How to Manage Pests
UC Pest Management Guidelines
The seedcorn maggot adult is a slender, light gray fly, about 0.20 inch (5 mm) long; it is less robust appearing than the housefly. The whitish eggs are slightly curved with their posterior bluntly rounded. Slightly raised ridges run the length and width of the eggs forming tiny rectangles twice as long as wide. Larvae range from 0.20 to 0.25 inch (5 to 6 mm) in length, are white to whitish yellow, cylindrical, and taper anteriorly. Pupae are small brown capsules. The seedcorn maggot is abundant during or following a wet cycle, which is primarily in spring, and is most common in fields containing a high amount of residue from a previous crop or where manure has been spread.
Seedcorn maggots burrow into bean seeds and prevent germination. Slow emergence and poor stand establishment are signs of seedcorn maggot activity. Where slow, spotty emergence is observed, seed should be dug up and inspected for maggot feeding. Soil and weather conditions such as cool soil temperature and periods of excessive moisture favoring slow seed germination and seedling emergence increase susceptibility to seedcorn maggot infestation.
Organically Acceptable Methods
UC IPM Pest Management Guidelines: Dry