Tomato pests can chew leaves, suck sap, damage fruit, or spread plant diseases. The best approach is to identify the culprit before treating, then use the least harmful effective control and check whether it worked. Before you begin, inspect both sides of leaves and look for insects, eggs, webbing, droppings, and feeding damage; symptoms alone can be misleading.
What You’ll Need
- Hand lens or magnifying glass, if available
- Gloves and a small container of soapy water for hand-picking pests
- Clean pruning shears for removing badly infested leaves
- A strong, adjustable spray of water or a hose nozzle
- Optional: insect netting, row cover, or a pesticide specifically labeled for tomatoes and the pest identified
Step-by-Step
- Inspect the whole plant. Check leaf undersides, new growth, stems, flowers, and fruit. Look early in the morning or evening, when many pests are easier to spot. Check several plants, including nearby weeds and plants in the same family, such as peppers and eggplants. Note the damage and where it appears.
- Identify the pest before acting. Holes, yellow leaves, or curling can also result from disease, weather, or watering problems. Look for the pest itself or clear evidence: clusters of small pear-shaped aphids, fine webbing and stippling from spider mites, white moth-like adults and tiny insects beneath leaves from whiteflies, or large caterpillars and dark droppings from tomato hornworms. Slugs often leave irregular holes and silvery slime trails. Take a clear photo or ask a local extension service or garden center if you are unsure.
- Remove pests by hand when practical. Pick off hornworms, beetles, and egg masses and drop them into soapy water. Remove only leaves that are badly infested or damaged, using clean shears; avoid stripping the plant of healthy foliage. Check the plant again every day or two while the problem is active. Wear gloves if handling insects or plants that irritate your skin.
- Dislodge small sap-feeding pests. For aphids, whiteflies, or spider mites, direct a firm but gentle stream of water at leaf undersides and growing tips. Support stems so they do not break. Repeat every few days as needed, and avoid keeping foliage wet overnight. This may reduce numbers but will not reliably eliminate an established infestation.
- Protect plants and reduce hiding places. Use insect netting or row cover before pests arrive, securing edges so insects cannot crawl underneath. Remove weeds and fallen leaves around the plants, and keep the area tidy. Do not cover plants during conditions that risk overheating or block pollinator access to open flowers; remove or open covers when necessary for pollination.
- Use a pesticide only if simpler measures are not enough. Choose a product whose label specifically permits use on tomatoes and names the pest. Follow the label exactly for mixing, application, protective clothing, re-entry, and the preharvest interval—the time to wait before picking fruit. Do not assume a product is safe because it is described as natural or organic. Test a small area first if the label allows, and never apply in wind, high heat, or when bees are visiting flowers. Avoid broad-spectrum sprays that can kill pollinators and beneficial insects.
- Recheck and record results. Inspect treated plants after a few days and repeat only as the label permits. Record the pest, date, and action that helped. Keep checking new growth and nearby plants, because eggs may hatch after the first cleanup.
Common Mistakes
- Treating symptoms without identifying the cause: A spray will not fix sunscald, nutrient problems, or disease, and can harm helpful insects.
- Spraying every insect: Lady beetles, lacewings, and parasitic wasps prey on pests. Learn to recognize them and leave them undisturbed.
- Using too much pesticide or mixing products: More is not more effective and can injure plants or expose people and wildlife. Never combine products unless their labels explicitly allow it.
- Ignoring leaf undersides: Many pests feed and lay eggs there, so a quick look at the top of leaves misses the problem.
- Removing too many leaves: Heavy pruning reduces the plant’s ability to grow fruit and can expose tomatoes to sunscald.
Tips
- Inspect plants at least weekly, and more often after spotting pests. Early action usually means less damage and less need for treatment.
- Water at the soil rather than over the foliage when possible. Avoid drought stress, which can make plants more vulnerable to spider mites.
- Rotate tomato planting locations each year where space allows, and clear plant debris at the end of the season. Rotation can help disrupt some pest life cycles, though it does not control every pest.
- Keep tomatoes properly supported and spaced for airflow and access. Follow the spacing guidance for your variety rather than crowding plants.
- Check that a product’s label covers the exact pest and crop, and observe its harvest waiting period every time you apply it.
Troubleshooting
The damage continues after hand-picking. Look for eggs, tiny newly hatched insects, or pests on neighboring plants. Repeat inspections and remove new pests. If the culprit remains unclear, get an identification before choosing a treatment.
Leaves look stippled or bronzed, but no insects are obvious. Inspect closely for spider mites and fine webbing, especially on leaf undersides during hot, dry weather. Rinse the foliage and reduce plant stress. If symptoms spread, confirm the pest before using a labeled treatment.
Leaves are sticky or curled. Check new growth for aphids or whiteflies and look for ants, which may be attracted to sugary honeydew. Wash pests off and monitor the plant; persistent symptoms without visible insects may have another cause.
Fruit has holes or is being eaten. Check fruit, stems, and nearby soil at dusk for caterpillars, slugs, or other feeders. Remove visible pests and damaged fruit. Do not apply a pesticide to ripening fruit unless its label explicitly allows it and you can meet the preharvest interval.
A treatment appears to have damaged the plant. Stop applying it, follow the label’s advice for exposure or plant injury, and seek local expert guidance. Do not add another product to counteract it.
Frequently Asked Questions
Can I use dish soap to control tomato pests?
Household dish soaps vary and may damage leaves, especially in heat or sunlight. Use an insecticidal soap labeled for tomatoes and the target pest, and follow its directions rather than making a homemade mixture.
Are tomato hornworms harmful?
Yes. They can quickly strip leaves and damage fruit. Pick them off when you find them. If a hornworm has white, rice-like cocoons on its back, leave it in place when possible; these are beneficial parasitic wasp cocoons.
Should I remove leaves with pests on them?
Remove a badly infested leaf if doing so will not leave the plant bare. For a few pests, washing or hand-picking is often better than removing healthy foliage.
Can I eat tomatoes after spraying?
Only after the product’s label-required preharvest interval has passed. Wash produce before eating, but washing does not replace the waiting period or other label instructions.
Do marigolds keep tomato pests away?
They may attract beneficial insects, but planting marigolds is not a dependable way to prevent or control tomato pests. Use inspection, identification, and targeted measures instead.
When should I ask for expert help?
Seek help if damage is spreading quickly, the pest is unfamiliar, or your identification is uncertain. Provide clear photos of the plant, the damage, and any insect or egg you find.