الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
Abstract
The present investigation aims to monitoring the resistance levels of adults of cowpea aphid, Aphis cvaccivora (koche,) in two successive years (2008-2009) using populations collected from four Egyptian Governorates, Behira, Gharbia, Sharkia and Beni-suief. Also, the study included an evaluation of efficiency of some insecticides belongs to four different chemical groups, i.e organophasphorus compounds (pirimiphos-methyl) and chloryrifos methyl and from carbamate compounds, (Carbosulfan and Pirimicarb), the novel compounds such as imidacloprid and thiamethoxame, then diafenthiuron from miscellaneous insecticides . Examination of obtained results clearly indicated a great effect of the novel compounds with LC50’s 0.14ppm, 0.94ppm for imidacloprid and thiamethoxame respectively followed by carbamate group pirimicarbe which was more potent than carbosulfan with LC50’s 1.32 ppm and 1.47 ppm respectively, then thioria compound diafenthiuron with LC50’s 1.66 ppm and finally the organophosphorous group; pirimiphos – methyl (LC50 6.54 ppm) followed by chlorpyrifos – methyl (LC50 8.56 ppm) for susceptible strain. These results indicated that Novel compounds were most effective than the other used conventional insecticides.
Laboratory selection pressure was applied for Behira strain to build up resistance toward imidacloprid insecticide. The level of selection pressure was carried out using LC50 value of the compound. After fifteen generations, the level of resistance to imidaclopride was 129.81 fold for susceptible strain and 2.53 fold for field strain.
There was no cross resistance between imidaclopride and pirimiphos-methyl and diafenthiuron while highly cross resistance was
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observed between imidacloprid and pyrethroid compound lambada- cyhalothrin which was determined by 121.8 fold.
Evaluation of the efficiency of different groups of insecticides has been studied through determination some biochemical parameters, i.e total protein content, AChE, alkaline and acid phosphatases. The analysis of protein patterns of different collected populations were also determined in two successive years. Differences in protein content, protein patterns, AChE and phosphatases activity were analysed and it was found that such parameters were differed from population to another. The highest resistant population showed the highest protein content, protein patterns, AChE and phosphatases activity.
Key words: Aphis crassivora, insecticides, resistance, protein, phosphatases and AChE.