33 
to the decay of tap roots and others to the tap root coming in contact 
with hard pan or underlying rock formation. To test this the tap 
roots of certain infected trees were exposed and examined. The tap 
root extended about 4 feet in one case and between 8 and 9 feet in an¬ 
other, and in every case had not extended below the sandy soil and 
were apparently healthy. Some attribute it to overbearing; still others, 
to some peculiar oiliness of the soil which prevents it from becoming 
thoroughly wetted. In regard to this we may state that, while the sur¬ 
face is usually very dry in most locations, the subsoil in all the exami¬ 
nations made on infected trees was wet and in one case water accum¬ 
ulated in the excavation at a level only a foot below the extremity of the 
tap root. Others liken the disease to pear blight. It differs, however, 
from that disease, in extending to parts of the same tree much more 
slowly and in spreading to trees adjacent to the center of the infection 
only after a considerable time, usually after the interval of a season’s 
growth. 
From all the evidence gathered in the field we incline to the belief 
that this disease is bacterial in its nature, and while the evidence is so 
scanty as only to create an impression it is strong enough to recommend 
investigation in the direction of this theory. With sufficient time (be¬ 
cause the action of the disease is rather slow) a skilled experimenter 
could doubtless prove its nature to be bacterial, if such be the case. 
The other causes assigned and probably still others connected with the 
methods of cultivation, and possibly some climatic conditions, may in¬ 
directly encourage the spread of the disease by furnishing conditions 
under which the tree can not successfully resist the attack of the dis¬ 
ease. It is well known, but too often not sufficiently taken into account, 
that certain physiological conditions render trees subject to ravages of 
disease, just as among men and other animals, and often a disease may 
be warded off by keeping the tree in the proper condition of vitality, 
more easily than it can be cured if once the disease has taken possession 
of it. • 
(4) Remedies .—There is little to say under this head at present. The 
following methods have been tried, but with indifferent success: 
(a) Prying up tlie trees, so as to raise tlie roots from the “hard pan. ” 
(&) Cutting hack the branches and fertilizing heavily. 
(c) Trimming off affected branches and burning them. 
(d) Trimming back branches, trenching at a distance of six or eight feet from the 
tree, so as to cut back roots proportionally, followed by heavy fertilizing. 
In addition to the above, a rather unique method of treatment was 
applied by the advice of a dealer in a commercial fertilizer “ specially 
adapted to the cure of diseased trees.” This consisted of cutting back 
all the branches of the tree to within two or three feet of the trunk, 
Ameariug the cut ends of the branches with coal tar as a preventive 
Against the ravages of the “crown borer,”* and then smearing the entire 
4289—No. 1—3 
* Elaphidion inerma Newman. 
