TEAR-STAIN OF CITRUS FRUITS. 
present and are not controlled tear-stain occurs and usually varies 
proportionately with the severity of the rust-mite attack; (4) rust- 
mite russet and wither-tip tear-stain develop simultaneously 
Usually in Florida a small proportion of late citrus blooms occur 
in June. Fruits from such blooms develop after the normal rust- 
mite period and almost invariably ripen free from tear staining 
unless rust mites happen to become abundant during the following 
winter or early-spring months. 
CULTURAL WORK. 
Fungi are admittedly capable of producing tear-streak patterns 
on the host; for example, Phomopsis citri is known definitely to 
produce melanose injury in distinct tear streaks on various citrus 
fruits. Consequently a careful study was made to determine the 
frequency of the occurrence of Colletotrichum gloeosporioides or 
other fungi in typical wither-tip tear-stain areas. 
In preliminary tests made during the fall of 1918 oranges and 
grapefruit were selected that showed typical wither-tip tear-stain, 
as well as fruit affected with rust-mite russet which shaded off into 
tear-stain. Usually 30 cultures were made from each fruit, 10 each 
from areas selected as follows: (1) Typical rust-mite russet, (2) 
typical tear-stained streaks or slightly discolored areas on fruits show- 
ing no streaking, and (3) normal areas not discolored. The fruits 
were washed 1 minute in 1-1,000 mercuric-chlorid solution and 
afterwards thoroughly rinsed in sterile water. Bits of tissue were 
then removed with flamed instruments to sterile Petri dishes and 
covered with melted corn-meal agar. These cultures were allowed 
to grow five days at room temperature. The results of this pre- 
liminary culture test are found in Table II, the percentages being 
based on the number of the bits of tissue used in each test. 
Table II. — Culture tests for the isolation of Colletotrichum gloeosporioides ' from normal 
■ and affected parts of orange and grapefruit rind. 
Series. 
Number 
of fruits. 
Bits of 
tissue 
cultured. 
Colletotri- 
chum 
gloeospori- 
oides. 
Miscel- 
laneous 
organ- 
isms. 
No 
growth. 
A . Russeted 
B. Tear stained 
C Normal 
17 
16 
19 
170 
160 
190 
38.2 
21.1 
6.2 
18.8 
19.3 
15.7 
43.0 
59.6 
78.1 
1 The use of the name Cillelotrichum gloeosporioides- in the culture data of t his publical ion merely follows 
established custom and is without prejudice as to the proper designation of the organism. Any Colletot- 
richum showing characteristic growth on corn-meal agar was recorded as this species. 
It thus appears that Colletotrichum gloeosporioides is recovered 
in rather low percentage from tear-streaked areas, that it is present 
to some extent in normal as well as badly russeted areas, and that 
the frequency of occurrence varies directly with the degree of injury. 
