460 Report of the Horticulturist of the 



a disease of the canes it may occur on any part of the plant above 

 ground. It is most destructive to black raspberries, but also 

 attacks purple raspberries and blackberries and perhaps still 

 other species of Rubus. Red raspberries appear to be exempt. 



Treatment.^^ — Since, in most instances, a raspberry plantation 

 reaches its limit of profitable production when three or four years 

 old it seems that a rotation of crops, combined with sanitary 

 measures, is tho surest method of preventing loss from this disease. 

 As the disease lives over winter in the canes, the old canes, to- 

 gether with the badly diseased new ones, should be removed as 

 soon as the fruiting season is over. 



Experiments have shown that the disease may be checked by 

 spraying with Bordeaux mixture, beginning when the new canes 

 are about six inches high and keeping them well protected with 

 the mixture until the fruit is two-thirds grown. Ordinarily, how- 

 ever, spraying for anthracnose is not likely to pay. 



RUST. 



(Puccinia pechiana Howe. Syn. Caeoma nitens Schw.) 

 Description, etc. — This disease is often called the orange rust 

 on account of the orange color of the spores which are produced 

 in dense masses on the underside of the rusted leaves. Sometimes 

 tlie spore masses occur also on the canes. The fungus attacks 

 blackberries, dewberries and raspberries. It is quite common on 

 wild plants and where these are growing in the vicinity of cul- 

 tivated varieties the diseased plants among them should be de- 

 stroyed to prevent them from becoming a source of infection. 



Treatment. — Clinton^^ states that the fungus enters the very 

 young underground shoots and growing up through the canes 

 finally appears in the leaves. Since the fungus grows within the 

 canes and infection appears to take place at the root, the only 



f50 Paddock, W. The Anthracnose of Black Raspberry. N. Y. Agr. Exp. 

 Sta. Bui. 124. 



5t Clinton, G. P. Orange Rust of Raspberry and Blackberry. 111. Agr. Exp. 

 Sta. Bui. 29. 



