CHE REFERENCE LIBRARY - Pole Shift Survival Information

192 THE NilJRSERY-MAN [JAI-,
chinr. With the dust method, the time of application is not
limited by soil conditions, inasmuch as the lightness of the
out.fit permits its transportation at all times ; also blocks of
trees on rough or hilly ground or in localities remote from an
adequate water supply nlay be protected without unusual
difficulty. The dusting method can be employed in controlling
a large percentage of the leaf diseases and foi+e-eating insects
in the nursery. The cost of spraying solutions is less than
dust materials. The actua,i expense for the dust method,
however, is practically the same as for the liquid since the
handling of a large bulk of water is eliminated, the outfit is
less expensive, and the operators are fewer in number.
The nursery-stock diseases caused by fungi a,nd bacteria
are particularly baffling because the organisms are not seen
and recognized. In former da,ys these disorders were ascribed
to the weather, t,o t?iect,ric currents and to other little understood
or occult phenomena.
FIRWHLIMW. - The fire-blight disease is most destructive
on the cultivated varieties of pear, apple and quince. Usually
in the nursery it means total loss or” t,he trees afleeted a,nd often
within a comparatively short t,ime thousands of young trees
are ruined by its rapid spread t,hrough the blocks.
Ik.script km . - The limbs, blossoms, twigs and fruit may he
attacked. In the nursery the disease is most commonly found
in the twigs (Fig. 210). In the case of two- and three-year-old
quince stock, however, the trees often blossom profusely in
the spring and when this happens blossom-blight (due to the
same organism) frequently occurs. The blight usually first
appears two or t.hree weeks after the blossoming period. The
first evidence of the trouble is the brown and subsequent