Question
QUESTION: Hi Elyse

It's been very cloudy, wet and generally humid here for the last few days.  I've just noticed some tiny jumping gnat-like insects on my tomato plants - I can't really tell what colour they are, but they seem to like sitting on the soil rather than the plants themselves, and hide in the edges of the pot and the potting mix.  I can't really tell what they are - could you recommend something precautionary that might work for flying bugs in general?  Would a commercial insectside spray do the trick?

On that note, what would be signs that they ARE affecting the plant itself?  They're only seedlings; small and green.

Thanks!

Dom

ANSWER: Dom:
If they are on the soil, they are probably fungus gnats. You can get a yellow sticky-trap and hang it (or attach it to a stick) above the soil. Or you could douse the soil with a neem oil or insecticidal soap solution.

They don't hurt the plant, they feed on fungi in the soil, but they can be a nuisance in numbers.

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

QUESTION: Thanks Elyse - are there particular ingredients in insecticides I should stay away from to avoid hurting the plants themselves?

Answer
Mostly, follow the directions on the product you buy. Insecticides are designed to kill insects without harming plants, but the inert ingredients can be harmful under certain conditions, e.g. hot temperatures. Insecticidal soap for example, should be washed off the next day lest is clog the leaf pores and smother the plant.

Elyse