Extension > Garden > Diagnose a problem > What insect is this? > Garden Pests > Flies, moths, wasps,and other insects with obvious wings - Under 1/4 inch long > Onion maggot
Onion maggot
Delia antiqua
Description: 1/4 inch long. Greenish gray slender body. Has dark stripes on the thorax. Wings are clear. Note: Similar looking flies may also be present. Have flies identified if there is concern that they may be pests.
Where/When: The female lays eggs at the base of onion plants and in nearby cracks in the soil. Active April and May.
Significance: The larva causes damage by feeding on the onions. Infested plants can appear discolored, wilted, or stunted and damage may kill young plants.
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