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
Beasley, C.A., and C.J. Adams. 1996. Field-based, degree-day model for pink bollworm (Lepidoptera: Gelechiidae) development. J. Econ. Entomol. 89:881-890.
- Location of study: Palo Verde Valley, California (field studies)
- Lower developmental threshold: 57.0°F (13.9°C)
- Upper developmental threshold: 91.0°F (32.8°C)
- Method of calculation: Single Sine
- Cutoff method: Horizontal
Degree-day accumulations required for each stage of development
Biofix: February 1
Host: Cotton
- Generation time (adult to adult) 885 (°F) 492 (°C)
- Biofix to beginning spring emergence 409 (°F) 227 (°C)
- Biofix to spring emergence 918 (°F) 510 (°C)
Model 2
Naranjo, S. E., and J. M. Martin. 1993. Comparative development, reproduction, and oviposition of pink bollworm (Lepidoptera: Gelechiidae) on a resistant okra-leaf cotton and commercial upland and pima cultivars. J. Econ. Entomol. 86: 1094-1103.
- Location of study: Phoenix, Arizona (field studies)
- Lower developmental threshold: 53.6°F (12.0°C)
- Upper developmental threshold: 90.5°F (32.5°C)
- Method of calculation: Hourly (UC IPM recommends Single Sine)
- Cutoff method: Horizontal Cutoff
Degree-day accumulations required for each stage of development
Host: American Pima Cotton ('Pima S-6')
- Larvae (egg hatch to cutout from bolls): 370.1 (°F) 205.6 (°C)
- Prepupae: 103.0 (°F) 57.2 (°C)
- Pupae: 267.1 (°F) 148.4 (°C)
Host: Upland Cotton ('DES-119')
- Larvae (egg hatch to cutout from bolls): 433.8 (°F) 241.0 (°C)
- Prepupae: 100.6 (°F) 55.9 (°C)
- Pupae: 269.2 (°F) 149.6 (°C)
Host: Upland Cotton ('Deltapine 90')
- Larvae (egg hatch to cutout from bolls): 426.1 (°F) 236.7 (°C)
- Prepupae: 101.5 (°F) 56.4 (°C)
- Pupae: 260.8 (°F) 144.9 (°C)
Host: Upland Cotton ('WC-12NL')
- Larvae (egg hatch to cutout from bolls): 446.2 (°F) 247.9 (°C)
- Prepupae: 103.7 (°F) 57.6 (°C)
- Pupae: 265.3 (°F) 147.4 (°C)
Model 3
Pink Bollworm. IN: Integrated Pest Management for Cotton in the Western United States. University of California Statewide IPM Project. University of Arizona Statewide IPM Project. New Mexico State University. U.C. Div. Agr. Sci. Publ. #3305.
- Location of study: California and Arizona
- Lower developmental threshold: 55.0°F (12.8°C)
- Upper developmental threshold: 86.0°F (30.0°C)
- Method of calculation: Huber's method
Degree-day accumulations required for each stage of development
Start date: January 1
- Start of spring emergence: 500.0 (°F) 277.8 (°C)
- Peak of spring emergence: 1180.0 (°F) 655.6 (°C)
- End of spring emergence: 2200.0 (°F) 1222.2 (°C)
- Summer generation time (adult to adult): 800.0 (°F) 444.4 (°C)
Model 4
Pink Bollworm. IN: Integrated Pest Management for Cotton in the Western United States. University of California Statewide IPM Project. University of Arizona Statewide IPM Project. New Mexico State University. U.C. Div. Agr. Sci. Publ. #3305.
- Location of study: Arizona
- Lower developmental threshold: 55.0°F (12.8°C)
- Method of calculation: not specified (UC IPM recommends Single Sine)
Degree-day accumulations required for each stage of development
Start date: January 1
- Start of spring emergence: 500.0 (°F) 277.8 (°C)
- Peak of spring emergence: 875.0 (°F) 486.1 (°C)
- End of spring emergence: 2250.0 (°F) 1250.0 (°C)
- Summer generation time (adult to adult): 750.0 (°F) 416.7 (°C)
Model 5
Sevacherian, V., N. C. Toscano, R. A. Van Steenwyk, R. K. Sharma, and R. R. Sanders. 1977. Forecasting pink bollworm emergence by thermal summation. Environ. Entomol. 6: 545-546.
SEE ALSO: Pink Bollworm. IN: Integrated Pest Management for Cotton in the Western United States. University of California Statewide IPM Project. University of Arizona Statewide IPM Project. New Mexico State University. U.C. Div. Agr. Sci. Publ. #3305.
- Location of study: Imperial Valley, California (field studies)
- Lower developmental threshold: 60.0°F (15.6°C)
- Method of calculation: Double Triangle
Degree-day accumulations required for each stage of development
Start date: January 1
- Start of spring emergence: 200.0 (°F) 111.1 (°C)
- Peak of spring emergence: 675.0 (°F) 375.0 (°C)
- End of spring emergence: 1100.0 (°F) 611.1 (°C)
- Summer generation time (adult to adult): 967.0 (°F) 537.2 (°C)
Model 6
Clavijo Albertos, S. 1974. Studies on diapause induction and development of the pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelichiidae), under controlled conditions. Ph.D. thesis, Entomology, University of California, Riverside. 76 p.
- Location of study: Riverside, California (laboratory studies)
- Lower developmental threshold: 51.3°F (10.7°C)
- Method of calculation: not specified (UC IPM recommends Single Sine)
Degree-day accumulations required for each stage of development
Host: Wheat germ diet
- Eggs: 193.1 (°F) 107.3 (°C)
- Larvae: 497.2 (°F) 276.2 (°C)
- Pupae: 300.6 (°F) 167.0 (°C)
- Generation time (egg to adult): 990.9 (°F) 550.5 (°C)
