Fruit flies: where they come from, how fast they multiply and how to catch them

Fruit flies almost always appear where fruit is ripening or fermenting. A female lays hundreds of eggs, and at room temperature an egg becomes a new fly in just over a week. That is why a few flies turn into a swarm so quickly. What works best is the combination: remove the source and put out a trap with an attractant.

Straight to the solution: Get rid of fruit flies or go straight to the Super Ninja Fruit Fly Trap.

What attracts fruit flies and where do they come from?

Fruit flies have a very keen sense of smell. They react to the substances released when fruit ripens or rots, such as alcohol and acetic acid. That is why you find them around the fruit bowl, the food waste caddy and empty wine, beer and juice bottles. Coffee grounds, wilted flowers and damp sponges attract them too. The eggs often come into the house on fruit from the shop.

When are fruit flies most common?

Fruit flies like warmth. They develop fastest between 21 and 25 °C. In the UK you see them mainly from June to September, with a peak in July and August. In a warm kitchen they are around all year.

How fast do fruit flies multiply?

Very fast. A female lays up to 500 eggs in her lifetime, preferably on ripe or fermenting fruit. At room temperature the larvae hatch within a day. After 8 to 11 days the egg has become a new fruit fly that lays eggs itself. Adult flies live for several weeks. So a few flies become hundreds within two weeks.

Where do fruit flies lay their eggs?

On fermenting, moist, sugary spots: the skin of ripe fruit, fruit scraps in the food waste bin, juice and wine left in bottles and the damp film in drains. The eggs are about half a millimetre long and barely visible to the naked eye.

Are fruit flies harmful or dangerous?

Fruit flies do not sting or bite. They can, however, carry bacteria and yeasts from spoiled scraps onto fruit and other food, and fruit with eggs on it goes off faster. Above all they are a nuisance: if you do nothing, you soon have a swarm in the kitchen.

How do you catch fruit flies?

With a trap that mimics the smell of fermentation. Homemade traps with vinegar, juice and a drop of washing-up liquid catch a few, but need refreshing often. The Super Ninja Fruit Fly Trap uses an attractant of 37.5 % vinegar and 5 % apple juice concentrate and works without insecticide. In independent testing under the European Biocidal Products Regulation the trap caught 84.9 % of fruit flies within 24 hours, with competing food in the same room (SAGEA, report 4540.SAG, 2021). One trap works for up to 3 weeks; allow one trap per 30 cubic metres of space.

View all fruit fly traps

How do you prevent fruit flies?

Prevention is easier than cure. These five steps help most:

1. Keep the kitchen and tables clean. Wipe surfaces with drink or food residue regularly.
2. Eat ripe fruit in time or keep it cool. Fruit flies do not lay eggs in the fridge.
3. Use a fruit bowl with a lid. That way the flies cannot reach the fruit.
4. Watch your waste and empty bottles. Keep food waste tightly closed and rinse bottles before putting them away.
5. Keep drains clean. Flush drains regularly with hot water so no residue builds up.

Use biocides safely. Always read the label and product information before use.