الفهرس | Only 14 pages are availabe for public view |
Abstract The cotton leafworm Spodoptera littoralis (Boisduval, 1833) is a destructive lepidopterous pest invading seriously many plant species all over the world. This destruction was the motivation for numerous studies to control this pest. In the present study the effect of the essential oil of camphor (Cinnamomum camphora), the organophosphorus insecticide, chlorpyrifos, and the insect growth regulator, lufenuron, were evaluated against the fourth instar larvae of S.littoralis which were evaluated at LC50 ( = the lethal concentration for half of the population of the pest). The effects were investigated by some toxicological, biological, and biochemical aspects. Three essential oils were investigated to throw light on the most potent one. Camphor, onion, and mustard oils were tested. Camphor was the most potent one. So, further investigations using camphor oil were done. Gas-Chromatography (GC) analysis for Camphor essential oil revealed that Camphor oil contains more than toxic constituents for insects like camphor, 1.8 Cineol, and Linalool. Results showed that the LC50 for lufenuron was ( 0.0002 ppm), chlorpyrifos ( 1.68 ppm) and Camphor oil was ( 20000 ppm). Some enzyme activities were estimated; acid and alkaline phosphatases, α and β Esterases, Transaminases (AST, ALT), Glutathione S-Transferase (GST), Mixed Function Oxidase (MFO), and Phenol Oxidase (PO). In addition, the total soluble carbohydrate, protein, and lipid contents also were evaluated. Finally, it may be concluded that camphor oil has the potentialities to reduce the population density of S. littoralis. So it may be used in combating the population of S.littoralis. Hoping that the obtained results may be of help in integrated pest management as it could be investigated in further researches. Keywords: Cinnamomum camphora, Spodoptera littoralis, Chlorpyrifos, lufenuron, Toxicity, Bio-insecticides, essential oils, enzymes, GC analysis. |