ne 
SECTION OF VEGETABLE PATHOLOGY. goo 
rauch greater in the early morning when the air and ground are damp, than later 
in the day when there is less moisture. 
At the moment of digging, count the rotton tubers found in the soil and also 
those which are spotted only. The weights of the crops from the treated plants 
and from those not treated should be determined, and they should be preserved 
separately during the winter, but under identical conditions, for the purpose of 
learning if there be any difference between them in respect to infection. 
Much may be accomplished in the prevention of potato-rot by renewal of seed. selec- 
tion of varieties, and especially by planting only in light and well drained soils; also, 
perhaps, by following certain systems of cultivation; but the evidences we have of 
the serious losses occasioned by this disease throughout the potato growing regions 
ot the United States render it imperative on the part of the Government to exer- 
cise all possible efforts for its prevention, and I respectfully recommend the imme- 
diate distribution of this circular, urging those who suffer directly from the rav- 
ages of the diseases named to experiment with the remedies and report to you the 
results obtained. 
Respectfully. 
F, LAMSON SCRIBNER, 
Chief of Section. 
Hon. NoRMAN J. COLMAN, 
Commissioner of Agriculture. 
- We have received no reports on the use of these remedies, and do 
not know that they have yet been tried, but we feel confident, how- 
ever, that the remedies here enumerated, when properly made and 
applied, will prove effectual in preventing the ravages of the potato 
blight and rot. 
ITV.—FIELD OBSERVATIONS AND EXPERIMENTS. 
In order to gain an accurate knowledge of habits of parasitic 
' fungi and the ravages they produce it is absolutely necessary to 
carry on field investigations. The Department ought not to be 
obliged to depend upon volunteer reports for a knowledge of facts 
acquired through private experiments. Such reports, especially 
when treating of matters relating to fungi, are very likely to be mis- 
leading, owing to the imperfect knowledge generally possessed re- 
garding this subject. And as to the matter of fungicides and the 
treatment of plant diseases, valuable conclusions can only be reached 
through field work carried on by some one familiar with the nature 
and habits of the fungi to be combated. 
If this work be continued in a manner at all commensurate with 
its importance, and results obtained that shall meet the approval and 
confidence of the people the Department is designed to serve, it is 
necessary that Congress provide for a station which shall be under 
the absolute control of the Department for the needed field experi- 
ments. Office work is necessary, laboratory work must be done, but 
to attain practical results, and it is the practical conclusions which 
the farmer and fruit-grower are after, 1t is imperative that we go 
outside of the office and laboratory, and continue our studies and ex- 
eriments in the field upon living plants. <A station containing not 
ess than 10 acres of land, located where a large variety of grains, veg- 
etables, vines, and fruit trees and shrubs could be cultivated, is essen- 
tial to the successful prosecution of the work required from this Sec- 
tion, and the development of its full power for usefulness. Here the 
effects of the parasites upon the host can be studied. inoculations of 
healthy plants made, and experiments carried on in the tfeatment of 
plant diseases. A small green-house is an important adjunct to such 
a station, and the work would be further facilitated by having in the 
