Studies on the relative toxicity of different bio-rational insecticides against second instar larvae and adults of onion thrips, Thrips tabaci were carried out on Experimental Farm and in the laboratory, Faculty of Agriculture, University of Suez Canal. Eight insecticides Dipel 2x, BioFly, Agrin, BioGuard, Spinosad, Neemix, Mectin and Match were all evaluated for their relative toxicity towards T. tabaci with recommended dose, half of recommended dose and quarter of recommended dose in the laboratory and only recommended dose under field conditions. Spinosad was the most toxic among the tested insecticides followed by Mectin, Match and Agrin when used against thrips adults. The respective values of LC₅₀ of those insecticides were 0.048 cm/l, 0.070 cm/l, 0.079 cm/l and 0.137 g/l. Also, Spinosad was the most effective insecticide against second instar larvae followed descendingly by: Agrin, Match and Dipel 2x. Toxicity index values at LC₅₀ level show such superior efficiency of Spinosad (100%) when applied against adults and second instar larvae of onion thrips under labora tory conditions. All insecticides under field conditions caused reduction of infestations of thrips. For the residual effect post application, all insecticides gave significant reductions in thrips numbers at the 21 day post treatment except for: Agrin and Match. Spinosad, Mectin, Neemix and BioFly gave the best control and continued to suppress thrips populations till 21 days after treatment. Spinosad was non harmful and Dipel 2x, Agrin were slightly harmful, BioGuard was significantly harmful whereas BioFly, Match and Mectin were very harmful to Orius albidipennis.

Surface topography assessments with valley exploration are of great importance. Two-process surfaces are often proposed for many combustion engines. One of the errors committed in surface topography measurements and analysis are those that occur during data processing. In this paper, improper areal form removal was taken into consideration for plateau-honed cylindrical surfaces with additionally burnished oil pockets. Usually, the reference plane is established by application of: fitting algorithms (e.g. cylindrical shape), polynomials, filters and other procedures. In many cases, the influence of the reference plane was not fully recognized during valley depth consideration. Moreover, the influence of areal form removal with edge-to-dimple and valley‑to-dimple distances was not precisely defined. In this research, commonly used algorithms for form separation in surface topography analysis were proposed for the applications being considered. The digital filter bandwidth was also specified for valley depth analysis. The distortion of edge‑located oil pockets was specified. It was assumed that application of robust techniques does not necessarily provide the desired results.