Group Title: Press bulletin University of Florida. Agricultural Experiment Station
Title: Citrus fruit rots
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 Material Information
Title: Citrus fruit rots
Series Title: Press bulletin University of Florida. Agricultural Experiment Station
Physical Description: 2 p. : ;
Language: English
Creator: Stevens, H. E ( Harold Edwin ), b. 1880
Publisher: University of Florida, Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1918
Subject: Citrus -- Diseases and pests -- Florida   ( lcsh )
Molds (Fungi) -- Control -- Florida   ( lcsh )
Anthracnose -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Statement of Responsibility: H.E. Stevens.
General Note: Caption title.
General Note: "December 7, 1918."
 Record Information
Bibliographic ID: UF00005191
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltqf - AAA6515
ltuf - AEP5887
oclc - 52786490
alephbibnum - 000934820

Full Text




Weather conditions during the past ten days have been
unusually favorable for the development of citrus fruit rots and
we may expect trouble from blue mold, stem-end rot and anthrac-
nose if moist conditions continue to prevail. Doubtless consider-
able damage has already occurred, which will become more evi-
dent within the next few days. Excessive moisture is favorable
to the growth of the rot-inducing fungi. The same condition
indirectly affects the fruit by making it more turgid, in which
case the rind is brittle and easily injured or bruised in handling.
Fruits that are highly turgid and filled with an excess of moisture
give off this excess later. If fruit is packed in this condition,
even tho the surface appears perfectly dry at the time, a con-
siderable amount of moisture will still be given off and absorbed
by the wrapper. Thus an ideal moist condition is provided for
the germination of any fungus spores on the surface of the
packed fruit. This probably explains the high percentage of
decay that develops in fruit that is packed and shipped during
periods of rain. Fruit gathered under such conditions should
be allowed to dry in the packing house for a few days before it
is packed.
While a considerable amount of decay may appear within
the next two or three weeks, some of which will be unavoidable,
steps may yet be taken to eliminate a good percentage of loss.
Blue mold is likely to be much in evidence in the groves,
packing houses and shipped fruit. This fungus cannot penetrate
the unbroken citrus rind and only gains entrance to the interior
of fruits thru scratches, bruises, breaks or injuries to the sur-
face. Following rainy periods, it is important to see that the
fruit is carefully handled from the tree to the packed box, avoid-
ing as far as possible all clipper cuts, long stems, thorn pricks,

December 7, 1918

scratches and bruising. Packing houses and field boxes should
be kept clean and all cull fruits should be promptly disposed of
and not allowed to decay. The fruit should be thoroly dry before
packing and it should be shipped under proper ventilation.
Where the percentage of blue mold is running high in the shipped
lots, it would be advisable to hold such fruit for several days
after picking in order that it may dry out and throw off the
excessive moisture.
Under moist conditions stem-end rot develops rapidly, and
it may be expected to appear in groves where the trees contain
much dead wood, especially if scale insects are present on the
fruit in any abundance. When sufficiently developed to detect,
the rot is distinct and quite characteristic. However, fruits
infected with the fungus may be picked from the tree and not
show any visible signs of the disease at the time. Such fruits
develop the rot after they are packed and during storage, and
this greatly affects the market value of the finished pack.
Stem-end rot can be more effectively avoided by keeping
the trees free from dead wood and scale insects. Where this has
not been done and the rot is present, the problem is to eliminate
the infected fruits. This will require close and careful inspection
in the packing house, and some degree of selection in the grove.
By holding suspected fruit for several days before packing a
large percentage of rot may be eliminated. All decayed and in-
fected fruits whether in the grove or packing house should be
If moist conditions prevail, anthracnose is apt to develop,
especially in groves where the trees show indications of wither-
tip. It may, however, appear sporadically in any grove. The
disease is first indicated by small red spots or blotches on the
surface of the fruit. When this condition is noted in any
abundance, spraying should be done at once. Two or three ap-
plications of ammoniacal solution of copper carbonate made at
intervals of ten days should check an outbreak of anthracnose.
In case of slight attacks where only a few trees are affected, it
may be necessary to spray only the affected and adjacent trees
if the sprayings are made promptly.
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