Insects Injurious to Fruits. 



I. INSECTS INFESTING THE PEAR. 



THE PEAR LEAF BLISTER. 

 Phytoptus pyri. 



Order A carina ; family Phytoptidae. 



Reddish spots an eighth of an inch or more in diameter appearing on pear 

 leaves in the spring, and changing to black corky spots in the autumn, 

 each with a minute opening in it. 



In the Report upon the Condition of Fruit-growing in Western 

 New York recently published by this station,* Professors Bailey 

 and Dudley, while describing the scab fungi of apple and pear 

 (Fusicladiiwi), incidently refer to black, corky spots abundant on 

 pear leaves and supposed to be produced by a gall mite. In 

 fact Professor Dudley states that most of the diseased spots on the 

 pear leaves that he has studied last season and this are of this 

 nature, and that there are only occasional bunches of the scab 

 fungus found in connection with them. 



Since the appearance of this report, this disease of pear leaves 

 has been carefully studied by the Entomological Department of 

 the station ; and we give below a brief review of what has been 

 learned regarding it. 



The supposition that the disease is caused by mites has been 

 proved to be correct, and a careful study of the spots on the leaves 

 and of the mites that produce them shows that we have to do with 

 a malady that has long been a scourge in Europe, but which has 

 attracted but little attention in this country. 



An excellent account of the disease, containing some important 

 original observations, was published by Prof. T. J. Burrill ten 

 years ago.f This is the only article on this subject worthy of 



^Bulletin XIX, August, 1890. 



jGardener's Monthly and Horticulturist, Jan. 18S0. 



