Effectiveness of some plant essential oil formulations on the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) and its predacious mites of the family Phytoseiidae
Shimaa Fahim Mohamed Fahim;
Abstract
Tetranychus urticae Koch is one of the most serious agricultural mite pests infested many crops; and the need for efficient control methods is important.
The use of natural pest control agents especially those derived from plants (as the essential oils and their formulations), may offer good alternatives in pest control.
Therefore, the present study aims to assess the potency of some essential oils and their formulations as acaricides against the mite pestT.urticae. In addition, the study investigated the efficiency of these materials on some associated predatoryphytoseiid mites (N. barkeri, N. californicus and T. swirskii); and that can be integrated with other methods of control in IPM programs.
The present study included the following points:
1-Identification of main components of the tested essential oils using GC/MS:
The relative percentages of theidentified main components of the tested essential oils were carried out by using Gas Chromatography / Mass Spectrometry (GC/MS) analysis.
The major components were identified asCamphor (93.07 %) forA. maritima oil, while they were Benzene 1(1,5dimethyl 4hexenyl) 4methyl (14.36 %) and Caryophyllene oxide (10.08 %) in case of M. officinalis oil.In addition, Piperitone oxide (83.32 %) was the major component of M. longifolia oil, while Thymol (31.73 %) and Methyl (1-methylethyl)-benzene (29.85 %) were the mainones of T. vulgaris. In case of Z. officinale, Zingiberene (31.30%) and beta-Sesquiphellandrene (14.27 %) were identified as the major components of the oil.
2. Physico-Chemical properties of the prepared formulations:
The tested oil formulations were prepared by mixing the tested essential oils with appropriate amounts of emulsifier, mineral and vegetable oils. Emulsion stability and foam formation tests were conducted for the prepared formulations according to WHO method. The results showed that the prepared oil formulations successfully passed the two previous tests.
3. Repellency and oviposition deterrence activity of the tested essential oils on T. urticae females:
The repellency and oviposition deterrence activity of each tested oil were evaluated against T. urticae females by treated one half of the plant leaf with one tested concentration while the other half served as a control. Four concentrations (1.00, 0.75, 0.50 and 0.25 %) were used for each tested oil. The obtained results revealed that the females preferred to feed and deposit their eggs on untreated leaf sections.
The highest values of the Deterrence Index (DI) were recorded at 1.00 % concentration while the lowest being recorded at 0.25 % for all tested oils.A significant reduction in the number of eggs deposited by females was recorded on treated leaf sections compared to control ones at all tested concentrations.
4. Acaricidal activity of the tested essential oils on T. urticae stages:
The acaricidal activity of the testedoils was evaluatedagainst eggs, nymphs and females of T. urticae by different application methods.
Based on the LC50 values, the most effective application method against T. urticae eggs was the direct spray application in case of A. maritima, M. officinalis and T. vulgaris oils, while the fumigant application was the least one. On the other hand, the fumigant application of M. longifolia oil was the most potent application on the eggs, while the leaf dipping application was the least one. In case of Z. officinale oil, thedirect spray application was the most toxic application on T. urticae eggs, while the leaf dippingapplication was the least one.
In case of the nymphs and females and based on the LC50 values, the results showed that the direct spray application of A. maritima, T. vulgaris and Z. officinale oilsbeing the most toxic application, while the systemic application was the least one. However, for M. officinalis oil, the direct spray application was the most effective application, while the fumigant application was the least one.
In case of M. longifolia oil, the fumigant application was the most potent application against T. urticae nymphs and females, whilethe systemicapplication being the least one.
5. Acaricidal activity of the tested formulations on T. urticae stages:
The acaricidal activity of the testedoil formulations was evaluated against different stages of T. urticae using the direct spray application. Based on the LC50 values, the results revealed that the eggsbeing the most sensitive to Misicide compared to the females and nymphs, while the reverse is true in case of Thymo. On the other hand, the nymphs beingthe most sensitive to Melissacide, Mento and Gingcidecompared to females and eggs of T. urticae.
6. Efficiency of the studied essentialoils on eggs and females of the tested predatory mites:
The obtained results showed that the eggs of the tested predatory mites were less susceptible tothe tested oils compared to the females when using the direct spray application. However, the eggs of the tested predators were more sensitive to M. longifolia oil than the females when using the fumigant application.
Based on the LC50 values, the results showed that T. swirskii females being the most sensitive to A. maritima, M. officinalis and M. Longifolia oils compared to the females of N. barkeri and N. californicus, respectively. In case of T. vulgaris oil,T. swirskii females being the most sensitive to the oil,followed by the females of N. californicusand N. barkeri, respectively. For Z. officinale oil, N. barkeri females being more sensitive to the oil compared to T. swirskii and N. californicus females.
7. Efficiency of the studied formulations on eggs and females of the tested predatory mites:
The results indicated that the eggs of the tested predators were less sensitive tothe tested formulations compared to the females.
Based on the LC50 values, thepresent study revealed that T. swirskii females being the most sensitive to Misicide and Melissacide compared to N. barkeri and N. californicus females, respectively. In addition, T. swirskii femalesbeing more sensitive to Thymo compared toN. californicusand N. barkeri females, respectively. The females of N. barkeri being more sensitive to Mento and Gingcide compared to T. swirskii and N. californicus females.
8. Efficiency of LC50 and LC90 values (recorded on T. urticae) of the studiedessential oils and their formulations on eggs and females of the tested predatory mites:
Eggs and females of the tested predatory mites were treated with concentrations equal to the values of LC50 and LC90 (recorded on T. urticae from its toxicity line) of each tested oil and its formulation and the obtained results could be summarized as follows:
The percentages of unhatched eggs of the tested predatory mites not exceed 4.52 % when they treated with LC50 and LC90 values of the testedoils (with the exception of M. longifolia oil ), while these percentages not exceed 25,00 % when they treated with LC50 and LC90 values in case of all tested formulations.
The use of natural pest control agents especially those derived from plants (as the essential oils and their formulations), may offer good alternatives in pest control.
Therefore, the present study aims to assess the potency of some essential oils and their formulations as acaricides against the mite pestT.urticae. In addition, the study investigated the efficiency of these materials on some associated predatoryphytoseiid mites (N. barkeri, N. californicus and T. swirskii); and that can be integrated with other methods of control in IPM programs.
The present study included the following points:
1-Identification of main components of the tested essential oils using GC/MS:
The relative percentages of theidentified main components of the tested essential oils were carried out by using Gas Chromatography / Mass Spectrometry (GC/MS) analysis.
The major components were identified asCamphor (93.07 %) forA. maritima oil, while they were Benzene 1(1,5dimethyl 4hexenyl) 4methyl (14.36 %) and Caryophyllene oxide (10.08 %) in case of M. officinalis oil.In addition, Piperitone oxide (83.32 %) was the major component of M. longifolia oil, while Thymol (31.73 %) and Methyl (1-methylethyl)-benzene (29.85 %) were the mainones of T. vulgaris. In case of Z. officinale, Zingiberene (31.30%) and beta-Sesquiphellandrene (14.27 %) were identified as the major components of the oil.
2. Physico-Chemical properties of the prepared formulations:
The tested oil formulations were prepared by mixing the tested essential oils with appropriate amounts of emulsifier, mineral and vegetable oils. Emulsion stability and foam formation tests were conducted for the prepared formulations according to WHO method. The results showed that the prepared oil formulations successfully passed the two previous tests.
3. Repellency and oviposition deterrence activity of the tested essential oils on T. urticae females:
The repellency and oviposition deterrence activity of each tested oil were evaluated against T. urticae females by treated one half of the plant leaf with one tested concentration while the other half served as a control. Four concentrations (1.00, 0.75, 0.50 and 0.25 %) were used for each tested oil. The obtained results revealed that the females preferred to feed and deposit their eggs on untreated leaf sections.
The highest values of the Deterrence Index (DI) were recorded at 1.00 % concentration while the lowest being recorded at 0.25 % for all tested oils.A significant reduction in the number of eggs deposited by females was recorded on treated leaf sections compared to control ones at all tested concentrations.
4. Acaricidal activity of the tested essential oils on T. urticae stages:
The acaricidal activity of the testedoils was evaluatedagainst eggs, nymphs and females of T. urticae by different application methods.
Based on the LC50 values, the most effective application method against T. urticae eggs was the direct spray application in case of A. maritima, M. officinalis and T. vulgaris oils, while the fumigant application was the least one. On the other hand, the fumigant application of M. longifolia oil was the most potent application on the eggs, while the leaf dipping application was the least one. In case of Z. officinale oil, thedirect spray application was the most toxic application on T. urticae eggs, while the leaf dippingapplication was the least one.
In case of the nymphs and females and based on the LC50 values, the results showed that the direct spray application of A. maritima, T. vulgaris and Z. officinale oilsbeing the most toxic application, while the systemic application was the least one. However, for M. officinalis oil, the direct spray application was the most effective application, while the fumigant application was the least one.
In case of M. longifolia oil, the fumigant application was the most potent application against T. urticae nymphs and females, whilethe systemicapplication being the least one.
5. Acaricidal activity of the tested formulations on T. urticae stages:
The acaricidal activity of the testedoil formulations was evaluated against different stages of T. urticae using the direct spray application. Based on the LC50 values, the results revealed that the eggsbeing the most sensitive to Misicide compared to the females and nymphs, while the reverse is true in case of Thymo. On the other hand, the nymphs beingthe most sensitive to Melissacide, Mento and Gingcidecompared to females and eggs of T. urticae.
6. Efficiency of the studied essentialoils on eggs and females of the tested predatory mites:
The obtained results showed that the eggs of the tested predatory mites were less susceptible tothe tested oils compared to the females when using the direct spray application. However, the eggs of the tested predators were more sensitive to M. longifolia oil than the females when using the fumigant application.
Based on the LC50 values, the results showed that T. swirskii females being the most sensitive to A. maritima, M. officinalis and M. Longifolia oils compared to the females of N. barkeri and N. californicus, respectively. In case of T. vulgaris oil,T. swirskii females being the most sensitive to the oil,followed by the females of N. californicusand N. barkeri, respectively. For Z. officinale oil, N. barkeri females being more sensitive to the oil compared to T. swirskii and N. californicus females.
7. Efficiency of the studied formulations on eggs and females of the tested predatory mites:
The results indicated that the eggs of the tested predators were less sensitive tothe tested formulations compared to the females.
Based on the LC50 values, thepresent study revealed that T. swirskii females being the most sensitive to Misicide and Melissacide compared to N. barkeri and N. californicus females, respectively. In addition, T. swirskii femalesbeing more sensitive to Thymo compared toN. californicusand N. barkeri females, respectively. The females of N. barkeri being more sensitive to Mento and Gingcide compared to T. swirskii and N. californicus females.
8. Efficiency of LC50 and LC90 values (recorded on T. urticae) of the studiedessential oils and their formulations on eggs and females of the tested predatory mites:
Eggs and females of the tested predatory mites were treated with concentrations equal to the values of LC50 and LC90 (recorded on T. urticae from its toxicity line) of each tested oil and its formulation and the obtained results could be summarized as follows:
The percentages of unhatched eggs of the tested predatory mites not exceed 4.52 % when they treated with LC50 and LC90 values of the testedoils (with the exception of M. longifolia oil ), while these percentages not exceed 25,00 % when they treated with LC50 and LC90 values in case of all tested formulations.
Other data
| Title | Effectiveness of some plant essential oil formulations on the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) and its predacious mites of the family Phytoseiidae | Other Titles | فعالية بعض مستحضرات الزيوت النباتية العطرية على الحلم العنكبوتى ذى البقعتين، تيترانيكس أورتيكا (أكارى: تيترانيكيدى) ومفترساته من عائلة فيتوسيدى | Authors | Shimaa Fahim Mohamed Fahim | Issue Date | 2016 |
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| File | Size | Format | |
|---|---|---|---|
| G12009.pdf | 502.18 kB | Adobe PDF | View/Open |
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