Toxicity of Some Essential Plant Oils Against Cotton Leaf Worm, Spodoptera littoralis (BOISD.)

The study aims to evaluate the bioactivity of plant essential oils (neem oil, garlic oil, marjoram oil, and menthol oil) on 2nd instar larvae of the cotton leafworm, Spodoptera littoralis in the laboratory. Also, LC50 of each treatment was established against 2nd instar larvae of S. littoralis under semi-field conditions. The obtained results reveal that neem oil was more effective than the other oils followed by, marjoram oil then garlic oil and then, menthol oil.LC50 was3022.50, 3803.41, 4630.13and5323.38ppm for neem oil, marjoram oil, garlic oil, and menthol oil, respectively, for 2nd instar larvae. While, when LC50of these oils applied on the 2nd instar larvae in the semi-field, the results indicated that, garlic oil was the most effective essential oil followed by, menthol oil, marjoram oil, and neem oil.