How to Manage Pests

UC Pest Management Guidelines


Seedcorn Maggot

Scientific Name: Delia platura

(Reviewed 5/13, updated 9/15, corrected 1/19)

In this Guideline:

Description of the Pest

The adult is a light gray fly about 0.2 inch (5 mm) long. Larvae are white, cylindrical, tapered anteriorly, and are also about 0.2 inch (5 mm) long. Larvae can be found inside damaged seeds or in the soil nearby.


Damage generally occurs in localized areas of the field and appears as areas where seedlings have not emerged. Seedcorn maggots hollow out seeds or eat portions of seedlings. Damage is most common in early plantings when the soil is cool, especially in fields with lots of organic matter. Damage tends to be worse on sandier soils.


If cotton follows corn in a crop rotation, seedcorn maggot may become a problem, especially if crop residue is present in soil for the maggot to overwinter on. Once damage occurs it is too late to treat. Planting later in spring when the soil isn't excessively moist and soil temperatures are warmer will help to reduce damage by this pest. Also, destroying vegetation from the previous crop at least 1 month before planting should help minimize damage.



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Cotton
UC ANR Publication 3444

Insects and Mites

  • L. D. Godfrey, Entomology, UC Davis
  • P. B. Goodell, UC IPM Program and Kearney Agricultural Research and Extension Center, Parlier
  • E. T. Natwick, UC Cooperative Extension - Desert Research and Extension Center, Imperial County
  • D.R. Haviland, UC Cooperative Extension, Kern County and UC IPM Program
  • V. M. Barlow, UC Cooperative Extension, Riverside County and UC IPM Program
Acknowledgment for contributions to Insects and Mites:
  • E. E. Grafton-Cardwell, Kearney Agricultural Research and Extension Center, Parlier
  • N. C. Toscano, Entomology, UC Riverside

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