8 
BULLETIN 686, U. S. DEPARTMENT OF AGRICULTURE. 
fallen, kept better than those picked during the hottest part of the 
day. 
BOTRYTIS. 
RELATION OF BOTRYTIS INFECTION TO MOISTURE CONDITIONS. 
Botrytis * is characteristically a cause of field rot of strawberries. 
It is, however, by no means of uniform importance. Its abundance 
seems to be closely correlated with moisture conditions. During 
the past three years the writers have observed three epidemics of 
Botrytis, all associated with abundant moisture. The first occurred 
in the early part of June, 1915, at the Arlington Experiment Farm, 
in Virginia. Not only were green and ripe fruits affected, but fruit 
pedicels and leaf petioles as well. 
The epidemic began during a week of almost continuous cloudy 
weather in which over 3 inches of rain fell, as indicated by the accom- 
panying report (Table VII) taken from the Monthly Meteorological 
Summary for Washington, D. C, published by the Weather Bureau 
of the United States Department of Agriculture. . 
Table VII.— Meteorological data, Washington, D. C, May 28 to June 3, 1915. 
Date. 
Temperature (° F.). 
Maximum. Minimum. 
Precipita- 
tion 
(inches). 
Character of day. 
Percentage 
of possible 
sunshine. 
\f ay 28 
76 4S 
37 
May 29 
61 
57 
73 
68 
64 
59 
57 
52 
52 
49 
54 
49 
0.12 
.10 
Cloudy 
do 
Clear« 

May 30 '. . 

May 31 
90 
.11 
3.00 
.03 
Cloudv 
26 
June 2 
.do... 

.do 
1 
a Corrected from the published Monthly Meteorological Summary on the advice of Mr. M.C. Bennett, 
acting chief, Climatological Division, Weather Bureau. 
This infection occurred on the experimental plats of the Office of 
Horticultural and Pomologicai Investigations, in which a test was 
being made of more than 300 varieties of strawberries. No difference 
in the susceptibility of the different varieties could be noted. 
A strongly localized epidemic which was of special interest because 
of its evident direct relation to moisture conditions occurred at 
Hammond, La., following a rain on April 16, 1917. On one field 
known for its high yields and careful culture there was great loss from 
Botrytis. The loss was markedly greater on one side of the field 
where a grove of tall trees shaded the plants during the early part of 
the day and evaporation took place more slowly than elsewhere. 
More than half of the berries picked in this field on one day were 
discarded as culls because of Botiytis infection. The inspection of 
1 While careful comparative studies of material from various localities have not been made, the collections 
of Botrytis on strawberry fruits appear to belong to a single species, probably B. cincrea Pers. 
