436 State Horticultural Society. 



which carry the disease to other leaves. These spots may become so 

 numeious as to destroy the leaves attacked and stunt the fruit growth. 

 In the late autumn the white areas of the infected leaves that have 

 fallen to the ground develop small black bodies beneath the epidermis. 

 These contain the winter spores which cause infection during the fol- 

 lowing spring. 



Bordeaux should be used before blossoming, after the petals fall, 

 and several times after the picking season. In severe cases the plants 

 should be removed. A selection of the less susceptible varieties also 

 helps in keeping down the disease. 



ANTHRACNOSE OF RASPBERRY AND BLACKBERRY. 



Gleosporium venetum Speg. 



The anthracnose of the raspberry and blackberry is a very common 

 disease, and, not being easily recognized, is liable to do much harm be- 

 fore being found. It attacks the canes, young shoots and leaves. On 

 the canes it produces spots which are purplish at first, but later become 

 white and sunken in the center. These spots may merge into each 

 other, forming large elongated areas, which, in some cases, entirely 

 encircle the cane. During the following season the spots dry out and 

 produce cracks in the wood. On the leaves somewhat similar but 

 smaller spots are formed. The leaf stems and small fruiting branches 

 are also often infected. 



The young shoots are the principal points of attack. The fungus 

 lies dormant during the winter in the canes. In the spring spores are 

 produced upon the diseased areas, and from these other plants are in- 

 fected. The disease reduces the vigor of the plant, causing the fruit 

 to mature improperly, and often to dry up before ripening. 



The deceased parts should be cut out and destroyed during pruning 

 time. After the new canes are attacked, the worst of these should be 

 cut away. Bordeaux should be used in the spring before the leaf buds 

 swell, soon after the foliage is out, and soon after the berries are picked. 

 In starting a new plantation, only healthy plants should be used, and a 

 short rotation of crops should be adopted. 



DOWNY MILDEW OF THE GRAPE. 



Plasmopara viticola, B. and C. 



The downy mildew is the most destructive disease of the grape. It 

 attacks all parts of the vines above ground. But the leaves are most 



