44 ASSOCIATION OF ECONOMIC ENTOMOLOGISTS. 



the mite was regarded as being generally distributed in the leading 

 pear-growing States. The mite has attained its prominence in this 

 country as an orchard pest because of its destructive work on pear 

 foliage, and for this reason our literature upon the species is en- 

 tirely concerned with the economy of the mite in its relationship to 

 pear growing. 



In recent years our attention has been called to the appearance of 

 the mite in another role — as a pest of apple foliage. The mite has 

 quite likely been active in this capacity for many years, but important 

 injuries by it were not brought to our notice till 190:2, when it was 

 found to be very abundant in an apple orchard at Williamson, on 

 Lake Ontario. In 1903 the infestation of these trees was much more 

 conspicuous, and the strange appearance of the foliage attracted much 

 attention from the fruit growers in attendance at the summer meet- 

 ing of the State Fruit Growers' Association which was held in 

 Geneva. Up to the present time its injurious numbers in this orchard 

 have been maintained. During the same year Prof. M. V. Slinger- 

 land a observed, through the central portion of the State, numerous 

 apple trees with many of their leaves showing the corky blisters 

 characteristic of the work of this creature. The area in which the 

 mite was present in conspicuous numbers has increased each year, 

 and in 1905 marked infestation of many orchards in Wayne, Ontario, 

 Monroe, and Niagara counties was noted. In his apple survey of 

 Wayne County in 1903, Dr. G. F. Warren h recorded the presence of 

 the mite in 53 orchards. It is stated that " the mites were not bad in 

 more than one-half of a dozen orchards, but in a few orchards some 

 trees had practically every leaf affected." A like survey of Orleans 

 County h in 1904 showed somewhat similar conditions of apple trees 

 with respect to this pest. Of 19 orchards showing mite injury, 4 

 were recorded as seriously infested, 4 considerably infested, and 11 

 slightly infested. During 1906 the work of the mite again attracted 

 much attention among fruit growers, and in addition to the above 

 counties the species was also present in large numbers in apple 

 orchards in Livingston, Wyoming, Seneca, and Yates counties. The 

 mite may be said to be common in our leading apple-growing sec- 

 tions in western Xew York, and its work upon apple leaves has also 

 been recognized in Pennsylvania and Illinois. 



The host plants of this mite, in addition to the apple and pear, are, 

 as recorded by Dr. Alfred Nalepa, the service-berry (Amelanchier 

 vulgaris), the common cotoneaster (Cotoneaster vulgaris), the wild 

 service tree (Sorbus terminalis) , the white bean tree (Sorbus aria), 

 and the EurojDean mountain ash (Sorbus aucwpa/ria) . 



a Bnl. 40. Bureau of Entomology, U. S. Dept. of Agriculture, 1904, p. 72. 

 & Cornell Bui. 220, 1905, p. 340 ; Bui. 229. 1905, p. 489. 



