Plant Diseases. 51 



Pear (Root-rot), continued. 



reddish, the leaves becoming yellowish or bronzed, and 

 there is an unusual tendency to form fruit buds. The 

 tree may die quickly or may live for several years. The 

 roots rot away and the tree tips over. The disease is 

 worst on poor and dry soils and in grassy orchards. 



Remedy. Give good culture. Remove the earth from 

 the crown and apply a dressing of lime. 



RUST. See under Apple. 



SCAB (Fusicladium pyrinum, Fckl.). Brown or blackish 

 scab-like spots on the leaves and fruit, arresting the 

 growth and causing the parts to become distorted. 



Remedy. Spray several times during June and July 

 with soda hyposulphite or potassium sulphide. 

 Plum. BROWN-ROT. See under Cherry. 



LEAF-RUST (Puccinia pruni-spinosce, Pers.) Small round 

 powdery spots of yellowish-brown on the under surface 

 of the leaves, and reddish spots on the upper surface 

 directly above them. 



Remedy. Spray trees early in the season with Bor- 

 deaux mixture, eau celeste, or other fungicides. 



PLUM-KNOT OR PLUM-WART (Plowrightia [Sphceria\ morbosa, 

 Sacc.). A black and irregular swelling, from one to five 

 or six inches long, appearing on the small limbs of plum 

 and cherry. Peculiar to America. 



Remedies. Burn all affected parts. Wash the parts as 

 soon as the swelling begins to appear, with linseed oil, ' 

 turpentine, or kerosene, using the two latter with caution. 

 A paint of red oxide of iron in linseed oil is recommended. 

 Probably spraying with the Bordeaux or similar mixtures 

 in spring will prove to be valuable remedies. 



PLUM-LEAF or SHOT-HOLE FUNGUS (Septoria cerasina, 

 Peck). Appears as spots upon the leaves in July, and 

 these spots assume definite outlines, and often fall out, 

 leaving holes like shot-holes. The leaves fall early, pre- 



