Percent Defoliation Charts for Determining Defoliation
Required for Economic Injury to Soybeans
(Excerpted from ENT-13 Insecticide Recommendations for Soybeans 1998,
University of Kentucky Entomology Extension Publication ENT-13, Lexington,
KY, 1998.)
The ability of soybeans to sustain defoliation without yield reduction
varies with the growth of the plant. Under favorable conditions the average
percent defoliation figures given in these tables can be used to determine
economic injury levels. When the percentage of foliage removed approximates
that given in the table for your particular set of variables (cost of
treatment, prejected yield, and projected selling price of the beans),
treatment should be considered.
For example, if your beans are in the bloom stage, you anticipate the
yield will be 35 bushels per acre with a selling price of $8 per bushel
and the cost of treating will be $6 per acre, defoliation must be 23 percent
or greater to justify treatment.
| Pre-bloom (5 to 6 trifoliates)
|
| treatment recommended when defoliation exceeds 35 percent.
|
Percent Defoliation
Full Bloom Stage - Anticipated Yield 25 bu/A
|
| Cost of Treatment per Acre:
| $6.00
| $8.00
| $10.00
| $12.00
| $14.00
|
| Soybean Value ($/bu)
|
|
| $6.00
| 32
| 37
| 41
| 45
| 49 |
| $7.00
| 30
| 34
| 34
| 42
| 45 |
| $8.00
| 28
| 32
| 32
| 39
| 42 |
| $9.00
| 26
| 30
| 30
| 37
| 40 |
| Full Bloom Stage - Anticipated Yield 35 bu/A
|
| Cost of Treatment per Acre:
| $6.00
| $8.00
| $10.00
| $12.00
| $14.00
|
| Soybean Value ($/bu)
|
|
| $6.00
| 27
| 31
| 35
| 38
| 41 |
| $7.00
| 25
| 29
| 32
| 35
| 38 |
| $8.00
| 23
| 27
| 30
| 33
| 36 |
| $9.00
| 22
| 25
| 28
| 31
| 34 |
| Full Bloom Stage - Anticipated Yield 45 bu/A
|
| Cost of Treatment per Acre:
| $6.00
| $8.00
| $10.00
| $12.00
| $14.00
|
| Soybean Value ($/bu)
|
|
| $6.00
| 24
| 28
| 31
| 34
| 36 |
| $7.00
| 22
| 25
| 28
| 31
| 34 |
| $8.00
| 21
| 24
| 27
| 29
| 31 |
| $9.00
| 20
| 23
| 25
| 28
| 30 |
| Pod Fill Stage - Anticipated Yield 25 bu/A
|
| Cost of Treatment per Acre:
| $6.00
| $8.00
| $10.00
| $12.00
| $14.00
|
| Soybean Value ($/bu)
|
|
| $6.00
| 20
| 24
| 27
| 30
| 32 |
| $7.00
| 19
| 22
| 25
| 27
| 30 |
| $8.00
| 18
| 20
| 23
| 26
| 28 |
| $9.00
| 16
| 19
| 22
| 24
| 26 |
| Pod Fill Stage - Anticipated Yield 35 bu/A
|
| Cost of Treatment per Acre:
| $6.00
| $8.00
| $10.00
| $12.00
| $14.00
|
| Soybean Value ($/bu)
|
|
| $6.00
| 17
| 20
| 23
| 25
| 27 |
| $7.00
| 16
| 18
| 21
| 23
| 25 |
| $8.00
| 15
| 17
| 19
| 21
| 23 |
| $9.00
| 14
| 16
| 18
| 20
| 22 |
| Pod Fill Stage - Anticipated Yield 45 bu/A
|
| Cost of Treatment per Acre:
| $6.00
| $8.00
| $10.00
| $12.00
| $14.00
|
| Soybean Value ($/bu)
|
|
| $6.00
| 15
| 17
| 20
| 22
| 24 |
| $7.00
| 14
| 16
| 18
| 20
| 22 |
| $8.00
| 13
| 15
| 17
| 19
| 20 |
| $9.00
| 12
| 14
| 16
| 17
| 19 |
| Approaching Maturity - Anticipated Yield 25 bu/A
|
| Cost of Treatment per Acre:
| $6.00
| $8.00
| $10.00
| $12.00
| $14.00
|
| Soybean Value ($/bu)
|
|
| $6.00
| 34
| 40
| 46
| 52
| 57 |
| $7.00
| 31
| 37
| 42
| 47
| 52 |
| $8.00
| 28
| 34
| 39
| 44
| 48 |
| $9.00
| 26
| 31
| 36
| 40
| 45 |
| Approaching Maturity - Anticipated Yield 35 bu/A
|
| Cost of Treatment per Acre:
| $6.00
| $8.00
| $10.00
| $12.00
| $14.00
|
| Soybean Value ($/bu)
|
|
| $6.00
| 27
| 33
| 38
| 42
| 46 |
| $7.00
| 25
| 30
| 34
| 38
| 42 |
| $8.00
| 22
| 27
| 31
| 35
| 39 |
| $9.00
| 21
| 25
| 29
| 33
| 36 |
| Approaching Maturity - Anticipated Yield 45 bu/A
|
| Cost of Treatment per Acre:
| $6.00
| $8.00
| $10.00
| $12.00
| $14.00
|
| Soybean Value ($/bu)
|
|
| $6.00
| 23
| 28
| 32
| 36
| 40 |
| $7.00
| 21
| 25
| 29
| 33
| 36 |
| $8.00
| 19
| 23
| 27
| 30
| 33 |
| $9.00
| 17
| 21
| 25
| 28
| 31 |
|
