THE CABBAGE MAGGOT. 



17 



ing" woods the affected plants are more and more scarce, till 

 just over his line in a patch of cauliflower, which is pretty well 

 upon the rise of ground, I was unable to find any sign of the 

 pest. * * * There was not an egg, maggot or pupa to 

 be seen. The number of maggots increased in direct propor- 

 tion as the protecting woods were approached. The notice- 

 able fact about the positions of the patches is that the flies took 

 the cabbages which were the more sheltered in preference to 

 going farther into the wind and getting the cauliflower." 



Trap Crops: Mr. B. planted radishes and turnips amongst 

 his cabbage as trap crops. At the time of the above visit, 

 June i6th. the radishes (which were next the turnips) were 

 practically ruined, hardly a sound root remaining, and the tur- 

 nips nearly as bad, while the adjacent cabbages were fairly 

 free. 



F J ;j 



a ^ 



Fig. 9.— Diagram to illustrate the life cycle of the different broods of the cabbage 

 maggot in Minnesota. (Author's illustration.) 



