The Portland daily press., 1896-03-27
opped up the plant withers and perish

stopped up the plant withers and perish
es right away.
This is exactly what happens to the
cotton plant. A species of flung US gets
into the lower part OF the stem and goes
right tor the water pipe, which by Its
own growth it stops up as etfectually as
CORK stops a bottle. In the course of the
investigation made by the government
experts, it was ascertained that the Sea
Island farmers make practice of sowing
COW peas in their cotton fields after the
cotton has been gathered. Late IN the
fall COW peas, which are rich in nitrogen,
are turned under by plowing for a green
manure.
An important discovery was that the
COW peas are the natural hosts of de-
structive fungus. When the latter finds
10 COW peas to prey Old, it attacks the cot
ton plants. Hence the trouble.
This has been verified in the hospital by
sprinkling healthy cotton plants with
water containing spores of the fungus
obtained from infected cow peas. I'm
fortunately, fungi of the same family and
with like habits attack the tomato, the
potato, the egg plant and the cucumber.
by stopping up their water pipes they cut
off their water supply. The seemingly
healthy cucumber vine thus assailed is
withered and practically dead within
two or three hours.
There is "a surgical ward ia the plan t
hospital. Here are to be found mum Der
of little pear trees in pots, stricken with
Kind of blight that turns leaves and
branches black. The only remedy is
amputation of the affected parts. The
discovery of the nature of this disease
and the manner in which it is spread is
one OF the greatest triumphs of Prof.
Galloway, the physioian-in- chief. In
TINS case, likewise. fungus is respon ST.
N fon ha s0p y
the cells of the pl ant and destroy ing
them. The spores of the fungus live over
the winter in the branches already at
tackled, aud begin work again in the
spring. Hence the care is to go through
the orchard carefully during the winter,
and cut from the trees every blackened
branch and twig. Thus the pest can be
absolutely done away with. It is simple
enough when you know how, but lack of
this bit OF knowledge has cost pear grow
ers au immense amount of trouble and
loss.
The remarkable part of the discovery,
however, relates to the manner in which
the disease is spread. A twig or branch
attacked by it exhibits it's distress by
exuding peculiar gum. OF this gum
bees are extremely fond. They get their
bodies smeared with it, and then per-
chance seek the nectar of pear blossom.
This nectar is exactly what the fungu
spores find most suitable as medium in
which to propagate their species. In the
manner described they are carried from
tree to tree and from orchard to orchard,
thus spreading the infection. The little
pear trees in pots at the hospital have
been infected artifcially. This was ac-
oomplished by growing the fungus spores
IN gelatine, and then prlcking the bark
Of the little trees with needle that h ad
been touched to the infected gelatine.
The department. of agriculture has a
number of agents in various parts OF the
country who travel about and collect
specimens of plants which are suffering
from diseases that cause trouble to the
farmers. Nearly all of such complaints
are occasioned by parasitic fungi of
which there are at least 80, 600 species.
In each instance the first problem is to
find the particular fungus that is doing
the mischief. One way of accomplishing
this is to break off a bit of sick leaf
and soak it in distilled water. Thus the
water is quickly filed with the germs of
the disease. A drop of it is put on some
sterilized gelatine, upon which the spores
obtained. A healthy plant is inoculated
with little of the culture, and if the
disease is reproduced it is proved that the
right germ has been discovered. 1t re-
mains then to ascertain by experiment
what will serve best for killing this par
tioular fungus. For example, a solution
of sulphate of copper and lime did the
business perfectly for a fungus that came
near to wiping out certain grape plan ia
tions in Virginia not long ago Likewise
the germ of potato rot has been discov-
cred and means have been ascertained for
fighting it effectually and oheaply.