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Effects of Buxus chinensis extract, Bacillus thuringiensis and nuclear polyhedrosis virus (NPV) mixture on certain biological aspects of Spodoptera littoraUs were studied against the 2nd and 4th larval instars of S. littoralis. The mixture of the three compounds was the most toxic against the 2nd and 4th instar larve, where it caused high percentage of mortality, while 8. thuringiensis (Dipel 2x) and nuclear polyhedrosis virus (NPV) mixture induced a slight effect against the 2nd and 4th instars. Regarding the ethanolic extract of Buxus chinensis leaves, it was more effective than 8. thuringiensis (Dipel 2x) or nuclear polyhedrosis virus(NPV) in respect of pupal mortality and larval, pupal and adult duration. This plant extract also reduced the fecundity and fertility of females emerged from the treated larvae of S. littoralis. [ABSTRACT FROM AUTHOR]

Bacillus thuringiensis strains that belong to B. thuringiensis, B. kurstaki and soil-isolated B.t. were assessed in the following phytopathogenic: Rhizoctonia solani, that had their mycelial growth decreased after incubation in the presence of the bacterial strains. The bacteria have also pathogenic effect against the insect pest Spodoptera littoralis. The isolate B.t. D-l and the B.t. kurstaki HD-203 were found to be inhibiting R. solani, the strain B. kurstaki HD-203 displayed the highest percentage of inhibition (64%) and B.t. D-l showed 49% of inhibition. Antagonistic activity was maintained up to pH 8.5, and the antifungal activity was stable to heat at 70 °C for I h. Minimal inhibitory concentrations were 152 and 131 μl/ ml for B.t. D-l and B. kurstaki HD-203, respectively. The two strains also have high efficacy against S. littoralis larvae, B.t-D1 gave 70% and the B. kurstaki HD-203 strain gave 80% mortality after seven days of treatment. [ABSTRACT FROM AUTHOR]

The influence of soil pH, moisture, temperature and indigenous microorganisms on the survival of Bacillus thuringiensis (local isolate) in different soil types was investigated. The pathogenicity of this isolate was determined using Spodoptera littoralis (Biosd.) larvae. The highest reduction in the number of spores present as CFU, in soils having different pH values was during the first two weeks post treatments, and then almost stabilized for the next weeks. The important factor affecting spore survival was the soil pH (soil type). The highest and lowest reductions in the spore numbers were shown with soils at pH (5.1) and pH (7.2) respectively. The pathogenicity fell rapidly until reached < 5 % after 8 weeks post treatment which may be due to that, the crystals were degraded far more rapidly than spores. There were no important effects on spore numbers under various moistening degrees, different temperatures or the indigenous microorganisms of all soil types. [ABSTRACT FROM AUTHOR]