CRANBERRY DISEASES ON THE PACIFIC COAST 7 
•early in May, especially during the prolonged rainy periods which 
are likely to occur at this time of year. Mature apothecia are 1 
centimeter or less in diameter and are borne on slender stalks that 
vary from about 1 to about 5 centimeters in length. Numerous 
apothecia sometimes arise from a single sclerotium. Sclerotia wholly 
or partly buried in the fallen leaves and trash beneath the vines seem 
to produce apothecia more freely than those in other situations. 
They are infrequently found in piles of rotten berries containing 
numerous mummies and are very difficult to force artificially. 
Little is known concerning the infection of the vines by ascospores. 
The latter are produced before or just as vines begin growing and 
infect the new growth, usually the uprights. No macroscopic evi- 
dence of infection is visible until the sudden wilting of uprights 
occurs about the time the bog is coming into bloom. The infected 
uprights, now nearly full grown, collapse a short distance back of 
their tips, become brown and shriveled, and soon the dead stems are 
covered with the grayish white powdery masses of conidia. Conidia 
are borne chiefly on the curved portion of the stem formed where the 
upright has collapsed. Flowers, pedicels, and leafstalks are also 
occasionally attacked, and the characteristic grayish masses of conidia 
are produced along the bent and curved parts of these organs. 
The tip-blight stage of this disease rarely affects a sufficient pro- 
portion of uprights to cause noticeable injury to the vines or to the 
crop. Diseased tips are rather hard to find even when relatively 
numerous, because they are so inconspicuous among the erect healthy 
uprights. The first tip-blight observed in 1923 was on June 12, in 
1924 on May 21, and in 1925 on May 22. 
The time of conidial production of this fungus coincides closely 
with the blooming period of the cranberry. Conidiospores unques- 
tionably are carried over to and infect the berries during the blos- 
soming period. Infected berries continue their normal increase in 
size all summer without showing any external evidence of infection. 
The fungus may easily be seen, however, upon cutting open an 
infected iruit any time after it has set, the seeds being invested with 
the cottony mycelium. This relation between fungus and berry is 
maintained until the latter reaches mature size — such berries fre- 
quently average somewhat larger than uninfected ones — when the 
fungus suddenly becomes very active and rapidly invades all the 
surrounding tissues, and the whole interior of the berry becomes filled 
with the cottony mycelium. The further development of the fungus 
takes place rather rapidly if other contaminating rots do not over- 
run the Sclerotinia. The flesh of the diseased berry becomes filled 
with hyphae, which eventually develop into a hard, compact, black 
sclerotium. The interior of the berry and some of the tissue mid- 
way between the four walls of the seed cavity rot away, entirely, so 
that the sclerotium as finally formed consists of circular plates of 
sclerotial tissue at either end of the berry, connected by four riblike 
formations of the same tissue which have replaced the fruit pulp at 
its junction with the four seed-cavity walls. The fruit epidermis 
usually remains intact over this sclerotium throughout the winter, 
the whole forming the characteristic mummy. These mummies some- 
times remain attached to the uprights all winter. The following 
spring they produce apothecia and start the life cycle over again. 
