The Control of Ixsfxt Pfsts and Plant Dise:.\sls. 



603 



ible with good growth. Keep the foliage free from 

 moisture. Train the plants so as to secure a free cir- 

 culation of air among them. Geneva Bulletin 100. 



CELERY. 



This is sometimes known as "early 

 Cerospora, blight." It often appears in the seed- 

 leaf -blight, bed and becomes destructive early 

 in the summer. It is favored by hot 

 weather, either wet or dry. Spray with ammoniacal 

 copper carbonate, 6-3-45, making about five or eight 

 applications and beginning while the plants are still in 

 the seed-bed. Bordeaux, 5-5-50, may be used for the 

 earlier application. Spray often enough to keep new 

 growths of leaves covered. Destroy diseased plants 

 and refuse. Cornell Bulletin 132. 



Leaf blight is a fungous disease 



Septoria, leaf- appearing late in the season. It is 



blight or often destructive after celery is 



"late blight." stored. The same treatment as 



for "early blight" is used except 



that spraying should be continued up to the time the 



plants are harvested. (Cornell Bulletin 132.) Well 



drained celery fields, half-shaded, do not seem to 



suffer from either blight. 



CHERRY. 



^^: 



Black-knot 



Fig. 



210. New York apple 

 tree canker. 



Cornell 



A fungus, the spores of which are 



carried from tree to tree by the 



wind and thus spread the infection, 

 is the cause of this disease. The same fungus also 

 affects plums. Cut out and bum all knots before 

 leaves appear in the spring. See that the knots 

 are removed from all plum and cherry trees in the neighborhood 

 Bulletin 81. 



Produced by the same fungus that causes the brown-rot of 



plums and peaches. Cornell Bulletin 98, pp. 409-410, and 



Geneva Bulletin 98. See also page 494. 



This is a fungous disease in which the leaves become thickly 



covered with reddish or brown spots and fall prematurely; 



badly affected trees winter-kill. Often, the dead spots drop out, 

 leaving clear-cut holes. Spray with lime-sulfur, 1-40 (32% Beaumd),or Bordeaux, 

 5-5-50. Make four applications: First, just before blossoms open; second, when 

 fruit is free from calyx; third, two weeks later; fourth, two weeks after third. 

 See Michigan Board of Agriculture Report 1906, p. 103, and Bureau of Plant 

 Industry Circular 27, p. 15. 



Brown-rot 

 of fniit. 



Leaf spot. 



