The control of narcissus leaf diseases III. Sclerotinia polyblastis Greg, on Narcissus tazetta var. Soleil d'Or


Gregory, P.H.; Gibson, G.W.

Annals of Applied Biology 33(1): 40-45

1946


[ 4 0
The
control
of
narcissus
leaf
diseases
III.
Sclerotinia
polyblastis
Greg.
on
Narcissus
tazetta
var.
Soleil
d'Or
BY
P.
H.
GREGORY,
Research
Officer,
Agricultural
Research
Council,
at
Rothamsted
Experimental
Station,
Harpenden,
Herts.*
AND
GORDON
W.
GIBSON,
Director,
Isles
of
Scilly
Experiment
Station,
St
Mary's
In
the
extreme
south-west
of
England
Narcissus
tazetta
grown
for
the
outdoor
flower
crop
is
regularly
attacked
by
narcissus
fire
(Sclerotinia
polyblastis).
A
randomized
strip
experiment
on
the
variety
Soleil
d'Or
laid
down
in
1937,
in
which
half
the
plots
were
sprayed
each
season,
gave
data
on
the
effect
of
controlling
this
disease
on
the
number
and
quality
of
flowers
produced
in
/939,
1940
and
1941,
and
on
the
weight
and
grade
of
bulbs
lifted
in
1941.
There
was
an
average
increase
of
z6
%
in
the
number
of
flowers
produced
on
sprayed
plots,
and
a
35%
increase
In
weight
of
bulbs.
There
was
no
evidence
of
a
cumulative
improvement
because
most
of
the
gain
in
one
year
appears
to
have
been
immediately
expended
in
increased
flowers
in
the
following
season,
but
the
sprayed
plots
maintained
a
higher
general
level
throughout.
The
quality
was
improved
by
spraying,
mainly
by
the
addition
to
the
inflorescence
of
an
average
of
one
extra
'
bell'.
Although
not
cumulative,
there
was
a
residual
effect
shown
by
the
increased
yield
of
bulbs
in
1941
after
a
season
in
which
only
one
post-flowering
spray
had
been
applied.
The
effect
of
treatment
on
the
date
of
flowering
(anthesis)
was
negligible
and
its
direction
depended
on
the
season.
In
this
respect
Soleil
d'Or
differs
from
Golden
Spur,
in
which
spraying
induced
the
marked
retardation
of
flowering
noted
in
1938
and
5939.
INTRODUCTION
The
experiments
described
here
record
the
effect
on
yield
of
preventing
narcissus
fire,
due
to
Sclerotinia
(Botrytis)
polyblastis,
which
is
the
chief
fungus
disease
of
the
Narcissus
tazetta
varieties
grown
for
com-
mercial
flower
production
in
the
open
in
the
south-
west
of
England
(Beaumont,
193o;
Gregory,
5937,
1
939).
When
the
work
started
there
was
no
information
on
methods
of
controlling
narcissus
fire,
or
upon
the
effects
of
the
disease,
if
any,
on
the
yield
of
bulbs
and
flowers.
Earlier
papers
(Gregory,
1940a,
b)
showed
that
when
white
mould
(Ramidaria
vallisumbrosae)
on
Narcissus
pseudo-narcissus
was
controlled
by
copper
sprays,
increased
yields
of
flowers
and
bulbs
were
obtained
in
the
following
season,
but
that
there
was
a
marked
retardation
of
flowering
date.
It
was
obviously
impossible
to
measure
the
loss
of
crop
due
to
Sclerotinia
polyblastis
until
some
method
of
controlling
the
disease
could
be
found
to
enable
a
comparison
to
be
made
between
diseased
and
healthy
plants
growing
under
the
same
conditions.
For
this
purpose
it
matters
very
little
whether
the
method
of
control
adopted
is
economically
practicable
or
not.
TREATMENTS
Preliminary
tests
were
started
in
1937
on
a
com-
mercial
field
of
Soleil
d'Or
which
had
been
planted
in
5934
at
the
Isles
of
Scilly
Experiment
Station,
These
studies
were
carried
out
while
at
Seale-Hayne
Agricultural
College,
Newton
Abbot,
Devon.
St
Mary's,
and
observations
were
continued
on
the
same
plots
until
the
end
of
1939.
Single
plots
each
consisting
of
several
beds
were
treated
as
summarized
in
Table
5.
Meanwhile
it
had
been
decided
to
test
the
effect
of
spraying
this
variety
with
Bordeaux
mixture
regu-
larly
over
a
period
of
years.
The
experiment
was
laid
down
in
the
summer
of
1937
and
consisted
of
ten
pairs
of
small
beds
of
narcissus
Soleil
d'Or.
The
foliage
on
one
bed
of
each
pair,
chosen
at
random,
was
sprayed
with
Bordeaux
mixture
once
or
twice
each
season
from
1938
to
1941.
The
number
of
flowers
produced
from
each
bed
was
recorded
in
1939,
1940
and
1941.
In
the
summer
of
594,
the
bulbs
were
lifted
and
weighed
and
records
were
then
discontinued
on
account
of
the
war.
The
site
chosen
was
typical
of
Scillonian
flower
farms.
The
field
measured
about
50
x
3o
yd.
and
was
surrounded
on
all
sides
by
windbreaks
of
veronica
hedges
with
occasional
elm
trees
:
con-
sequently,
the
end
plots
were
liable
to
severe
com-
petition
from
the
surrounding
trees
and
hedges.
The
bulbs
were
planted
after
early
potatoes
which
had
been
manured
with
wool
waste.
The
stock
of
bulbs
used
was
lifted
from
an
ad-
jacent
field
and
stored
for
some
weeks
in
an
un-
heated
glasshouse.
Small
non-flowering
'
rounds
',
weighing
approximately
45
lb.
per
s000,
were
selected
for
planting
in
the
plots,
other
grades
being
used
elsewhere.
The
plots
were
planted
on
1
Sept.
5937
by
setting
in
plough
furrows.
They
were
arranged
in
beds
4
ft.
6
in.
wide
by
twenty
furrows
P.
H.
GREGORY
and
GORDON
W.
GIBSON
4
1
long.
Each
bed
contained
340
bulbs,
but
the
number
was
subsequently
reduced
by
an
unusually
heavy
attack
by
bulb
fly,
mainly
during
the
first
season,
and
the
number
of
plants
surviving
in
each
bed
in
5939
is
shown
in
Table
to.
The
fungicide
used
throughout
the
experiment
was
Bordeaux
mixture
containing
4
lb.
copper
sulphate,
4
lb.
fresh
hydrated
lime
and
4o
gal.
water.
A
wetting
agent
was
always
added
(usually
Agral
2
at
6
oz.;
4o
gal.).
Spray
was
applied
with
a
pneumatic
knapsack
machine
at
the
rate
of
about
1zo
gal./acre.
Each
year
one
or
two
applications
were
given,
one
soon
after
the
flowers
had
been
picked,
and
a
second
if
possible
about
.1
month
later.
In
1938
spraying
was
carried
out
on
24
Feb.
and
z8
Mar.
As
commonly
happens
with
newly
planted
only
small
lesions
and,
with
their
bigger
leaves,
could
be
recognized
at
a
distance.
On
to
June
the
control
plots
were
dead,
while
the
sprayed
plots
were
still
partly
green.
Jan.
1940
was
exceptionally
cold
in
the
Isles
of
Scilly,
and
plots
1-3,
which
were
situated
at
the
bottom
of
the
slope
above
a
hedge,
suffered
particu-
larly
from
frost
and
wind
damage.
The
plots
were
sprayed
on
17
Feb.
and
17
Apr.,
and
the
prolongation
of
life
of
the
protected
leaves
appeared
to
be
similar
to
the
previous
year.
In
1941
the
plots
were
sprayed
only
once
after
flowering,
on
7
Apr.
Control
of
disease
on
the
sprayed
plots
was
as
usual
considered
satisfactory.
In
general
it
may
be
said
that
the
stock
was
subject
to
the
usual
epidemic
of
narcissus
fire
in
each
of
the
TABLE
I.
Preliminary
test
at
St
Mary's,
Scilly
Cuprous
oxide
plot
Beds
3-1
s
Sprayed
o.i25
%
Cu
as
cuprous
oxide
Do.
Do.
Appreciably
better
than
control
Flower
count:
120
per
too
plants
No
spray
Sprayed
Cu
t
O
as
above
Unsprayed
control
Beds
x2-18
Foliage
badly
attack-
ed
S.
polyblastis
tog
per
too
plants
Bordeaux
mixture
plot
Beds
r9-2.4
Sprayed
4-4-4o
Bordeaux
with
Agral
2
No
spray
as
flowers
begin-
ning
to
open
Sprayed
as
8
Dec.
Foliage
green
and
standing
well
544
per
too
plants
Sprayed
Bordeaux
mixture
as
above
Do.
Date
1937:
8
Dec.
1938:
27
Jan.
24
Feb.
4
May
1939:
14
Jan
5
Feb.
i6
Mar.
20
July
Bulbs
lifted
12
Nov.
Produce
of
the
following
beds
analysed
Beds
15-18
Beds
19
-
22
Bulb
wt.:
go
lb./1000
118
lb./t000
Bulbs
cut
open
and
flower
buds
counted:
75
buds/too
bulbs
113
buds/too
bulbs
bulbs
very
little
disease
appeared
on
the
foliage
of
the
plots,
and
on
4
May
it
was
recorded
that
no
spray
damage
was
evident
on
the
treated
foliage
and
that
both
treated
and
control
plots
appeared
to
be
ripen-
ing
off
fairly
equally.
The
yield
of
flowers
in
1939
showed
that
the
sprayed
plots
had,
however,
sub-
stantially
benefited.
After
the
usual
cultivations
during
the
previous
summer
the
plots
were
hand-weeded
in
Jan.
1939
after
the
flower
buds
had
appeared
above
ground.
The
plots
were
sprayed
on
15
Feb.
and
again
on
15
Mar.
By
z8
Apr.
there
were
obvious
differences
to
the
eye
between
sprayed
and
unsprayed
beds,
but
the
foliage
of
all
plots
was
beginning
to
go
down,
especially
on
unsprayed
plots.
By
18
May
the
control
plots
were
estimated
by
eye
to
have
lost
about
half
their
leaf
area
as
a
result
of
attack
by
Sclerotinia
polyblastis,
while
the
sprayed
plots
had
years
1039
-
4
1
,
and
that
Bordeaux
mixture
gave
good
visual
control
and
prolonged
the
life
of
the
foliage
by
several
weeks
in
each
season.
As
a
secondary
effect,
possibly
attributable
to
the
longer
retention
of
foliage,
there
was
an
obvious
reduction
on
sprayed
plots
of
the
quantity
of
Oxalis
cernua,
a
trouble-
some
weed
in
Scilly.
FLOWER-CROP
RECORDS
Table
2
shows
the
number
of
flowers'
harvested
from
the
plots
in
each
of
the
years
1939-4x.
The
bulbs
had
been
graded
as
non-flowering
rounds
when
planted
and
produced
only
about
half-a-dozen
flowers
in
1938.
The
1939
figure
is
based
on
a
count
of
the
buds
made
before
picking
started.
The
194o
and
1941
records
are
based
on
the
totals
picked
from
each
plot
on
each
picking
occasion.
(The
term
4
2
The
control
of
narcissus
leaf
diseases
flower'
in
the
tazetta
group
is
applied
in
common
language
to
what
is
botanically
a
cymose
in-
florescence.
The
true
flower
is
known
to
growers
as
a
'
bell'
or
'
pip'.)
A
comprehensive
analysis
of
variance
showed
the
effects
of
treatments,
blocks
and
years
to
be
highly
significant.
The
increase
in
crop
on
sprayed
plots
amounted
to
zo
%
in
5939,
18
%
in
1940
and
37
%
in
1941
over
the
unsprayed
controls,
or
approximately
26
%
as
an
average
over
all
seasons.
The
almost
con-
sistently
better
performance
of
plots
towards
the
because
drift
of
spray
from
treated
to
control
plots
should
tend
to
increase
the
yield
from
untreated
plots
and,
similarly,
spore
drift
from
control
plots
would
in
time
contaminate
the
treated
plots.
Small,
contiguous
plots
are
ill-adapted
to
the
study
of
epidemic
foliage
diseases
because
of
the
effect
of
one
plot
on
its
neighbours.
In
1940
and
1941
studies
were
made
on
the
effect
of
spraying
on
anthesis.
The
retardation
of
sprayed
narcissus
Golden
Spur
has
already
been
shown
to
be
a
serious
factor
in
spraying
crops
of
this
variety
TABLE
2.
Total
numbers
of
flowers
picked
from
sprayed
and
unsprayed
plots
Plot
Unsprayed
plots
Total
Plot
Sprayed
plots
Total
1
939
1940
1
94
1
1939
1
94
0
1
94
1
no.
1
939
-
4
1
no.
1
939
-
4
1
i
118
152
151
4
21
2
121
173
193
4
8
7
3
95
163
184
44
2
4
123
217
272
612
6
112
195
215
522
5
151
232
280
663
7
122
189
201
512
8
1
54
266
325
745
10
138
250
267
655
9
188
259
33
1
77
8
II
171
2
43
287
701
12
161
264
258
683
13
i68
272
288
728
1
4
164
270
374
8o8
15
1
44
258
276
678
16
185
316
403
904
i8
1
4
8
226
230
60
4
17
158
293
368
819
19
88
204
204
496
20
163
251
256
670
Totals:
1
3
0
4
2152
2303
5759
1568
2541
3060
7169
TABLE
3.
Anthesis
on
sprayed
and
unsprayed
plots,
5940
Picking
date
Unsprayed
plots
Sprayed
plots
No.
picked
Total
picked
up
to
date
Total
%
No.
picked
Total
picked
up
to
date
Total
%
ii
Jan.
75
75
3'5
94
94
3'7
26
210
285
1
3'3
190
28
4
11'2
27
5
1
336
I5-6
35
3
1
9
12'5
29
2
35
57
1
26.6
262
585
22'9
3
1
1
34
705
23'8
1
53
734
28'9
2
Feb.
190
895
41'6
215
949
37'3
6
457
1352
62
.
9
556
/505
59'2
8
212
1
564
72'8
310
1815
7
1
'5
I0
62
1626
75.6
57
1872
73'
8
15
78
1
7
0
4
79'4
9
6
1968
77'4
19
204
1908
88.8
275
2243
884
23
212
2120
9
8
'5
250
2493
98-2
4
Mar.
32
2152
100-0
4
8
254
1
100'0
Totals
2152
2
54
1
middle
of
the
field
is
worth
notice
and
suggests
other
problems
needing
investigation,
because
the
crop
appears
to
be
reduced
to
one-half
by
some
such
factors
as
proximity
of
hedges.
As
already
noted,
plots
1-3
suffered
from
exposure
in
1940.
Plot
29
was
also
abnormal
because,
by
1941,
it
had
developed
a
bare
patch
of
about
1
sq.
yd.
where
the
bulbs
had
been
killed
by
Rosellinia
necatrix.
(These
white
root-
rot
patches
commonly
develop
in
Scilly
where
piles
of
vegetable
matter
are
left
to
rot
on
the
surface.)
The
differences
in
yield
would
probably
have
been
still
larger
if
whole
fields
could
have
been
sprayed,
grown
for
early
flowers.
It
was
therefore
important
to
look
for
a
comparable
effect
on
anthesis
in
Soleil
d'Or.
In
1940
and
1941
the
number
of
flowers
picked
from
each
bed
on
each
picking
date
was
re-
corded
and
the
results
are
shown
in
Tables
3
and
4.
Picking
was
carried
out
in
both
seasons
under
com-
mercial
conditions
in
which
neither
the
interval
between
pickings
nor
the
stage
in
which
the
flower
was
picked
were
standardized.
The
interval
between
successive
pickings
depended
on
the
weather,
and
the
beds
were
picked
over
when
enough
flowers
had
opened
to
make
gathering
worth
while.
In
general,
P.
H.
GREGORY
and
GORDON
W.
GIBSON
43
the
inflorescence
was
picked
when
one
of
its
flowers
was
open,
but
with
windy
weather
threatening,
the
picking
might
be
`closer'
to
avoid
loss
of
flowers
by
mechanical
damage.
However,
on
each
occasion
standards
were
similar
for
both
sprayed
and
un-
sprayed
plots,
and
the
records
cover
the
entire
season,
so
the
lack
of
standardization
cannot
in-
validate
the
conclusions
drawn.
The
records
thus
appear
to
indicate
a
slight
effect
of
spraying
on
the
date
of
flowering
of
the
order
of
I
day.
However,
the
effect
differed
in
its
direction
flower
bud,
which
is
normally
laid
down
very
early.
Narcissus
tazetta
has
apparently
different
physio-
logical
requirements,
and
flowering
is
favoured
by
warmth
in
summer.
Studies
Carried
out
by
one
of
us
(G.W.G.)
have
shown
that
the
flower
bud
is
not
formed
until
much
later
than
is
the
case
with
daffodils
(N.
pseudonarcissus),
and
its
initiation
is
therefore
not
likely
to
be
delayed
by
prolonging
the
life
of-
the
foliage.
As
judged
by
the
seasons
1940
and
1941
the
effect
of
spraying
on
anthesis
is
negli-
gible
in
Soleil
d'Or.
TABLE
4.
Anthesis
on
sprayed
and
unsprayed
plots,
1941
Picking
date
Unsprayed
plots
Sprayed
plots
No.
picked
Total
picked
up
to
date
Total
%
No.
picked
Total
picked
up
to date
Total
%
3
Feb.
121
I2I
5'
2
213
213
6.7
8
I90
311
I3'5
284
497
1
5'7
so
298
6o9
26'4
462
959
30.3
426
1035
44-6
563
1522
4
8.
2
15
563
1598
69
.
4
792
2314
73.2
16
226
1824
79'
1
275
2589
81-6
18
253
2077
90.2
3
0
7
2896
91.6
21
124
2201
95'5
144
3040
9
6
'
1
7
Mar.
7o
2271
98'4
85
3125
9
8
'9
9
32
2303
100.0
35
316o
sow0
Totals
2303
316o
TABLE
5.
Bell
count
on
3i
Jan.
and
2
Feb.
1940,
and
16
Feb.
1941
(mean
number
of
flowers
per
inflorescence)
Plot
no.
Unsprayed
plots
Plot
no.
Sprayed
plots
1940
1
94
1
16
Feb.
1940
w
1941
16
Feb.
3s
Jan.
2
Feb.
3s
Jan.
2
Feb.
1
6.9
7'4
6.9
2
7'5
7'
1
7-o
3
8.5
8.1
7'
1
4
10.5
9.8
7-8
6
8
.
4
9'
1
7
.
3
5
9'9
9'4
7'
8
7
8.i
7'9
8.x
8
9'3
9'
1
8.7
so
so•8
9.6
8-o
9
so•3
8.6
8'4
Is
8.6
8.3
7'3
12
8.5
8
.
4
8'3
13
8.6
8.2
7.9
1
4
so•9
9.2
8.3
15
9.6
9'3
8.3
16
11.8
)•I
8.6
18
7'
1
7'4
7.6
17
12.7
to•5
8.8
19
7'8
8.3
7'
1
20
8.6
9'4
7'5
Mean
8.44
8.36
7.56
so-o3
9'
06
8.12
in
different
years.
In
1940
the
sprayed
plots
were
slightly
later
in
flowering,
while
in
1641
they
were
slightly
earlier.
This
effect
is
quite
different
in
magnitude
from
that
noted
with
the
variety
Golden
Spur,
where
there
was
a
retardation
due
to
spraying
of
from
4
to
8
days.
It
is
unfortunate
that
similar
studies
with
Golden
Spur
had
to
be
discontinued
before
1940,
because
we
do
not
know
whether
the
effect
in
that
variety
might
not
also
be
capable
of
seasonal
reversal.
It
is
likely,
however,
that
the
effect
depends
on
the
presence
of
living
foliage
in
Golden
Spur
retarding
the
initiation
of
the
following
season's
FLOWER
QUALITY
Previous
experiments
with
narcissus
Golden
Spur
showed
that
sprayed
plots
produced
heavier
flowers
and
stems
than
unsprayed
plots.
The
stems
were
not
of
any
greater
length,
but
their
extra
weight
was
due
to
increased
thickness.
In
assessing
quality
in
a
N.
tazetta
variety
like
Soleil
d'Or
an
extra
criterion
is
available,
that
of
the
number
of
flowers
or
'
bells'
in
the
inflorescence.
Accordingly,
in
1940,
on
two
dates
in
mid-season,
all
flowers
picked
from
the
plots
were
examined
for
bell
count,
stem
length,
weight
of
inflorescence
and
pedicel
cut
at
base
of
spathe,
and
Unsprayed
plots
Plot
,
no.---"-----,
31
Jan.
2
Feb.
Plot
no.
Sprayed
Plots
,
31
Jan.
2
Feb.
x
266
257
2
303
266
3
259
257
4
284
247
6
7
2
2
6
5
2
4
247
241
5
z6
26
4
4
22
6
45
2
10
258
25o
9
264
244
I1
248
231
22
2
53
2
54
1
3
242
239
14
245
244
15
234
218
16
256
266
28
256
250
17
245
236
19
255
268
20
288
202
Mean
253
246
266
253
weight
of
stem.
In
1941
similar
information
was
gives
the
number
of
bulbs
in
the
various
flowering
available
for
one
picking
date.
grades
from
13
cm.
upwards.
The
mean
number
of
'
bells
'
as
judged
by
counts
In
each
block
the
greater
weight
of
bulbs
was
lifted
on
all
flowers
picked
on
these
three
sampling
oc-
from
the
sprayed
plot,
and
the
mean
increase
in
total
TABLE
8.
Mean
stem
length
(nun.)
on
1940
casions
was
consistently
about
1o%
greater
on
sampling
dates
sprayed
plots.
Spraying
has
clearly
increased
the
weight
of
both
flowers
and
stems.
The
increase
in
stem
length,
although
consistent,
is
slight.
The
in-
creased
weight
of
the
flower
is
apparently
due
to
the
addition,
on
the
average,
of
about
one
extra
'
bell'
to
the
inflorescence.
BULB
YIELD
In
August
1941,
4
years
after
planting,
the
bulbs
were
lifted,
weighed
and
graded,
and
the
experiment
was
then
discontinued.
Table
9
shows
the
total
weight
lifted
from
each
plot.
The
sprayed
plot
of
each
pair
gave
a
higher
yield
than
the
unsprayed,
and
a
test
of
significance
showed
values
of
t
corre-
sponding
to
odds
of
over
1
in
50.
The
total
number
of
bulbs
of
all
grades
was
not
recorded.
Table
to
44
The
control
of
narcissus
leaf
diseases
TABLE
6.
Mean
wt.
(g.)
of
inflorescences
on
sampling
dates
Plot
no.
Unsprayed
plots
Plot
no.
Sprayed
plots
1
94
0
1941
16
Feb.
1940
A
1941
26
Feb.
31
Jan.
2
Feb.
32
Jan.
2
Feb.
i
2.50
2'57
2'33
2
2'70
2'42
2'40
3
2'19
2/2
2'46
4
3'
08
3.05
2'80
6
2'75
2.89
2435
5
3'34
3-05
2-69
7
2/5
2.61
3'07
8
3'05
2'97
3'15
10
289
3.00
2'89
9
3'3
1
2.69
2.90
11
2'87
277
2'66
12
2'85
2'75
3'
0
9
13
2'89
2'60
2'80
1
4
3'
2
9
2'85
2'76
1
5
3.zo
2.85
3.09
x6
3'
60
278
3'
06
18
2.22
2'37
2-76
27
3-00
3'06
3.03
19
2
-
55
2.56
2'50
20
2.77
2.68
2.72
Means
2.67
2.69
2'74
3-2o
2.83
235
TABLE
7.
Mean
wt.
(g.)
of
stems
on
sampling
dates
Unsprayed
plots
Sprayed
plots
1940
2940
2942
194
1
31
Jan.
2
Feb.
16
Feb.
Plot
no.
31
Jan.
2
Feb.
26
Feb.
7'
00
7-22
6.07
2
8-oo
7'06
6.90
7'57
7'73
6-54
4
8.62
8.36
8.27
7
.,6
8.22
7
66
5
8.68
8.54
8'43
7/4
7.62
8.27
8
7.86
8.32
9.22
7.56
8'57
7.28
9
8.58
7'48
8.56
7.44
7'15
7'53
12
74
0
8.00
8'53
7-1
1
7'40
7'29
14
8'3o
7'85
8'54
7
.
5
0
7'53
8'33
26
9.20
7.56
8.85
6-28
6.62
7.13
17
8-00
9'06
8.76
6.34
7/1
6.67
20
6'92
8'36
8'10
7
.
17
757
7.27
8-26
8-o6
8
-
42
Plot
no.
1
3
6
7
20
11
13
25
28
29
Means
P.
H.
GREGORY
and
GORDON
W.
GIBSON
45
TABLE
9.
Yield
of
bulbs
(lb.)
compared
with
weight
planted
Unsprayed
plots
1
Sprayed
plots
Block
total
(lb.)
Wt.
(lb.)
No.
,
Wt.
(lb.)
Wt.
(lb.)
No.
,
Wt.
(lb.)
Plot
no.
1
937
1
939
1
94
1
Plot
no.
1
937
1
939
1
94
1
1
94/
I
1
4
2
77
28
2
14/
217
32
6o
3
131
237
3
1
4
1
4+
257
5o
81
6
1
5+
268
39
5
15
252
5o
89
7
15
257
38
8
14+
283
54
92
to
14f
301
44
9
1
51
285
55
99
11
15
312
50
12
151
326
61
Hi
13
s61
328
54
1
4
1
51
3
2
4
70
124
15
15f
3
2
4
67
56
I5i
310
8
4
151
18
161
291
53
17
1
5i
301
83
136
59
1
5+
287
42
20
151
282
63
105
Total
istf
2882
446
isif
2837
602
1o48
Plot
no.
TABLE
10.
Numbers
of
bulbs
of
flowering
size
(from
s3
cm.
upwards)
Unsprayed
plots
Sprayed
plots
13
cm.
14
an.
15
cm.
and
up
Total
13
cm.
and
up
Plot
no.
13
cm.
14
an.
75
cm.
and
up
Total
13
cm.
and
up
,
63
4
1
9
113
2
61
6z
26
1
49
3
5o
54
2
5
129
4
4
2
75
89
206
6
46
74
56
176
5
3o
61
126
217
7
4
1
7
1
65
1
77
8
21
64
139
224
10
31
85
97
213
9
22
6z
152
236
II
43
86
90
219
12
27
57
1
75
259
13
52
75
130
257
1
4
21
63
180
264
15
44
84
90
218
s6
9
66
152
227
18
34
86
98
218
17
i8
48
13o
196
19
3
8
75
71
184
20
(records
incomplete)
Total•
404
656
66o
1720
251
558
1169
1978
Omitting
plots
19
and
zo.
bulb
weight
was
about
34%
.
The
general
effect
of
spraying
on
the
grades
of
bulbs
lifted
was
to
increase
the
total
number
of
bulbs
of
flowering
size
by
about
15
%
and
to
increase
the
15
cm.
grade
by
about
77
%
at
the
expense
of
the
13
and
14
cm.
grades.
There
was,
therefore,
every
prospect
that
had
the
bulbs
been
replanted
and
crop
records
continued
as
originally
planned
before
the
war,
the
sprayed
plots
would
have
given
an
increased
flower
crop
of
better
quality
again
in
1942.
The
results
obtained
should
not
necessarily
be
interpreted
as
evidence
that
spraying
with
Bordeaux
mixture
is
a
commercially
feasible
control
measure.
Spraying
of
any
kind
is
highly
inconvenient
in
the
climate
and
working
conditions
of
the
south-west,
but,
in
view
of
the
obviously
large
effect
of
the
disease
on
the
flower
and
bulb
crop,
search
should
obviously
be
made
for
simpler
control
measures
based
on
good
cultural
practices.
The
significance
of
this
experiment
must
be
regarded
merely
as
a
stage
in
the
investigation
of
this
and
other
narcissus
diseases.
Meanwhile,
spraying
of
narcissus
Soleil
d'Or
with
Bordeaux
mixture
in
districts
where
Sclerotinia
polyblastis
is
prevalent
can
be
recom-
mended
as
likely
to
give
an
increased
yield
without
risk
of
delaying
flowering.
This
work
was
carried
out
under
a
scheme
financed
jointly
by
the
Great
Western
Railway
Co.
through
the
Cornwall
Farmers'
Union
and
the
Ministry
of
Agriculture
and
Fisheries
upon
the
re-
commendation
of
the
Agricultural
Research
Council,
to
all
of
whom
grateful
acknowledgements
are
made.
REFE
BEAUMONT,
A.
(193o).
Narcissus
fire.
Rep.
Dep.
Pl.
Path.
Seale-Hayne
agric.
Coll.
6
(1929),
20.
GREGORY,
P.
H.
(1937).
Narcissus
leaf
diseases.
R.H.S.
Daffodil
Yearb.
1937,
pp.
4
6-
5
2
.
(
1
939)•
Narcissus
leaf
diseases.
II.
R.H.S.
Daffodil
Yearb.
1939,
PP.
49
-
53.
RENCES
GREGORY,
P.
H.
(1940a).
The
control
of
narcissus
leaf
diseases.
I.
White
mould
and
fire
on
'Golden
Spur'.
Ann.
appl.
Biol.
27,
338
-
47.
(1940b).
The
control
of
narcissus
leaf
diseases.
II.
The
effect
of
white
mould
on
flower
and
bulb
crop.
Ann.
appL
Biol.
27,
472
-
88.
(Received
23
May
1945)