Insects, etc., Injurious to the Pear. 



355 



LiFE-HlSTOKY AND HaBITS, 



The small mites winter under the hud scales, and as soon as the 

 leaves open they enter them through the stomata. They winter 

 preferably under the second and third layers of bud scales, often in 

 colonies of as many as fifty. 



In spring they are seen in numbers first towards the base of the 

 growing bud scale and here they seem to moult. At first they produce 

 a small red pustule, no bigger than a pin point, by the end of a week 

 it may reach the size of a pin's head. Each gall contains but a single 

 female, and she deposits a few eggs, from five 

 to six, as far as obst^rved, and these at an 

 interval of several days. 



As the leaves unfold, the mites which breed 

 in the galls crawl out and enter fresh stomata 

 on the same or other leaves, and so the disease 

 spreads. They keep on migrating through 

 June, 'Tuly and August, and even into Sep- 

 tember. As the galls grow older tliey change 

 in colour, eventually getting to black spots of 

 dead tissue. 



As the leaves mature off the mites migrate 

 to the forming buds and there they enter be- 

 tween the outer scales. The terminal buds 

 seem to harbour the most. In May and June, 

 if there has been very rapid increase, the mites 

 may be found upon the pubescence of the 

 young wood and on the leaf petioles. In 

 autumn they leave the foliage and may be 

 found moving on the trees and entering the 

 buds. The mite is very like the Big Bud Mite of the currant. In 

 America, the late Professor Lintner found that " under ordinary 

 circumstances it spreads rapidly and proves quite injurious if allowed 

 to continue through the season and for successive years." 



Lounsbury (3) considers it a recent importation into the Cape, 

 for only young and newly grafted trees have become infested. The 

 effect of weather on this mite seems important in Canada (2). 

 Mr. Dickson of Guelph Agricultural College has informed me that 

 while artificial means of checking this pest have failed, the extreme 

 severity of the winter in Canada had checked their numbers. 



The eggs are found lying in the soft tissue of the leaves ; they are 

 oval in form, bluntly rounded at each end, whitish and translucent. 



■y.ii.—Ei-iiiphijexinjn 



{After Nalepa.) 

 (Greatly enlarged.) 



