PLANT-DISEASES. 67 



most commonly used, and is a specific when properly 

 applied. 

 EooT-RoT (Polyponis versicolor, Fries). — Attacks the roots, 

 the white and felt-like threads of the fungus at length 

 becoming very abundant and conspicuous. The trees 

 produce a short and thick growth, the new wood being 

 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. 



Bemedies. — Give good culture. Remove the earth from 

 the crown and apply a dressing of lime. 

 Rust. — See under Apple. 



Scab {Fusidadium pyrinum, Fuckl.). —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 May, June, and 

 July with Bordeaux mixture, the same as for apple-scab. 

 Plane-Tree. Leaf-Scorching (GlcEosporium nerviseqtium, 

 Sacc.).— Attacks the leaves in spring, causing them to 

 appear as if scorched. -They finally fall off. Attacks both 

 the native and oriental planes. 



Bemedies. —Burn all leaves when they falJ. Spray with 

 copper compounds. 

 Plum. Browx-Rot. — See under Cherry. 



Leaf-Blight or Shot-Hole Fungus (Cylindrosporium Padi 

 or 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, preventing the fruit from maturing. The disease 

 is sometimes designated simply "Falling of the leaves." 

 Very serious. Some varieties are very liable to attack. 



Bemedies. — Bordeaux mixture, modified eau celeste, or 

 ammoniacal carbonate of copper applied several times dur- 

 ing the season, beginning as soon as the leaves appear. 

 Leaf-Rust {Paccinia Pnnu'-siJi?zoscB, Pers.). — Small, round, 



