The eggs are white and elongated and are laid in groups on the shoots, leaves, and bulbs of host plants and on the ground nearby.

[2][3] The onion fly is found in North America, Western Europe, Russia, Central Asia, China, Japan, and Korea, but is absent from deserts.

[2] The larvae damage bulbs of onions, garlic, chives, shallots, leeks, and flowering plants.

The first generation of larvae is the most harmful because it extends over a long period owing to the females' longevity and occurs when the host plants are small.

When plants are attacked, the leaves start to turn yellow and the bulbs rot quickly, especially in damp conditions.