CHE REFERENCE LIBRARY - Pole Shift Survival Information

t:ERTAIN Ei,EMENTS IN NlrRSERY PRACTICE 201
is often the chief cause of the dropping of currant leaves and
inay be destruc%ivc also on gooseberries.
Ihmipfio~r. .-.--- The septoria leaf-spot disease causes rather
large angular lesions with grayish centers and brown borders.
Wit.hin tile grayish center of old spots may bc~ observed several
minute black specks. The spots may be few or many on the
leaf ; whm they al*e numerous, the leaf turns yellow and falls
prematurely- (Figs. 2 15,
Zlti). The septoria
leaf-spot is tlisting&lied
easil>- from hhe
antluxc~nosc disease by
thtl much larger and
well-defined lesions,
with characteristic
light-colored centers.
Ccr~usr. - The disease
is caused by the
fungus A~1yms]dllr~clbn
tJ ross7i It1 r ilr . The minute
black specks in
the center of the okI FI(;. 2l(i. Sty\tori:t Icnf-spot of currnnt and
goos~bcrry.
sp0t.s are fruit~ing
bodies (pycnidki) of the fungus. The pycnidia contain spores
which a,re disseminateci by the wind a,nd rain, and are thus a
means for further spread of the fungus. Falling 011 currant or
gooseberry leaves, the spores germinate a,nd produce new infect
ions. The fungus lives over winter in t.he old leaves on
the ground and in the spring sptxG1 spores nre produced that
&tack the new foliage. As with most leaf-spot fungi, heavy
rains, followed by da~up cloudy weather, grea’tly augment
the sprk2acl of this p;krasite.
C’orrtrol. -- hkasures suita,ble for the anthracnose disease
control a.lso the septoria leaf-spot. The first application