3296 REPORT OF THE COMMISSIONER OF AGRICULTURE. 
The mycelium of the fungus (Coniothyrium diplodiella) is found | 
to be abundant in the pulp of the berries attacked, and it sometimes 
fruits upon the surface of the seeds. Generally, the fungus first 
attacks the common peduncle or branches of the cluster.and, by in- 
terrupting the circulation of the nourishing fluids, causes the ber- 
ries to wither and dry up. In such cases the berries may or may not — 
be directly attacked. Infection of the peduncle or pedicels with 
germinating spores is easily effected, but attempts to infect the ber- 
ries have so far failed. 
OV O 
Q 
‘Oh (6, 
i} 
a 
Mg 
2 O80; 
Fie. 3. A vertical section through one of the fruiting pustules—pycnidia—of the fungus of White-rot. 
cc, cuticle of the berry that has been broken through by the development of the fungus. d d, 
browned and dry tissue of the berry. The simple spores are borne on slender stalks arising from a 
layer of very delicate tissue at the bottom of the pycnidium. 
Like the black-rot fungus, this produces minute pycnidia or spore 
conceptacles, which appear at the moment when the berrie=: com- 
mence to ripen. These le just beneath the cuticle, through which 
they finally burst, first appearing as shining, rosy points, then white, 
and finally brown. When fully developed, the pycnidia are sur- 
rounded by a thin membrane of a rather dark brown color. The 
ovoid spores are borne upon slender stalks or basidia, either simple or 
branched, which spring from a layer of very delicate tissue oc¢upy- 
ing the lower part of the pycnidium. They are at first colorless, but 
eventually assume a brown tint. Ata temperature of 65° they germ- 
inate readily in water, pushing out germ-tubes from any part of 
their surface. - 
No remedy is known for white-rot, but it has been observed here, 
and very generally in France, that where the vineyards have been 
treated with eau celeste or the Bordeaux mixture the disease was far 
less prevalent than in similarly located vineyards not treated. 
C.—Grape-leaf spot disease and black-rot. 
In Bulletin 2 of the Botanical Division, page 40, Grape-leaf spot 
disease was treated as distinct from black-rot, for the writer at that 
