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).

This study was carried out at Quesna district, Menoufia governorate during 2017 growing season under semi field conditions against 2 nd and 4 th instar larva of Spodoptera littoralis (Boisd.) to evaluate the efficiency of combining Beauveria bassiana with certain insecticides (emamectin benzoate, methomyl and Bacillus thuringiensis) in tomato field. In general, data revealed, clearly, that methomyl had the highest efficacy against 2nd larval instar, where, the percentages corrected mortality were 98.28, 62.68 and 27.09% at concentrations RC,1/2RC and 1/4RC respectively. While, when 4 th larval instar treated by emamectin benzoate, the observed total percentage corrected mortality was the highest value (90.54%) at RC followed by methomyl (85.79%) at RC, whereas, when treated 2 nd and 4 th larval instar with fungi had the lowest values of percentage corrected mortality at all concentrations compared with remaining treatments. When treated larvae with mixture of fungi (B. bassiana) and insecticides percentages mortalities of second and fourth larval instar of emamectin benzoate + B. bassiana and methomyl + B. bassiana had the highest values after 24hrs. then decreasing gradually, but the highest values of percentage mortality of second and fourth larval instar when mixtures of Bacillus thuringiensis + B. bassiana were after fifth days at concentrate of insecticide 1/2RC and after third day at concentrate of insecticide 1/4RC. So mixing increases the efficiency of their insecticides.

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