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Plant Diseases/Spotting on tomato plant leaves


Tomato plant leaves
Tomato plant leaves  
QUESTION: Hello!  I recently planted sugar baby tomato plants.  I used new garden soil and planted them in a raised bed with legs.  They get lots of sunshine and water.  I feed them about every 10 days or so with Miracle-gro tomato plant food.  They are over a foot tall now and were doing so well.  About 2 weeks ago I began to notice a growth on the leaves and need to what that is and how to treat it.  I am attaching a photo of the leaves for you to review.  Thank you in advance for any advice or help you can provide.

ANSWER: Hi Karen,

Are all leaves affected or only some of the leaves.  From the photo, the problem looks like edema (oedema).  This occurs when the soil is wet and the leaves are not using much water.  Often that will occur when the humidity is high, the plants may be partially shaded or if the soil is not well-drained.

If this is edema, the problem should improve once the temperatures increase and the weather becomes drier.  I would hold back on watering the plants and only provide water when the soil feels moist when you stick your finger in about 1-2 inches.  The spots will not go away on the old leaves.  But, the new leaves should appear normal and healthy if edema is to blame.

If you are still having problems when the plants put on new leaves, please let me know.  I will try to help you through the problem.

Good luck!

---------- FOLLOW-UP ----------

QUESTION: Hi Jennifer,
Thank you for such a quick response! The leaves are the worst at the bottom although the spotting is starting to affect some of the top ones as well.  Should I remove the spotted leaves?
  They are in well drained soil in a wooden bed raised off the ground on legs.  There is a liner underneath the soil , the kind that is used on garden beds to prevent weeds from growing under mulch. It is not solid and does allow for excess water to drain.
 I forgot to mention hat I live in NY if that makes any difference or helps in anyway.  Thank you for any further advice!

If there are only a few leaves, you can remove them.  But, if there are many damaged leaves, I would hold back.  

If the leaves are green and unwilted, they are still photosynthesizing in the undamaged areas.  When the plant is ready, it will suck the nutrients out of the affected leaves and send them to other parts of the plant.  The damaged leaves at that point will most likely turn yellow and drop from the plant.  If you remove them, the plant does not get the chance to divert those nutrients to other parts of the plant.  

Give it a week or so and see if the plant improves.  If you are having rainy or overcast weather, the problem may continue.  Once you have clear, warm days is the time to check the new growth and I would expect it to be normal.

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Jennifer Olson


Plant diseases affecting vegetables, fruits, nuts, lawns, trees, shrubs and ornamental plants. I have just volunteered as an expert on this site as of 01/2011.


Identification and management of plant diseases. Have been employed as a Plant Disease Diagnostician since 2002 and currently work in the Plant Disease and Insect Diagnostic Laboratory at the Oklahoma State University.

National Plant Diagnostic Network, Great Plains Diagnostic Network

B.S. Biology - Lebanon Valley College; M.S. Plant and Soil Sciences,concentration Plant Pathology - University of Delaware; Ph.D. in progress - Oklahoma State University.

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Home gardeners, Hobbiests, Plant Breeders, Extension Educators, Nurseries, Greenhouses, Golf Courses, Departments of Agriculture, Industry professionals

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