Eyespot risk
An HGCA project was funded to develop a risk algorithm to accurately
predict the need for eyespot treatment in wheat crops, and was undertaken by SAC.
Over three seasons, commercial crops and fungicide trials were evaluated to test the influence of agronomic
factors on eyespot development and to judge the cost effectiveness of treatment.
The individual risk factors were added to form a single risk Score. Each factor was scaled according to
their contribution to overall risk.
Calculate a Risk Score for your crop sown in autumn 2007
The table below shows the values which should be used to calculate a risk score.
| Factor | Level | Risk points |
| Sowing Date | <= 6 October > 6 October |
0 5 |
| Eyespot GS31-32 | <= 7% > 7% |
0 10 |
| Rain (mm) in March/April/May | <= 170 mm > 170 mm |
0 5 |
| Tillage | Minimum till Plough |
0 10 |
| Soil type | Light Medium Heavy |
0 1 5 |
| Brash or limestone soil | 5 |
|
| Previous crop | Non-host Other cereal Wheat |
0 10 15 |
The maximum risk a crop can be assigned is 50. There are two treatment thresholds:
- risk-sensitive = 20 points
- predicting final disease incidence of 30% - risk-tolerant = 29 points
- predicting final disease incidence of 45%
