Home and Landscape

Fruittree Leafroller

  • Archips argyrospilus
Updated: 04/2026

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

Judd, G. J. R., M. G. T. Gardner, and D. R. Thomson. 1993. Temperature-dependent development and prediction of hatch of overwintered eggs of the fruittree leafroller, Archips argyrospilus (Walker) (Lepidoptera: Tortricidae). Can. Entomol. 125: 945-956.

  • Location of study: Kelowna, B. C. (laboratory and field studies)
  • Lower developmental threshold: 41.0°F (5.0°C)
  • Upper developmental threshold: 81.5°F (27.5°C)
  • Method of calculation: Double Sine
  • Cutoff method: Horizontal Cutoff

Degree-day accumulations required for each stage of development

Start date: February 1

Host: Apples

  • 50% egg hatch: 277.2 (°F) 154.0 (°C)
Larva on a semi-rolled leaf showing black head and prothoracic shield, 1X; ; Tulare Co. Credit: Jack Kelly Clark, UC IPM. Credit: Jack Kelly Clark, UC IPM
Fruittree leafroller, Archips argyrospila, larva exposed. Note the silk strands (lower right) the larva secreted to tie and curl the leaf within which it was feeding. Credit: Jack Kelly Clark, UC IPM