Phenology models predict timing of events in an organism's development. For many organisms which cannot internally regulate their own temperature, development is dependent on temperatures to which they are exposed in the environment.
Information in this database comes from published articles. It may be used in conjunction with field monitoring and a degree-day calculator.
Note: Before using a model that was not field tested in your location, you should test the model for one or more seasons under your conditions to verify that it will work for you.
Model 1
Wilen, C.A., J.S. Holt and W.B. McCloskey. 1996. Predicting yellow nutsedge (Cyperus esculentus) emergence using degree-day models. Weed Science. 44: 821-829.
See also: Wilen, C.A., J.S. Holt and W.B. McCloskey. 1996. Effects of soil moisture on observed and predicted yellow nutsedge (Cyperus esculentus L.) emergence. Weed Science. 44: 890-896.
- Location of study: Southern California (field studies) Note: This model is for well-watered conditions.
- Lower developmental threshold: 53.0°F (11.67°C)
- Upper developmental threshold: 78.0°F (25.56°C)
- Method of calculation: Single Sine
- Cutoff method: Intermediate
Degree-day accumulations required for each stage of development
Biofix: Date of lowest air temperature or planting date, whichever is later
- First emergence of tubers 204.6 (°F) 113.7 (°C)
Cultivation can be timed to remove the first flush of tubers to allow for approximately 2 weeks of reduction of yellow nutsedge competition.
Model 2
Wilen, C.A., J.S. Holt and W.B. McCloskey.1996. Predicting yellow nutsedge (Cyperus esculentus) emergence using degree-day models. Weed Science. 44: 821-829.
See also: Wilen, C.A., J.S. Holt and W.B. McCloskey. 1996. Effects of soil moisture on observed and predicted yellow nutsedge (Cyperus esculentus L.) emergence. Weed Science: 44 890-896.
- Location of study: Southern California (field studies) Note: This model is for well-watered conditions.
- Lower developmental threshold: 52F (11.11°C)
- Upper developmental threshold: 86F (30.00°C)
- Method of calculation: Single Sine
- Cutoff method: Vertical
Degree-day accumulations required for each stage of development
Biofix: Date of lowest air temperature or planting date, whicher is later
- First emergence of tubers 235.7 (°F) 130.93 (°C)
Cultivation can be timed to remove the first flush of tubers to allow for approximately 2 weeks of reduction of yellow nutsedge competition.
Model 3
Wilen, C.A., J.S. Holt and W.B. McCloskey. 1996. Predicting yellow nutsedge (Cyperus esculentus) emergence using degree-day models. Weed Science. 44: 821-829.
See also: Wilen, C.A., J.S. Holt and W.B. McCloskey. 1996. Effects of soil moisture on observed and predicted yellow nutsedge (Cyperus esculentus) emergence. Weed Science. 44: 890-896.
- Location of study: Southern Arizona (field studies) Note: This model works for well-watered conditions.
- Lower developmental threshold: 50F (10.00°C)
- Upper developmental threshold: 63F (17.22°C)
- Method of calculation: Double Sine
- Cutoff method: Intermediate
Degree-day accumulations required for each stage of development
Biofix: Date of lowest air temperature or planting date, whichever is later
- First emergence of tubers 205.6 (°F) 114.24 (°C)
Pre-plant cultivation can be timed to remove the first flush of tubers to allow for approximately 2 weeks of reduction of yellow nutsedge competition.
This Arizona model needs further validation to be useful for weed management.
