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Aphids On Tomato Plants (Treatment and Prevention)

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It’s not uncommon to feel a sense of panic when you notice aphids on your tomato plants. They’re one of the most annoying garden pests you can find, and they reproduce incredibly fast. One day, your tomato plant was doing just fine. The next day, you go out and its covered in this nasty pest!

Fear not! This is our ultimate guide for treating and preventing aphids on your tomato plants in the vegetable garden. This treatment will apply whether you’re growing tomatoes in raised beds or in containers.

Aphids on tomato plant

What are aphids?

Aphids are small, sap-sucking insects that attach themselves to the leaves of your precious tomato plants. Female aphids don’t need a male to reproduce, and many of them are born pregnant.

So as you can imagine, an infestation can get out of control very quickly. You’ll want to act in a timely manner if you notice a lot of aphids congregating on your tomato plants.

If you only see a few aphids, and your plants do not appear to be suffering any damage, it may be worth waiting. Nature does a great job at balancing itself out!

​Identifying aphids on your tomato plants

There are many different species of aphids, and they come in a variety of colors and sizes. They can also be difficult to see with the naked eye. This doesn’t make it any easier to identify them when you’re pest-hunting in the garden. Here are some tips for identifying aphids:

  • Check your foliage carefully – If you’re looking for aphids on your tomato plants, you’ll want to check very carefully on the undersides of the leaves or in any curled leaves. These pests love to hide in the crevices of your tomato plants.
  • Look for cornicles – Aphids are soft-bodied insects, pear-shaped, and always have cornicles protruding from their posterior end. Think of these cornicles as “tail pipes.” If you see them on a pear-shaped body, it is likely an aphid.
  • See how they move – When disturbing an aphid on a plant, it’s worth noting they will not jump or scurry away. You’ll also often find them in a large group with other aphids, but not always. Some aphids also have wings, but not all of them do.
  • Keep an eye on new growth – Be sure to place close attention on the new growth of your plant foliage as well. Aphids tend to prefer the tender, young leaves.
  • Look for honeydew – If you notice a lot of ants on your tomato plant, it may be an indication you have aphids. Aphids excrete a sticky substance called honeydew which ants feed on.

How to get rid of aphids on your tomato plants

Aphids on plant stem

Now that you have identified that you have an issue with aphids, it’s time to get rid of them. It’s tempting to immediately reach for the strongest pesticide, but you don’t want to do that!

This is our preferred order of managing aphids on our tomato plants.

Note: This guide is for treating aphids on your tomato plants. If you notice aphids on your non-edible indoor houseplants, you may consider treating with systemic insecticides. These are not suitable for edible plants.

1. Use a strong stream of water

Stream of water from hose

If you notice a large amount of aphids on your tomato plant, the first thing you should consider doing is blasting them off with a garden hose. The strong spray of water will knock these pests off without the use of any pesticides.

Don’t do this on any fragile or young plants, as you run the risk of them breaking from the pressure. You’ll also want to move the plant (if possible) away from the rest of your garden to avoid spraying the aphids off onto other plants.

This isn’t a one-and-done treatment, but it is a good first step. Some gardeners have told us they use this method as their only defense against aphids in the garden. It’s a great way to get the aphids off your plant quickly and reduce the population and damage.

Tip: Use your thumb over the edge of the hose to create a stronger jet of water. You can also purchase a purpose-built bug sprayer attachment for your hose.

2. Beneficial insects

Ladybug larvae
Ladybug larva on tomato leaf.

Beneficial insects are one of the best ways to manage aphids on your tomato plants. Natural predators feast on aphids, keeping your garden in healthy balance. While ladybugs (a.k.a lady beetles) are great natural predators for aphids, we do not recommend purchasing them. By doing so, you may be introducing non-native ladybugs to your garden.

Instead, consider green lacewing eggs which are much more effective against this pest. You can also attract predatory insects, like parasitic wasps and ladybugs, to your garden to manage the aphid populations. Plant alyssum and other flowers to attract these natural enemies to your garden.

3.  Insecticidal Soap

Insecticidal soap

If you are not having any luck with beneficial insects or the occasional spray from the hose, the next option for treatment is a good insecticidal soap. Many people recommend using something like dish soap to control aphids on their tomatoes, but this is not recommended.

Dish soap is a detergent and is much too harsh for your plant’s foliage. Think about how well Dawn cleans the oil off your dishes. Do you really want to strip your plants leaves of any protective coating?

The best soap you can use is a purpose-made insecticidal soap. These soaps are made with potassium salts and are gentle on plant foliage. The fats in the soap break down the body of the aphid and dehydrate them.

Depending on the soap you choose to purchase, the directions for application will vary. Insecticidal soap is sprayed directly on your plant and reapplied every few days. Avoid spraying your plant when direct sunlight is reaching the leaves.

Good insecticidal soap options:

4.  Neem Oil

We use 100% cold pressed neem oil as a last resort for managing aphids. It’s commonly the first product people reach for, but we like to try other options first. Neem oil is not an instant fix, and it takes a bit of time to work.

This oil smothers the pest while also interfering with their reproductive cycle. Neem oil can be a bit messy, so you will want to designate a specific spray bottle for this mixture. The mixture itself needs to come in direct contact with the aphids in order to be effective.

Dr. Bronners castile soap mixed with neem oil and water is a good base solution for treatment. We like using the peppermint scent as it also works to repel aphids. But, the unscented version works as well.

​Neem oil spray recipe for tomatoes:

  • 1 tablespoon (0.5oz) 100% cold-pressed neem oil
  • 1/2 – 1 tablespoon (0.25 oz – 0.5 oz) castile soap
  • 1 gallon water (lukewarm)

5.  Consider Companion Planting 

Nasturtiums with variegated leaves

This option may not be ideal if it is later in the season. But, it’s always good to plan for next year. Planting the right flowers and herbs in your garden can help keep aphids away from your precious tomato plants.

  • Nasturtiums – Not only are the foliage and flowers beautiful, but the aphids will be more attracted to these plants than your vegetables. These flowers will act as a “trap” as they lure the pest away. Using sacrificial plants like this can help keep populations under control.
  • Alyssum – This easy-to-grow flower attracts all those good predatory insects to your garden. You’ll want to attract these beneficial bugs to your garden not only to control aphids, but other pests as well.
  • Garlic / onions – Alliums naturally deter aphids from your garden. And, they’re a tasty companion plant for your tomatoes!

Remember, treatment for this pest is more about controlling the aphid population in your garden rather than eradicating it. This is best done with the help of beneficial insects. Though, severe infestations, or those that happen indoors, may require a few extra steps.

There is no “best” way of treating pests in your garden. The most you can do is try to maintain a healthy ecosystem of life amongst your plants. This will result in healthy plants and tasty harvests.