Thermal requirements for development of Earias insulana boisd [Egyptian strain]

ABSTRACT

Earias insulana shows optimal preimaginal development and survival at temperatures between 25?C and 27°C. Its development, from oviposition to adult emergence, requires an effective temperature sums [k] of 329.9 heat degree days above the theoretical threshold for development [t%] of 14.3°C. The [t%] values for all stages vary between 13.2°C. and 15.9°C. The lowest [t%] value is observed for the egg stage. The [t%] values are varying between 15.5-123 heat degree days above the theoretical threshold for their development. Based on thermal characteristics, this species may produce six to eight generations per year allover Delta region. The number of generations, calculated by the effective temperature sums [k], has been approved by the periodical system of development and reproduction which is designed for this species. The t o/n value, calculated for different regions in Delta, varied between 19.9°C. and 21.3°C. The value of [t o/1] which is the actual temperature for development is also calculated