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White spots on tomato plants

Craig Allen here, from the Apron Blog


Here's a timely question about tomato plants from reader Michelle:


"What do I do for tomato plants that have white spots on them?"


What should Michelle, and the other tomato gardeners having this problem, do?


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Posted 2012-06-11T16:31:50+0000  by HomeDepotCraig HomeDepotCraig

Howdy Michelle and HomeDepotCraig,


Well, it seems "Hortman" identified one of the most common reason for white spots in Tomatoes. I'd like to add to his answer with common reasons for white spots on tomatoes here on the West Coast.


Powdery mildew occurs in most soft leaf plants like tomatos. The fungus is carried by spores that are carried by wind to plants. Watering too late in the day, poor drainage, and lack of sun increase disease development.


                     pwdrmldw (270x186).jpg


To treat this mildew use multiple applications of non-systemic fungucides like Danconil,Lilly Miller Sulfur Dust, or Safer Garden Fungicide.


daconil (139x270).jpg   sulfur (85x270).jpg   safer.jpg




Leaf Spot can also be a problem. This disease begins in the leaves of tomatoes, starting with the oldest leaves. Both light and dark spots can be seen on both the top and bottom surfaces of the leaves. The spots enlarge and turn a grayish brown. Plants affected by gray leaf spot disease should be treated or removed from the garden to avoid affecting the other plants.



                              graylfspt (171x156).jpg  


Fungicides like the ones mentioned above are effective if applied on a every week for at least 3-4 weeks. If you discover you have Leafspot, do not plant in the same place the following season to prevent reintroduction of fungus. The following year should be fine.

Another common pest is the Leafminers. These bugs are regarded as pests by farmers and gardeners because they cause damage to plants. They can be difficult to control with common insecticide sprays because they are protected inside the plant's leaves.


                  LFMiner (270x231) (2).jpg

  Spraying the infected plants with an non systemic insecticide like Bayer Advanced, Bonide,Ortho Fruit and Vegetable, or Monterey Garden are all effective treatments.

bayernS (80x200).jpg  all-seasons-oil-spray-bonide (85x200).jpg  ortho_ffv_insect_killer_rtu_std (90x200).jpg  unnamed.jpg           


The most important part of dealing with garden problems is addressing the problem quickly rather than putting it off till it's too late. Please feel free to ask more questions you might have concerning your tomatoes.


Happy Gardening,

Best Answer

Posted 2012-06-11T21:47:20+0000  by Dave_HD_OC

Hello Michelle. Ken here in the Chicago area. Thanks for your question.

Your white spots on your tomatoes is sunburn. It is caused by too much

light, too much heat, and/or insufficient moisture. Provide proper moisture.

Provide proper cultural care. Keep pruning down to no more than 20% per year.

I hope this helps. Good luck and take care.

Posted 2012-06-11T18:43:26+0000  by Ken_HD_CHI

Great answers! Thanks so much. 


I'll make sure Michelle sees this. 

Posted 2012-06-12T14:56:14+0000  by HomeDepotCraig
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