COOLING CERTAIN LEPIDOPTEROUS INSECT EGGS IN RELATION TO THEIR HATCHABILITY

Different ages of the pink stalk borer, Sesamia cretica (Led.); Eu-ropean corn borer, Ostrinia nubilalis (Hubn.), cotton leaf worm, Spodop-tera littoralis (Boisci.) and greasy cutworm, Agrotis ipsiion (Hufn.) eggs were cooled at 5±0.5, 10±0.5 and 15±0.5°C for different periods to evaluate their viability under these conditions. The following results were achieved: - Cooling eggs of the considered insects delayed hatching in most cases and decreased their viability_ - It could successfully keep Sesamia eggs, 2 days old, for 5, 9 and 11 days at the three mentioned temperatures, respectively without affecting their viability (100%). - Ostrinia eggs, aged 2-3 days, could be kept at 10±0.5°C for about 2 days with 88_6 - 100_0% viability. At higher temperature, eggs of 3 days old were successfully kept for a longer period (9 days) with a complete viability. Agrotis eggs (2 days old) could be kept for 10, 3 and 2 days with their normal viability at three cooling degrees, respectively. Spo‌doptera eggs of the same age were kept for relatively shorter periods; 1, 4 and 4 days at these degrees with their complete viability.