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
Jorgensen, C. D., R. E. Rice, S. C. Hoyt, and P. H. Westigard. 1981. Phenology of the San Jose Scale (Homoptera: Diaspididae). Can. Ent. 113: 149-159.
- Location of study: California (field studies)
- Lower developmental threshold: 51.0°F (10.6°C)
- Upper developmental threshold: 90.0°F (32.2°C)
- Method of calculation: Single Sine
- Cutoff method: Vertical Cutoff
Start date: January 1
- Set out traps to detect 1st male emergence: 200.0 (°F) 111.1 (°C)
Degree-day accumulations required for each stage of development
Biofix: First male scale from overwintering generation.
Host: Stonefruits
- Pre-larvisposition females: 541.0 (°F) 300.6 (°C)
- First instar: 231.0 (°F) 128.3 (°C)
- Second Instar: 220.0 (°F) 122.2 (°C)
- Tight cap females: 58.0 (°F) 32.2 (°C)
- Generation time: 1050.0 (°F) 583.3 (°C)
Model 2
Rice, R. E., F. G. Zalom, and C. Jorgensen. 1982. Monitoring San Jose Scale development with degree-days. California Agricultural Sciences Leaflet #21312.
- Location of study: California
- Lower developmental threshold: 51.0°F (10.6°C)
- Upper developmental threshold: 90.0°F (32.2°C)
- Method of calculation: Single Sine
- Cutoff method: Horizontal Cutoff
Degree-day accumulations required for each stage of development
Biofix: First male scale from overwintering generation.
Host: Almonds
- Crawler emergence: 405.0 (°F) 225.0 (°C)
- Optimum timing for crawler treatment: 600-700 (°F) 333-389 (°C)
- Generation time: 1050.0 (°F) 583.3 (°C)
