Entomology and Plant Pathology, Oklahoma State University
127 Noble Research Center, Stillwater, OK74078
Vol. 12, No. 14
May 9, 2013
Check Canola for Aphids, and Cabbage Maggot
Tom A. Royer, Extension Entomologist
I received a report of a canola field that was heavily infested with green peach aphids, and had some activity from cabbage maggot. Both insects are known pests of canola, as well as other crucifer crops.
Cabbage maggot is the larvae of a fly that was introduced from Europe in the 19th century. The fly resembles a common house fly be is smaller and ash grey in color. It overwinters as a pupa and emerges in spring. Flies begin to lay eggs (up to 200 per female) about 1 week after emergence. The larva is a small, white, legless maggot. When they hatch, they move into the soil and start feeding on small roots and root hairs, and eventually tunnel into the taproot. They will feed for 3-4 weeks and pupate in the root or in the soil near the root. They may cause swollen, hollowed out area at the base of the stem at the soil line. Heavy infestations can cause reduced bloom, severe lodging and yield loss. Infestations will be much greater during cool wet springs. There is no registered insecticide available to control cabbage maggot.