I recently noticed that some of my plants are getting some spots on their leaves.

First it was my eggplants: eggplant white spots

And now my marigolds: Marigold white spots

Both are isolated to a single pot, so I moved the affected pots to a different location in case it's something that can move from pot to pot.

What are these spots? Should I have to work about them? And it's there something I can do to fix them?

Update: I found this guy messing around my plants (less than 1mm long). Any idea if this is related?

Some kind of insect

1 Answer 1


This looks like thrip. Very difficult to control because the kids live inside the leaves and make those pale miniature tunnels.


  • black dots called frass on the leaf
  • pale tunnels that look like trail maps
  • no webbing or white fluffy spots that would indicate mites or mealy bug
  • in cases where there are lots of adults they look like a black exclamation point

The adults are good fliers and move when disturbed so quick action will save you loosing more plants.

My recommendation is to bag and throw the plants out and any you may find in the future. I was unable to control thrip using a variety of pesticides that are much more lethal than soap and water.

These plants look to be in a greenhouse so I recommend putting a fine mesh over any vents so pests cannot fly in.

  • Do these bugs just like, fly in? This is not a greenhouse, but my balcony. I like in a 14th floor in the middle of ultra-urban Tokyo, and I find it a bit hard to believe something like that would just fly in, in an area with very little vegetation around. Maybe the soil I used had something inside? Commented Jun 30, 2021 at 23:15
  • @user36149 well they are not great flyers. If it's unlikely that they flew up to your balcony the other way to arrive is with plants that you bought from a store. They don't come in with soil.
    – kevinskio
    Commented Jun 30, 2021 at 23:57
  • I looked at the plants with a magnifying glass, and there were indeed lots of black dots on the leaves. Is this something that if you find it it means it's too late and all your plants are likely affected (the only way to fix this is to burn the entire house down, or something like that?). I also added a photo of an insect I found messing around my plants. Is this related? Commented Jul 1, 2021 at 2:06
  • @PandaPajama the new picture is not a thrip. I recommend you remove the infected plants, check for new outbreaks daily and remove any problems
    – kevinskio
    Commented Jul 1, 2021 at 11:13
  • Thanks for the suggestion. It breaks my heart, but I removed these two pots. If I see a localized infection, do you think it would be okay to just remove the affected leaves? I'll continue inspecting every plant with a magnifying glass every day. Commented Jul 1, 2021 at 11:15

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