THE RHIZOCTONIA BROWN ROT AND OTHER FRUIT 
ROTS OF STRAWBERRIES 1 
By B. O. Dodge and Neil E. Stevens, Pathologists , Fruit-Disease Investigations , 
Bureau of Plant Industry , United States Department of Agriculture 
INTRODUCTION 
The fruit rots of strawberries have received much less attention than the 
importance of the crop and the great losses from decay would seem to justify. 
A number of fungi are known which attack strawberries and it is to be expected 
that as investigation continues there will be discovered numerous other species 
which in certain localities or under some conditions are capable of causing serious 
fruit rots. Very recently Rose 2 has published the results of an extensive study 
of a fruit rot of strawberries found to be destructive in the Arkansas and Ten¬ 
nessee regions and which he calls “leather rot.” In the present paper the writers 
report a new or little known field rot which is very important in Florida. Since 
both these diseases produce a brown discoloration, and at least two other so-called 
“brown rots” of strawberries are already known, it seems necessary to briefly 
discuss at this time the distinguishing characters of these rots. 
THE BROWN RHIZOCTONIA ROT 
Each season since 1920 as strawberries have come into the Washington market 
from Florida the waiters have observed a peculiar rot on many of the berries 
which appeared to be perfectly sound on one side. Some of these berries were 
deformed as though one side had failed to fill out properly. This part of the 
berry was commonly affected with a somewhat dry brown rot which often had 
a blackish color, due chiefly to the adhering black sandy soil. This suggested 
that the rot might be due to some soil organism. 
Study of the rots in Florida strawberry fields, especially in the vicinity of Plant 
City in 1923, and Kissimmee in 1924, shows that while Botrytis appears in 
epidemics, suddenly and with very destructive effects during or soon after brief 
periods of rainy weather, the rot just mentioned as found in the Washington 
markets develops much more regularly in the fields and makes it necessary to 
cull out large numbers of berries during picking and packing. As this disease 
is almost always present, yet rarely if ever epidemic, it attracts relatively little 
attention among growers. Continued observation has convinced the writers, 
however, that it is a constant source of loss to strawberry growers in central 
Florida and, until a remedy is discovered, will remain a handicap to the industry. 
Careful observation has convinced the writers that Rhizoctonia caused at least 
half the loss from field rots in this region during the season of 1923-24. 
The characters of this rot are so pronounced that it can be distinguished 
readily from the other so-called brown rots of strawberry. Affected berries are 
generally one-sided, and show a hard brown rot, to which often adhere quanti¬ 
ties of sandy soil. Decay regularly starts on the under side of the berry where 
it comes in contact with the soil, and a small amount of soil will usually be found 
clinging to the decayed spot even in dry weather. If the soil is of the black 
1 Received for publication Feb. 25, 1924 
* Rose, D. H. leather rot of strawberries. Jour. Agr. Research, 28: 357-376, illus. 1924. 
Journal of Agricultural Research, 
Washington, D. C. 
(643) 
Vol. XXVIII, No 7 
May 17,1924 
Key No. G-382 
