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The direct toxicity of two essential oils,Majorana hortensis,Moench and Rosmarinus officinalis L.to adult females of the predacious mites,Amblyseius zaheri Yousef and El-Borolossy,Amblyseius barkeri (Hughes)and Typhlodromus athiasae Porath and Swirski were tested.Rosemary oil was the most toxic to fe- males of A.barkeri and the least to A.zaheri.In contrast,sweet marjoram oil was relatively toxic to T.athiasae and slightly toxic to A.barkeri.Both essential oils,decreased the food consumption rate at the concentration used for A.barkeri and A.zaheri.Females of A.barkeri and A.zaheri suffered a depression in reproduction when treated with 1% of rosemary oil.Both material used seems to be harmless to T.athiasae at 1%.

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The direct toxicity of four essential oils, Majorana hortensis Moench, Ros­marinus officinalis L., Mentha piperita L. and Lavandula officinalis Chaix, to adult females of the predacious mite Amblyseius swirskii Athias-Henriot were tested. Peppermint oil was the most toxic to females A. swiriskii while the French lavender oil was the least toxic to the pre­dator. All essential oils, at the two concentrations used, decreased the food consumption rate as well as egg laying. All four materials tested, at con­cen­tration 0.25% were considered to be safe for the predator since no mortalities had been recorded.

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The direct toxicity of the essential oil, Ocimum basilicum L. to females of six species of predacious mites of the family phytoseiidae was tested. The phytoseiid mites tested namely, Typhlodromus athiasae Porath and Swirski, Euseius yousefi Zaher and El-Borolossy, Amblyseius zaheri Yousef and El-Borolossy, Amblyseius deleoni (Muma and Denmark), Amblyseius swirskii Athias-Henriot and Amblyseius barkeri (Hughes). Sweet basil oil was highly toxic to females E. yousefi and was relatively intoxic to females A. swirskii. The essential oil has a close toxic effect for predator species, T. athiasae and A. barkeri. With the exception of A. zaheri, females of all predacious mites tested suffered a depression in reproduction and food consumption when treated with sweet basil oil at conc. 2%.

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The direct toxicity of the essential oil Lavendula officinalis Chais to egg stage and adult females of the predacious mites, Euseius yousefi Zaher and El-Borolossy, Neoseiulus barkeri (hughes), Amblyseius zaheri Yousef and El-Borolossy and Typhlodromus athiase Porth and Swirski was studied. French Lavender oil was highly toxic to both stages of E. yousefi and relatively in toxic to T. athiase. A depression on consumption was recorded on A. zaheri and E. yousefi, while a depression on reproduction was reported only in case of E. yousefi, when females treated with LC25 concentration. French Lavender oil, at concentration of (LC25) was considered to be safe for A. zaheri, N. barkeri and T. athiase, since no mortalities had been recorded.

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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.

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The deterrent and toxic effect of two essential oils, Majorana hortensis. Moench and Rosma- rinus officinalis L. on the two tetranychid mites Tetranychus urticae Koch and Eutetranychus orientalis (Klein) were studied under laboratory conditions. Both materials used were more potent for E. orientalis than against T. urticae with a significant increase in repellency. Leaf discs treated with increasing concentrations of the two oils showed increased mortality of both spider mites and reduction in the total numbers of eggs laid. This result could be due to the oil of the higher oxygenated compounds content that was more effective in this respect.

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Two essential oils, namely Ocimum basilicum L. and Lavandula offi­ci­nalis Chaix, were tested for their repellency, toxicity and oviposition deterrence against two tetranychid mites, tetranychus urticae (Koch) and Eutetranychus orientalis (Klein). Fifty-seven and forty-seven compounds, comprising about 96.7 and 95.4% of sweet basil and French lavender oil, respectively, were positively identified using GC-MS technique. Oil analysis revealed the dominant occurrence of the oxygenated terpenes in either oils (91.172 and 64.317%), respectively. The essential oil of French lavender was more potent for E. orientalis than against T. urticae. The ODI of both oils was ranged between (100-80) for both mite species at conc. (2- 0.5%). For both oils, a significant reduction in the total number of eggs laid by both tetranychid species was recorded at all con­centrations used. A high percentage of E. orientalis mortality was recorded for both materials while oil of sweet basil was more effective than French lavender oil in case of T. urticae. The results obtained chemically and biologically may suggest that the dominant occurrence of the oxygenated hydrocarbon compounds (91.172% of oil content) in sweet basil were responsible for the toxic effect.

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The direct toxicity of some mineral and plant oils to the eggs and females of the two spotted spider mite Tetranychus urticae Koch was tested. KZ oil was toxic to the egg stage compared to adult female. In contrast, Natur'l oil has a close toxic effect for both stages of T. urticae. Bio-dux oil was proved to be toxic to adult female and relatively in toxic to egg stage. Females of T. urticae suffered a depression in reproduction and shortened longevity when kept on plant leaves previously treated with different oils. Laboratory studies indicated that the vegetable oil Natur'l oil was effective on all biological aspects of T. urticae studied.

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The direct toxicity of some mineral and plant oils to adult females of the predacious mites, Amblyseius barkeri (Hughes) and Amblyseius zaheri Yousef and El-Borolossy were tested. KZ oil was the most toxic to females of A. barkeri and A. zaheri (LC50 = 0.391 and 0.308%, respectively). In contrast, Natur'l oil was relatively intoxic to females A. zaheri and A. barkeri. Bio-dux, Capl-2 and Natur'l oils have a close toxic effect for both predacious mites. Females of A. barkeri and A. zaheri suffered a depression in reproduction when sprayed with conc. = LC50 of each oil and kept on plant leaves previously treated with different oils. Laboratory studies indicated that the vegetable oil Natur'l oil was the least effective oil on all biological aspects of both predacious mites A. barkeri and A. zaheri in the laboratory.

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The direct toxicity of some essential, mineral and plant oils to the eggs and females of the predacious mite Neoseiulus cucumeris (Oudemans) was tested in the laboratory. Sweet basil oil was the most toxic essential oil to females N. cucumeris, while sweet marjoram oil was the least toxic one (LC50=2.315 and 7.021%, respectively). In contrast, rosemary oil was toxic to eggs of N. cucumeris, while sweet basil oil was the least effective oil against predator eggs (LC50 = 2.695 and 11.950%, respectively). The mineral oil capl-l 1was the most toxic one to adult females (LC50= 0.849%) while natur'l oil was the least (LC50= 4.691%), respectively. In contrast, natur'l oil was proved to be highly toxic to predator eggs while bio-dux oil was the least effective oil against the egg stage. Females of N. cucumeris suffered a depression in reproduction when females treated and fed on prey formerly kept on treated plant leaves with LC50 concentration of each oil used in our studies. Rosemary and sweet marjoram as well as bio-dux oils seem to be slightly harmful to N. cucumeris at (LC50) concentration of each oil.

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