The adult is a tiny gray fly with black legs and scattered bristles on its body.
It’s only around a quarter-inch long.
The larva is a typical fly maggot, with legless skin, a pointed head, and a rounded tail.
It is white to yellowish white and about 1/4 inch long when grown. Both adults and larvae are nearly identical to onion maggots.
Host plants:
It is most widespread in late spring and early summer, wreaking havoc on crops like beans and peas. Larvae also cause injury to spinach leaves by feeding on the terminal buds of overwintered plants.
Territory:
Delia platura seems to be the most widespread anthomyiid in all regions except Antarctica. It was first documented in Germany and has since spread throughout the United States, including Alaska, Hawaii, and southern Canada. It is a significant pest across North and South America and Europe and is also present in Japan, India, Australia, and northern Africa.
Damages caused by Seedcorn Maggot:
Seedcorn maggots destroy newly planted seeds by feasting on seed contents, leaving empty shells and leading to poor germination. The seedlings that do emerge are tall and wiry, with few leaves. Feeding is frequently followed by an invasion of decay organisms, which causes black staining of the leaves in 2 or 3 days. Damage is particularly probable in cold, rainy springs and organic-rich ground. Plants are seldom destroyed. However, they suffer from moderate to severe weight loss.
Life history and habits:
The seedcorn maggot pupates in the soil throughout winter. Adults emerge in early spring and feed for a varying amount of time on nectar and honeydew. Following eating, each fertilized female begins depositing an average of 270 eggs in damp soil, either singly or in tiny clusters. Ovipositing females prefer freshly disturbed soil, fields with decaying seed or crop residues, and organically treated soils. Larvae feed on seeds or decaying vegetable debris and hatch in 7 to 9 days. They can survive in temperatures as low as 40 degrees Fahrenheit. After 1 to 3 weeks of eating, the larvae dig deeper into the earth to pupate. Pupation can extend anywhere from 7 to 26 days or even all winter. There are 3 to 5 generations every year. The spring and fall generations are the most numerous and destructive. Only a few adults survive the summer. According to trapping data, adults are most active in Oklahoma from February to early June and from early September to early December.
