New York AGRICULTURAL EXPERIMENT STATION. 211 
PLUM DISEASES. 
BLACK KNOT. 
(Plowrightta morbosa (Schw.) Sace.) 
About 20 years ago plum growing was an important industry 
in the Hudson Valley, particularly in Greene Co. About 1884 
there was an epidemic of black knot which ruined most of the 
plum orchards and so discouraged fruit growers that few have 
had the courage to replant on a large scale. Another, but less 
destructive epidemic occurred in 1891. At the present time the 
Japanese plums are being planted quite largely. They are not 
affected to an injurious extent by the black knot. On the 
European varieties it is still very troublesome and an epidemic 
may be expected whenever a favorable season occurs. It has prob- 
ably spread but little during the past season. 
FRUIT ROT. 
(Momilia fructigena P.) 
The Hudson Valley plum grower has another serious enemy in 
the brown rot of the fruit. In spite of the very dry season this 
disease has been quite bad in some localities. At Millbrook, 
Dutchess Co., it is reported to have destroyed two-thirds of the 
crop; at Old Chatham, Columbia Co., 50 per ct. of the crop; at 
Annandale, Ulster Co., Newburgh, Orange Co., and at Blauvelt, 
Rockland Co., 25 per ct. It was also abundant in Westchester 
Co., and occurred to a considerable extent in Greene and’ Rensse- 
laer counties. 
¢ d 
LEAF BLIGHT OR “SHOT HOLE” DISEASE. 
This disease is commonly caused by the fungus Cylindrosporvum 
padi Karst., but Duggar® has recently shown that it may be 
produced by Bordeaux mixture, especially if improperly pre- 
pared ; by other chemicals and even by certain weather conditions. 
32 Duggar, B. M. Peach Leaf-Curl and Notes on the Shot Hole Effect of 
Peaches and Plums. Cornell Agr. Exp. Sta. Bul. 164. F. 1899. 
