Onion Maggots / Onion Fly

Catalogue Type
Plant Pests Catalogue
Scientific Name
Delia antiqua
Family
Anthomyiidae
Distinguishing Characters
The onion fly has an ash-grey body and resembles a housefly. The male has a longitudinal stripe on the abdomen which is lacking in the female. The legs are black, the wings transparent, and the compound eyes brown. 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. The larvae are white and cylindrical and hatch in 3 to 8 days. Each batch of larvae tends to keep together and collectively create large cavities in bulbs. More than 50 maggots may feed on one bulb, sometimes originating from eggs laid by several females. The larvae moult three times, feed for about 20 days, and grow to about 1.0 cm long. The pupa is brown, ringed, and ovoid and measures 7 mm (0.28 in) long. Pupation occurs in the ground with the pupal phase from the spring generation lasting two or three weeks. Late-generation pupae overwinter in the soil
Host Crop
Onion , Garlic
Order
Diptera
Photo of Insect
Photo of Damaged Crop
Description

Nature And Damage of Maggot:
The maggots feed on seedlings, transplants and bulbs. Infested plants wilt and turn pale green to
yellow. First generation maggots in the spring cause the most damage. Young plants are more
susceptible to attack and can be killed, established plants are damaged but not usually killed.
Feeding damage causes misshapen bulbs and allows the entry other species of maggots and decay
organisms.
Control:
The onion maggot life cycle lasts from 37 to more than 60 days.The first-generation adults emerge
from pupae around mid-May in the northeastern US, with peak flights occurring about 2 weeks
later. Adults can survive for 2-4 weeks and may lay hundreds of eggs, beginning approximately 7
to 10 days after emergence.

Nature And Damage of FLY

It feeds on onion, garlic and chews both in the field and in stores. When plants are attacked, the
leaves start to turn yellow and the bulbs rot quickly, especially in damp conditions. Control
measures include crop rotation, the use of seed dressings, early sowing or planting, survey and
removal of infested plants, and autumn digging of the ground to destroy the pupae.
Control Measures
Application consist of placing sand soaked with a cupful of kerosene in a bucket of dry sand at the
base of the plants along the row is very effective for deteriing the parent files from depositing their
eggs. This will also kill young maggots that might attempts to work through sand.