388 Report of the Horticulturist of the 



rot as with four sprayings, and that four sprayings gave about as 

 good results as did six sprayings. Two of the four sprayings 

 were made before the blossoms opened; the third was made two 

 weeks after the date of full bloom and the fourth was made 

 twelve days after the third. 



The same fungus which causes the fruit rot of peaches also 

 causes the ripe rot of plums and in some instances attacks the 

 blossoms, giving them a blighted appearance. Figure 7 illus- 

 trates the appearance of fruit attacked by the fruit rot fungus. 

 It is gratifying to learn that Bordeaux mixture checks to -some 

 extent the spread of this disease, although as Dr. Thaxter has 

 observed in the citation given above, it is not always effective 

 in preventing its ravages. 



From these observations we conclude that the treatment which 

 has been advocated above as a preventive of plum leaf -spot may 

 also be expected to show some beneficial results in lessening the 

 prevalence of fruit rot and black knot in the treated orchards. 

 Nevertheless, it is not expected that spraying will ever do away 

 with the necessity of cutting off and burning the knots to prevent 

 the spread of plum black knot, and it will still be advisable to 

 remove and burn or bury the rotted and mummified fruit before 

 the blossoms open the following spring for the purpose of check- 

 ing the spread of the fruit rot fungus. In case there is reason 

 to fear an attack of the fruit rot fungus on the blossoms spray 

 thoroughly with Bordeaux mixture before the blossoms open, and 

 follow with the line of treatment advocated above for leaf -spot. 



NATURE OF THE PLUM LEAF-SPOT. EXPERIMENTS IN 



TREATING IT. 



Appearance of the disease. Its destructive character. Details of ex- 

 periments in controlling it. Work of 1895. Work of 1896. Course of 

 treatment now recommended. Remarkable increase in yield of Italian 

 Prime as a result of the spraying. 



On the preceding pages are given the objects of the experi- 

 ments in treating the plum leaf-spot disease which were tried in 

 ISOf) and 1800, and a line of treatment is recommended for or- 



