146 INSECT PESTS OF BERRIES AND GRAPES 



on the bark. The caterpillar, on hatching, enters the stem and 

 tunnels up and down the canes. This causes a yellowing of the 

 leaves and death of the canes. They pass the winter, full grown, 

 in the stem. At this time they are one-half of an inch long, with 

 brown head. In the spring they transform to pupae just beneath 

 the bark, and soon emerge, leaving the empty skins of the pupae 

 projecting from the bark. 



Control. Infested canes are always easily detected and should 

 be cut off below the injured portion and destroyed by burning; 

 this kills the borers within. Since the bearing qualities of 

 currant and gooseberry are improved by cutting out old canes, 



FIG. 165. The currant borer; larva, adult, and pupal case on left. (Lugger.) 



this yearly practice on the part of the growers would materially 

 help to control this pest. These old canes should always be 

 burned, even when borers have not been noticed. 



Attacking the Leaf. 



The Imported Currant Worm. This insect is a saw-fly (Ptero- 

 nus ribesii Scop.). The adult female is one-third of an inch long, 

 light yellowish in color, marked with black. The male is smaller 

 than the female and somewhat darker. 



The Eggs and Larvae. Eggs are glued to the main ribs of the 

 leaf, not inserted in pockets as is usual with saw-flies. They hatch 

 in four to ten days and at first the larvae are whitish, with dark spots 

 on each side. As soon as the caterpillars begin to feed, this color 



