144 OBSERVATIONS ON THE CALIFORNIA VINE DISEASE 
of his investigations determined that Brunissure was caused 
by a fungus which he referred to the genus Cladochytrium 
Nowakowski. Ducomet, on the other hand, concluded that the 
vacuolate, plasmodium-like bodies were degenerate chloroplasts, 
and the globoids, granular and homogeneous matters, products 
of decomposition, and his results were confirmed later by Ravaz. 
Both Ducomet and Ravaz claimed that Brunissure was a physi- 
ological disease; they did not agree, however, as to its cause. 
Ducomet believed that the disease was induced by rapid changes 
of temperature, a sudden rise or fall of the thermometer being 
causal. Ravaz argued that the malady was due to over-produc- 
tion, and, in support of his thesis gave a great deal of data; 
he further strengthened his opinion by asserting that he could 
produce Brunissure at will. 
Shelling.—In this disease “ the leaves at the outer extremities 
of the shoots first show a yellow discoloration which follows 
more or less continuously the outer margin. . . ." This “ yel- 
low portion dies and turns brown," and the leaf, as a conse- 
quence, curls at the edges. In older leaves and young leaves in 
which foliar development is exceedingly slow the following char- 
acters will be observed: “ Small irregular blotches of a dark color 
appear between the veins, these enlarge rapidly, . . . and coalesce 
to fill up the space between the veins which remain green or yel- 
low. These changes occur so rapidly that the foliage seems 10 
change color suddenly. The contrast between the green or light 
yellow veins and dark purplish brown of the intervening tissues 
gives a peculiar streaked appearance to the leaves. In the most 
serious cases they curl up, become dry and brittle, and finally 
drop from the vine, leaving it nearly bare.”? The most striking 
feature of the disease is, however, the fall of the berries from the 
pedicels.? 
The ва а — 
Lodeman, E. G. Some ра troubles of. Western Kë у York. Corne 
Univ. Agric. Exp. Sta. Bull. 76 
oe D. G. Diseases of zi grape in Western New York. Jour. МУС 
891. 
