Get rid of fruit flies

Fruit flies appear out of nowhere: you put a bunch of bananas on the worktop and two days later ten of them are circling the fruit bowl. Harmless but persistent, and waving them away does nothing.

Where do fruit flies come from?

They rarely fly in from outside. In almost every case the eggs travel in on fruit and vegetables you bought at the shop. Those eggs are barely visible and sit on the skin. As soon as the fruit ripens they hatch, and within a day you have a population.

What attracts them?

Fermenting sugars. Overripe fruit is the classic, but also a half empty wine glass, the bottom of a soft drink can, the sponge by the sink, the bin, a damp cloth and the drain itself. Coffee grounds on their own do not attract them, but a damp coffee container with residue around it does.

How quickly do fruit flies reproduce?

This is the heart of the problem. A female lays up to five hundred eggs and the full cycle from egg to adult takes roughly eight to ten days at room temperature. Two fruit flies become hundreds within a fortnight. That is why they seem to appear everywhere overnight, and why swatting the occasional one changes nothing.

Are fruit flies dangerous?

They do not bite or sting and carry no disease to people. They do walk over the bin and then over your fruit, so hygienic they are not. The main objection stays that there are many of them and they will not leave on their own.

How to tackle them

A trap with a natural lure catches the adults so no new generation follows. Place it next to the fruit bowl or by the bin, because that is where they search. At the same time remove the source: overripe fruit out, bin emptied, drain flushed, and fruit into the fridge or under a cover. The trap breaks the cycle, you remove the reason.

Do not confuse them with fungus gnats

If the flies come out of the soil of your houseplants rather than from the fruit, they are fungus gnats. Those need a different approach, namely the larvae in the compost. In that case see get rid of fungus gnats.