Crop Insurance Today September 2017 - 15

Table 9 POTATOES Colorado
Treatment

Control
Tuber In.-33
Tuber In.-66
Tuber In.-95
Early Bulking-33
Early Bulking-66
Early Bulking-95
Late Bulking-33
Late Bulking-66
Late Bulking-95

Russet Norkotah
Russet Nugget
Yield (CWT/A)

503
426
395
287
420
355
320
466
487
456

479
442
405
319
392
395
236
474
427
443

Table 10 POTATOES North Dakota
Treatment

Control
Tuber In.-33
Tuber In.-66
Tuber In.-95
Early Bulking-33
Early Bulking-66
Early Bulking-95
Late Bulking-33
Late Bulking-66
Late Bulking-95

Russet Norkotah
Russet Ranger
Yield (CWT/A)

458
383
361
202
373
329
225
381
316
254

ulated hail applied at three growth stages: Tuber
Initiation (TI), Early Bulking (EB) and Late Bulking (LB).
Damage was applied at 0, 33, 66 and 95 percent and later were harvested. Losses varied depending on the maturity of the potatoes as shown
with the medium maturity variety having losses
very close to the current charts. The late maturing variety had losses that were lower than what
the current charts would suggest. (Table 10) The

400
279
245
172
327
299
238
374
338
191

Soybean plot that was defoliated 50% at R4
in Iowa.

data from this trial, along with that conducted
in Colorado, Washington, and Michigan will be
reviewed and incorporated into the NCIS potato
loss procedures.

SOYBEANSArkansas

A study began in 2013 to investigate the defoliation charts for both indeterminant and determinant type soybeans in Arkansas. Arkansas
has historically grown more determinant soy-

Table 11 SOYBEANS Arkansas
Defoliation%

Growth
Stage

R1
R1 Chart
R3
R3 Chart

5
1
14
4

100

10
5
35
16

39
12
82
33

100

40
26
36
36

96
56
94
75

Loss%

12
3
20
8

Table 12 SOYBEANS Arkansas
Defoliation%

Growth
Stage

R4
R4 Chart
R5
R5 Chart

7
6
16
9

50
Loss%

19
12
27
17

beans, but more recently there has been a trend
to start growing an earlier maturing indeterminant variety.
When viewing additional research, NCIS has
seen greater amounts of loss associated with defoliation damage occurring during the early to
mid-reproductive stages (R1 and R3) of development and wanted to see if this was true. Two
different varieties were used-MG 4.7 indeterminant and MG 5.4 determinant variety were planted at Newport Arkansas.
Defoliation was applied at 0, 25, 50, 75 and
100 percent at either R1 or R3 stage of growth.
Losses were significantly greater for the indeterminant MG 4.7 variety at the higher levels of
damage than the current charts show (Table 11).
The determinant MG 5.4 variety also showed
higher losses at the highest damage level (100
percent); this occurred only during the R3 stage
(27 percent greater loss).
A second study was initiated in 2016 to determine the losses from defoliation at the R-4 and
R-5 stages of development. The same varieties of
soybeans were used as was previously discussed
with regards to defoliation at R-1 and R-3. The
losses at R-4 for the indeterminate soybean variety were between six and 40 percent greater than
the current charts suggest at the 50 percent to 100
percent defoliation levels (Table 12). The losses at
R-5 for the indeterminate variety were very close
to what our current chart would suggest. The defoliation at R-4 and R-5 for the determinate variety were also very similar to what the current
charts would suggest.
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Table of Contents for the Digital Edition of Crop Insurance Today September 2017