Research and IPM

Phenology Model Database

San Jose Scale

Scientific name: Quadraspidiotus perniciosus

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.

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 of 2

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)

Developmental thresholds

Lower:	51.0°F	(10.6°C)
Upper:	90.0°F	(32.2°C)

Method of calculation:	Single Sine
Cutoff method:	Vertical Cutoff

Start date: January 1

	DD (°F)	DD (°C)
Set out traps to detect 1st male emergence	200.0	111.1

Degree-day accumulations required for each stage of development

Biofix: First male scale from overwintering generation.

Model 2 of 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

Developmental thresholds

Lower:	51.0°F	(10.6°C)
Upper:	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