BULLETIN 543, U. S. DEPARTMENT OF AGRICULTURE. 
biiity of different varieties, but the Bilyeu, Elbert a, Carman, Cham- 
pion, Oldniixon, Sneed, and Waddell appear to be more susceptible 
than such varieties as the Hiley, Belle, Fox, Edgemont, Rivers, Early 
Crawford, and Salway. Rolfs 1 gives an extensive list of varieties, - 
with estimates as to relative susceptibility and resistance. All 
varieties were found by him to be susceptible to some extent. 
CONTROL EXPERIMENTS. 
It was not until 1913 that the problem of control came directly 
before the Bureau of Plant Industry. During that year one section 
of an orchard in the Ozark region of Arkansas in which spraying 
experiments for the control of brown-rot and scab were being con- 
ducted suffered severely from an attack of this disease. Twigs, leaves, 
and fruit were badly infected, and no control by the spraying was 
apparent. It may be said both from the experiments of this bureau 
and from those of Rolfs 1 that the sulphur mixtures (not lime-sulphur 
solution) , which, are the only known fungicides that can be used with 
safety on the peach during the growing season, will not control this 
disease. In Georgia in 1909 the writer noticed that trees which were 
in good growing condition, that is, which had been well pruned, 
fertilized, and cultivated, were practically free from the disease, 
whereas those which had been allowed to go without pruning, fer- 
tilization, and cultivation were to a considerable extent damaged 
by the disease. Similar observations were made in Georgia in 1912, 
but the disease did not then appear to be of sufficient importance 
to demand experiments in control. 
When, therefore, in 1913 it seemed desirable to work out proper 
means of control, the first things that suggested themselves were nat- 
urally pruning, fertilization, and cultivation. The writer's observa- 
tions were further supported by a statement in the report of the 
Director of the Missouri Agricultural Experiment Station for 1912 2 
to the effect that in the case of winter-injured trees the plats fertilized 
with nitrogen were nearly free from the bacterial disease, while in 
adjacent unfertilized plats the damage was very great. 
During the seasons of 1914 and 1915 the same orchard in which 
the spraying experiments had been conducted in 1913 was used 
for experimental work in the control of bacterial spot. This orchard 
consisted of a block of Elbert a trees which was bounded on one side 
by a road, on the second side by a cultivated field, on the third side by 
a meadow, and on the fourth side by an apple orchard. The disease 
had been particularly severe in the corner adjacent to the meadow 
and the apple orchard. Accordingly, the experiments were con- 
i Op. cit. 
sMumford, F. B. Fertilizing peach trees. In Mo.Agr.Exp. Sta. Bui. Ill (Rpt. [1911J12), p. 247-248, 
1913. 
