Circular No. 5. May, 1907 



MASSACHUSETTS AGRICULTURAL EXPERIMENT STATION. 



ROOT MAGGOTS. 



BY H. T. FERNALD, PH. D. 



For many years persons who have tried to grow cabbage, cauli- 

 flower, onions, turnips or radishes, have realized that maggots are 

 most formidable enemies to these plants. It has been said that 

 tens of thousands of acres of these vegetables have been ruined in a 

 single season by these pests. 



THE CABBAGE ROOT MAGGOT. 



Phorbia brassicce, (Bouche). 



This was considered as a serious pest in the U. S. as early as 

 1833. It, like its food plants, is probably of European origin, and 

 was probably first introduced into Massachusetts, from which in a 

 little over half a century it has spread practically all over the 

 United States and Canada. 



This insect as its name implies feeds upon the cabbage, but it 

 also attacks cauliflower, radishes, turnips and hedge mustard. The 

 presence of the pest where it occurs in considerable numbers is 

 indicated by a checking of the growth of the plant, a tendency to 

 wilt badly in the hot sun and a sickly bluish cast to the leaves. 



The adult fly somewhat resembles the common house fly but is 

 smaller. It makes its first appearance in the spring, about the last 

 of April or the first of May and lays its eggs near the stalk of the 

 plant on which the larvae or young maggots are to feed when they 

 hatch. 



In from three to five days the eggs hatch and the young commence 

 feeding on the roots of the plant. They continue to feed and grow 

 for about three weeks. At this time they are footless and of a shin- 

 ing white color and the body is cylindrical, blunt at one end and 

 tapering somewhat at the other. When full grown they are about 

 one-third of an inch long, and they -then usually work their way into 

 the soil an inch or two and there enter the pupal stage. This stage 

 is spent in the puparium which is elliptical-ovate in form, dark 

 brown in color and consists of the dried outer skin of the maggot. 



After remaining in this stage from two to three weeks the adult 

 fly emerges about the middle of June and lays its eggs for another 

 generation of maggots which work in July. Whether there is still 

 another brood of flies in one season has not been definitely worked 



