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, 
usuall} 7 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 {Rhagoletis pomonella Walsh, fig. 42) 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 cingulata Loew, tig. 43) infests 
cherry in much the same manner as the apple maggot infests apples, 
and has a similar life history. 
The plum curculio (Conotrachelus nenuphar 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 soon hatches and feeds in the fruit, causing it to ripen 
Fig. 43.— Rhagoletis cingulata. (Slingerland). 
