Onion Flies

several species of insects of the family of true flies and bulb flies, which are dangerous pests of onions.

Onion flies are found in Europe, Asia, and North America; in the USSR they are found wherever onions are raised. The larvae harm the plants by feeding on the juicy bulb tissues. The damaged bulbs rot, and the leaves of the plant dry and turn yellow. The onion fly Hylemyia antiqua is 5-7 mm in length and light gray, with a faint greenish tint on the back. The larva is up to 10 mm in length and white. In addition to onion bulbs, they cause damage in leeks, garlic, shallots, and scallions. The onion bulb fly (Eumerus strigatus) is 6.5-9 mm in length and bronze green. The larva is up to 11 mm long and dirty yellow to greenish gray in color, with wrinkles. It attacks onions, garlic, tulips, narcissus, irises, and at times the underground parts of potatoes, carrots, and beets. The lesser bulb fly (Eu. tuberculatus) is similar morphologically and in life cycle to the onion bulb fly. Countermeasures include fall plowing, early planting and transplanting of onions, use of healthy sets, and application of insecticides before planting. Onions with full tops should never be treated with pesticides.