The Canadian Horticultun^ 



Vol. XXXVI 



OCTOBER, 1013 



No. lo 



Raspberry YcIIoavs and Cane Blight 



THESE are two serious diseases of 

 raspberries that are becoming pre- 

 valent in Ontario, and about which 

 very little is known. The writer has 

 found Raspberry Yellows in the Niagara 

 District and in gardens near Guelph . 

 Canes attacked by Yellows have been 

 sent to the Botanical Department from 

 Green River, Stirling, and Whitby, On- 

 tario. It would seem, therefore, that 

 Raspberry Yellows is pretty widely dis- 

 tributed in the province. Cane Blight 

 up to the present time has been observed 

 only in the Niagara District. 



The cause of Raspberry Yellows has 

 not yet been determined. The name 

 Yellows is given to this disease not 

 because it is supposed to have any rela- 

 tion to Peach Yellows, but because it 

 describes the appearance of affected 

 pjants. Th!is disease is reported iby 

 Prof. Stewart, of the New York Agricul- 

 tural Experiment Station, as being most 

 destructive to the Marlboro, but by no 

 means confined to this variety. The 

 writer has found Yellows destroying 

 King and Cuthbert. 



The first indication of the presence of 

 Raspberry Yellows is the curling down- 

 wards of the margin of the upper leaves 



Prof. J. E. Howitt, O.A.C., Guelph 



which later become faintly mottled with 

 yellow. As the disease progresses the 

 plants become stunted and yellow, and 

 the berries dry up without ripening or 

 remain small and tasteless. The Yel- 

 lows seems to spread through a patch 

 in a comparatively short time, as cor- 

 respondents report t'hat they noticed 

 only a few plants, here and there, in the 

 rows the first season, and the next sea- 

 son found a considerabl , portion of their 

 plantation stunted and yellow. 



No remedy or prevention for Rasp- 

 berry Yellows is known. Spraying with 

 Bordeaux mixture has been tried, but 

 does not prevent the disease. As Yel- 

 lows appears to spread quite rapidly, 

 care should be taken to dig out and burn 

 any canes showing signs of the disease. 

 If these are left, the probability is that 

 in a comparatively short time the whole 

 plantation will be rendered useless by 

 the disease. Raspberry Yellows is an 

 important disease, and careful investi- 

 gations should be made to discover the 

 cause and means of preventing it. 



Raspberry Cane Blight, while com- 

 mon in the Niagara District, has not 

 become so serious or so widespread as to 

 attract much attention as yet. It has 



been proved to be a fungus disease. It 

 attacks both the red and the black var- 

 ieties of the raspberry. In New York 

 .State it has been found that Cuthbert, 

 Marlboro, Ohio, Gregg, and Kansas are 

 varieties susceptible to Cane Blight, 

 while Columbian is notably resistant. 



APPEARANCE OF AFFECTED PLANTS 



The leaves and fruit on plants at- 

 tacked by Cane Blight wither and dry up 

 from the tops downward, and the canes 

 become brittle and easily broken. The 

 diseased canes are easily seen in the 

 rows, and are often mistaken for those 

 destroyed by the Snowy Tree Cricket or 

 injured in cultivation. If the diseased 

 canes are examined, the bark is seen 

 to be lighter in color and near the base 

 will be found discolored dead areas, in 

 which numerous minute black dots, the 

 fruiting bodies of the fungus, can be 

 seen. Frequently these diseased areas 

 are discolored and smoky, due to the 

 presence of immense quantities of ex- 

 ceedingly small spores. 



Very little is known in regard to the 

 control of Cane Blight. The results 

 with spraying have not proved satis- 

 factory, and the only practical methods 

 of preventing the disease appear to be : 



A 







A Bq»y Day at Warchou*« pf th« St. Catharines Cold Sitorage and Forwarding Co,, the 01de»t Cooperative FruH (Jrowor*' Organi««tion in CMl«d« 



