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The deterrent and toxicity effects of mint, Mentha virdis L. and peppermint, Mentha piperita L. on Tetranychus urticae Koch were studied under laboratory conditions. M. virdis was more potent for T. urticae than M. piperita, with a significant increase in repellency. Leaf discs treated with increasing concentrations of both materials showed reduction in the total numbers of eggs laid. A high percentage of T. urticae mortality was recorded in case of M. virdis. The direct toxicity of both essential oils to the female of the predacious mites namely Typhlodromus athiase Porath and Swirski Phytoseius finitimus Ribaga, Amblyseius barkeri (Hughes), Amblyseius zaheri Yousef and El-Borolossy, Amblyseius yousefi Zaher and El-Borolossy and Amblyseius deleoni (Muma and Denmark) were tested. At LC 50 level, M. virdis was the most toxic to females A. yousefi and the least to females T. athiasae. With the exception of A. zaheri, M. piperita proved to be more toxic to the predacious mites tested than M. virdis. The results obtained chemically and biologically, may suggest that the higher percentage of the hydrocarbons of M. virdis were responsible for the toxic effect.

Nine phytoseiid species were tested to evaluate their potential as predators of Eutetranycbus orientalis (Klein). Typhlodromus atbiasae Porath and Swirski, Amblyseius barkeri (Hughes) and Amblyseius olivi Nasr and Abou-Awad had a shorter developmental period than Typhlodromus transvalensis (Nesbitt). Typhlodromus athiasae and Amblyseius barker/showed the highest oviposition rates. Amblyseius olivi showed a low rate of oviposition although Typhlodromus transvalensis has not able to lay any eggs. Immatures survival of Typhlodromus talbii Athias I-Ienrlot, Typhlodromus balanites EI-Badry, Amblyseius badryi.Yousef and EI-Borolossy, Amblyselus cabonus (Schicha) and Amblyseius lindquisti Schuster and Pritchard were very low on Eutetranychus orientalis and all failed to develop to adulthood. ReferencesABou-AwAD, B. A., 1983: Amblyseius gossipi (Acarina: Phytoseiidae) as a predator of the tomato erineum mite, Erioghyes lycopersici (Acari: Eriophyidae). Entomophaga 28, 363-366. ABoU-AWAD, B. A.; EL-BANHAWY, E. M., 1986: Biological studies of Amblyseius olivi, a new predator of eriophyid mites infesting olive trees in Egypt (Acari: Phytoseiidae). Entomophaga 31, 99-103. ABou-AwAD, B. A.; NASR, A. K.; GOMAA, E. A.; ABoU-ELELA, M. M. , 1989: Life history of the predatory mite, Cydnodromella negevi and the effect of nutrition on its biology (Acari:

The biology of Typhlodromips swirskii (Athias-Henriot), Typhlodromus athiasae Porath and Swirski and Paraseiulus talbii (Athias-Henriot) was studied using Aculops lycopersici (Massee) active stages as food source. For T. swirskii, development was faster and reproduction was higher than in T. athiasae. Survival of immatures of P. talbii was low on A. lycopersici and all failed to develop to adulthood. A total of 35.4 and 30.3 eggs per female, respectively, were obtained when T. swirskii and T. athiasae were fed on active stages of the tomato rust mite. A diet of A. lycopersici provided the shortest female longevity and highest mean total fecundity, which resulted in the highest net reproductive rate (Ro ¼ 26.785), intrinsic rate of natural increase (r m ¼ 0.235) and finite rate of increase (l ¼ 1.265) for T. swirskii. The mean generation time ranged between 13.97 and 17.85 days for T. swirskii and T. athiasae, respectively.