Home and Landscape

Armyworm

  • Mythimna (= Pseudaletia) unipuncta
Updated: 03/2026

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

Guppy, J. C.1969.Some effects of temperature on the immature stages of the armyworm, Pseudaletia unipuncta (Lepidoptera: Noctuidae), under controlled conditions.Can. Ent. 101: 1320-1327.

  • Location of study: Ottawa, Canada (laboratory studies)
  • Lower developmental threshold: 50.0°F (10.0°C)
  • Upper developmental threshold: 84.2°F (29.0°C)
  • Method of calculation: not specified (UC IPM recommends Single Sine)
  • Cutoff method: not specified (UC IPM recommends Vertical)

Degree-day accumulations required for each stage of development

Host: Oat foliage

  • Eggs: 113.4 (°F) 63.0 (°C)
  • Larvae: 498.6 (°F) 277.0 (°C)
  • Pupae: 297.0 (°F) 165.0 (°C)
  • Generation time (egg to adult): 909.0 (°F) 505.0 (°C)
  • Pre-egglaying adults: 126.0 (°F) 70.0 (°C)
  • Generation time (egg to egg): 1035.0 (°F) 575.0 (°C)
Larva on leaf, 1/2X; . Credit: Jack Kelly Clark, UC IPM Credit: Jack Kelly Clark, UC IPM
Larva of armyworm. Credit: Jack Kelly Clark, UC IPM