THE MONTHLY BULLETIN. 



257 



period, makiny numerous burrows, causing rot and injury to the plant. 

 In about three weeks they are ready to pupate either in the old burrows 

 or in the soil. They form a smooth brown puparia from which the 

 adult flies emerge in one or two weeks and at once begin to lay eggs 

 for another brood. The winters are passed in the pupal and adult 

 stages. There are several generations a year. 



Distribution. — This insect occurs as a pest particularly in the north- 

 ern part of the State, but its distribution is wide. 



Fig. 2.5.5. — Work of the cabbage maggot on Swedish turnips. (Original.) 



Food Plants. — The maggots burrow into the roots of many of the 

 cruciferous plants, including the cabbage, cauliflower, radish, turnip 

 and rutabaga. The young plants sufi^er most from their attacks, entire 

 fields being badly injured. This is particularly true of young cabbage 

 plants. Radishes and turnips not killed, when young continue to afford 

 food for the maggots. 



Control. — The control of such a pest is extremely difficult and relief 

 measures are usually employed as preventatives. Among the most 

 efi^ective of these are the placing of sand, soaked in kerosene, around 

 the bases of each plant as soon as transplanted or well up in the field. 



12— H 



