How to Manage Pests
UC Pest Management Guidelines
Scientific Name: Delia platura
(Reviewed 12/09, updated 6/12)
In this Guideline:
DESCRIPTION OF THE PEST
The seedcorn maggot is the larva of a small, light gray fly that is about 0.15 inch (4 mm) long. The whitish, legless maggots are about 0.3 inch (8 mm) long and attack the planted seed of a number of crops during the winter and early spring months, particularly if there is a cold period that prevents quick germination of the seed. Maggots may overwinter in the soil or hatch from eggs laid in spring.
The maggot attacks germinating seeds or transplants, but is only a pest early in the season before the soil warms up. Little damage is likely to occur once favorable growing conditions set in. Seedcorn maggots are particularly damaging when residues of the previous crop have not thoroughly decayed before planting cucurbits.
A preventive seed treatment is particularly important when planting in no-till, conservation-till, and when planting through cover crops to prevent seed corn maggot damage. Additionally, good field sanitation, and production measures that ensure rapid seed germination are important in controlling seed corn maggots.
Fields with moist, heavy-textured soil usually have the worst problem with this pest. To reduce attractiveness of the field to egg-laying adults, disc or plow early in the season to incorporate residues from the previous crop and allow time for residues to completely decompose before planting. Destroy weed growth. Avoid planting cucurbits after root crops or cole crops, including cabbage, cauliflower, broccoli, and Brussels sprouts, and after fall tomatoes. Assure rapid seed germination by planting in moist soil and not too deep (1.25 to 1.5 inch depth is ideal for melons) when weather conditions are ideal. The longer the germination the greater the risk of infestation. Late-season planting may avoid the early season infestation of this pest.
Organically Acceptable Methods
Cultural controls are acceptable to use in an organically certified crop.
Monitoring and Treatment Decisions
A preventive seed treatment is the best method of control.
UC IPM Pest Management Guidelines:
Insects and Mites
Acknowledgment for contributions to Insects and Mites: