844 
ment of Agriculture has conducted some 
investigation as well as the Wisconsin 
Experiment Station. The results are em- 
bodied in what follows. 
Cranberry Anthracnose 
Gloeosporium Sp. 
Cranberry anthracnose seems to be’most 
common in Massachusetts and New Eng- 
land cranberry bogs. It closely resembles 
the species so injurious to the apple and 
other fruits. The appearance of the dis- 
ease upon the fruits is similar to that of 
scald and rot, and can only be distin- 
guished certainly by microscopic exam- 
ination. 
Cranberry Blast 
Guinardia Sp. 
Cranberry blast is a name given to that 
form of the disease which attacks the very 
young fruits as soon as the blossoms fall. 
It causes the fruit to shrivel up, become 
black, and finally become covered with 
one of the spore-producing forms of the 
fungus, which is a species of Guignardia, 
very closely related to the species which 
produces the black rot of the grape. The 
spores produced upon these young berries 
are the probable source of infection of 
most of the other fruit. This fungus pro- 
duces two kinds of fruit, or, in other 
words, passes through two stages of devel- 
opment. The earliest stage produces its 
spores in small black spherical recepta- 
cles. This fruiting form of the fungus is 
the most abundant, and it is probably 
from this source that most of the leaves 
and fruits are infected. The second stage 
in the development of the fungus is that 
in which the spores are produced in sacs. 
These are inclosed in receptacles as in 
the other stage mentioned. 
Blight 
This trouble has appeared on Wisconsin 
bogs as a dying of blossoms and very 
small fruit just at the time of setting. 
It is sometimes attributed to hot weather. 
Investigations at the Wisconsin station, 
however, seem to disprove this theory. 
As yet no specific cause has been worked 
out. If the vines are kept in a vigorous 
and thrifty condition the trouble seems 
to be largely avoided. 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
Cranberry Rot 
Cranberry rot has until recently been 
confused with and attributed to the same 
cause as the scald. Its effect upon the 
berry is very similar to that of the scald 
fungus. It is produced, however, by a 
quite different species of parasite, though 
belonging to the same large group known 
as the “black fungi.” In some cases 
where the fruit is in an advanced stage 
of the disease, the presence of the fungus 
is indicated by irregular black blotches 
just beneath the skin of the diseased por- 
tion. 
Cranberry Seald 
The name “scald” originated as a re- 
sult of the belief formerly prevalent among 
cranberry growers that the injury was due 
to the effect of the hot sun upon the ber- 
ries when they were wet, thus producing 
what was regarded as a real scalding of 
the tissues of the fruit. Fruit which has 
been overflowed for a half day or more 
during hot weather may be injured as a 
result, and the effect in many instances 
closely resembles that produced by the 
scald fungus. A. microscopic examination 
of the berries shows at once the differ- 
ence. In the berry which has been affect- 
ed by being covered with water no fun- 
gous threads or filaments can be found, 
whereas in the case of the berry attacked 
by the scald fungus an abundance of such 
filaments may readily be observed in the 
pulp of the diseased berry. Only in the 
rarest instances does the scald fungus 
fruit on the berries after they have be- 
come half grown. 
The disease first becomes noticeable as 
a small light-colored softened spot on the 
surface of the berry. This spot rapidly 
increases in circumference and finally en- 
velops the whole fruit. Sometimes the 
diseased portion shows more or less dis- 
tinct brownish zones. In other cases the 
zones are lacking and the whole fruit be- 
comes very soft and has a light watery 
color. In many instances it is very diffi- 
cult to tell from the external appearance 
only whether the disease is due to the 
scald fungus or the rot fungus. 
