تأثير فترة الإضاءة على حياتية الأطوار المختلفة لدودة ورق القطن (lepidoptera : Spodoptera littoralis (BOISD.)‎ noctuidae)‎

Abstract EN

The effect ofthree photoperiods (continous light, alternate light (12 h.) and dark (12 h.), and continuous darkness) on the biology of the different stages of the cotton leaf-worm, Spodoptera littoralis (BOISD.) (Lepidoptera : Noctuidae) was investigated under constant laboratory conditions of 25+l'C and7}fiYoR.H.

Incubation period, pupation period, female adult longevity and post-oviposition periods were not affected by photoperiod.

However, egg-hatchability, larval period, male adult longevity, pre+viposition period, oviposition period and total life cycle duration were signifrcatly influenced by it.

Under continouous light, alternate light and dark and continouous darkness the totla life-cycle duration ranged between 29-53 days, with means of 40.9, 34.3 and 39.7 days, respectively, for female individuals, and 44.0, 34.4 and 41.8 days, respectively, for male individuals.

Response to photoperiod varied from one stage to another.

It is recommended to maintain egg-masses under continuous light and to place oviposition cages in the dark.

Other stages are recommended to be maintained under an alternate light and dark photoregime.