THE EFFECT OF THE ENDROT FUNGUS ON CRANBERRIES 
Neil E. Stevens and Fred W. Morse^ 
Introduction 
The fungi which cause decay of cranberry {Oxycoccus macrocarpus) 
fruits have been the object of considerable study. Very little, however, 
has been written as to the chemical or morphological changes produced in 
the berries by any of these fungi. This is due chiefly to the practical im- 
possibility of obtaining for inoculation cranberries which may safely be 
assumed to be free from fungi (5, pp. 21-23). The small size of the fruit, 
and the relatively slow rate at which the fungi grow render it impracticable 
to quarter the fruit and inoculate two portions, holding the others as 
controls, as was successfully done by Hawkins in peaches and potatoes 
(3, 4). Certain characteristics of Fusicoccum putrefaciens Shear are, how- 
ever, so distinctive as to make it possible to secure a quantity of berries 
affected by this fungus and apparently free from all others. 
Distinctive Characters of Growth of Fusicoccum Putrefaciens 
According to Shear (6, p. 35) F. putrefaciens is of first importance as a 
cause of rot of cranberries and has been found on different varieties in 
Maine, Massachusetts, New Jersey, Michigan, Wisconsin, Oregon, and 
Washington. A very striking characteristic of this fungus in its attack on 
the cranberry is the fact that, so far as has been observed, decay always 
begins at the end of the berry. This has given rise to the name "endrot" 
for this disease. 
The importance of endrot in Massachusetts has been pointed out by 
Franklin (i, p. 100; 2). In temperature studies of cranberry rot fungi it 
has been found that while the minimum temperature for growth of most of 
them is above 5° C, the endrot fungus will grow somewhat even at 0° C. 
(8). Unlike most cranberry fungi, F. putrefaciens when grown in pure 
culture has a bright-colored mycelium, and the fungus is thus readily identi- 
fied even before it fruits (6, p. 39). 
As described by Shear (6, p. 36), "Endrot first appears as a softening of 
the tissues accompanied by a slightly yellowish or brownish yellow watery 
discoloration of the skin. The diseased part is lighter-colored than the 
sound portion of the berry." The rot begins usually (at least in Massa- 
chusetts) at the side of the calyx and spreads until the entire inner tissue of 
the berry is reduced to a pulp, though the epidermis is rarely broken. The 
fruit thus "becomes soft and elastic to the touch, but remains turgid." 
^ The chemical work described in this paper was done by Morse, the histological work 
by Stevens. 
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