STATE POMOLOGIOAL SOCIETY. 61 



of spores (stylospores.) The fungus remains alive in the knot till 

 the following spring when it dies leaving simply a spongy mass of 

 dead tissue, which may as before remarked afford a harbor for 

 insects. 



The best remedy for black-knot is "a good sharp knife and 

 courage to use it." Many successful growers favor an application 

 of kerosene to the wound after removing a "knot." Such an appli- 

 cation should be made with a small brush, and care must be used 

 that the oil does not run down on the bark. It is well to add a 

 little pigment, as red lead, to the kerosene to better indicate where 

 work has been performed. 



4. Plum-Rot or ^'•Mummied Fruit." 



Phims, cherries and peaches are frequently attacked by a "rot" 

 which may destro}' the entire product just before ripening. This 

 rot {Monilia fructigena) appears on the surface of diseased fruits 

 in the form of a grayish white mould. This mold consists mostly 

 of little tufts of spores, the mycelium being among and through 

 the tissues of the fruit. On a single diseased plum may be pro- 

 duced thousands of the little spores, each capable of infecting 

 another fruit. 



The rapidity with which the disease may spread in warm, moist 

 weather is almost incredible. In two days, under favorable con- 

 ditions, a spore may germinate and grow sufficiently to produce 

 more spores. 



The fruit which is affected often dries up and remains on the 

 tree ; and the fungus lives over winter in this "mummied fruit" or 

 in the twigs which are sometimes affected. 



The treatment of this disease is that already suggested in general 

 terms, viz : collect and burn all affected fruit ; spray the trees 

 early in the season with the copper sulphate solution and after the 

 fruit has set spray once with Bordeaux mixture. 



A second spraying with Bordeaux mixture is hardly advisable 

 because of injury to the appearance of the fruit ; but if the season 

 is very favorable to the growth of fungi, it is well to make an 

 application of modified eau celeste. This material is prepared as 

 follows : Dissolve two pounds sulphate of copper in two gallons 

 of hot water. In another vessel dissolve two and one-half pounds 

 carbonate of soda (sal soda) ; mix the two solutions and when 

 ready for use add one and one- half pints strong ammonia water 



