Group Title: Press bulletin
Title: Gummosis of citrus trees
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Permanent Link: http://ufdc.ufl.edu/UF00090359/00001
 Material Information
Title: Gummosis of citrus trees
Series Title: Press bulletin
Physical Description: 2 leaves : ; 21 cm.
Language: English
Creator: Fawcett, H. S ( Howard Samuel ), b. 1877
University of Florida -- Agricultural Experiment Station
Publisher: Florida Agricultural Experiment Station
Place of Publication: Gainesville
Publication Date: 1909
 Subjects
Subject: Citrus -- Diseases and pests -- Florida   ( lcsh )
Gummosis -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by H.S. Fawcett.
General Note: Caption title.
General Note: "December 18, 1909."
 Record Information
Bibliographic ID: UF00090359
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: oclc - 79003347

Full Text




PRESS BULLETIN 134


florida Agricullural Experiment Stlalon





GUMMOSIS OF CITRUS TREES
BY H. S. FAWCETT
SThis disease has been reported from many parts of Florida during the
past two years, and inquiries are constantly being received as to its treat-
ment. Itappears to be most common on the East Coast. The trouble has
been known in Florida since 1902, when it was at first called "gum disease;"
Sbut it has not assumed considerable importance until within the last two or
Three years. The cause of gummosis has not yet been shown. There is
strong evidence that it is an infectious disease, and that it may spread from
one tree to another in a grove.
DESCRIPTION
Tjg diseased parts of the tree are usually at a considerable distance from
the ground, on the trunk or larger limbs, being rarely found on the smaller
branches or twigs. The disease first makes itself apparent by the oozing out
of a thin watery gum, which sometimes runs down the bark in lines, forming
"tears." This gum comes from a crack or rupture in the bark. Later on, the
gum thickens and collects in large quantities at the cracked places in the bark.
As the disease'progresses, the bark cracks still more, an'd assumes a scaly ul-
cerated appearance over patches a few inches to a foot or more in length.
The diseased patches may extend entirely around the limb, or may be con-
fined to one side bf a branch. Gum may continually ooze out all over the
affected areas, or the gumming may cease for a 'time and the old gum be
washed away by the rain. This will leave only a scaly appearance which may
easily be mistaken for scaly bark-a name that has already been applied to a
different trouble, found mostly on the West Coast. In cases where the gum-
mosis is not too severe, new bark is formed under the old; and the surface be-
comes marked by ridges, warts, and resinous-looking" deposits, resulting from
the hardening of the gummy exudations. In severe cases the bark dies to the
wood, and the wood decays inward, often destroying the limb or. the entire
tree.
DISTINCTIONS FROM SCALY BARK AND FOOTROT
Gummosis differs from scaly bark in the following points. Gummosis
does notaffect all the tree from the trunk to the smallest twigs as doep'scaly
bark; nor does it spot the fruit. It does not appear as round or oval "nail-


December 18, 1909






head rust" spots, reddish rusty on the branches and dark brown on the fruit,
as does scaly bark. Gummosis presents a scaly shaggy appearance on the
trunk and larger limbs, almost identical with scaly bark; but lacks the marks
on the small twigs and fruit, and usually more gum is exuded.
Gummosis may be distinguished from footrot by the following characters.
Gummosis almost never occurs at the base of the tree; nor does gum ooze
from near the ground, as in.footrot; and it does not usually have the sour pu-
trid odor that accompanies footrot.
TREATMENT
Gummosis may be successfully checked in most cases by scraping off the
outer diseased bark, and painting the places over with Avenarius' carbolineum.
In preparing for.the application of the carbolineum, care should be taken to
scrape off all the old dead bark. If there are any decayed places. 'these
should be carefully cut out with a sharp knife or chisel. Carbolineum has
been used in full strength without injury. If new diseased spots occur on the
edges of the old ones during the next year, the treatment should be repeated.

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