants all in one go, add the full amount of fertilizer in smaller quantities throughout the growing season. You could alternatively carry out less frequent fertilizations using a slow-release formula. 

Control Ant Populations on Tomato Plants

Ants will protect populations of ants on tomato plants in order to feed on their honeydew. Monitor your tomato plants for ant infestations and treat them as necessary. 

Check Tomato Plant Seedlings Before Transplanting

One of the most common ways that aphids spread around a garden is through infested seedlings. Seedlings are particularly vulnerable to aphid infestations as these pests have a preference for young, tender growth. 

Before transplanting, check your tomato plant seedlings for aphid infestations. Avoid transplanting any seedlings infested with aphids and treat the affected plant as soon as possible. 

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