The Florida agriculturist., 1908-02-01
Introduction.


to get at the necessary facts for this
tory, however, between 1880 and 1900,
have drawn largely on B. 7. Gallo
ways paper, "Twenty Years of Pro
gress in Plant Pathology" published
in 1900
The systematic study and treatment
Of plant diseases dates back scarcely
more than twenty-five years. Its de-
velopment has been almost coincident
with the development of baCterlOlOgy,
with which it has much in common.
The plant "doctor,'' therefore, does not
have the two centuries Or more Of ex-
perience and pains-taking labor to
guide him, as does the medical man.
Much progress, however, has been
made in this short period of quarter
of a century. The foundations have
been laid for much more rapid de-
ve1opment in the FUTURE Although the
subject as such begins perhaps no
earlier than 1880, yet the basic facts
and principles for it were very slowly
accumulating ever since the invention
of the microscope, over two hundred
years BEFORE
Purpose of the Paper.-It will be the
purpose Of the paper to review very
briefly these preparation periods, and
then touch some of the more important
developments since the year 1880. In
treating of the subject, the history in
relation to insect diseases will be omit
ted, since the work of the plant patholo-
gist as now carried on is usually con-
fined to the diseases due to parasitic
fungi, bacteria, and in some cases (as
root knott, those caused by microscopic
worms.
The Fungi, as is we'll known, are
lower forms of plant life, ranging from
species so small that you can see them
only by means Of a compound micro
scope, to the large mushrooms and
shelf fungi, the largest of which grow
to a weight of scores of pounds. The
entire group lack the green matter
(chlorophylD so necessary to the life
Of green plants These forms repro
duce themselves, not by seeds, as in the
case Of Towering plants, but by minute
bodies called spores, that are carried
invisibly through the air, on the bodies
Of insects, by water, or by other means.
1t is difficult to realize the extreme
smallness of these spOres-these in
visible carriers Of life. A spore was
being measured under microscope the
other day, that was only three micro
millimeters, or 3.25,ooo of an inch long.
Fifty of these spores could easily move
abreast through the eye Of a fine
needle. Eight thousand placed end to
end would reach only an inch. If one
were enlarged to the size Of a pea, an
ordinary man would have to grow about
$4,000 feet, or twice the height Of Mt.
Washington. to maintain his dlgnifled
position in the life Of the world. These
spores are often produced in countless
numbers. It has been estimated that
a single grain Of s1nutted wheat may
contain as many as 100000 spores.
The Bacteria, some Of which are
responsible for plant diseases, Are
unicellular organisms usually much
smaller than the fungi These are gen
orally treated of in a class by them
selves. They are so minute that 1,ooo,-
900 individuals can easily be suspended
in a drop of water 1t is with the
parasitic forms of both fungi and bac-
terra that the plant pathologist concerns
himself
Plant Pathology Before 1850.
Records of Plant Diseases in Early
Times-In very early times we have
few records of plant diseases. There
is mention of mildews and blights in
the older books Of the Bible, and Aris-
totle as early as $50 B. c., writes of
wheat rust. Later in history. Shake
speare seems to have had knowledge of
L. Ao4