White spots on tomato leaves appear due to either fungal disease or insect infestations. As far as fungal diseases go, powdery mildew is the most likely culprit. Tomato psyllids, whiteflies, and spider mites can also leave white spots on the leaves. Fortunately, you use the same treatment for both causes. You must prune off the damaged leaves and apply neem oil. After that, it’s just a matter of watching your plant health carefully for changes. Then, reapply the neem oil weekly until the problem resolves.
Why Do Your Tomato Plant Leaves Have White Spots?
The two main causes of white spots on tomato leaves are fungal growth and various kinds of insect infestations. Either way, the problem can escalate quickly without intervention.
More often than not, white spots on tomato leaves develop due to fungal diseases, like powdery mildew. To infect your tomatoes, the fungal spores travel through the wind and create fungal spots where they stick to the leaves. At first, it just looks like white spots here and there. As the pathogen grows, the infected leaves start to turn white all over.
The fungus will attack all the plants in your garden if left untreated. The wind continues to carry the spores through the air to each of your plants. Eventually, the powdery mildew will damage all the leaves and ruin your tomato crop.
White spots on your tomato leaves can also arise from insect infestations. The insects may leave behind white matter or create the appearance of tomato leaf spots with their mere presence.
The insects that make white spots on tomato leaves most often include:
A type of plant lice, tomato psyllids leave behind tiny white granules as they feed on the leaves. At 1/32 of an inch long, they’re rather hard to see at a glance. Their damage to the leaves is unmistakable, however.
Whiteflies often mimic the appearance of white spots on leaves when gathered in huge numbers. Their ultra-tiny bodies prove difficult to see individually. But as a group, they look like white marks underneath the leaves.
Spider mites create webs that look an awful lot like white mold on tomato leaves. Plus, their feeding activity damages the leaves and gives them a mottled or bleached appearance. Although the mites are tiny, you can usually see them grouped up on the webs.
Many insects invade tomato plants that are spaced too close together or otherwise stressed by their growing conditions. Keep infestations from getting out of control by checking your plants daily for signs of a problem.
With a close look, you should be able to tell if your plant has a fungal disease or insect infestation. Even if not, however, the treatment is the same. So, don’t worry too much if you cannot pinpoint the exact cause.
How Do You Treat White Spots on Tomato Plants?
The same treatment applies whether fungal disease or insects cause the white spots to develop. Just follow these steps to help your plant recover from the issue.
- Remove the damaged leaves using sterilized pruning tools.
- Apply a pesticide and organic fungicide, like neem oil, to all the tomato plants in your garden.
- Monitor the health of your plants closely to see if you need to repeat the steps.
Prevention is key, of course. You can keep the white spots from developing the next growing season if you space tomato plants properly. Stress from crowding increases the risk of plants falling ill and getting infested. Apply neem oil early and often to help keep your plants healthy.
Prune Off the Damaged Leaves
Remove the seriously damaged leaves using these sharp pruning shears. It’s important to make sure they are clean before starting. Leave the minimally damaged leaves if white spots cover much of the plant. Disinfect your tools with an alcohol or bleach solution after pruning each plant. Discard the dead plant material in your yard waste bin or burn pile. Do not put it in the compost. Composting infected leaves can cause fungus spores to infect plants in the future.
Apply Neem Oil
Spritz your tomato plants with this ready-to-use neem oil spray. Only apply the neem oil in the evening. Otherwise, exposure to direct sunlight may damage the remaining leaves. Cover all the plant surfaces with the solution, including underneath the leaves. If you cannot find ready-to-use neem oil, get a concentrated formula. Then, mix it with a small amount of dish detergent and water as directed on the package.
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Monitor Your Plant Health
Neem oil is a pesticide and fungicide. So, it should quickly eliminate the white spots on your tomato leaves, no matter the cause. Carefully monitor the health of your plants after spraying them. Check them daily for signs of insects and fungal growth.
Reapply the neem oil mixture one week later if you still see more white spots appearing. Continue the weekly applications until the problem resolves fully and you see healthy growth in your garden tomatoes again.
What Do White Spots on Tomato Plant Leaves Mean?
White spots on your tomato plant mean it has a fungal disease or insect infestation. Powdery mildew is the most likely cause of the white spots on your tomato leaves. Insects, such as tomato psyllids, whiteflies, and spider mites, can cause similar issues.
- Fungal diseases and insect infestations cause white leaf spots on tomato leaves.
- Powdery mildew is the most common type of fungal disease affecting tomatoes.
- Tomato psyllids, whiteflies, and spider mites all prove problematic for tomato plants.
- Treatment includes pruning off the damaged leaves and applying a neem oil spray.
- Reapplication of the neem oil may be needed depending on the severity of the problem.
Both fungal diseases and insects require the same treatment. To get rid of the white spots, prune your plants and apply neem oil. Then, watch your plants for further signs of a problem. Reapply the neem oil if you still see more white spots developing.
Inspect your tomato plants daily to spot problems as they develop. Fungal diseases, insect infestations, and other issues are much easier to solve in the beginning stages. So, by practicing due diligence, you’re really doing yourself a favor. Plus, you’ll have a much better chance of getting a nice tomato harvest when you keep your plants healthy from the start.