Seedcorn maggot

The seedcorn maggot (Delia platura) is a significant agricultural pest belonging to the order Diptera and the family Anthomyiidae. This insect is widely distributed and known for causing substantial damage to germinating seeds and young seedlings across various horticultural and field crops.

The larvae of the seedcorn maggot attack a broad range of hosts, including legumes like beans and peas, cucurbits such as cucumbers and squash, as well as corn and onions. By feeding on the endosperm or the embryo, they destroy the seed before it can emerge, leading to poor crop stands.

The biology of this pest involves several generations per year. They overwinter as pupae within the soil. Adults emerge in early spring, and females are attracted to fields with high organic matter content or recently tilled soil, where they deposit their eggs near the moisture-rich, germinating seeds.

The primary damage occurs underground when larvae bore into the seeds or tunnel into the stems of emerging seedlings. Plants that do survive often show stunted growth and increased susceptibility to secondary infections by soil-borne fungi and bacteria, which can be just as devastating as the insect feeding itself.

Integrated management practices include:

• Utilizing high-quality, vigor-tested seed to ensure rapid germination.
• Delaying planting until soil conditions are warm enough for fast plant emergence.
• Avoiding incorporation of raw manure close to the time of sowing to reduce adult attraction.
• Practicing proper crop rotation to break the cycle of pest buildup.
• Applying preventative insecticidal seed treatments in fields with a history of infestation.