Common names: Seedcorn maggot
Scientific name: Delia platura
Synonyms: Corn seed maggot, Corn root maggot, Canola root maggot, Bean seed fly
Beans, corn, cabbage, cucumber, lettuce, onion, peas, seed potatoes, spinach and other crucifers
Asia, Africa, Europe, North America, USA
The maggot burrows into the seeds and the seedlings, proceeds into the lateral roots, then tunnels into the taproot, and sometimes bores into the base of the stem. Damaged plants will wilt, stunt, and/or eventually die.
In corn, damaged seedlings have curled, dried, or dead leaves.
In beans, damaged seedlings do not have primary
leaves and/or severely damaged primary leaves.
In seed potatoes, feeding damage causes bruised, decayed, or diseased ones which fail to germinate.
Eggs are elongate and pearly white with a diagonal pattern. They are deposited near the seeds or seedlings, especially those grown in soil with abundant organic matter.
Larvae are small maggots, yellowish-white to dirty-yellow, and legless. They undergo three larval stages. Larval development lasts for about 12-16 days.
Pupae are tan to brown in color. They are situated near the host plant. The pupal stage is about 7-20 days.
The adult flies are grayish-brown and look like small houseflies. The female adults prefer to lay their eggs in newly harrowed fields. They can lay about 100 eggs over a 3-4 week period. Life span is about 1-2 œ months.