Activity of two photosensitizer compounds were studied on different stages of Spodoptera littoralis under laboratory
conditions. Copper chlorophylline and magnesium chlorophylline as a photosensitizer compounds with different
concentrations were tested on S. littoralis immature stages, egg, larvae and pupae. Data showed that copper chlorophylline
has a slight effect while magnesium chlorophylline has no effect on egg stage of S. littoralis. The copper chlorophylline
was more toxic on 2nd and 4th instar larvae than magnesium chlorophylline under both dark and photo conditions.
Therefore, both compounds were more toxic under sunlight than dark conditions when pupae were immersed at different
concentrations of the both photosensitizers' compounds. These results reflected that photosensitizers could be a potentially
effective for S. littoralis control in Egypt.