2 FARMERS’ BULLETIN 122. 
speck. Although the mites themselves are probably unfamiliar to 
most orchardists, their work is well known to pear growers and 
apple growers in the reddish or greenish pimples or blisterlike spots 
to be noted in early spring on the young foliage of these plants. 
Later these blisters become brown and dead, spotting and blotching 
the leaves, the injury resembling that due to leaf-spot fungi or from 
sprays, with which injury, in fact, the work of this mite is frequently 
confused. When the creatures are abundant the foliage may be 
almost covered with the blisters or brown spots, and the usefulness 
of the leaves to the tree is thus greatly impaired. Foliage severely 
injured will fall prematurely, retarding the development of the fruit, 
and in extreme cases much of the crop will fall to the ground. 
(See fig. 1.) 
The leaf blister mite is not an insect but belongs to that class of 
animals containing the spiders, scorpions, daddy-long-legs, etc., and 
to the order represented by such well-known forms as the scab mite 
of sheep, the cattle tick, and the red spider. Its family contains 
numerous species, all of which are plant feeders, attacking prin- 
cipally the buds and leaves. Several members of the family are of 
much economic importance. One? infests vinifera varieties of grapes 
in portions of Europe and in California, producing the so-called 
“erinose” of the vine. Another? is the cause of the nail-like galls 
sometimes found on the leaves of plum. A third* infests the fruit 
and foliage of the orange, producing a russeted condition. A fourth * 
feeds upon the upper surface of the leaves of the peach, so injuring 
them as to give the foliage a silvery sheen. Still another® occurs 
on the foliage of the apple, and in Montana very important injuries 
have been attributed to it. 
ORIGIN AND DISTRIBUTION. 
The leaf blister mite is not native to the United States and was 
probably introduced at an early period, presumably from Europe on 
nursery stock, buds, or scions. It was first recorded in the United 
States in 1872, and since that date has made its appearance in the 
principal pear-growing regions of the United States and Canada. 
It is known to occur in England, Russia, and certain other European 
countries, is recorded from Tasmania, and: is probably present in 
other fruit-growing regions of the world, being at the present time a 
truly cosmopolitan pest. 
1Briophyes vitis Landois. 
2 Briophyes padi Nalepa (—E. pruni-crumena Walsh). 
3(Typhlodromus) Phyllocoptes oleivorus Ashmead, 
4Phyllocoptes cornutus Banks. 
5 Phyllocoptes schlechtendali Nalepa, 
