PEARS GALL MITE. i 5I 



in them, small, yellow at first, then changing to red. In bad cases the blisters extend 

 almost over the whole surface of the leaves, and greatly impair the health of the tree. 

 The blisters or galls are caused by mites, which enter by a small hole on the under-side 

 of the leaf, and pass in and out freely. A section through a blister shows the cellular 

 tissue to be loosened and the surfaces of the leaves pushed farther apart ; between and 

 under this part are found the eggs and mites. The mites are white in their young state, 

 and easily seen with a pocket lens near the mouth of the gall when this is disturbed. 

 They are shorter than the currant-bud mite (Fig. 52, /, page 165, Vol. II.), and shelter 



Fig. 42. PEAK GALL MITE, ATTACK ON PEAE LEAVES, AND SECTION OF LEAF GALL. 



References: W, winter form eight-legged mite found on buds in spring. X, summer form four-legged mite 

 found in galls. F, pear leaf showing early attack of mite. Z, leaf with black (mature) galls. A, section of leaf gall ; 

 p, opening of gall. 



themselves in the crevices of the young wood during winter, and are then a dirty slate 

 colour, with six or eight legs. Directly the buds open the mites enter them, and pro- 

 duce the swelling in the leaf before described, and shown in Fig. 42. 



The eggs are deposited and the young brought forth in the galls, so that prevention 

 is the only safe means of combating the mites. Trees liable to the attacks of mites 

 should be sprayed with bisulphide of calcium (Vol. I., page 248) before the buds com- 

 mence swelling early in spring or in late winter. The soft soap, sulphur, and soda 

 wash (Vol. I., page 270) is equally destructive and distasteful to the mites.. If the 



