*1 PER YEAR. 
ANNUAL CATALOGUE NUMBER. 
Vol. LVIII. No. 2563. NEW YORK, MARCH 11, 1899. 
ADVICE FROM THE PLANT HOSPITAL. 
THE “ WHY ” ABOUT SOME PLANT DISEASES. 
A Talk with Dr. B. D. Ha/sted. 
A Plant Hospital. —Dr. Byron D. Halsted, of the 
New Jersey Experiment Station, is regarded as one of 
our best authorities on plant diseases. At the Sta¬ 
tion, he conducts a remarkable “plant hospital”, 
which is a plot of ground on which various plant dis¬ 
eases such as scabs, rots and blights 
are propagated. For instance, we have 
seen a part of this plot piled high with 
potato vines that have died with the 
blight, while another plot will be well 
“ loaded ” with rotting or scabby pota¬ 
toes. The object of this is to fill the soil 
with disease germs. Then various 
crops are planted and treated with sul¬ 
phur, lime, Bordeaux Mixture and 
other remedies, to see whether the 
plants can be saved under the worst 
possible conditions of infection. Such 
experience has, of course, given Dr. 
Halsted a remarkable chance for study¬ 
ing plant diseases. Most of the fol¬ 
lowing questions were suggested by 
readers who have been obliged to 
fight these plant diseases without fully 
understanding them. We hear quite a 
little complaint about the ordinary 
lime Bordeaux Mixture. The lime seems 
to clog the nozzles. Dr. Halsted uses 
what he calls a “ soda Bordeaux”, and 
our first question was : 
Tlie “ Soda Bordeaux”.— “ What 
can be said of the ‘ soda Bordeaux ’ ? 
Has it proved as effective as the regu¬ 
lar Bordeaux ?” 
“ The soda Bordeaux, in all my ex¬ 
tended tests during the past three 
years, has proved equal to the ordinary 
Bordeaux. It is made as follows : Cop¬ 
per sulphate, three pounds ; Lewis lye 
(1 can), one pound ; lime (unslaked), 
five ounces; water, 30 gallons. Dis¬ 
solve the copper as in the prepara¬ 
tion of ordinary Bordeaux. The can 
of lye will dissolve readily in two 
gallons of water. Hot water should 
be used in slaking the lime. After 
diluting the copper sulphate to 15 gal¬ 
lons, pour into it the solution of lye 
diluted to five gallons, stirring thor¬ 
oughly. Strain the lime through loose 
sacking, dilute to five gallons, and add 
to the copper and lye, diluting to 30 gal¬ 
lons. In order to prevent the mixture 
turning brown, a small quantity of 
lime is used to neutralize any excess 
of acid, and in this way, a permanent 
bluish color is obtained in the mixture. 
The only advantage claimed for this 
fungicide is the absence of a large part 
of the lime in the ordinary Bordeaux 
Mixture, and it, therefore, may prove 
of considerable value as a fungicide in 
the fruit garden and vineyard, particularly when the 
fruit is nearing full size. I have had no experience in 
using Paris-green with the soda Bordeaux, and cannot 
recommend the combination.” 
What Favors Disease ?—“ Under what condi¬ 
tions do plant diseases spread most rapidly ? I would 
like to kno v, in connection with this, something 
about the amount of moisture, a ad whether an excess 
of nitrogen causing a rank, quick growth, would in¬ 
vite disease ? ” 
“ Plant diseases develop most rapidly in warm, moist 
surroundings. Thus, if an artificial culture is to be 
made, the plant is placed under a bell jar, and sup¬ 
plied abundantly with moisture and heat. It is on 
this account that diseases need to be guarded against 
very carefully, in the growing of p’ants in green¬ 
houses. Thes3 are the external favo.ing conditions, 
and the internal ones are a succulent growth and a 
delicate exterior, while any weakness on the part of 
the plants is a predisposition to disease. Many kinds 
of destructive fungi succeed only in attacking seed¬ 
lings, that is, before the exterior becomes covered 
with a firm cuticle. A thick skin is a natural barrier 
against the infection of plant diseases, and much may 
be done in the breeding of plants with this end in 
mind. For example, some kinds of potatoes are less 
susceptible to the scab than others, and it is to be 
presumed that the reason lies in the greater skin de¬ 
velopment in the one variety than the other. Any¬ 
thing that produces a rank growth of tissue in a plant 
provides a softness and succulence that is doubly in¬ 
viting, because of the excess of juices upon which the 
fungi feed, and a thin skin through which the germ 
may readily pass. Nitrogen may, for example, stimu¬ 
late a plant to an excessive growth of stems and 
leaves, and produce thereby a condition that renders 
the plant particularly susceptible to disease. It seems 
in 
to be established that high feeding of pear trees in- 
. duces the fire blight, and the same 
seems to be true of annual plants like 
grains and even potatoes. The oats 
upon the manure-heap ground will be 
more rusted than upon the other parts 
of the field, and the Phytophthora is 
liable to attack the most overgrown 
plants in the potato field. It is possible 
that a difference in susceptibility of 
two varieties of the same species may 
be due to as small a matter as hairiness. 
A plant to the surface of which spores 
will not adhere from any natural cause, 
is favored in so far, and may escape 
when its neighbor succumbs.” 
Feeding and Inoculation. —“Are 
there any circumstances where potash 
or phosphoric acid properly used will 
render the plant less susceptible to 
disease?” “Potash and phosphoric acid 
may be of use in rendering the plant 
less susceptible to disease when by 
adding them the plant is in a better 
state of health. There are many fungi 
that are not truly parasitic, that will 
attack and injure sickly plants when 
healthy ones escape. There are some 
fungi that directly do only a small 
amount of injury, but they prepare 
the way for fungi that cause much 
damage when these latter fungi would, 
of themselves, be inactive. In short, 
the potash and the phosphoric acid 
are useful in combating fungous dis¬ 
eases in somewhat the same way as the 
pruning knife in a fruit tree. When a 
tree top is overloaded with branches 
and foliage, the conditions obtain for 
the inception of disease, while in an 
open, airy, sunny top, they are not.” 
“Is there any hope or probability 
that plants may, some day, be rendered 
immune to disease by some method 
similar to inoculation in animals ? ” 
“ The idea that the time will come 
when we can inoculate plants, and 
thus make them immune to various 
fungous diseases, is not new and does 
not appeal to me very strongly. It is 
often dangerous to reason from the 
diseases of animals to those of plants. 
When we find the pumping engine in 
a plant, and can diagnose its condition 
by pulse and thermometer, there will 
be time enough left to consider the 
subject of plant vaccination and all 
such things. The time might better 
be spent in finding the reason why one sort of 
fruit or vegetable is less susceptible to disease 
than another, and attempt from such discovered fact 
to improve the varieties of cultivated plants along 
such lines. To be specific, I seriously doubt whether 
any amount of black-knot upon a tree will make the 
new branches less liable to the diseass, or any grafts 
or buds from that tree. If there is anything in the 
thought, it will be in connection with the bacterial 
diseases, which are those most nearly akin to the 
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A PROFITABLE SUMMER BOARDER COMES TO TOWN. Fig 60. 
