Insects, etc., Injnrions to tJie Pear. 



355 



lj[|-E-lllSTn|;V AXIi HaIIITS. 



Th 



liu small mites winter uiuler the bud scales, and as soon as the 

 leaves open they enter tJiem through the stomata. The)- winter 

 preferaljly ruider the second and third layers of ].)ud scales" often m 

 colonies of as many as fifty. 



In spring they are seen in nundiers first towards the liase of the 

 growing bnd 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 contaiirs but a single 

 female, and she deposits a few eggs, from fiye 

 to six, as far as oliserved, and these at an 

 inter\'al 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 lea\-es, and so tlie disease 

 spreads. They keep on migi'ating throu^'li 

 June, duly and August, and even into Sep- 

 temlier. As the galls grow older tliey change 

 in colour, eventually getting to blaclv spots of 

 dead tissue. 



As the leaves mature off the mites nugrate 

 to the forming buds and there they enter be- 

 tween the outer scales. Tlie terminal buds 

 seem to harbour the most. In May and June, 

 if there has been very rapid increase, the mites 

 may lie found upon the pubescence of the 

 3'oung wood and on tlie leaf petioles. In 

 autumn they leave the foliage and may be 

 fViund moving on the trees and entering the 

 buds. The mite is very like the Big l!ud Mite of the currant. In 

 America, the late Professor Liutner found that " under ordinary 

 circumstances it spreads rapidly and proves rjuite injurious il' 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 (Janada (!'). 

 Mr. DiclvSonof Guelph ^Vnricultural College has informed me tliat 

 wdiile artificial means of checking this pest have failed, tlie extreme 

 severity of the winter in Canada had checked their uuml.iers. 



The eggs are found l>'ing in the soft tissue of the leayes ; they are 

 oval in form, Iduntly rounded at eacli end, whitish and translucent. 



'2 A 2 



