# Nematode Management

Document Sample

```					             FIXED COST ECONOMIC THRESHOLD CALCULATOR FOR NEMATODES
Based on: Ferris, H. 1978. Nematode economic thresholds: Derivation, requirements, and theoretical considerations.
Journal of Nematology 10:341-350.
User-defined Parameters:                                                                                Fixed Cost Economic Threshold
Economics            Primary Crop                                                             600
Max Val.      1188                                                                500

Net Returns (\$)
Prod. Cost       627
400

Interest Rate (%)         5                                                              300
Nematode Population                                                                           200
Damage function (y=m+(1-m)z(P-T))                                                             100
z 0.999999                                                                0
T        25                                                                    0            5
Nematode Population (Ln)
m        0.1
Starting Population Level
Pi      241                                                                 Crop Loss at Current Population
Crop Loss at ET Population
Enter cost of this management option      195
Economic threshold for this option   488135.5 13.09835 (Ln value)
CURRENT POPULATION BELOW ECONOMIC THRESHOLD FOR THIS TREATMENT;
TREATMENT IS NOT JUSTIFIED

W=          0.952381
Fixed Nematode management Cost:
CM=              195 **********
Calculate ET Population:
PET = (Log(((((MV - PC - CM) / (MV - PC)) - m) / (1 - m))) / Log(z)) + T
If PET<T, PET = T            366
PET=        488135.5
488135.5 13.09835

Nematode Damage Function
Crop
Ln Nematodes Value          CV at Pi
0       561   366     560.891
1       561
2       561
3       561
4 560.9851
5 560.9377
6 560.809
7 560.4592
8 559.5097
9 556.9378
10 550.0128
11 531.6686
12 485.1745
13 380.4982
14 207.7811
15 75.30876
13.09835             366
13.09835               0
5.484797                     560.891
5.484797                           0
Dec. 2000 Version

onomic Threshold

10            15
ode Population (Ln)

0.109047
195
Baseline Values

User-defined Parameters:
Economics            Primary Crop
Max Val.      1188
Prod. Cost       627

Interest Rate (%)         5
Nematode Population
Damage function (y=m+(1-m)z(P-T))
z    0.9986
T        25
m          0
Starting Population Level
Pi       241

```
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