196 ECONOMIC ENTOMOLOGY 



Larva. — Variable in color, pale green or brownish caterpillar, ij^^ 

 inches long, often dark striped; head amber-yellow; legs black. 



Pupa. — In a small oval cell in the ground. 



Life-history. — In Canada there is one brood, perhaps two in some 

 southern localities. The insect hibernates as a pupa. The moth 

 emerges the following July, when eggs are laid on the silk of the ears. 

 The young caterpillars feed upon the young kernels until fully de- 

 veloped, when they descend to the ground and transform to pupae in 

 small oval cells. Known in the South as the Cotton Boll Worm. 



(/) Stalk Borers 



Several species of Stalk Borers are injurious to various cultivated 

 plants, such as hop vines, columbines, corn, potatoes, tomatoes, rasp- 

 berries, asters, dahlias, and also to burdocks. The caterpillar lives 

 inside the stem and makes a burrow by devouring the interior. As 

 a result the plant often withers and dies. Before maturity it works 

 its way down to the root where it changes to a pupa. The Stalk 

 Borers have been placed mthegeneTa,Gortyna,Hydroeciaa.ndPapaipema. 

 Gortyna immanis occurs in hop vines; Papaipema piirpurifascia in 

 columbine; P. nitela in corn, dahlia, aster, potatoes, etc; P. cata- 

 phrada in burdock; Gortyna micacea in rhubarb, corn, potatoes, etc. 



Garden Stalk Borer {Papaipema nitela Guen.). — This borer tunnels 

 the stalks of potatoes, tomatoes, and other garden crops, and many 

 weeds. Sometimes feeds on strawberry. One brood a year. 



Adult. — A mouse-colored noctuid moth, with outer third of fore 

 wings paler and bordered within by a whitish cross-line. Late August. 



Eggs. — Grey, circular, with radiating ridge, 3^^o iiich in diameter; 

 hatch in late May or early June. 



Larva. — Mines in the leaf at first, then enters the stalk and tunnels 

 it. Full grown about August; i inch long, purplish to light brown 

 and marked with white stripes except on first four segments of ab- 

 domen; head, neck-shield and anal-shield light reddish-yellow. 



Pupa. — Brown, formed in lower part of stalk. Duration about 

 2 weeks. 



Control. — Clean cultivation; removal and burning of old stalks. 



Potato Stalk Borer {Gortyna micacea Esp.) . — ^A European insect, and 

 a general feeder. Reported on rhubarb, corn, potatoes in N. S. and 

 N. B. 



