Recently I saw these black bugs on my tomatoes' leaves. I wonder what bug they are and would they harm my tomatoes, and if they do, how can I get rid of them ?: https://i.stack.imgur.com/YEsnK.jpg https://i.stack.imgur.com/2roAS.jpg

Thank you.

EDIT: Finally, I know the source that produces these flies. It turns out that these flies come from the soil tray nearby that I used to plant curly lettuce.

Yesterday I realized that there are many flies and larvae hiding in the soil, after googling I believe that they are FUNGUS GNATS. https://i.stack.imgur.com/PTH8e.jpg It seems that Ithe soil was overwatered that it attracted the flies.

I used the hydrogen peroxide solution to kill the larvae and used yellow sticky to trap the adults The problem is the adults did fail into the trap, but they still outnumbered and keep increasing in number.

That I'm afraid that the hydrogen peroxide did kill the larvae but it also made the soil wet, and the adults which were not trapped, waiting for the hydrogen peroxide to break then came back breeding in the soil. Please help me to handle the situation, the flies are spreading all over the place :(

  • What are we talking about - the black fly or the whiteish dunno-what?
    – Stephie
    Feb 16, 2019 at 15:26
  • @Stephie the black fly, sorry to confuse you but the whiteish is eggshell dust
    – Kujin
    Feb 16, 2019 at 15:32
  • The fly just looks like a house-fly to me. House fly larvae (maggots) only eat dead material, so they won't harm the plant directly, but the flies may be breeding in the soil and eating roots that have died because of a different problem, like over-watering. (@Stephie - that's not an answer disguised as a comment, because it's mostly guesswork!)
    – alephzero
    Feb 16, 2019 at 17:35
  • @alephzero thank you a lot, it seems that they are house-flies. I just touched the soil this morning to check and and found a bunch of them landing on the soil, because of the dark soil it is difficult to spot them. Do you know what natural way I can get rid of them ?
    – Kujin
    Feb 17, 2019 at 2:03
  • No, they look like a small sucking insect (species unknown). Could it be a species of "leaf hopper". I do see that there is a species of black stink bug that looks somewhat similar (when I searched online with "black bug tomatoes". Perhaps you should ask at your local garden center.
    – user22542
    Feb 17, 2019 at 13:33

1 Answer 1


I posted this as a comment first, but thought the information might offer a reasonable answer or reasonable advice (lacking more information).

No (they are not flies), they look like a small sucking insect (species unknown). It could be a species of "leaf hopper", but it is impossible to tell from the photo. I do see that there is a species of black stink bug that looks somewhat similar (when I searched online with "black bug tomatoes"). Perhaps you should ask at your local garden center(s). They may be able to give you some more specific answers.

  • Thanks a lot, I believe they are Fungus gnats. I edited my question. Please read and give me your suggestions, thank you
    – Kujin
    Feb 20, 2019 at 2:55
  • All of the three new photos have different species of flies in them. They are not the same insect that were in the original photo. I really don't know what you should do to avoid the larger flies, but they usually don't harm outdoor plants. The very tiny ones on the white surface may be fungus gnats, but they might also be fruit flies. I can't tell. There is much information online about how to deal with them. Careful watering is definitely part of a solution to control fungus gnats.
    – user22542
    Feb 20, 2019 at 3:44
  • Thank you for your fast reply. I'm not sure the original photo you saw but I have not changed the photos. The 1st and 2nd are the same that I captured at night. and the 3rd is captured at day. Maybe the light and angle confuse you but they are the same species when you see it here. I've noticed these bugs for days before posting the question. I guess I must water carefully from now, thank you :D
    – Kujin
    Feb 20, 2019 at 4:08

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