208 REPORT OF THE BOTANIST OF THB 
in Western New York, and in 1900 it probably did about the 
usual amount of damage. Plantations with 10 per et. of rusty 
plants were frequent; and occasionally plantations were found 
in which 25 per ct. or more of the plants were rusty. We 
have often noticed in Western New York, as in the Hudson Val- 
ley, that rusty plants bear fewer prickies. In Chautauqua 
County the parasitic fungus Tuberculina persicina, was common 
on raspberry rust as well as on blackberry rust. Where the 
parasite was present the affected plants were less conspicuous, 
the leaves being purplish instead of bright yellow. 
In September the teleuto form was frequently observed. 
Powppry Minpew (Oidiuwm ruborum Rabenh.).—In several local- 
ities we observed, during May and June, a powdery mildew on 
the foliage of black raspberries. In every case it was confined 
to plants infested by rust, Cwoma nitens, never occurring on 
healthy plants. It occupies both sides of the leaves. No peri- 
thecia were found. It is probably referable to Oidiwm ruborum 
Rabenh. The same mildew has been found on blackberries. 
(See page 185.) 
Cane Buigur (Coniothyriwm sp.).—This is the cane blight de- 
scribed in Bulletin 167, pages 305-307. It has been found to be 
common in the raspberry plantations of Western New York as 
well as in the Hudson Valley. At Peruville it injured a crop of 
Cuthberts to the extent of about 50 per ct. On black varieties 
it often begins its attack in the dead stub which results from 
heading back the plants by cutting after they have become large 
and woody. From this point the disease works its way down- 
ward killing successively the lateral branches. | 
It has now been proven by inoculation experiments with pure 
cultures that the Sphropsideous fungus found in such abun- 
dance on the diseased canes is really the cause of the disease. 
(See Plate XXVIII.) The fungus properly belongs to the genus 
Coniothyrium rather than to Phoma as stated in Bulletin 167. 
As a rule, the spores are decidedly brownish. 
We have also learned to recognize the disease on the young 
canes. In August and September new canes of red raspberry 
