Comparative bioactivity of essential oils from two Mentha pulegium (Lamiaceae) chemotypes against Aphis gossypii, Aphis spiraecola, Tetranychus urticae and the generalist predator Nesidiocoris tenuis

The essential oils of the three aromatic plants, Mentha pulegium, Thymus capitatus and Origanum compactum, are toxic to agricultural pests. This experiment was carried out with the aim of testing toxicity by direct contact with these essential oils, under laboratory conditions, on adult individuals of Tetranychus urticae Koch (Acari: Tetranychidae) and predator spider Phytoseiulus persimilsi Athias-Henroit (Acari: Phytoseiidae) which is one of the most important natural enemies of this pest. The residual activity of these essential oils has also been tested. The oil preparations were prepared for the study according to increasing concentrations: 0.5, 1, 2, 4 and 8% of each essential oil. The results showed the following: All the tested essential oils showed high toxicity towards the adult individuals of T. urticae, but pennyroyal and thyme oil are more effective than oregano oil. We obtained 100% total mortality at a concentration of 1% in the case of pennyroyal and thyme versus 84.99% in the case of oil oregano. Also, the residual activity of these oils decreases over time. On the other hand, these oils are less toxic to adult individuals of P. persimilis. At a concentration of 1% of pennyroyal, thyme and oregano oil, mortality ratios estimated at: 44.94, 16.82 and 6.9% respectively. Conclusion: These results indicated that these essential oils may represent a promising alternative to synthetic pesticides on the horizon of developing biological pest control within integrated control programs as the best and safe option for human health and the environment in general.

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Activité Acaricide Des Huiles Essentielles Du Mentha Pulegium, Origanum Compactum Et Thymus Capitatus Sur L’acarien Phytophage Tetranychus Urticae Koch (Acari : Tetranychidae)

European Scientific Journal ESJ ◽

10.19044/esj.2018.v14n3p118 ◽

2018 ◽

Vol 14 (3) ◽

pp. 118 ◽

Cited By ~ 2

Author(s):

Asmae Bakkali Aissaoui ◽

Amal El Amrani ◽

Said Zantar ◽

Larbi Toukour

Keyword(s):

Essential Oil ◽

Essential Oils ◽

Tetranychus Urticae ◽

Contact Toxicity ◽

Mentha Pulegium ◽

Plant Essential Oils ◽

Thymus Capitatus ◽

Origanum Compactum ◽

Main Component ◽

Tetranychus Urticae Koch

The use of botanical acaricides extracted from plants as an alternative to replace the chemical acaricides is an interesting and efficient option to control pests and ameliorate their toxic effects to humans and the environment. The aim of this work was to evaluate the contact toxicity of Pennyroyal mint (Mentha pulegium), oregano (Origanum compactum) and thyme (Thymus capitatus) essential oils against adults, larvae and eggs of two-spotted spider mite Tetranychus urticae Koch (Tetranychidae). The chemical composition of these three plant essential oils was also characterized. Laboratory tests were conducted to determine the acaricidal effect of plant essential oils at several doses in geometric progression. The consequences of treatments on mortality were measured in relationships with concentrations of essential oils. On the other hand, the major constituents of the three essential oils were identified by gas chromatography-mass spectrometer (GC-MS) techniques. GCMS analyses proved that the major compound present in the essential oils of thyme and oregano is carvacrol (55.59 and 55.28% respectively) while the main component of pennyroyal mint essential oil is pulegone (67,63%). Laboratory bioassay results indicated that essential oils of thyme and pennyroyal mint caused the most important acaricidal effects in comparison with the essential oil of oregano. At a concentration of 1%, thyme and pennyroyal eradicate all adults of the mite while oregano causes a mortality of 84.99%. On larvae, the mortality rate of thyme, pennyroyal and oregano is 97.7; 89.47 and 57.89% respectively. The results of the present study concluded that plant essential oils could be useful in promoting research aiming at the development of new agent for pest control from the plants with medicinal values.

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