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form was most common shortly after the blooming period, 
and the reason seems apparent. 
The points of access are then three in number. The 
flower, the young and growing shoots, and wounds in the 
bark. 
CONDITIONS WHICH AGGRAVATE THE DISEASE. 
It remains for us to consider briefly the conditions which 
may aggravate the disease and what maybe done to check 
or prevent it. It is a matter of common observation that 
the disease varies greatly in different localities and in diff- 
erent seasons. It may progress slowly or with great rapidity. 
Knowing as we do now, the cause of the disease, and the 
conditions under which the organism most rapidly propa- 
gates, we can account for this variation by the different 
conditions prevailing. The old theory that rich soils, and 
moisture were the cause of the disease was a favorite one, 
and undoubtedly arose from the observation that on rich 
soil, and in moist seasons the disease was most virulent and 
destructive. Rich soils with accompanying moisture is con- 
ducive to rank, rapid growth. The tissues formed are gorged 
with sap, and are very succulent. In this condition of things, 
we find all that is necessary for a rapid growth of our mi- 
crobe. On a soil of only moderate fertility the growth is 
slow, less succulent tissue is produced, and if the supply of 
moisture is small, we have conditions not advantageous to 
the organism, and its development is slow. In this matter 
of growth we find a reason for the various opinions regard- 
ing clean culture, or grass in the orchard. One man has no 
blight and attributes his escape to clean culture. Another 
has no blight and thinks it is because his orchard is in grass. 
Both may be right, though the reasons they give for the im- 
munity are wrong. An orchard on rich soil may receive 
just the necessary check in growth to prevent too great 
succulency by having grass in the orchard. An orchard on 
poor soil may need the clean culture to keep it in healthy 
growth. Anything then, whether in the choice of soil or 
manner of treatment that gives the trees a slow growth 
which will thoroughly ripen and harden, will render them 
less liable to attack from blight. Close planting is objec- 
tionable, because the ground being too much shaded, moist- 
ure is retained, and moisture favors blight. 
In irrigating, care should be taken not to apply an 
excessive amount of water. I believe the general tendency 
is toward the use of too much water, and that by this means 
that succulentgrowth so readily attacked by blight is induced. 
