PEAR LEAF-BLISTER MITES. 129 



were unusually observable, enquiries were sent from various 

 correspondents regarding this attack, and in the following 

 year enquiries were also sent from localities respectively in 

 Kent, Surrey, and Somersetshire ; but, excepting the observa- 

 tion that in one instance even the very young leaves which 

 had not yet uncurled appeared affected on the two trees 

 examined, the notes gave no additional information as to 

 appearance of the attack. 



The following notes, taken partly from Canadian and partly 

 from German observations, give the life-history of the in- 

 festation in short plain form, available for practical service. 

 The first is by Dr. J. Fletcher, Entomologist of the Depart- 

 ment of Agriculture, Ottawa, Ontario, Canada : — 



"Pear Leaf-blister Mite, Phytoptus 2)yri. — An insect 

 which is giving a considerable amount of trouble in Canada 

 at the present time [1892] is the Pear Leaf-blister Mite. . . . 

 The mites, which are hardly visible with the naked eye, 

 emerge from the scales of the leaf-buds early in spring, and 

 attack the tissues of the unfolding leaves. The blisters soon 

 begin to show as small red spots, each of which has a small 

 central hole on the lower side of the leaf. The eggs are laid 

 inside these blisters, and the young, escaping through the 

 central opening, at once form new galls, until sometimes the 

 greater part of most of the leaves is rendered unfit to perform 

 its functions. 



" When mature the galls are brown and spongy in texture, 

 and are raised perceptibly above the surface of the leaf. 

 Before the leaves fall the mites leave the galls, and secrete 

 themselves beneath the scales of the winter buds, where they 

 remain throughout the winter." * 



All of us who are troubled by these blisters on our Pear 

 leaves can see for ourselves that the attack may go on 

 spreading throughout the summer, but the following notes by 

 Dr. E. L. Taschenberg give special details. He observes that 

 the "sexually developed mites move about fairly nimbly on 

 the under side of the leaves. They are found throughout the 

 whole year, from May onwards, of various ages, and have 

 many broods ; so that multiplication continues uninterruptedly 

 until the winterly season. They disperse themselves, both as 

 larvte and developed mites, in the leaf- and flower-buds of the 

 one-year-old twigs, embedded in the felt-like layer of hairs on 

 the inside of the outer bud-scales." t 



And again, with regard to their condition during winter, 

 Dr. Taschenberg mentions : — " This they pass as larvae, or as 



* From " Report of the Ontario Fruit Growers' Association," p. 113, pub- 

 lished in the ' Annual Report of Dept. of Agriculture of Ontario for 1892.' 

 t ' Praktische Insektenkunde,' von E. L. Taschenberg, pt. v. pp. 159, 160. 



K 



