Delia antiqua or onion fly maggot damage the bullbs of onions, garlic, chives, shallots, leeks and flowering plants.

The onion fly itself has an ash-grey body and resembles a housefly.  The male has a longitudinal stripe on the abdomen.

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


Photo By Rasbak at Dutch Wikipedia, CC BY-SA 3.0