Research and IPM

Phenology Model Database

Tobacco Budworm

Scientific name: Helicoverpa (Heliothis) virescens

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 4

Potter, M. F., R. T. Huber, and T. F. Watson. 1981. Heat unit requirements for emergence of overwintering tobacco budworm, Heliothis virescens, (F.), in Arizona. Environ. Entomol. 10: 543-545.

Location of study: Tucson, Arizona (field studies)

Developmental threshold

Lower:	55.0°F	(12.8°C)
Upper:	86.0°F	(30.0°C)

Method of calculation:	Single sine
Cutoff method:	Horizontal

Degree-day accumulations required for each stage of development

Start date: January 1

Model 2 of 4

Hartstack, A. W., Jr., J. P. Hollingsworth, R. L. Ridgeway, and J. D. Lopez. 1976. MOTHZV-2: A computer simulation of Heliothis zea and virescens population dynamics. User manual. 1976. U.S.D.A. ARS-S-127.

Location of study: College Station, Texas (field studies)

Developmental threshold

Lower:	54.7°F	(12.6°C)
Upper:	91.9°F	(33.3°C)

Method of calculation:	Single sine
Cutoff method:	Intermediate cutoff

Degree-day accumulations required for each stage of development

DD (°F)	DD (°C)
Eggs:	72.9	40.5
Small Larvae (1-3RD instars):	147.1	81.7
Large larvae (4+5TH instars):	217.1	120.6
Pupae:	323.1	179.5
Generation time (egg to adult):	760.1	422.3
Pre-egglaying adults:	112.7	62.6
Generation time (adult to adult):	872.8	484.9

Model 3 of 4

Butler, G. D., Jr. and A. G. Hamilton. 1979. Development time of Heliothis virescens in relation to constant temperature. Environ. Entomol. 6: 759-760.

Location of study: Phoenix, Arizona (laboratory studies)

Developmental thresholds

Lower:	55.9°F	(13.3°C)
Upper:	91.4°F	(33.0°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: Wheat germ medium	DD (°F)	DD (°C)
Eggs:	74.2	41.2
Larvae:	342.0	190.0
Pupae:	327.8	182.1
Generation time (egg to adult):	743.9	413.3

Model 4 of 4

Butler, G. D., Jr., A. G. Hamilton and F. I. Proshold. 1979. Developmental times of Heliothis virescens and H. subflexa in relation to constant temperature. Ann. Entomol. Soc. Amer. 72: 263-266.

Location of study: Phoenix, Arizona (laboratory studies)

Developmental thresholds

Lower:	55.9°F	(13.3°C)
Upper:	91.4°F	(33.0°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: Wheat germ medium	DD (°F)	DD (°C)
Larvae:	379.1	210.6
Host: Cotton	DD (°F)	DD (°C)
Larvae:	540.4	300.2