If you garden for long enough, chances are, you’ll find aphids on your plants. Aphids are an incredibly common pest in the organic garden. They impact almost every plant and they can be incredibly frustrating to deal with.
Take a deep breath. We’ve got you covered. We’ve been handling aphids organically for years, and we’ve got all of our tips, tricks, and control methods for you today. Let’s send those pesky bugs packing!
Are Aphids Bad for Tomato Plants? How to Identify. Prevent and Get Rid of Them
Aphids are tiny sap-sucking insects that can wreak havoc on tomato plants An aphid infestation can stunt growth, cause leaves to curl and turn yellow, spread diseases, and reduce yields With a rapid reproduction cycle, just a few aphids can quickly turn into an out-of-control infestation. So are aphids bad for tomato plants? The short answer is yes. Left unchecked, these prolific pests can decimate a tomato crop.
Identifying Aphids on Tomato Plants
Aphids are soft-bodied insects that measure about 1/8 inch long. Most are green or yellow but they can also be pink, brown, red, or black. Some species have wings while others do not. Aphids have piercing-sucking mouthparts which they use to feed on plant sap. Signs that your tomato plants have an aphid problem include:
- Curled, yellowing leaves
- Leaf drop
- Stunted plants
- Sticky residue on leaves and stems
- Deformed tomatoes
- Black sooty mold on leaves
- Small white shed skins on leaves (from nymphs molting)
- Clusters of small bugs on stems and undersides of leaves
On close inspection, you’ll find the aphids themselves congregating on young shoots, the undersides of leaves, and where the stem meets main branches. Ant trails may also lead to infested plants since ants feed on the honeydew secretions of aphids.
Why Aphids Are Bad for Tomato Plants
Aphids weaken tomato plants by consuming the sap, depriving the plant of nutrients. The toxins they inject while feeding cause further harm. As they feed, aphids also transmit viral diseases from plant to plant. The honeydew they secrete promotes fungal growth like sooty mold. Left uncontrolled, aphids can utterly devastate tomato crops:
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Leaves yellow, curl, and drop due to loss of nutrients and plant stress. This decreases photosynthesis.
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Growth is stunted.
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Plants become more susceptible to bacteria and viruses.
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Fruit can become deformed, blemished, and covered in sooty mold.
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Tomato yield declines. Severely infested plants won’t produce any fruit.
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Plants weakened by aphids are more vulnerable to other pests like spider mites.
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Aphids can kill young transplants and seedlings.
The takeaway is that aphids spell trouble for your tomato garden. Their feeding inhibits plant processes and they spread disease. Fruits become blemished and yields plummet. And since each female can produce up to 12 offspring a day, a small infestation quickly mushrooms into disaster. The earlier you take action, the better.
How to Prevent Aphids on Tomato Plants
An ounce of prevention is worth a pound of cure when it comes to aphids on tomato plants. Here are some effective ways to help safeguard plants:
Use Row Covers
Covering plants with fabric row covers excludes winged aphids that would otherwise fly in and attack your tomatoes. Make sure to secure the edges well so pests can’t sneak underneath.
Employ Companion Planting
Certain plants naturally repel aphids through their strong scents. Planting onions, garlic, chives, nasturtiums, and marigolds around your tomatoes can deter aphids. Trap crops like mustard and nasturtiums lure aphids away from your tomatoes.
Use Reflective Mulch
Silver reflective mulch confuses aphids and deters them from plants. The light bouncing off the mulch’s surface makes it harder for them to navigate toward tomato plants.
Release Beneficial Insects
Ladybugs, lacewings, and other predatory insects feed on aphids. Attract them to your garden by planting flowers like daisies and cosmos. You can also buy live ladybugs and release them around your veggies.
Use Neem Oil
Applying neem oil spray early in the season smothers aphid eggs before they hatch. It also repels the adults. Mix 1-2 tablespoons of neem oil with water and spray tomato plants every 2-3 weeks.
Avoid Stressful Growing Conditions
Aphids target stressed, weakened plants. Follow optimal tomato growing practices to keep your plants as vigorous and healthy as possible. This includes rotating crops, watering adequately, and maintaining the proper soil pH.
Regular Scouting
Inspect your tomato plants closely each day so you can spot any aphid invaders right when they first arrive. Handpick or prune away infested parts before they multiply. Catching infestations early is key.
How to Get Rid of Aphids on Tomato Plants
If preventive measures have failed and your tomato plants become infested, it’s crucial to get the aphids under control quickly before they spread. Here are effective organic and chemical remedies:
Blast Them Off With Water
Aim a strong jet of water directly at the aphids to knock them off the plant. Focus on the undersides of leaves and other hiding spots. Repeat daily until all aphids are gone.
Apply Insecticidal Soap
Insecticidal soaps based on potassium salts of fatty acids kill aphids on contact. Coat all plant surfaces, especially the undersides of leaves. Reapply every 5-7 days for 2-3 weeks.
Use Neem Oil
The azadirachtin in neem oil disrupts the aphid lifecycle. It’s most effective on young nymphs but also kills adults. Follow label instructions for timing and dosage.
Spray With Horticultural Oil
These highly refined petroleum oils smother aphids when applied directly to infested plants. Thorough coverage is important for good results. Don’t apply horticultural oils during hot weather.
Apply Pyrethrins
Pyrethrins are plant-derived insecticides that quickly knock down aphid populations when sprayed on infested tomato plants. However, pyrethrins can also kill beneficial insects. Use cautiously.
Employ Insecticidal Soap
Insecticidal soaps also work by penetrating the aphid exoskeleton and causing cell damage. Mix 2-3 tablespoons per gallon of water and spray plants until dripping. Rinse leaves after 3 hours.
Use Neonicotinoids
Systemic insecticides like imidacloprid are absorbed by plants and make the foliage toxic to sucking insects. Apply as a soil drench or seed treatment for longer-lasting control. Avoid spraying neonicotinoids where pollinators are present.
Sprinkle Diatomaceous Earth
The razor-sharp edges of diatomaceous earth damage the waxy coating on aphids causing fatal dehydration. DE is non-toxic when used as directed but will also kill beneficials. Apply a light dusting to dry foliage.
Prune Heavily Infested Areas
Remove badly infested leaves and branches where aphids are concentrated. This instantly reduces their numbers. Just be careful not to overprune and stress the plant.
Wipe Leaves With Oil
Mix 1 part vegetable oil with 2 parts water in a spray bottle. Gently wipe leaves, especially the undersides, to smother aphids on contact. The oil clogs their breathing pores. Rinse leaves after 30-60 minutes.
Set Out Sticky Traps
Yellow sticky traps lure aphids in, trapping them on the adhesive surface. Position traps near infested plants to help catch dispersing aphids. Combine traps with other methods for better control.
Sprinkle Flour on Leaves
Coating leaves with flour is an old-fashioned remedy for aphids. The fine particles get wedged in their feeding tubes, causing dehydration. Rinse the flour off after several hours before it harms plant tissues.
Use a Strong Water Spray
Blasting aphids off plants with a high-pressure stream of water can help manage light infestations. Focus on the undersides of leaves where aphids hide. Avoid using this method on delicate plants.
Remove Ants
Ants tend and protect aphid colonies. They harvest the honeydew secretions. Getting rid of ants deprives aphids of their guardians. Apply sticky barriers around plant stems to exclude ants.
The key with any aphid treatment is persistence. Keep inspecting and reapplying controls until every last aphid is gone. This prevents them from rebounding and attacking your tomatoes again.
Are Aphids Bad for Tomato Plants?
Water and Dish Soap
If you don’t want to make our bug repellent, you can also spray the plants with a mixture of water and dish soap. This homemade insecticidal soap works by coating the aphids and suffocating them. Make it by mixing mix a few teaspoons of liquid dish soap with one quart of water, then spray or wipe the solution onto the leaves, stems, and buds of the plant. If you have a bad infestation, you might want to go the wiping method—it’s tedious, but it will make sure you get all the aphids on all parts of the plant.
Many people will attempt to control aphid populations by introducing predatory insects such as ladybugs or lacewings to their gardens. While these insects do prey on aphids, we don’t typically recommend this route. Usually, the predatory insects you add yourself are better suited for another environment, and they will leave before controlling the aphids. Instead, we recommend using companion planting and interplanting your tomato plants with herbs and flowers that will attract the predatory insects that are native to your area. Working on having a robust beneficial insect and pollinator garden will also help you reduce all pests (not just aphids) in the long term.
Don’t forget the birds! Birds (especially small birds like hummingbirds) love to snack on a meal of aphids, so when you’re planning your garden, make sure to make your garden bird-friendly. You help them out, they’ll help you out!
Diatomaceous earth (DE) is a silica-rich powder made from fossilized algae. While it doesn’t feel like much to us, to soft-bodied insects like aphids it can be deadly. The jagged edges of each grain cut into the aphids, leading them to dry up and die.
A sprinkling of DE on both the soil and the plant can help kill aphids. Be sure to select food-grade DE, which is safe for humans, instead of filter-grade DE, which is not. Diatomaceous earth doesn’t work when wet, so apply in the early morning after the dew has dried, or later in the evenings.
Growfully Tip: Do not use DE when plants are in bloom, as it can hurt pollinators like bees! If you must use DE during these times, apply it in the evening, when bees are sleeping and pollinator activity is low.
Neem oil is a horticultural oil that works in a few ways—it can work similar to insecticidal soap by suffocating aphids, and it can also work as a systemic insecticide by messing with the hormone receptors in an insect. Because neem is a broad-spectrum insecticide, it is pretty much our last-resort aphid control method. While neem oil is all-natural and organic, it is also a powerful insecticide that can harm bees and other pollinators. We prefer to work on aphid infestations using other control methods.
Symptoms of Aphids on Tomato Plants
Stunted leaves that are misshapen or curling around the edges are a sure sign of aphids. Because this pest sucks the sap and other nutrients out of leaves and stems, the leaves struggle to grow properly. If you suspect there is an aphid infestation, look closely at the tops and undersides of the leaves, as well as the stems. Aphids are visible to the naked eye, but they can still be pretty small, making it difficult to see them at a glance.
Another sign of an aphid infestation? Ants! Yup, aphids produce a substance called honeydew—it is clear and sticky and will coat the areas where the aphids have been. Ants are attracted to this sugary honeydew, so if you see a lot of ants on or around your tomato plants, you may have an aphid problem. The ants are larger and easier to see than the aphids, so if you see a bunch of ants, look closely to see if aphids have set up shop.
If the leaves or stems of your plants appear black, that might also be another sign. The honeydew that aphids secrete can harbor sooty mold, which tints the plants black.
How To Get Rid of Aphids On Tomato Plants
FAQ
How do you get rid of aphids on your tomato plants?
To eliminate aphids on tomato plants, start by blasting them off with a strong stream of water from a hose. For persistent infestations, consider using insecticidal soap or neem oil sprays, ensuring to cover the undersides of leaves where aphids often hide.
What does aphid damage look like on tomato plants?
Aphid feeding can cause severe damage to plants including yellow spots on leaves and blighting. Early stage symptom of aphid feeding include small spots with silver color on the upper side of the leaves.
Will soapy water kill tomato plants?
Should I remove aphids from plants?
Yes, be concerned. Aphids can devastate plants. Luckily you can just spray the off with the hose and a little pressure. In my experience, if you get them off, they don’t return.