CHE REFERENCE LIBRARY - Pole Shift Survival Information

CERTAIN ELEMENTS IN NURSERY PRACTICE 197
Pen frol. -- Spraying with lime-sulfur solution I to 40, or
dusting with 90 parts dry sulfur plus 10 parts powdered arsenate
of lead, proves etiective in the control of apple- and pear-scab.
For nursery stock, the first treatment should be made soon
after the first new Icaves appear. This application should be
followed 1-q. at least three more treatments at intervals of two
t,o three Fveeks.
ilS a, general recommendation for nurseries, it is not consiclered
necessary to treat varieties of pear trees for scab except
the I”letnish. In most nurseries it is not necessary to treat
applt~s each yc~ for sca.b, but in some cases the treatment
pro\‘cs profitahlC Where t.hc: disease is commonly observed
on c(r’rtain \Gt+t~s of apples, such as McIntosh and Transcendctlt
NY&~, spra.ying or dusting is advisa,ble.
:\PPIX I’( ~WDISI~Y-MILDEW. ---.- This disease is most commonly
ohserved in the nursery on the foliage and young shoots of the
apple seedling stoc*k. When it appears early in the summer,
the growth of the seedlings is checked and the bark does not
peel readily at budding time.
Ikscriptin~~. - ‘I’llt~ disease appears as grayish white, feltlike
areas on the foliage, varying in size from a minute speck
to an inch in diatnctt-ar. The diseased leaves are stunted and
haye a tcndcnq, t.o crinkle and curl up. Aft’ected shoots are
stunted ;tticl appear tnuch shorter than healthy twigs.
(‘n Ilsr’. -- The disease is caused by a fungus, .Z%~!osph~~a
lwcotricho. The grayish patches of mildew on the leaf or the
shoot. consist of a tangle of fine threads or strands of the
fungus. Tl lis . 1 oosely interwoven mass of threads (known as
m~*celium) produces spores that, are carried by wind and rain
to other lea,ves where they produce new patches of mildew.
The fungus lives over winter between the dormant bud-scales
or by means of special fruiting bodies.
C~olltrol. -- Lime-sulfur solution 1 to 40 is eflective to a