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My cherry tomato plant has been showing some yellowing of leaves over the past week or so. Just today I noticed the formation of these cluster of white granules - not sure if it's connected to the yellowing or not. It looks like grains of salt more than anything else; if it's an insect of some sort, I can't get a close enough look to see any legs.

Can you help me identify and respond to this?

Updates:

  • They are stationary when poked
  • They were getting more dense, so I took a toothbrush and knocked them off. They are fairly sticky, so that took some doing. I'll wait to see if they return and examine more closely for legs.
  • I was able to examine some white granules I'd missed earlier in detail under a magnifying glass, and couldn't find any signs of legs. At this point, the waxy response hypothesis seems like the most likely answer. I'll keep the question open for a few more days to see if the white granules return.

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white bits on tomato plant, looks like grains of salt

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  • Do they move (when poked or otherwise) or are they stationary? They could be white fly, which is common in tomatoes...
    – Lorem Ipsum
    Jun 18, 2012 at 5:38
  • I poked one with garden shears; it is entirely stationary and sticks to the end of the shears.
    – Jonathan
    Jun 19, 2012 at 2:52
  • get a magnifying glass and observe with it. If they have legs then spray as @Norm advises, otherwise it could be a waxy exudate sometimes found on plants to reduce water loss
    – kevinskio ♦
    Jun 21, 2012 at 22:04
  • Hi @kevinsky, unfortunately this morning I took a toothbrush and knocked them all off! They were fairly sticky but generally came up in solid grains, they didn't smear. Do you have any examples of beads of wax like this? I did some googling but it seems the wax is supposed to be more evenly distributed.
    – Jonathan
    Jun 22, 2012 at 2:10
  • I cannot find an academic reference to what I've seen on some plants in hot areas but you are better off going with a "bug" diagnosis. A little soap never hurt...
    – kevinskio ♦
    Jun 22, 2012 at 3:19

4 Answers 4

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Aphids ! Use 2tsps of dishwashing liquid to one quart of water, mix and spray to cover all of the insects. Wait 4-7days repeat as needed. Don't spray during heat of the day!

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I used an organic insecticidal soap, it has fatty acid salts in it. Destroys the organisms. I think aphids were my gardenias problem

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Those white granules are crystallized sugar dew from an insect infestation such as scale. You can see a light green scale like insect on the top most leaf of the first image. Alternatively that could be a nymph of the tomato potato psyllid. Check the leaf edges for the adult.

tomato potato psyllid nymph with wings

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OK, I'm very late coming to the party on this - but for anyone else that stumbles upon this, wondering what might be causing the sandy deposits on their otherwise healthy tomato plant stems and leaves - I may well have the answer for you! In my case (which looks and sounds identical to the original poster) the sandy deposits were due to ants hollowing out one of the nearby bamboo stakes holding up the tomato plant (I notice that there is a bamboo stake in the above photo!) Look for damage / a crack in the bamboo and prize it apart with a knife - if ants and/or the same sort of sand-like substance falls out of the crack then you have found the problem! Just replace the bamboo!

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