PLUM PESTS. 123 



more or less brown, and finally whitish. The blisters will 

 be found on the under surface. 



PtEMEDY. — Sprajdng the foliage with Bordeaux Mixture 

 (Formulae 20 or 21) in the early stages of its growth will 

 prevent the disease spreading. Gather and burn all fallen 

 leaves when possible. 



Pear.leaf Cluster Cups (Roestelia caneellata).— 

 A fungus of a parasitical nature, which produces rugged 

 swellings on the leaves of the pear. The fungi seen on 

 the upper sides are flask-shaped, pale brown, and pro- 

 duced in clusters. On the opposite side are orange or 

 reddish spots containing black dots. 



Remedy. — Pick off and burn the infected leaves. The 

 disease is not of a serious natiu'e. 



Pear Scab (Fusicladium pirinum). — There seems to 

 be a doubt in the minds of some mycologists as to 

 whether this fungus is not the same as that which pro- 

 duces the Apple Scab. Anyway, it produces similar 

 results on the fruit of the pear, and the same precautions 

 and remedies should be adopted to guard against its 

 attacking pear leaves and fruit. 



CHAPTER VIII. 



PLUM PESTS. 



A INSECTS. 



Plum Aphides. — The Plum Aphis (Aphis pruni) and 

 the Clearwing Aphis (Hyalopterus pruni) are both inju- 

 rious to the foliage of the plum and damson. The former 

 are green or olive-brown in colour, and covered with a 

 mealy powder. The latter are bluish-green, and also 

 covered with mealy powder. Both infest the young 



