176 MONTANA EXPERIMENT STATION. 



THE PEAR-LEAF BLISTER-MITE. 



The pear-leaf blister-mite is another pest that is particularly liable 

 to be distributed on nursery stock,- scions, etc. The almost micro- 

 scopic mites hibernate under the scales of the buds and their detec- 

 tion through inspection is out of the question. 



In the spring- as the young, tender leaves are being put forth the 

 over-wintered mites pass to the under side of the leaves and pro- 

 •duce whitish or reddish blisters under which they later produce 

 young which migrate and cause new blisters. 



The pest is severe on individual trees but does not spread rapid- 

 ly . Over short distances the young might be carried on the feet 

 of birds or might be blown with the fallen leaves late in the season. 



The blisters, often highly colored and usually arranged in rows 

 parallel with the mid rib, one row on each side, are characteristic. 

 This pest occurs in some of the fruit growing regions of Montana. 



Fig. 23. The Pear-leaf Blister-mite: greatly enlarged. (Comstock, Man- 

 ual for the Study of Insects, 1897.) 



THE STRAWBERRY LEAF-ROLLER, i. 



The strawberry leaf-roller is a fairly well known pest in some 

 parts of the United States. In the state of Washington it has been 

 looked upon as their most serious insect enemy of strawberries. 

 Though it has been in Montana for a number of years we have no 

 record of great injury from it.. It occurs at Missoula, Helena, and 

 •Miles City. It receives its name from its habit of rolling and 

 crumpling the leaves of its host-plants. The larva which is small 



I. Phoxopteris comptana Frol. 



