INJURIOUS TO CABBAGE AND RELATED CROPS 29 



The Cabbage Root-INIaggot 



Phorbia brassiccL Bouche 



Throughout the greater part of the United States and Canada 

 and in Europe, cabbage, cauhflower, turnip, radish and related 

 crops are subject to serious injury by a small whitish maggot 

 that burrows in the roots. It is also destructive in Alaska. 

 In the northern states and Canada it is especially injurious to 

 early cabbage and is 

 very troublesome in the 

 seed-beds of late cab- 

 bage. Radishes also 

 rarely escape attack. 

 In some regions the 

 growing of these crops 

 has been abandoned 

 temporarily because of 

 the ravages of this pest. 



The parent flies, as a 

 rule, emerge in early 

 spring and have been 

 recorded as feeding on 

 the pollen of flowers. 

 In the latitude of New 



York they emerge from the middle of ^Nlay till the middle of 

 June and may be seen around the plants searching for a 

 favorable place in which to deposit their eggs. In British 

 Columbia eggs have been found as early as April 10. The fly 

 is about -g- inch in length and resembles the house-fly in general 

 appearance. The male (Fig. 25) is dark ash-gray in color with 

 three blackish stripes on tlie thorax ; there is also a wide })lack 

 stripe on the abdomen, which is continued laterally along the 

 edge of the segments. The female is lighter in color and the 



Fig. 25. 



Male fly of the cabbage root- 

 maggot (X 5|). 



