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I haven't been able to find a picture on the web that looks exactly like this. Although I am suspicious that it is early blight. Any help is appreciated. I have quarantined it but need to know if I should just chuck it.

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I am in Sacramento, CA which is zone 9B. These are plants I started from seed. I used those expanding pellets from Jiffy. I have hand watered and kept them pretty moist. They are about 5 weeks old and about two weeks ago I transplanted to 4" pots with bagged mulch soil. Kellogg's raised bed mix and gave them their first fertilizer at 1/4 strength. Also of note I just started hardening them off the last couple of days. But this is the only plant affected out of 36. I did notice it is just around the veins. I hope this picture will suffice. I will post another one that shows what suspect may be a slime trail, so maybe a baby snail came over from the nearby agapanthus. I had put them on the patio table in full sun for three hours and then put them in the shade, which is 10 feet from the agapanthus until I brought them in around 11pm.

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The only leaves affected are the first set of true leaves. The newer sets, about 4, seem unaffected. Thank for your very thorough information and interest!

  • Please use the edit link underneath your post if you want to update it to add new information. Thanks!
    – Niall C.
    Commented Mar 12, 2017 at 23:15
  • OK. I just couldn't figure out how to add more than 1 picture.
    – Susan Ross
    Commented Mar 14, 2017 at 16:45
  • Were the affected leaves grown indoors? Commented Mar 18, 2017 at 7:03
  • Yes they started indoors. They started the hardening off period before the spots showed up
    – Susan Ross
    Commented Mar 24, 2017 at 18:24

2 Answers 2


You are right to quarantine the plant from others.

The magnified photo showing the underside of the leaf is out of focus, but it appears there might be an infestation of mealy bug.

The photo showing the top of the leaf indicates damage throughout the leaf structure that I though appears consistent with spider mite infestation, however this can also be caused by mealy bug.

Please attempt to upload a photo of sharper focus to the underside of the leaf for confirmation.

If this is mealy bug, then I'd recommend...

Chemical treatment: a half dose (due to age of plant) white oil spray over every part of the plant.

Organic / biodynamic treatment: a half dose (due to age of plant) neem oil spray over every part of the plant.

Adding a very small amount of detergent will assist coverage of leaves and pests as it destroys the natural surface tension in water. This also helps to suffocate pests - instead of forming droplets/bubbles on objects, water collapses and literally drowns pests.

Don't use half strength fertiliser. Tomatoes, even as seedlings, are hungry plants and need a lot of food.

Also consider applying a "tonic" that might contain seaweed and/or soil micro-organisms in suspension.

I'd highly recommend planting basil amongst your tomatoes. The aromatic oils emitted from the basil help to repel potential pests and make the tomatoes taste so much sweeter.


"Tonics" that contain seaweed or seaweed extract are:

  • a good fertiliser that will support strong and robust plant growth; and
  • a good soil builder to help improve the organic matter content of soil and soil microbiology.

Seaweed and its extracts have a broad and balanced range of nutrients and importantly trace elements.

Peter Bennett's book "Organic Gardening" taught me how trace elements facilitate or catalyse the "uptake" / absorption of both nutrients and other essential trace elements.

For example, certain ratios of trace elements that benefit absorption of ionic Magnesium can benefits plants, as Magnesium is essential for many plant functions, including:

  • Photosynthesis: Magnesium is the central element of the chlorophyll molecule;
  • Carrier of Phosphorus in the plant;
  • Magnesium is both an enzyme activator and a constituent of many enzymes;
  • Sugar synthesis;
  • Starch translocation;
  • Plant oil and fat formation;
  • Nutrient uptake control;
  • Increase Iron utilization;

and the list goes on...

So healthy soil containing a broad and balanced range of nutrients and trace elements will help your plants grow strong, fruit/flower well and be resilient to pests and disease.

  • I do have basil growing as a companion. I also growing borage and marigolds. I hope to have a health peaceful community surrounding my tomatoes. Thanks for the advice. Also, when I transplant into the garden. Do I bury up to the seed leaves or up to the true leaves? I can't find anybody being specific about that. Thanks.
    – Susan Ross
    Commented Mar 24, 2017 at 0:40
  • While the plant is young bury to the seed leaves. It shouldn't matter too much - plants are resourceful - but my philosophy is to attempt to place as little stress on the plant as possible. With older plants you can safely plant deeper so more of the "trunk" is covered in soil. There is the philosophy that burying the original root ball deeper provides greater resistance to drought, but honestly in my experience it is better to encourage the plant to grow deeper roots with deep watering regime. Commented Mar 24, 2017 at 0:55
  • Thanks for your input. It is very helpful. Did the new picture of the underside suffice or do you need it magnified? It's a little hard to focus with the scope but if it will help diagnosis I am happy to do it. And what does the seaweed tonic do for my babies?
    – Susan Ross
    Commented Mar 24, 2017 at 18:30
  • The photo showing the underside of the leaf is still out of focus. It may be easier to take a standard photo, as close as you can to the leaf and maintaining focus, but without the glass... we can use the zoom feature in the software to get a closer look. See updated answer re tonics. Commented Mar 26, 2017 at 1:34
  • Wow that is a lot of great information. I really appreciate it. I think have all my amendments ready to go. Along with the seaweed (maxsea), bat guano and chicken manure and of course a tomato specific fertilizer with 4 - 6 - 2. Plus mulch to work into my impossibly dense clay soil.
    – Susan Ross
    Commented Mar 27, 2017 at 19:11

Doesn't look like blight to me...please turn that leaf over and look at it with a magnifying glass...send us a picture. This looks like the work of some sucking tiny insect. One HAS to get an ID BEFORE any treatment. This is like a major honor system for pesticide applicators. How many leaves have been affected like this? What are your watering methods? The blight I know, early and late are very dark patches. If you do get blight all the plant material needs to go into a burn pile. Your soil will be full of blight spore. No tomatoes, potatoes, egg plant, peppers...plants in the same family should be planted there the next year...I'd wait for two and then take measures so no spore is able to splash up onto your plants.

But I am dying to see the underside of that leaf. See how the majority of necrotic tissue is around the veins? This would be an insect thingy. Do not do anything until you send us more pictures and more information. Sometimes we get leaf miners or similar that cause some leaf decimation but no big deal for producing fruits. Tell us what you have done for fertilizer. Where did these plants originate? Did you start them? How old are these plants? Again, need to understand your watering methods. What kind of soil? Are these raised beds and WHERE do you live, what zone are you in?

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