Calcium Supplement Alone or In Combination With Ronilan
Fungicide at Three Timings for Control of White Mold in Canola
Scott Halley
Langdon Research Extension
Center-North Dakota State University,
Box 310 Hwy 5 E Langdon, North Dakota 58249
*Corresponding author PH:
(701) 256-2582, E-mail: shalley@ndsuext.nodak.edu
Objective
A two year study was initiated to determine if white mold, (Sclerotinia
sclerotiorum (Lib.) de Bary), infections could be reduced in canola by
calcium supplement at an early growth stage.
Materials and Methods
Two trials, designed as randomized complete block and
arranged as a 5 x 3 factorial with four replicates, were conducted at the Langdon
Research Extension
Center in 2002 and 2003. The
factors included spray applications of the fungicide Ronilan (vinclozolin), the
calcium supplements, (calcium chelate and calcium sulfate), and tank mixes of
the calcium supplements and the fungicide. The calcium chelate (12% calcium and
4% chelate) and calcium sulfate (29.2 % calcium and 17% sulfate) were
commercial products supplied by NWC, Inc of Emerado,
North Dakota. Application timings were made
at rosette or first flower growth stages or at both growth stages. An untreated
check was included in the trial but omitted from statistical analysis. The
cultivars �Invigor 2733� and �Hyola 357 Magnum� were seeded with a double disk
drill on 20 May 2002 and 13 May 2003, respectively. The 2002
site received sclerotia from a sunflower source that was hand broadcast and
lightly incorporated. The sclerotia were conditioned by three freeze thaw
cycles in laboratory during the winter. The 2003 site received sclerotia from a
similar source. These sclerotia were conditioned by mixing with soil, wetting
the mix by adding 30% water by weight, and freezing for several weeks. The
sites were adjacent to a site that had severe white mold infections on canola
in previous years but no recent infections on the particular trial area. Each
trial received a spray application of ascospores at early flowering growth
stage to improve chance of disease infection and supplemental water at
sufficient amount to wet the soil surface to promote carpogenic germination of
sclerotia and ascospore germination on the canola plant and subsequent
infection. Spray applications were made by C02 backpack sprayer with
XR8002 nozzle oriented vertically spraying 18.4 gpa @ 40 psi. A visual
incidence assessment was made of one row the length of the plot. Plots were
seven 6-inch rows16 ft. long with two additional rows planted next to the
adjacent plot as a guard against spray drift to other treatment areas. Yield,
test weight, and percent oil were record in both years. Stand and plant height
were recorded in 2002. Sclerotinia incidence and 1000 seed weight were recorded
in 2003. Data was analyzed with the general linear model (GLM) in
SAS. Least significant differences (LSD) were used to compare means at the 5%
probability level.
Results and
Discussion
The 2002 crop season was not conducive to white mold disease
development in the region and efforts to create a disease environment were
ineffective. A visual plant height appeared across some plots so plant stand
and height were measured. No differences in plant stand and height, yield, test
weight, and percent oil were measured by any of the factors in 2002. The 2003
crop season was also not conducive to white mold disease development in the
region. However, a change in strategies including sclerotia conditioning was
effective in creating a very high level of disease in the trial. No differences
in sclerotinia, yield, test weight, 1000 seed weight, test weight, or percent
oil were measured. One would conclude from the limited research that the
calcium supplement under these conditions had no effect on the components
measured.. The research also indicated, though data is limited, that a Ronilan
fungicide application at rosette, first flower, or the combination was not
effective in reducing disease development.
The author wishes to acknowledge financial support from the
State Board of Agriculture Research and Education (SBARE) and the Northern
Canola Growers Association and NWC, Inc. for the calcium supplements.
Table 1. Yield, test weight, plant stand, plant
height, and percent oil by fungicide or calcium
fertilizer supplement and timing, Langdon 2002.
|
Fungicide/
|
Timing
|
Yield
|
Test
|
Stand
|
Plant
|
Oil
|
|
Fertilizer
|
|
|
Weight
|
|
Height
|
|
|
|
|
lb/a
|
lb/bu
|
plants/ft2
|
inches
|
%
|
|
|
|
|
|
|
|
|
|
Untreated a
|
|
1358
|
52.1
|
8.0
|
27.5
|
41.9
|
|
|
|
|
|
|
|
|
|
Ronilan
|
Rosette
|
1384
|
51.9
|
6.6
|
31.0
|
41.7
|
|
|
First Flower
|
1617
|
52.0
|
7.8
|
27.5
|
41.7
|
|
|
Ros. + FF b
|
1524
|
52.4
|
9.7
|
28.5
|
42.8
|
|
Calcium Chelate
|
Rosette
|
1417
|
52.3
|
7.4
|
29.5
|
43.0
|
|
|
First Flower
|
1546
|
51.9
|
8.3
|
29.0
|
42.7
|
|
|
Ros. + FF
|
1651
|
52.0
|
9.6
|
30.5
|
41.6
|
|
Calcium Sulfate
|
Rosette
|
1425
|
52.1
|
8.0
|
27.5
|
42.4
|
|
|
First Flower
|
1300
|
52.0
|
9.3
|
28.0
|
42.5
|
|
|
Ros. + FF
|
1415
|
51.9
|
8.0
|
31.0
|
41.9
|
|
Ronilan +
|
Rosette
|
1519
|
51.8
|
8.2
|
29.0
|
42.2
|
|
Calcium Chelate
|
First Flower
|
1438
|
52.0
|
7.7
|
30.0
|
42.1
|
|
|
Ros. + FF
|
1538
|
52.1
|
7.9
|
31.0
|
42.2
|
|
Ronilan +
|
Rosette
|
1660
|
52.0
|
7.3
|
28.0
|
41.9
|
|
Calcium Sulfate
|
First Flower
|
1527
|
52.3
|
7.9
|
32.0
|
41.8
|
|
|
Ros. + FF
|
1500
|
51.6
|
7.6
|
28.0
|
40.3
|
|
|
|
|
|
|
|
Fungicide/supplements averaged over timings
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Rosette
|
1481
|
52.0
|
7.5
|
29.0
|
42.2
|
|
|
First Flower
|
1486
|
52.0
|
8.2
|
29.3
|
42.1
|
|
|
Ros. + FF
|
1526
|
52.0
|
8.6
|
29.8
|
41.8
|
|
|
|
|
|
|
|
Fungicide/supplements averaged over timings
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Ronilan
|
|
1509
|
52.1
|
8.0
|
29.0
|
42.1
|
|
Calcium Chelate
|
|
1535
|
52.1
|
8.4
|
29.7
|
42.4
|
|
Calcium Sulfate
|
|
1380
|
52.0
|
8.4
|
28.8
|
42.2
|
|
Ronilan + Calcium Chelate
|
1498
|
52.0
|
7.9
|
30.0
|
42.1
|
|
Ronilan + Calcium Sulfate
|
1563
|
52.0
|
7.6
|
29.3
|
41.4
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Fung/Fert
|
|
NS
|
NS
|
NS
|
NS
|
NS
|
|
Timing
|
|
NS
|
NS
|
NS
|
NS
|
NS
|
|
Fun*Tim
|
|
NS
|
NS
|
NS
|
NS
|
NS
|
|
% C.V.
|
|
18
|
1
|
19
|
11
|
5
|
a Not include in statistical analysis
b Rosette + First Flower
Table 2. Sclerotinia incidence, yield, test weight, 1000
seed weight, and percent oil by fungicide or
calcium fertilizer supplement and timing, Langdon 2003.
|
Fungicide or Supplement
|
Application Timing
|
Sclerotinia
Incidence
|
Yield
|
Test Weight
|
1000 Seed Weight
|
Oil
|
|
|
|
plants/row
|
lbs
|
lb/bu
|
g
|
%
|
|
|
|
|
|
|
|
|
|
Untreated a
|
|
17.0
|
1377
|
53.0
|
2.68
|
41.1
|
|
|
|
|
|
|
|
|
|
Ronilan
|
Rosette
|
16.1
|
1229
|
53.5
|
3.03
|
40.2
|
|
|
First Flower
|
16.5
|
1248
|
54.0
|
2.67
|
40.1
|
|
|
Ros. + FF b
|
11.0
|
1301
|
53.4
|
2.67
|
40.8
|
|
Calcium Chelate
|
Rosette
|
9.4
|
1177
|
53.6
|
2.78
|
40.4
|
|
|
First Flower
|
18.1
|
1300
|
53.3
|
2.84
|
39.1
|
|
|
Ros. + FF
|
21.0
|
1226
|
53.6
|
2.88
|
40.3
|
|
Calcium Sulfate
|
Rosette
|
13.1
|
1239
|
53.5
|
2.67
|
40.2
|
|
|
First Flower
|
15.5
|
1296
|
53.6
|
2.92
|
39.2
|
|
|
Ros. + FF
|
19.9
|
1308
|
53.8
|
2.85
|
40.5
|
|
Ron. + Cal. Chel.
|
Rosette
|
18.5
|
1322
|
53.6
|
2.91
|
41.0
|
|
|
First Flower
|
16.9
|
1447
|
53.3
|
2.60
|
41.4
|
|
|
Ros. + FF
|
18.6
|
1384
|
53.8
|
2.73
|
40.9
|
|
Ron. + Cal. Sulf.
|
Rosette
|
14.1
|
1221
|
53.8
|
2.95
|
41.0
|
|
|
First Flower
|
16.5
|
1345
|
53.8
|
2.75
|
39.7
|
|
|
Ros. + FF
|
19.1
|
1294
|
53.6
|
2.98
|
42.0
|
|
|
|
|
|
|
Timings averaged over fungicide/supplements
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Rosette
|
14.3
|
1238
|
53.6
|
2.87
|
40.6
|
|
|
First Flower
|
16.7
|
1328
|
53.6
|
2.76
|
39.9
|
|
|
Ros. + FF
|
17.9
|
1303
|
53.6
|
2.82
|
40.9
|
|
|
|
|
|
|
Fungicide/supplements averaged over timings
|
|
|
|
|
|
|
|
|
|
Ronilan
|
|
14.5
|
1259
|
53.6
|
2.79
|
40.4
|
|
Calcium Chelate
|
|
16.2
|
1235
|
53.5
|
2.83
|
40.0
|
|
Calcium Sulfate
|
|
16.2
|
1282
|
53.6
|
2.81
|
40.0
|
|
Ronilan + Calcium Chelate
|
18.0
|
1385
|
53.5
|
2.75
|
41.1
|
|
Ronilan + Calcium Sulfate
|
16.6
|
1287
|
53.7
|
2.89
|
40.9
|
|
|
|
|
|
|
|
|
|
Treatment
|
|
NS
|
NS
|
NS
|
NS
|
NS
|
|
Timing
|
|
NS
|
NS
|
NS
|
NS
|
NS
|
|
Treat.*Tim.
|
|
NS
|
NS
|
NS
|
NS
|
NS
|
|
% C.V.
|
|
43
|
15
|
1
|
9
|
5
|
a Not include in statistical analysis
b Rosette + First Flower
