Cabbage root maggot flies are little, hump-backed gray-brown flies that are around 5-7 mm in length. Onion, seed corn, and cabbage maggot flies are difficult to discern with the naked eye, but each will only be seen on or near the crop family that they are associated with.
Small (1/18″) white bullet-shaped eggs are placed in dirt. Maggots are white, legless insects that live in and around roots.
Cabbage maggot flies have the ability to travel up to 1.6 kilometres in search of host plants. They deposit their eggs in the dirt at the plant’s base.
The eggs’ survival is aided by chilly, damp environments. When the larvae hatch, they feed on the plant’s roots.
Host plant:
Cruciferous plants such as cabbage, radish, turnip, Chinese cabbage, and various mustard family weeds.
Territory:
Cabbage maggot (cabbage root fly) is a pest in the northern hemisphere. It was supposedly mistakenly brought from Europe to North America in the early 1800s. Cabbage maggot flourishes in chilly environments and is rarely observed to be a nuisance south of roughly 45 degrees north, and when it is, it is generally at a high elevation. It is found in some of the northernmost agricultural locations and is quite cold tolerant.
Damages caused by Cabbage Maggot:
Cabbage maggot may cause serious damage to cabbage, cauliflower, turnip, radish, and other crucifer crops. The immature maggot feeds on the delicate rootlets before rasping a channel in the plant’s main root. If such a plant is dug up, the white maggots in the soil surrounding the wounded plants’ roots should be visible.
Life history and habits:
This insect spends the winter as a pupa in soil or agricultural leftovers. Adult flies emerge in the Pacific Northwest in early spring, around 200DD (growing degree days) after January 1st. Female flies lay their eggs around the base of host plants or in surrounding broken soil. Maggots hatch in 4 to 10 days and travel below ground, feeding constantly for about 3 weeks. They then emerge from the roots and pupate on or near the soil’s surface. Depending on the time of year, pupae will either a.) Emerge as adult flies 2 weeks later or b.) Overwinter as pupae. Every year, there are several generations.
