Abstract: The green cestrum (Cestrum parqui) is a Solanaceae which provoke toxicity on cotton leaves noctuid (Spodoptera littoralis; Noctuidae). This toxicity is demonstrated by some larval mortality caused by exuviation difficulties for Spodoptera. We observed some nymphal mortalities caused by desiccation of the chrysalis or by emergence impossibility of adults, these mortalities are due to different types of malformations. Some rare case of adults mortality are observed, these mortalities are due to the difficulties to redject the nymphal integuments. The toxicity could be also chronicle: An elongation of the larval stadiums until development stopping, the reduction of nymphal weight, of the adults wing-span and of their reproductive potential are observed.