Control of Fruit Flies Indoor Basil

Asked June 24, 2020, 10:23 AM EDT

A friend of mine grows basil indoors in a somewhat enclosed terrarium. Lately he has noticed a lot of bugs as he describes in the quote of his email below. Attached are 3 photos that may help in identification of the insect. My thinking is that they may be fruit flies and I know how to create the vinegar and soap in a jar trap to kill the adults if they are fruit flies. My thinking is also that the damp soil may be the breeding ground. If so, how would one safely kill the eggs and larvae and still be able to eat the basil? Quote: "As far as I can tell there aren’t any nibbles on the leaves. It’s more of they’re just a nuisance to see. I got a photo of the larva form of them which do have red eyes. They’re white grubs with red eyes in that form. I would say when they’re in their fly form they flit about. They don’t really fly that much. The fly looking ones have teeny tiny legs. And if it helps I only see them on the underside of the leaves. They’re never on top of the leaves. That could just be coincidence by I don’t know. They’re only between the plastic wrap and the window. No where else in the house. The basil is in the front bay window of the house so not in the kitchen where all the other food is."

Frederick County Maryland

5 Responses

Hi- yes, these are fruit flies. The basil is safe to eat after rinsing leaves to remove any larvae. Larvae feed on organic material.
https://extension.umd.edu/hgic/topics/fruit-flies
Jon

Is there any safe way to kill the eggs and larvae in the soil?

Hi- we are not aware of any safe insecticide that could be applied to potting soil to kill eggs and larvae. Reducing the adult population with a vinegar trap and by removing any soft or rotting fruits from countertops is the surest way to reduce the overall population. It's also possible that there are fungus gnats in the potting soil. They can be eliminated by allowing the top of the media to dry out before watering.
Jon

Many thanks!!!