CHE REFERENCE LIBRARY - Pole Shift Survival Information

The spots are first small, but tliP;\r increase in size to a half
inch in diameter. Often a number of spots coalesce involving
a considerable part of the leaf tissue. A very marked character
is the fringed border of the spots. Severely affected
lea,ved usually turn yellow and fall prematurely.
t-21 l1Sf. -- The cause of the disease is the fungus I)$ocqarpon
rostx . Spores of the fungus which are borne in the black spots
on the leaves are disseminated
by wind and rain to new foliige
where they produce
new infe&ms. Special fruiting
bodies which develop in
the diseased leaves that fall
to the ground carry the fungus
over winter.
t ?I~7 trol. - Bordeaux mixture,
or a dust mixture consisting
of 95 pa,rts finely
ground sulfur and 5 parts
powdcrcd lcnd arsenate, will
control t,he black-spot disease.
The first application
should be made in early summer,
soon after the first new
leaves arc I lcvclopcd. Four. or five subsequent trea,tments
should be made at intervals of about two weeks.
~h.JIW Ok’ ~k.,SE AND h4CII. - Mildew is found on both
the peach and the rose, but it is commoner on the latter. AS
a rule, peach mildew is of little importa,nce in the nursery, but .
rose mildew often causes considerable damage. The disease
on roses checks the growth of the plants in the field, and some
growers are of the opinion that severely mildewed rose stock
does not keep well in storage. The affected shoots tend to