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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