Hail Damage in Corn & the Impact of Bruising and Stalk Damage

Hail in the recent days have impacted some corn acres in Manitoba.  In an earlier Crop Chatter post (Assessing Hail Damage in Corn), typically yield reduction due to hail damage is a result of leaf loss.

However, there can be an impact if hail injured the stalk (see Figure 1).

Bruising of Corn Stalk from Hail - June 2016 (Photo by P. de Rocquigny)

Figure 1: Bruising of Corn Stalks from Hail (Photo by P. de Rocquigny, June 2016)

The following information is adapted from articles “Recovery From Hail Damage to Young Corn” by R.L. Nielson of Purdue University and “Differentiating Superficial and Deeper Hail Damage” by C. Shapiro of Haskell Ag Lab.

Q: What will be the impact to yield? The eventual yield effects of severe bruising or damage of the stalk tissue itself can be quite difficult to predict. Consequently, it can be difficult to determine whether to count severely bruised plants in assessing plant stands. Observations reported from an Ohio on-farm study suggest that bruising from hail early in the season does NOT typically result in increased stalk lodging or stalk rot development later in the season.

Early season bruising of stem tissue may, however, have other consequences on subsequent plant development; the occurrences of which are hard to predict. If the plant tissue bruising extends as deep as the plant’s growing point, that important meristematic area may die; thus killing the main stalk and encouraging the development of tillers. If the plant tissue bruising extends into the area near, but not into, the growing point; subsequent plant development may be deformed in a fashion similar to any physical damage near the hormonally active growing point.

Q. How can I tell how badly damaged corn may be from bruising? Bruising is difficult to determine. You can make an initial assessment about a week to 10 days after the storm. Peel the sheaths away from the stalk and determine if the damage has actually penetrated the stalk. The outer stalk (rind) is strong and can resist some damage. However, if the stalk has brown areas, that may indicate stand problems later in the season.

Cutting the stalk vertically from node to node will help determine the extent of damage (Figure 2). Brown areas in the pith where the hail hit indicate the potential for problems later in the season. The stalk in Figure 2 does not show any bruising from the pith. These areas will disrupt the movement of fluids in the plant and reduce growth. Bruised plants that show stalk damage in the pith should probably be considered as missing plants in yield calculations.

Split corn stalk

Figure 2. Cut the corn stalk vertically from node to node to help determine the extent of damage. Source: Differentiating Superficial and Deeper Hail Damage

 

Remember that estimating yield loss due to hail is only an estimate, particularly if the damage is not severe and depending upon growth stage of the plant when the hail event occurred.  The remainder of the growing season will help determine final yields.  Please contact your hail insurance provider for their procedures in assessing hail damage as they may be different that what has been provided here.

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture

Manitoba Agriculture website: www.manitoba.ca/agriculture
Manitoba Agriculture on Twitter: @MBGovAg
Manitoba Agriculture on YouTube: www.youtube.com/ManitobaAgriculture

 

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Assessing Hail Damage in Cereal Crops

Over the last few days, hail has been reported in several areas of Manitoba, potentially impacting cereal crops. Assessing damage will take a few days, and impact will largely depend on stage of the crop and how severe the hail event was, i.e duration of storm, size of hail.

Generally, cereal crops prior to stem elongation can recover from hail, even if there is substantial leaf damage as the growing point is below the soil surface and will likely not be damaged.

Hail damage occurring during stem elongation or the boot stage can be difficult to assess. Spikes can still pollinate and fill, and regrowth from new tillers can occur. Generally speaking, hail causes the greatest damage to small grains from the boot stage through later stages.

In a study by R.H. Busch in North Dakota in wheat, the greatest yield reduction resulted when stems were broken in the milk stage, followed by anthesis, soft dough, boot, and hard dough stages – see Table below (Busch, 1975).

Grain yield reduction in spring wheat with 100 percent of stems bent.
Growth stage Yield reduction (%)
Boot (Zadoks 45) 28 to 39%
Anthesis (Zadoks 65) 15 to 60%
Milk (Zadoks 75) 30 to 70%
Soft dough (Zadoks 83) 16 to 55%
Hard dough (Zadoks 87) 3 to 47%
Table derived from Busch, 1975

 

Remember to contact your hail insurance provider for their procedures in assessing hail damage as they may be different than what has been provided here.

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture

Source:  Busch, R. H. 1975.  The effect of simulated hail injury on spring wheat. North Dakota AES Bulletin 497. 18 pp.
Manitoba Agriculture website: www.manitoba.ca/agriculture
Manitoba Agriculture on Twitter: @MBGovAg
Manitoba Agriculture on YouTube: www.youtube.com/ManitobaAgriculture
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Should I apply fungicide after a hail event?

Originally Published August 19, 2014

A fungicide application cannot recover yield potential lost due to hail damage. Fungicides protect yield potential by reducing disease.  Many studies have been conducted in the United States looking at fungicide application to hail damaged corn crops.  Most results show no yield response when a fungicide has been applied to hail damaged corn.  If after the hail event, conditions are conducive for fungal disease development, an application of fungicide may provide yield protection.  But again it won’t recover the yield lost due to the hail event.

Also keep in mind that bacterial diseases, such as Goss’s Wilt that infect plants through wounds, are not controlled by fungicide application.  And many diseases do not require a wound to infect the plant, including common smut and stalk rots.  Furthermore, foliar diseases that can be managed with foliar fungicides, such as gray leaf spot, do not need wounds for infection.

Bottom line is disease pressure plays a critical role in the magnitude and consistency of a yield response to a foliar fungicide application in corn.  So instead of basing a fungicide application on the fact that it hailed, it should instead take into account disease risk factors such as:

  • Susceptibility of the corn hybrid to various diseases that would be controlled by a fungicide application.
  • Previous crop as many foliar pathogens can survive on corn residue.
  • Weather since the risk for disease development will increase in rainy and/or humid weather.

If you do choose to apply a fungicide to hail damaged crops this year, it would be a good idea to conduct a replicated on-farm trial in the field to allow for a comparison of treatment effectiveness at the end of the growing season.

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture

 

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Hail Damage in Wheat

Originally Published June 23, 2014

Over the last few days, hail has been reported in several areas of Manitoba, potentially impacting the cereal crops in those areas.  Assessing damage will take a few days, and impact will largely depend on stage of the crop and how severe the hail event was, i.e duration of storm, size of hail.

Generally, cereal crops prior to stem elongation can recover, even if there is substantial leaf damage as the growing point is below the soil surface and will likely not be damaged. However, once the growing point is above the soil surface it is susceptible to damage. Hail damage occurring during stem elongation or the boot stage can be difficult to assess. Spikes can still pollinate and fill, and regrowth from new tillers can occur.

Figure 1: Growth Stages in Wheat

L_IMG_fig2

Hail causes the greatest damage to small grains from the boot stage through later stages. For additional information on the Impact of Hail in Cereal Crops refer to the following Crop Chatter post: http://cropchatter.com/impact-of-hail-in-cereal-crops/.

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, MAFRD

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Hail Damage in Young Corn

Originally Published June 23, 2014

Over the last few days, hail has been reported in several areas of Manitoba.  Generally, young corn has the ability to recover from early season hail damage.  In corn, the growing point remains below the soil surface until the V5 to V6 stage. Therefore, the growing point should be protected and the young corn plants can recover even with significant damage to leaves.  However, it is still important to examine the growing point to see if hail has by chance damage the growing point or the stalk below the soil surface.  To examine the growing point, cut the stalk vertically. A healthy growing point is creamy white in color. If the growing point is watery with a brownish color, the plant is likely dying.  Remember that producers and agronomists are encouraged to wait a few days to allow the crop to improve before doing any decision-making assessments.

Another consideration in corn is plants that are damaged by hail are susceptible to Goss’s Wilt infection as the bacteria can enter through the wounds caused by hail. As you are scouting for Goss’s Wilt throughout the season, focus your attention on fields that are:

  • planted to a Goss’s susceptible hybrid,
  • have a history of Goss’s Wilt,
  • have surface corn residue, and
  • may have been injured by severe weather.

Initial symptoms of Goss’s Wilt include water-soaked lesions on the leaves later accompanied by “freckling”. Bacterial ooze may also occur on the lesion, giving it a wet or greasy appearance. When the ooze dries, it leaves a shiny residue on the surface of the lesion.  More information and photos can be found at: http://www.gov.mb.ca/agriculture/crops/miu/2012/2012-08-24/report.pdf.

Submitted by:  Pam de Rocquigny, Provincial Cereal Crops Specialist, MAFRD

 

 

 

 

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Assessing Hail Damage in Corn

Damage to a corn crop by hail can differ in severity, ranging from mild to total crop loss.  Yield loss will be dependent on the stage of crop at the time of the hail event and the level of crop damage.  In corn, most yield reduction due to hail damage is a result of leaf loss but can also be from reduced stands.

To determine yield loss due to defoliation, both the growth stage and the percent leaf area removed from the plant must be determined (Table 1). Significant yield damage due to defoliation occurs immediately after silking and decreases as the plant matures.  When making this estimate of defoliation, consider both leaf area removed and leaf area still attached to the plant but no longer green.  Live green tissue, although damaged, should not be considered as leaf area destroyed.  It can also help delaying your assessment seven to 10 days to provide a more accurate picture as it can be difficult to distinguish living from dead tissue immediately after a storm.

Table 1. Estimated Percentage Corn Grain Yield Loss
Due to Defoliation at Various Growth Stages1

Growth
Stage2

% Leaf Defoliation /% Yield Loss

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

7 leaf

0

0

0

0

0

0

1

1

2

3

4

4

5

5

6

7

8

9

9

9 leaf

0

0

0

1

1

2

2

3

4

5

6

6

7

7

9

10

11

12

13

11 leaf

0

0

1

1

2

3

5

6

7

8

9

10

11

12

14

16

18

20

22

13 leaf

0

1

1

2

3

4

6

8

10

11

13

15

17

19

22

25

28

31

34

Tassel

3

5

7

9

13

17

21

26

31

36

42

48

55

62

68

75

83

91

100

Silked

3

5

7

9

12

16

20

24

29

34

39

45

51

58

65

72

80

88

97

Silks brown

2

4

6

8

11

15

18

22

27

31

36

41

47

54

60

66

74

81

90

Pre-blister

2

3

5

7

10

13

16

20

24

28

32

37

43

49

54

60

66

73

81

Blister

2

3

5

7

10

13

16

19

22

26

30

34

39

45

50

55

60

66

73

Early milk

2

3

4

6

8

11

14

17

20

24

28

32

36

41

45

50

55

60

66

Milk

1

2

3

5

7

9

12

15

18

21

24

28

32

37

41

45

49

54

59

Late milk

1

2

3

4

6

8

10

12

15

18

21

24

28

32

35

38

2

46

50

Soft dough

1

1

2

2

4

6

8

10

12

14

17

20

23

26

29

32

35

38

41

Early dent

0

0

1

1

2

3

5

7

9

11

13

15

18

21

23

25

27

29

32

Dent

0

0

0

1

2

3

4

6

7

8

10

12

14

15

17

19

20

21

23

Late dent

0

0

0

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Nearly mature

0

0

0

0

0

0

0

0

1

2

3

4

5

5

6

6

7

7

8

Mature

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1Adapted from the National Crop Insurance Services Corn Loss Instruction (Rev. 1984).
2As determined by counting leaves using the leaf over method (i.e., those with 40% – 50% of leaf exposed from whorl and whose tip points below the horizontal).

After silking, and if the hail event hasn’t caused total crop loss, additional assessments are made including determining:

  1. yield loss due to stand reduction,
  2. yield loss due to defoliation,
  3. direct ear damage, and
  4. impact of bruising and stalk damage.

Remember that estimating yield loss due to hail is only an estimate, particularly if the damage is not severe and depending upon growth stage of the plant when the hail event occured.  The remainder of the growing season will help determine final yields.  Please contact your hail insurance provider for their procedures in assessing hail damage as they may be different that whan has been provided here.

Submitted by:  Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture

 

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Impact of Hail in Cereal Crops

Originally Published September 3, 2014

Impact of hail on cereal crops will depend on growth stage of the crop at the time of the hail event and the severity of damage.  In a study by R.H. Busch in North Dakota in wheat, the greatest yield reduction resulted when stems were broken in the milk stage, followed by anthesis, soft dough, boot, and hard dough stages – see Table below (Busch, 1975).

Grain yield reduction in spring wheat with 100 percent of stems bent.
Growth stage Yield reduction (%)
Boot (Zadoks 45) 28 to 39%
Anthesis (Zadoks 65) 15 to 60%
Milk (Zadoks 75) 30 to 70%
Soft dough (Zadoks 83) 16 to 55%
Hard dough (Zadoks 87) 3 to 47%
Table derived from Busch, 1975

 

Yield losses can also be directly attributed to shattering of the mature crop.  A simple and rough estimate of grain loss requires the use of a one-foot square frame:

  1. Pick a typical area of the field.
  2. Place a 1 ft by 1 ft (inside dimension) box on the ground and count the kernels found within the box.

A one (1) bushel per acre loss equates to 20 wheat kernels per/ft2, 14 barley kernels/ft2 and 10 oat kernels/ft2.  Keep in mind that this is a ‘fudge factor’ but for the purpose of rough field estimation is an adequate estimate.

Remember to please contact your hail insurance provider for their procedures in assessing hail damage as they may be different than what has been provided here.

Source:  Busch, R. H. 1975.  The effect of simulated hail injury on spring wheat. North Dakota AES Bulletin 497. 18 pp.

Submitted by:  Pam de Rocquigny, Provincial Cereal Crops Specialist, MAFRD

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What is the impact of hail to yield of cereal crops?

Impact of hail on cereal crops will depend on growth stage of the crop at the time of the hail event and the severity of damage.  In the article “Hail Damge in Small Grains” by Joe Lauer, Universityof Wisconsin, it states before jointing, small grains are least susceptible to hail damage. The spike is still below ground and protected from injury.

In a study by R.H. Busch in North Dakota in wheat, the greatest yield reduction resulted when stems were broken in the milk stage, followed by anthesis, soft dough, boot, and hard dough stages – see Table below (Busch, 1975). 

Grain yield reduction in spring wheat with 100 percent of stems bent.
Growth stage Yield reduction (%)
Boot (Zadoks 45) 28 to 39%
Anthesis (Zadoks 65) 15 to 60%
Milk (Zadoks 75) 30 to 70%
Soft dough (Zadoks 83) 16 to 55%
Hard dough (Zadoks 87) 3 to 47%
Table derived from Busch, 1975

Source:  Busch, R. H. 1975.  The effect of simulated hail injury on spring wheat. North Dakota AES Bulletin 497. 18 pp.

Remember that estimating yield loss due to hail is only an estimate.  The remainder of the growing season will help determine final yields.  Please contact your hail insurance provider for their procedures in assessing hail damage as they may be different than what has been provided here.

Submitted by:  Pam de Rocquigny, MAFRI Cereal Crops Specialist

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How can I assess hail damage in corn?

Damage to a corn crop by hail can differ in severity, ranging from mild to total crop loss.  Yield loss will be dependent on the stage of crop at the time of the hail event and the level of crop damage.  In corn, most yield reduction due to hail damage is a result of leaf loss but can also be from reduced stands.

To determine yield loss due to defoliation, both the growth stage and the percent leaf area removed from the plant must be determined (Table 1). Significant yield damage due to defoliation occurs immediately after silking and decreases as the plant matures.  When making this estimate of defoliation, consider both leaf area removed and leaf area still attached to the plant but no longer green.  Live green tissue, although damaged, should not be considered as leaf area destroyed.  It can also help delaying your assessment seven to 10 days to provide a more accurate picture as it can be difficult to distinguish living from dead tissue immediately after a storm.

Table 1. Estimated Percentage Corn Grain Yield Loss
Due to Defoliation at Various Growth Stages1

Growth
Stage2

% Leaf Defoliation /% Yield Loss

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

7 leaf

0

0

0

0

0

0

1

1

2

3

4

4

5

5

6

7

8

9

9

9 leaf

0

0

0

1

1

2

2

3

4

5

6

6

7

7

9

10

11

12

13

11 leaf

0

0

1

1

2

3

5

6

7

8

9

10

11

12

14

16

18

20

22

13 leaf

0

1

1

2

3

4

6

8

10

11

13

15

17

19

22

25

28

31

34

Tassel

3

5

7

9

13

17

21

26

31

36

42

48

55

62

68

75

83

91

100

Silked

3

5

7

9

12

16

20

24

29

34

39

45

51

58

65

72

80

88

97

Silks brown

2

4

6

8

11

15

18

22

27

31

36

41

47

54

60

66

74

81

90

Pre-blister

2

3

5

7

10

13

16

20

24

28

32

37

43

49

54

60

66

73

81

Blister

2

3

5

7

10

13

16

19

22

26

30

34

39

45

50

55

60

66

73

Early milk

2

3

4

6

8

11

14

17

20

24

28

32

36

41

45

50

55

60

66

Milk

1

2

3

5

7

9

12

15

18

21

24

28

32

37

41

45

49

54

59

Late milk

1

2

3

4

6

8

10

12

15

18

21

24

28

32

35

38

2

46

50

Soft dough

1

1

2

2

4

6

8

10

12

14

17

20

23

26

29

32

35

38

41

Early dent

0

0

1

1

2

3

5

7

9

11

13

15

18

21

23

25

27

29

32

Dent

0

0

0

1

2

3

4

6

7

8

10

12

14

15

17

19

20

21

23

Late dent

0

0

0

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Nearly mature

0

0

0

0

0

0

0

0

1

2

3

4

5

5

6

6

7

7

8

Mature

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1Adapted from the National Crop Insurance Services Corn Loss Instruction (Rev. 1984).
2As determined by counting leaves using the leaf over method (i.e., those with 40% – 50% of leaf exposed from whorl and whose tip points below the horizontal).

After silking, and if the hail event hasn’t caused total crop loss, additional assessments are made including determining:

  1. yield loss due to stand reduction,
  2. yield loss due to defoliation,
  3. direct ear damage, and
  4. impact of bruising and stalk damage.

Remember that estimating yield loss due to hail is only an estimate, particularly if the damage is not severe and depending upon growth stage of the plant when the hail event occured.  The remainder of the growing season will help determine final yields.  Please contact your hail insurance provider for their procedures in assessing hail damage as they may be different that whan has been provided here.

Submitted by:  Pam de Rocquigny, MAFRI Cereal Crops Specialist

 

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