If you grow tomatoes, nothing will ruin your harvest faster than potato aphids getting on your plants. These insects feed on tomato stems and leaves, turning the leaves yellow and curled and dropping off. Left unchecked, entire crops can be decimated.
If you catch potato aphids early, they are easy to spot and get rid of. With some knowledge and hard work, you can get rid of these pests in your tomato patch and keep your plants safe.
What Are Potato Aphids?
Pests called potato aphids (Macrosiphum euphorbiae) are small, pear-shaped bugs that eat the sweet sap inside tomato leaves and stems. They range in color from pinkish-red to green to a mix of the two.
These bugs are true gluttons – a single female can produce up to 200 offspring in her lifetime! Colonies multiply rapidly, covering the undersides of leaves and new growth. Their feeding prevents proper nutrient transport in the plant, leading to stunted growth and reduced yields.
How to Identify Potato Aphids on Tomato Plants
Learning to recognize the signs of an infestation is key to controlling potato aphids. Be on the lookout for:
- Curled, yellowing leaves with dried edges
- Stunted plant growth
- Sticky residue (honeydew) on stems and leaves
- White molted skins of juveniles on the undersides of leaves
- Misshapen fruits that don’t ripen properly
- Sooty black mold on leaves and stems
- Large colonies of pinkish-red bugs on terminals and undersides of leaves
- Ants crawling on plants – they “farm” aphids for their sweet honeydew secretions!
Carefully inspect the undersides of leaves, as this is where potato aphids tend to gather. Look for the earliest signs of infestation and take quick action to avoid major crop damage.
Organic Ways to Control Potato Aphids on Tomato Plants
If you see potato aphids on your tomatoes, don’t worry! Here are some safe, natural ways to get rid of the bugs:
1. Spray Plants with Insecticidal Soap
Mix a few teaspoons of liquid dish soap with water and spray plants, especially the undersides of leaves, every 5-7 days to kill aphids through contact. Be sure to cover stems too.
2. Apply Horticultural Oils
These oils smother soft-bodied insects like aphids. Spray all parts of plants, including leaf undersides, with neem, canola or soybean oil diluted in water every 7-10 days.
3. Release Ladybugs and Lacewings
These beneficial bugs devour aphids. Buy them from garden stores or attract them with flowering plants. They provide free pest control!
4. Use Organic Pesticides
Diatomaceous earth, garlic/pepper sprays or pyrethrin-based insecticides can control light to moderate potato aphid infestations. Follow label directions carefully.
5. Prune Heavily-Infested Parts
Remove badly infested leaves and stems to eliminate concentrated colonies before they spread.
6. Use Row Covers
Install fabric row covers over plants to create a physical barrier against pests. Remove at bloom time so pollinators can access flowers.
When to Use Chemical Pesticides for Potato Aphids
For heavy infestations, systemic insecticides or neonicotinoids applied to soil or foliage may be warranted but should be used as a last resort. Always follow label directions carefully to avoid harm to pollinators and the environment. Rotate chemical classes to avoid resistance.
Prevent Potato Aphids from Returning
Stop potato aphids before they start by taking a few simple precautions:
- Use aphid-resistant varieties when possible
- Clean up and destroy leftover plant debris after harvest
- Apply diatomaceous earth or compost around plants
- Use reflective mulches which deter aphids
- Rinse plants weekly with a strong spray of water
- Avoid over-fertilization which encourages aphid growth
- Scout for early signs of infestation and take quick action
With close monitoring and a willingness to intervene early and often, you can keep potato aphids in check and enjoy a bountiful, damage-free tomato harvest. Don’t let these sap-sucking pests take over your patch!
What Do Aphids Look Like?
Aphids are tiny bugs with soft, pear-shaped bodies. They tend to cluster on the stems and leaves of plants, which they bite into to suck out the liquids inside.
Depending on the type of aphid, they may be pale green, black, red, or yellow. On tomato plants in particular, you are most likely to see potato aphids, which tend to be pink, or green peach aphids, which tend to be pale yellow-green.
Organic Methods To Get Rid Of Aphids On Tomato Plants
Integrative Pest Management is very important to us at Growfully Gardens. This means that we use a mix of biological, chemical, cultural, and physical methods to keep pests under control. Lots of layers of gentle protection lead to strong, healthy plants! We’ll talk in a bit about how we prevent aphids from taking hold in the first place, but for now, let’s walk through what we do when we first spot aphids on our plants.
If you only see a few aphids, you can pick them off and drop them into a bucket of soapy water to kill them. Be sure to check the undersides of leaves, as that’s where aphids love to lurk. Check daily for new aphids to determine if you need to take another step to get rid of them.
A sharp blast of water from the garden hose can knock the aphids right off the tomato leaves and stems, lowering the number of aphids in the garden. This is useful if you don’t like getting rid of them by hand or if you have a lot of tomato plants. Check for new aphids every few days to see if you need to spray the plants again. One problem with this method is that water doesn’t care what it hits, and it can also kill good bugs that are on your plants.
We make our own bug repellent for our plants with garlic, rosemary or peppermint, water, and dish soap. It is all-natural and gentle on the plants. While this spray doesn’t kill insects, it does mask the scent of their host plants (the tomatoes) so they get confused and hopefully go somewhere else!
To use this bug repellent, spray the stems, leaves, and undersides of leaves of plants. Reapply every few days until you see few to no aphids on your plants.
How to Easily Treat Aphids on Tomato Plants – Soapy Water & Peppermint Spray: Two Minute TRG Tips
FAQ
How to get rid of potato bugs on tomato plants?
…killing the adult beetles by hand, removing leaves that have eggs that haven’t hatched yet, and using an organic bug killer to kill any potato bugs that hatch (Aug. 4, 2017)
Can tomatoes recover from aphids?
Tomato plants can tolerate large numbers of aphids without suffering yield loss. However, severe infestations can cause leaves to curl and may stunt plants. Decreased leaf area can increase sun scald to the fruit. Aphids are also vectors of certain plant viruses.
What is the best spray for aphids on tomatoes?
Use rubbing alcohol to kill aphids. Dilute it heavily, with 20 parts water to 1 part rubbing alcohol and spray on foliage and stems.
How do you control potato aphids?
Control with natural or organic sprays like a soap-and-water mixture, neem oil, or essential oils. Employ natural predators like ladybugs, green lacewings, and birds. Grow the right plants that attract predatory insects, plants that repel aphids, and plants that “trap” aphids.