Title: EFFICIENCY OF CERTAIN PESTICIDES ON SOME BIOLOGICAL ASPECTS OF SPODOPTERA LITTORALIS (BIOSD) UNDER FILED AND LABORATORY CONDITIONS
Abstract: Efficiency of four pesticides belonging to different groups of chemicals ,namely : Chlorosan, Agrinate , Daizinone and Nasractine on some biological aspects of 2nd and 4th instar larvae of the cotton leaf worm S. littoralis (Boisd) under field and laboratory conditions were investigated . The LC50 and LC 90 values were calculated after 24 , 48 , and 72h. Post – treatment . The obtained results showed that a wide range of toxicity of the tested pesticides , however the insecticide Chlorosan proved itself to be the highest toxic compound to the treated larvae as LC50 and LC90 values after 72h. post – treatment recording 0.01 , 0.83 ppm and 0.13 , 5.23 ppm for 2nd and 4th instar larvae , respectively . On the other hand , the compound Diazinon exhibited the lowest toxicity to the tested larvae at the both levels of toxicity (LC50 and LC90 values after 72h. were 16.86 ,69.31 ppm and 39.59 , 186.67 ppm) for 2nd and 4th instar larvae , respectively . The other tested pesticides occupied an intermediate position. The tested pesticides increased the larval , pupal duration and malformed pupae and decreased the percentage of pupation , adult emergence compared with control.