Contribution to the Physical Ecology of Tortrix postvittana, Walk. (Lep.)

Abstract

1. The thermal constant and the zero of the velocity curve have been determined for each of the pre-adult stages of Tortrix postvittana, Walk. The experimental methods are described. The thermal constant for the eggs is 153 day degrees C. and the zero of the velocity curve 4·80°C. The corresponding constants for the larvae are 469 day degrees C. and 8·05°C, and for the pupae 182 day degrees C. and 5·93°C.2. The experimentally determined constants and the mean monthly temperatures have been used to calculate the peak of the flight period of the adult moths at Huonville, Tasmania, during the 1935, 1936 and 1937 seasons. In three cases out of four the calculated dates approximate very closely to the observed dates for the peak of the flight period.3. The results of observations on the number, duration and head-widths of the larval instars are given. The majority of larvae fed on young apple leaves had four instars. A greater proportion of the larvae fed on mature apple leaves had more than four instars. The length of larval life at 25°C. is significantly longer for both male and female larvae when they are fed on mature leaves. The head width of the final instar of four-instar female larvae is significantly greater than that of the final instar of four-instar male larvae. Food quality has no apparent influence on the head width of the final instar of either male or female larvae.4. At 25°C. the length of larval life of female larvae is significantly longer than that of male larvae when both are fed on the same food ; the same tendency is exhibited at other temperatures. The separate velocity curves for male and female larvae are not significantly different in slope. The difference between velocity values for male and female larvae at the mean temperature approaches significance.5. Larval mortality increases rapidly at temperatures above 30°C. and 100 per cent, mortality occurs at 35°C. Starved larvae at low temperatures and high humidities show a tendency for the survival time to increase with the size of the larvae. Final instar larvae under these conditions can survive for two and a half months.

Improved quality management to enhance the efficacy of the sterile insect technique for lepidopteran pests

“…Most trapping systems for Lepidoptera are baited with the female sex pheromone, and therefore are limited to sampling male moths. However, baits to attract female Lepidoptera do exist, and include crude fermentation or other baits (Dumbleton 1939; El‐Sayed et al. 2005), refined baits based on semiochemicals (Light et al.…”

Aseptic rearing ofEpiphyas postvittana(Lepidoptera: Tortricidae) on a meridic diet

“…On the meridic diet with and without mould inhibitor, the average numbers of eggs laid per female were 598 and 502 respectively. Dumbleton (1932) recorded larval and pupal periods of 42 and 14 days respectively on apple, at an average temperature of 20° C. Dumbleton (1932Dumbleton ( , 1939 also reported a considerable variation in the length of developmental period of individuals in any one generation, and noted that different generations overlap to a great extent. This view was supported by Thomas (1965 in spite of the controlled conditions of environment and nutrition, a similar pattern is evident; for example, the ranges of larval periods for males and females were 19-42 days and 22-49 days respectively.…”

“…Dumbleton (1932) reported that a female deposits an average of 100 eggs on apple; Thomas (1965) obtained an egg count of 856 for an oligidic diet based on sheep nuts. On the meridic diet with and without mould inhibitor, the average numbers of eggs laid per female were 598 and 502 respectively.…”

The hymenopteran parasitoids of light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae) in Australia

“…Species of Australoglypta Gauld are known only from Australia and Papua New Guinea (Gauld 1984a), with this species recorded from Bundoora, Warrandyte and Studley Park in Victoria (ANIC, VDAM) and Coonawarra in South Australia (WINC). There is a description of an unidentified species of 'Glypta' reared from E. postvittana from Tasmania (Dumbleton 1939), which is probably this species. However, we have been unable to locate any voucher material to confirm this.…”