The Wilmington morning star., 1940-03-25
CONTROL OF APPLE
DISEASE OUTLINED
a.. 1uther Shaw Explains I'm
,artant Steps Necessary
To Protect Fruit
~ mr.. LUTHER SHAW
r,..osiop Plant Pathologist
,.'..b Carolina State College

North Carolina State Co'lese
-. The rapid increase in home
S W. orchards and the gradual in
Gs IN commercial apple produc-
Hs'ss North Carolina it is well
nn while to review some Of the
'~ .n.nt steps that must be taken
s.ro1 the serious diseases af-
pass this fruit
-. is subject to attack by a NUM-
N' ~ disease.producing organisms,
4 which is capable of causing
S ..,s trouble. Outstanding among
diseases are: (1) fire blight.
t|s, affects twigs, leaves and
n.4 %, rust sometimes called
, ,,.r rust) which affects the leaves
trnit; 80 scab, which affects
D.l.s and fruit; az olotch, which
s,.,s twiss and fruit; () bitter
y. which affects the fruit; and
!" tack rot which affects the
.". and leaves. With so many dis
,as, affecting the apple crop, it is
., srrprising that disease control
mo of the most important and
.,J,ljzed phases of apple produc-
". For satisfactory disease con.
.l if is. unfortunately, necessary
~, Tho small home orchardist to
,,y opt as complete a disease con.
81 ,rocram as the large CONNER.
Al mchardlst.
What are some of the important
.,rrices that must be followed to
.moI these apple diseases? Their
,td nature makes it necessary
,ary out a number of practices
F. htain satisfactory control.
Gmd Management Important
,ioDtjon of the best known Or
ind MANAGEMENT practices is OF
aajte value in apple disease con.
h, Pruning is especially impcr-
nf and a special effort should be
nd, 10 prune out as much dis
si wood as is feasible. Further
NM. the trees should be trained
tpush pruning to facilitate thor.
RIB leverage Of all parts with the
rsv materials. Such thorough
rerase is distinctly favored by
Eu1jns the tree toward a relatively
zen type Of growth.
Much has been said and written
kaIt both winter and summer
ming in the control of fire blight.
is a fact that the results of eX-
amental tests on the value of
lnng in the control Of fire blight
y contradictory. The weight OF
Hence seems to be az that prun'
!: whether it be in winter or sum-
b. cannot lie depended upon as
mans Of complete control of fire
teht, but may be definitely bene'
fl- especially in orchards where
b Epidemic is moderate to light
A G) that an effort to prune ore
Of the blishted wood in tres
li have blighted badly is fre-
Fsntly more harmful than bene.
2A In such cases the trees often
et less the following year II
H1ed lightly or not at all. One
The most serious mistakes of fire
sa, especially on the more sus. |
pl0ls varieties, is the formation
uank and limb cankers. These
ASels usually arise from water
aot or fruit spur infectioNs.
VIZ canker formations can be eff.
aVely prevented by a systematic
l0al of the water sprouts and
WILL spurs from the main trunk
Y oasa! portions of the main
W. This "a be done by strip
y mem off by hand. A pair of
~! gloves will have to be worn
project the hands.
Rust Disease
tt Or cedar rust is one of the
y" diseases affecting the apple.
vaaness is found in the fact
'e parasite causing it spends
A' Of its life cycle on the apple
part OH the common red cedar.
IsflAore' the presence Of both
~sse plants is essential for the
nSD'e OF the parasite. This con-
vi iss proven to be a pitfall for
"sl fungus, and the .elimina-
me red cedar for a distance
~ mile Or more from the or.
VIII give control of the dis.
M; Geoar removal is the only
T iva means known at the pres
Ne rust.
,,,,: Must Spray Properly
s,,. "s constitutes the most
M, @ill practice in a program to
apple diseases. The proper
b materials must be used; they
w. w. properly mixed, and ap.
Ms au'tly and thoroughly.
North Carolina conditions
|Yss Of spray materials have
No. s'eu IN the control of apple
mn,.. namely, % sulphur and
HpsF' Two basic factors neces-
h :. me use of these materials.
/ # 'pl0f Vii burn foliage and
s n applied at temperatures
,.t' w 10 Is degrees Fahrenheit.
b sulphur applications have
b lihed to the dormant and
at @v"lng season. Under most
ann, 1t Is usually safest to
psts m,'eatlons of sulphur after
b sors fall or with the first
aean'' N.Y. Second, copper sprays
b II a mlXture) are not as
lerat apple tree at the high
slmra. that prevail during
Asrna months, as is sulphur.
he t,s copper is more toxic
dsesnsl which cause the sum.
Atcrs olotch. than is sulphur.
10 upper has a double ad.