Plant- Diseases. 53 



Peach (Yellows) , continued. 



dies. The disease spreads from tree to tree. It attacks 

 trees of any age. Known at present only in regions east of 

 the Mississippi. Peculiar to America, so far as known. 



Preventive. — Burn all trees as soon as the disease appears. 

 Laws aiming to suppress the disease should be enacted in all 

 peach-growing states. 



Pear. Blight {Micrococcus amylovorus, Burrill). — Distinguished 

 by the blackening of the entire leaf, and the blackening of 

 the bark. Attacks the flower clusters. It may destroy 

 branches or the whole tree. Generally distributed east of 

 the 100th meridian. Known only in America. Attacks the 

 apple. 



Remedy. — As soon as the disease is discovered, cut off the 

 affected pails a foot below the point of lowest visible attack, 

 and burn them. 

 Leaf-Blight and Cracking of the Fruit (Entomosporium 

 maculatum, Lev.; Morthiera Mespili, is the same). — Attacks 

 nursery-stocks of pears, beg-inniug as small and circular 

 brown spots on the leaves ; soon the entire leaf turns brown 

 and falls. Also causes the cracking of the finiit. 



Remedies.— Bordeaux mixture, eau celeste, or ammoniacal 

 carbonate of copper, applied four or five times. Begin when 

 the leaves are half -grown, and follow at intervals of from 

 two to four weeks. 



Root-Rot (Polyporus versicolor, Pries). — 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 ten- 

 dency 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. 



Remedies. — Give good culture. Remove the earth from the 

 crown and apply a dressing of lime. 



Rust.— See under Apple. 



Scab (Fiisicladium pyrinum, Fckl.) . — Brown or blackish scab- 

 like spots on the leaves and fruit, arresting the growth and 

 causing the parts to become distorted. 



