Background
Tomato, Solanum lycopersicum L. (Solanales: Solanaceae) is the second most important vegetable crop in Egypt and is infested with many insect pests. The cotton leafworm, Spodoptera littoralis (Boisd.) causes severe economic losses in tomatoes and many other crops. Many management strategies were developed in order to manage the economic losses obtained. In this context, the present study was conducted to evaluate the effectiveness using a mixture of Emamectin benzoate and lufenuron or using them solely against the 2nd and 4th instar larvae of S. littoralis under semi-field conditions.
Results
The obtained results showed that the mixture compound show high initial killing effect against 2nd and 4th instar larvae in both growing seasons. Furthermore, the residual effect of the tested compounds also showed the efficiency of the mixture over the solitary active ingredients. In addition, the treatment of the 4th instar larvae with the LC50 of the tested compounds showed significant impacts against the soluble protein, carbohydrate, lipid contents, and the detoxification enzymes.
Conclusion
In conclusion, the results showed that the emamectin benzoate and lufenuron could be safe and effective substitute for conventional insecticides either applied solely or in combination.
he present study aimed to evaluate the effect of Emamectin benzoate and Bacillus thuringiensis as bioinsecticides as well as the organophosphorus compound, chlorpyrifos on the 2 nd and 4 th instar larvae of S. littoralis under laboratory conditions. The results showed a decrease in both larval and pupal duration after larvae treatment. Results also showed a decrease in the pupation and the adult emergence percentage compared to the control. Moreover, adult longevity of male and female moths was affected. In addition, mean number of eggs laid and hatched /female as a result of treatment was reduced. Results showed also that the treatment with tested compounds presented and biochemical components impact on the activity of certain enzymes, e.g. total carbohydrates, total proteins, digestive enzymes, Acetylcholinesterase (AChE) and Glutathione S-transferase (GST).
Six inorganic salts were evaluated as possible sterilants against the cotton leaf worm, Spodoptera littoralis, by applying the pupal dipping technique. Results showed that all of the tested salts adversely affected the adult emergence and reduced the egg laying capacity and egg hatchability. The salts, NaoH, Ca (oH) 2 and ZnSO 4 gave 100% percent sterility with all tested nontoxic concentrations. Percentage of sterility increased with the increase of the concentration. All other salts induced degrees of sterility ranging from 55 to 75%. Treatment with these inorganic salts also caused several malformations in pupae and resulted moths.
The journal of Toxicology and pest control is one of the series issued twice by the Egyptian Academic Journal of Biological Sciences, and is devoted to publication of original papers related to the interaction between insects and their environment. The goal of the journal is to advance the scientific understanding of mechanisms of toxicity. Emphasis will be placed on toxic effects observed at relevant exposures, which have direct impact on safety evaluation and risk assessment. The journal therefore welcomes papers on biology ranging from molecular and cell biology, biochemistry and physiology to ecology and environment, also systematics, microbiology, toxicology, hydrobiology, radiobiology and biotechnology. www.eajbs.eg.net
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