INJURIOUS TO CABBAGE AND RELATED CROPS 41 



Control. 



Both the nymphs and adults of the harlequin cabbage bug 

 are very resistant to contact insecticides. In fact it is prac- 

 tically impossible to kill them in this way without injuring the 

 plants. Loss may be prevented in large measure by practicing 

 clean cultural methods of farming. After the crop has been 

 harvested, all cabbage stumps and other refuse should be plowed 

 under or destroyed in some other way. Hibernating shelter in 

 the form of overgrown fence rows or patches of rank weeds 

 should be reduced to a minimum. It is sometimes advised to 

 leave a few piles of rubbish in the field in the fall as traps for the 

 hibernating bugs. After they have collected in such shelter, 

 the rubbish should be burned. 



Very effective work can be carried on against the bugs in the 

 spring by the use of trap crops. Kale, mustard and rape are 

 often utilized for this purpose. If a few of these plants are sown 

 so as to be available for food before the crop it is desired to protect 

 is up, the insects will congregate on these plants where they may 

 be killed by spraying with pure kerosene or in some other way. 

 In the fall it is a good plan to leave a few cabbage, turnip or kale 

 plants after the remainder of the field has been cleaned. The 

 bugs will collect on these plants where they may be easily de- 

 stroyed before going into hibernation. The destruction of the 

 adults early in the spring is the most important measure for the 

 control of the insect ; if this work is done with thoroughness the 

 crop will remain relatively free from attack for the remainder of 

 the season. If the bugs are not destroyed in early spring, the 

 only recourse is to hand-pick them into pans of kerosene — a 

 tedious and laborious operation. 



References . • 



N. C. Dept. Agr. Ent. Circ. 8. 1904. 



U. S. Bur. Ent. Circ. 103. 11)08. 



Smith, Jour. Ec. Ent. 2, pp. 108-114. 1909. 



