| Life Cycle: | The adult seedcorn maggot is grey with black legs and resembles a small housefly. It is 5 mm long. It emerges from its overwintered pupa in April. Initially the fly will feed on nectar and honeydew. After mating the female fly will search for hosts around which she will lay her eggs. The adult female is attracted by the odour given off by decaying organic matter. Each female will lay upto 300 eggs in the soil, either singly or in batches. The larvae once hatched will feed on organic matter in the soil including seeds of the hosts. The maggots are yellowish-white, legless and tapered from a narrow head to its flat anterior end. After feeding for approximately 3 weeks, the maggot will pupate. Pupae are shaped like a football and are dark brown in colour. There are generally fewer than four generations each year depending on the weather. |
| Host: | The seedcorn maggot attacks the seeds beans, soybean and peas. Its secondary hosts include corn, cucumber, onion, cabbage, turnip and radish. |
| Bio Region: | Throughout North America. |
| Damage: | The seedcorn maggot is particularly destructive in cold and damp conditions often typical in Atlantic Canada in the springtime. IDamage also seems to be more prevalent in field with high organic matter. The seedcorn maggot burrows into a seed and feeds on its content. It often leaves nothing but the shell of the seed. In some cases, the seedcorn maggot will burrow into the newly emerging stalk of an adjacent plant. Host seeds rarely germinate and those that do rarely mature. Damaged plants can also be subject to disease which may spread to healthy plants. |
| Management: | Consider planting later when the ground has warmed or dried if seedcorn maggot is a persistent problem. Manures or compost should be incorporated into the soil well in advance of planting and preferrably in the fall. This is also true of green manures. Seeds should be planted as close to the surface as possible. High quality seed with the highest germination rates are also adviseable. |
| Controls: | There are no chemical controls for the seedcorn maggot that are allowed in organic systems. |
