The effects of exposure to high temperature on egg survival and rate of development were measured in Heliothis armigera
Hübner and H
No adverse effect was observed on egg hatch at short exposures ( < 1h ) to temperatures of 44° C and below. 50 % mortality may occur when the eggs of both species are exposed for ca 2 hours to 44° C. High humidity ( 100 % ) significantly influenced egg hatch in both species.
Rate of development increased with exposure time at 35 °C but decreased at temperatures > 35° C. This retardation increased with longer exposures and higher temperatures. Overall H. punctigera eggs required more developmental time and heat units (degree-h) to hatch than H. armigera.
The data could be used to simulate egg survival and development in the field under high summer temperatures conditions.