VOL. LII. No. 2252. 
NEW YORK, MARCH 25, 1893. 
PRICE, THREE CENTS. 
St.00 PER YEAR. 
THE CORROSIVE SUBLIMATE TREATMENT OF 
POTATOES-TO PREVENT OCCURRENCE 
OF POTATO SCAB. 
BY H. L BOLLEY. 
In work done at the Indiana Experiment Station dur¬ 
ing the seasons of 1889 and 1890, it was demonstrated 
that the blackened, rmghened, pock-marked like 
eondition of potatoes, commonly spoken of as potato 
scab, is due to the direct action of a parasitic cause, 
which not only originates the disease on the tubers, but 
also attacks the roots and bases of the vines. It was 
also shown that the disease was propagated in the 
new crop from that on the seed tubers, and that, under 
claimad ta have investigated the subject, encouraged 
the idea of treatment, or indicated that it would be 
economically possible. 
Again in December, 1891, in Bulletin No 4 of the Ex¬ 
periment Station for North Dakota, an article was 
published citing numerous tests in the field, showing 
clearly the possibility of the economic prevention of 
the disease, with an immense increase of the yield for 
so doing. After this, however, (Annual R-ports of 
the Connecticut Agricultural ^Experiment Station for 
1891) so good a general authority as Dr. Thaxter, of 
the Connecticut Station, after considering the results 
of his season’s works, writes as follows : “In regard 
to the question of prevention by treatment, little can 
In writing this article, it is my wish to impress the 
idea that it is not only possible to entirely avoid dis¬ 
ease in the new crop, but that the treatment is easy 
of application and the yield increased, and that under 
the present conditions, w.thout treatment, a crop ex¬ 
empt from disease is never a cert linty, hence the state¬ 
ment that the planting of what appears to be healthy 
(smooth) seed tubers will be an effectual means of 
prevention should be given no weight except that, 
under certain possible conditions, the disease may be 
light from such seed as compared with the injury it 
does to a crop from heavily diseased seed. 
In defense of my position against continuously pub¬ 
lished results which only tend to show the uselessness 
Fio. 80. 
Fig. 79 
From a photograph of potatoes representative of those used for seed In the treatment tests of the 
season of 1S92.— Dolleu* 
From a photograph of the product of three hills, representative of the product from untreated 
seed —Bolley 
Fig. 81. 
From a photograph of the product of three hills, representative of the product obtained from 
seed tubers soaked in Bordeaux Mixture three hours.— Bolley 
Fig 85 
From a photograph of the product of three hills, representative of the product obtained from 
seed tubers soaked l'/£ hour In a 1-1,000 solution (Hg Ch)-Corrosive subllmat e.-BolUy. 
certain methods of treatment, healthy tubers could be 
raised from diseased seed. 
These results, together with refutations of various 
theories concerning the origin of the disease, were 
published in Agricultural Science, Vol. IV, Nos. 9 and 
10. The disease had, however, in the past been assigned 
to so many different causes, and had so successfully 
resisted all attempts at treatment, that the statement 
of a possible preventive made in the article seemed to 
give little hope to investigators and writers who wrote 
concerning it in the following year. In spite of the 
fact that in this work of 1890, p 252-6, it was clearly 
shown that the writer had in various ways grown a 
perfectly healthy product from seed which, untreated, 
never gave a sound tuber, no writer in 1891, who 
*AB for all these photographs the focal distance was the same, the 
«m':s allow of a comparison upon an equal basis, i. e., the comparative 
size of the tubers Is shown. 
be said. Prof. Bolley, in the bulletin referred to, gives 
the results which he obtained by treating the seed 
potatoes in various ways, in order to kill the fungus 
upon seed tubers before planting \ but the use of clean 
seed would seem to be a simpler and more effectual 
means of avoiding infection of this nature.’ 
This statement, coming from Dr. Thaxter, has more 
weight than his field tests would warrant, and I fear 
may retard the general acceptance of thoroughly 
economic methods of ridding the potato grower of one 
of his most pernicious pests In the light of these con¬ 
siderations and on the completion of another season s 
tests in the line of my past werk, I feel that it may 
not be superfluous to give the subject here another 
airing, knowing, as I do, that it means fair-skinned 
potatoes with an increased yield and value for all in¬ 
telligent growers who will each invest 40 or 50 cents 
and a day’s labor per year. 
of trying preventive means, I can conscientiously 
state that the vagueness or lack of definite results 
from all experiments in that line, which have come to 
my notice, rests on either a lack of appreciation of the 
capabilities of the scab parasite or on methods of 
experiments which disregard those characters. Accord¬ 
ing to the published statements of experiments, which 
have come to my notice, none is free from one or 
more of the following sources of error : 
1. The seed tubers are not known to be free of the 
disease germs. 
2. The soil upon which they are planted is not 
known to be free from them. 
3. The method of application is not such as to be 
effective against a pirasite of the known character of 
the one under consideration. 
4 Tne capabilities of dissemination of the disease 
are not considered. 
