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
Campbell, A. and M. Mackauer. 1975. Thermal constants for development of the pea aphid (Homoptera: Aphididae) and some of its parasites. Can. Ent. 107: 419-423.
- Location of study: Burnaby, British Columbia (laboratory studies)
- Lower developmental threshold: 41.9°F ( 5.5°C)
- Upper developmental threshold: 82.4°F (28.0°C)
- Method of calculation: not specified (UC IPM recommends Single Sine)
- Cutoff method: not specified (UC IPM recommends Horizontal)
Degree-day accumulations required for each stage of development
Alfalfa: Apterous Form
- Generation time (nymph to adult): 197.1 (°F) 109.5 (°C)
Alfalfa: Alate Form
- Generation time (nymph to adult): 214.0 (°F) 118.9 (°C)
Model 2
Siddiqui, W. H., C. A. Barlow and P. A. Randolph. 1973. Effects of some constant and alternating temperatures on population growth of the pea aphid, Acyrthosiphon pisum (Homoptera: Aphididae). Can. Ent. 105: 145-156.
- Location of study: Ottawa, Canada (laboratory studies)
- Lower developmental threshold: 36.3°F ( 2.4°C)
- Upper developmental threshold: 82.4°F (28.0°C)
- Method of calculation: not specified (UC IPM recommends Single Sine)
- Cutoff method: not specified (UC IPM recommends Horizontal)
Degree-day accumulations required for each stage of development
Host: Peas
- Generation time (nymph to adult): 270.7 (°F) 150.4 (°C)
