FARMERS’ 
BULLETIN 
WasuincTon, D.C. 72 Aprit 21, 1916 
Contribution from the Bureau of Entomology, L. O. Howard, Chief. 
THE LEAF BLISTER MITE OF PEAR AND APPLE.* 
By A. Ll. QUAINTANCE, 
In Charge of Deciduous Fruit Insect Investigations. 
INTRODUCTION. 
Leaf blister mites are among the smallest of animal forms which 
attack horticultural crops. These minute creatures, only one one- 
Fic. 1.—Apple leaves injured by the leaf blister mite. (Original.) 
hundred-and-fiftieth of an inch in length, are invisible to the un- 
aided eye, and as seen under a good hand lens appear as the merest 
. 
1 Briophyes pyri Pagenstecher; order Acarina, family Eriophyidae, 
28132°—Bull. 722—16 
