TOBACCO BUDWORM (LEPIDOPTERA, NOCTUIDAE) - EFFECTS OF TEMPERATURE ANDPHOTOPERIOD ON LARVAL AND PUPAL DEVELOPMENT, LARVAL MORTALITY AND INDUCTION OF PUPAL DIAPAUSE

Tobacco budworm, Heliothis virescens (F.), pupal diapause did not diff er when parent adults and eggs were exposed to photoperiods of 10:14, 12:12 and 14:10 L:D (light:dark), respectively, at 26.7 and 21.1-degre es-C. Highest percentages of diapause were induced after larval exposu res of 10:14 L:D and temperatures of 21.1-degrees-C and 10:14 L:D and 12:12 L:D at 18.3-degrees-C. When larvae only were exposed, high perce ntages of diapause were induced at 15.6-degrees-C under all photoperio d conditions and no pupal diapause was induced at 21.1-degrees-C and 1 4:10 L:D or temperatures of 26.7-degrees-C or 32.2-degrees-C under any of the photoperiods tested. Larval mortality was > 60% at 15.6-degree s-C and was extremely variable in some tests. The cause of larval mort ality was not determined and a number of factors may be involved other than the direct adverse low temperature effect. Larval and nondiapaus e pupal development was extended under 10:14 L:D at 21.1-degrees-C as was pupal development at 26.7-degrees-C when compared to development a t 14:10 L:D at the same temperature. Temperature and photoperiod affec ted larval and pupal development under certain other temperature and p hotoperiod regimes.