Warm evening, window ajar, and your fruit bowl is suddenly surrounded by a tiny brown cloud of fruit flies just as the peaches hit perfect ripeness. Cleaning and interiors experts say it can stop the swarm right where it starts: around the fruit bowl. Why fruit flies swarm your fruit bowl in hot weatherFruit flies, or drosophila, measure only a few millimetres, with brown bodies and red eyes, yet they zero in on the sugary juices that bead on overripe nectarines and bananas. With early summer heat, a fruit bowl left on the worktop or a compost caddy not quite shut behaves like an open buffet. Lemon and cloves act as a shield, pushing fruit flies away from your fruit bowl rather than luring them in.