New York Agricultural Experiment Station, 363 



dark olive green mold. In this stage the summer spores are pro- 

 duced which spread the infection to other trees. 



Late in the season the knot becomes hard with a black surface, 

 which finally becomes covered with fine black pimples, inside of 

 which are matured the winter spores. The winter spores escape 

 late in the winter or early in spring, and serve to spread the disease. 

 A more extended discussion of this disease is given in Bulletin ISTo. 

 40 of this Station and in the Annnal Report for 1893 : 086. 



Remedy. — The best known remedy for this trouble is to cut out 

 and burn the knots. They can be found most readily after the 

 leaves have dropped in the fall. They should then all be removed 

 before mid- winter so as to be sure of destroying them before the 

 spores mature and escape. Early in the summer the new knots 

 should be watched for and promptly removed and destroyed. The 

 infection frequently comes from the knots on neglected plum or 

 cherrv trees along fence rows or in neighboring orchards. The 

 black knot law, a copy of which is herewith inserted, provides for 

 the destruction of infested branches wherever found. In removing 

 the knots the branch should be cut off three or four inches or more 

 below where the knot appears, so as to remove the threads of the 

 fungus that may extend down the branch to a considerable distance 

 from the knot. The same disease also affects various wild plums 

 and wild and cultivated cherries. It is rarely found on sweet 

 cherries but sometimes is very destructive to the Morello class. 



Neio York Black Knot arid Peach YeUoios Law, 



§ 82. The prevention of disease in fruit trees. — No person 

 shall knowingly or willfully keep any peach, almond, apricot or 

 nectarine tree affected with a contagious disease known as yellows, 

 or offer for sale or shipment, or sell or ship to others any of the 

 fruit thereof. Nor shall any person knowingly or willfully keep 

 any plum, cherry or other trees infected with the contagious dis- 

 ease of fungus, known as black knot. Every such tree and the fniit 

 of a tree infected with yellows shall be a public nuisance, and no 

 damages shall be awarded for entering u}>on premises and destroy- 

 ing such trees and fruit if infected with yellows or for cutting away 

 the diseased part of any tree infected with black knot or altogether 

 destroying such tree if necessary to suppress such disease, if done 

 in accordance with the provisions of this article. Every person 

 when he becomes aware of the existence of such disease in any tree 

 or fruit owned b}' him, shall forthwith destroy or cause such tree 

 or fi-uit to be destroyed or the infected part to be cut away. 



