Crop Insurance Today Third Quarter 2020 - 18

TABLE 2

Effect of Multiple Defoliation Events on Corn Production
Illinois-2 Year Average
	

Stage of 50% Defoliation	

Loss (%)

			
	1st Defoliation	 2nd Defoliation	
Appraised	 Measured	
Difference	

	 10-Leaf	 -	
	 15-Leaf	
-	
	
Blister	 -	
	
Milk	 -	
	 Soft Dough	-	
	 10-Leaf	Blister	
	 10-Leaf	
Milk	
	 10-Leaf	
Soft Dough	
	 15-Leaf	Blister	
	 15-Leaf	 Milk	
	 15-Leaf	
Soft Dough	

Significantly
Different?

6	 -5	-11	No
15	17	 2	 No
22	18	 -4	 No
18	15	 -3	 No
12	 10	 -2	 No
25	 20	 -5	 No
22	19	 -3	 No
16	
13	
-3	
No
28	 24	 -4	 No
26	21	 -5	 No
22	
23	
1	
No

TABLE 3

Effect of Multiple Defoliation Events on Corn Production
Ohio-2 Year Average
	

Stage of 50% Defoliation	

Loss (%)

			
	1st Defoliation	 2nd Defoliation	
Appraised	 Measured	
Difference	

	 10-Leaf	 -	
	 15-Leaf	
-	
	
Blister	 -	
	
Milk	 -	
	 Soft Dough	-	
	 10-Leaf	Blister	
	 10-Leaf	
Milk	
	 10-Leaf	
Soft Dough	
	 15-Leaf	Blister	
	 15-Leaf	 Milk	
	 15-Leaf	
Soft Dough	

6	8	 2	 No
15	13	 -2	 No
22	25	 3	 No
18	18	 0	 No
12	 8	 -4	 No
25	 24	 -1	 No
22	22	 0	 No
16	
17	
1	
No
28	 24	 -4	 No
26	25	 -1	 No
22	
21	
-1	
No

tive performance of the model was likely due to
canola's indeterminate growth characteristics and
the plant's rapid response to changes in growing
conditions.
TABLE 4

Corn-Stand Reduction
Minnesota-2019

Significantly
Different?

CORN Second Loss

Minnesota, Illinois, Ohio
In 2018, NCIS began research in Minnesota,
Illinois, and Ohio to evaluate second losses on
TABLE 5

Corn-Stand Reduction
Nebraska-2019

			Stand Reduction %
		
25	50	75
	 Growth Stage	
Loss%

			Stand Reduction %
		
25	50	75
	 Growth Stage	
Loss%

	
15-Leaf	 10	30	55
	 11-Leaf Chart	16	31	60

	
15-Leaf	 14	28	56
	 11-Leaf Chart	16	31	60

	
18-Leaf	 16	34	50
	
Tassel	 16	38	58
	 1-for-1 Chart	25	50	75

	
18-Leaf	 18	48	62
	
Tassel	 13	44	71
	 1-for-1 Chart	25	50	75

18

THIRDQUARTER2020

Popcorn may respond to high levels of stand
reduction by increasing the number of ears
per plant.

corn. Prior research assessed defoliation at the 10
and 15-leaf stages followed by additional defoliation at either 15-leaf or tassel stage. The current
research focuses on defoliation at the 10 and 15leaf stages with second defoliations occurring at
reproductive stages during grain fill. Results are
presented in Tables 1, 2, and 3.

CORN Stand Reduction

Minnesota, Nebraska, Iowa
Research began in 2019 in Minnesota, Nebraska, and Iowa to continue evaluating stand reduction losses on corn. Prior research evaluated stand
reduction from the 10 to 17-leaf growth stages and
resulted in the development of a separate stand
reduction chart for the 11 to 17-leaf growth stages. Current research evaluates stand reduction at
the 15-leaf, 18-leaf, and tassel stages to determine
whether stand reduction losses after the 17-leaf
stage should be counted on a 1-for-1 basis. Due
to wet soil conditions, researchers in Iowa were
unable to apply the stand reduction treatment at
TABLE 6

Corn-Stand Reduction
Iowa-2019
			Stand Reduction %
		
25	50	75
	 Growth Stage	
Loss%

	
18-Leaf	 -2	 10	39
	
Tassel	 -2	 13	47
	
Blister	
4	 24.1	33.7
	 1-for-1 Chart	25	50	75
Crop Insurance Today Third Quarter 2020

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