INJURIOUS TO CABBAGE AND CRUCIFEROUS CROPS 361 



The Potherb Butterfly * 



This species is more common in the North and East and is 



distinguished from its near rela- 

 tives by the wings being uniform 

 white without spots. The larvse 

 are veiy similar to those of the 

 imported species and the habits 

 are very similar. Like the south- 

 ern species, though formerly very 

 common and often injurious, 

 this species . is now rarely com- 

 mon enough to do much injury 

 and feeds mostly on w r ild plants. 



FIG. 261. The potherb butterfly 

 and caterpillar. (After Harris.) 



The same remedies as for the imported species should be used. 



The Cabbage Looper f 



Next to the imported cabbage worm the looper is probably 

 the most serious pest of cabbage and closely resembles it in the 

 way it strips the foliage. The name " looper " is derived from 

 its " looping " habit of walking like a measuring worm, due to the 

 absence of legs on the third and fourth abdominal segments. 

 The larvse are pale to dark green in color, marked with several 

 longitudinal white lines, as shown in Fig. 262, which become 

 obscure as they become full grown, so that they might be easily 

 mistaken for the common cabbage worms were it not for the loop- 

 ing gait. The species occurs throughout the territory east of the 

 Rockies, but is much more commonly injurious in the Middle and 

 Southern States. Although cabbage and cauliflower are the 

 favorite food plants, it attacks all of the cruciferous crops, is 

 frequently injurious to lettuce, peas, celery and beets, and has 

 been found upon quite a list of cultivated crops and various weeds. 



* Pontia napi Linn. Family Pieridce. 



t Avtographa brassicae Riley. Family Noctuidce. See F. H. Chittenden, 

 Bulletin 33, n. s., Div. Ent., U. S. Dept. Agr.; F. A. Sirrine, Bulletin 144, 

 N. Y. Agr. Exp. Sta. 



