DEVELOPMENT OF IMMATURE STAGES OF THE LUCERNE LEAFROLLER MEROPHYAS DIVULSANA (WALKER) (LEPIDOPTERA: TORTRICIDAE) UNDER CONSTANT TEMPERATURES AND ON SEVERAL LARVAL DIETS

Of 5 diets tested, 1 comprised principally of agar-lucerne was judged better than an agar-bean, non-agar-lucerne, potted lucerne or cut lucerne diet for larval and pupal development of M. divulsana. Development times of eggs, larvae and pupae were determined over a range of constant temperatures from 6.9 to 34.2 °C. All stages developed between 11.3 and 30.7 °C. Using thermal summation, the following threshold temperatures and thermal constants were calculated: eggs, 8.9 °C, 2010.5 h ° female larvae, 8.2 °C, 269.7 d° male larvae, 8.8 °C, 243.2 d ° female pupae, 8.0 °C, 97.1 d ° male pupae, 8.0 °C, 110.2 d °. The data were also fitted to Pradhan's and Stinner's formulae. All three development-rate functions fit the data well (R2 > 0.90).