I08 L. R. JONES 
fore, most lucky that when the professional "plant doctor" was 
introduced to the American rural constituency by the state experiment 
stations and national Department of Agriculture, he could step for- 
ward with Bordeaux mixture in one hand and formaldehyde in the 
other, two specifics which could at once be used and misused in a most 
amazing variety of cases without serious danger of loss of life or 
reputation. And just as these were becoming somewhat common- 
place lime-sulfur was brought to our aid and with it the added enter- 
prise of the American commercial advertiser. 
Please do not misunderstand me. I recognize clearly that the 
highest duty in plant pathology is service, and that the chief aim in 
that service is to lessen loss from plant diseases. The only question 
is, how can we best serve to this end? 
Perhaps as conditions have been, we could not at the outset have 
done much better. It was necessary first to educate the public as to 
the amount of their loss from plant diseases, as to the general nature 
of the parasites, and as to the great gains from the use of fungicides. 
In order to do this, the pathologist must familiarize himself with 
these things by repeated observations and trials and must contribute 
in turn to the education of the horticulturist, the agronomist and the 
agricultural press. This has taken time, in many cases nearly all of 
his time. But we may have satisfaction in the idea that it has been 
well done. No other country has had like service and in no other 
country has the agricultural public followed the teachings so fully. 
It is important, however, for us to remember that this is the pioneer 
service, necessary and best at the outset; but that, as fast as con- 
ditions permit, we must be moving on to the attack on the more funda- 
mental problems, to the performance of the more enduring service. 
The fundamental idea in plant disease control is prevention. It is 
surprising if one goes over the list how many diseases cannot be pre- 
vented by the use of fungicides. For the great classes of bacterial 
diseases, rusts and soil fungi, we must look to other measures. The 
three fundamental ideas which here deserve increased attention are 
sanitation, exclusion, disease resistance. 
Spraying and seed treatments are only one part of sanitation in 
any case and have no part in many cases. Full data as to the life 
histories and modes of dissemination of causal organisms are more 
important fundamentals for improved sanitation than are further 
demonstrations with fungicides. The importance of fertilization, 
