45 



leaf becomes thickly spotted with them. Their feeding causes a 

 thickening of the leaf at that spot, commonly called a blister or gall. 

 This blister is at first of a reddish color, but it gradually turns brown, 

 and finally black. In early fall, when the leaves ripen, the mites 

 leave their galls and take refuge in the buds for the winter. 



INSECTS INFESTING FRUITS. 



Although few of the insects infesting fruit are liable to be trans- 

 ported upon nursery stock, several of them are such destructive pests 

 as to merit the attention of all interested in horticulture. 



* * * » * * » 



The codling moth {Oarpocapsa pomonella Linn.) passes the winter 

 as a caterpillar in a cocoon in crevices or under loose pieces of the 

 bark. However, they are not apt to occur on nursery trees. The 

 cocoon is made of whitish silk 

 and partially covered with bits 

 of bark so that it is not easily 

 seen. In early spring they 

 pupate, and the moths issue to 

 lay their eggs on young apples. 

 The larva bores into the apple, 

 usually from the blossom end, 

 mines to the core, and then, 

 when about full-fed, bores to 

 the surface. It leaves the 

 apple to pupate on the trunk 

 or larger branches of the tree. 

 Some issue in late June or July 

 and again lay eggs on the 

 apple, making a second brood. 

 In the Northeastern States there 

 is but one brood a year. The codling moth also attacks pears and 

 quinces. 



The apple maggot {Rhagoletli^ pomonella Walsh, fig. ■1:2) is a two- 

 winged fly that appears in June and lays its eggs just beneath the skin 

 of apples. The white maggots, upon hatching, burrow throughout the 

 apple in various directions. When full-fed the maggot drops to the 

 ground, under which it pupates and emerges as a fly the next spring. 



The cherry fruit-fly {Rhagoletis cingiilata Loew, fig. 43) infests 

 cherry in much the same manner as the apple maggot infests apples, 

 and has a similar life history. 



The plum curculio {Conotrachelus nenuphxir Herbst.) is a small, 

 grayish weevil that passes the winter under the bark of a tree or 

 among rubbish. In spring it deposits eggs within the plum (peach 

 or cherry) and then cuts a crescentic slit in the skin near by. The 

 larva or grub goon hatches and feeds in the fruit, causing it to ripen 



Fig. 43. — Rhagoletis cingulata. (Slingerland). 



