Biological effects of essential oils and extracts
s. Akbari; Sh. Aramideh
Abstract
Aphis gossypii Glover. is one of the most important pests of Cucurbitaceae family. Nowadays, control of the pest population using the environmentally compatible compounds has been increased. In this study, fumigant toxicity of different concentrations and time intervals of Achillea millefolium L. and ...
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Aphis gossypii Glover. is one of the most important pests of Cucurbitaceae family. Nowadays, control of the pest population using the environmentally compatible compounds has been increased. In this study, fumigant toxicity of different concentrations and time intervals of Achillea millefolium L. and Mentha pulegium L. essential oils (EO) was studied in a completely randomized design on adults of mentioned pest. Also, sublethal effects of EOs were evaluated on life table parameters of adult aphids. The results showed that these plants EOs caused significant mortality of adult insects. LC50 of A. millefolium and M. pulegium EOs on A. gossypii were 34.90 and 23.34 µl.l-1 of air, respectively. LT50 of EOs were obtained 12.30 h in 34.90 µl.l-1 of air concentration of A. millefolium EO and 12.02 h in 23.34 µl.l-1 of air concentration of M. pulegium EO. Intrinsic rate of population increase (rm) as the most important life table parameter of the pest was obtained 0.28 (female/female/day: the number of female individuals produced per female each day) in the M. pulegium EO treatment and 0.27 (female/female/day) in the A. millefolium EO one, which had a significant decrease compared to control (0.34). The study results of sublethal effects of these two essential oils on population growth parameters indicated that age-specific survival rate of the aphid was lower in the treatments compared to control. Life expectancy (ex) was the lowest in the M. pulegium treatment (10.97 days) and highest in control (20.73 days). Net reproductive rate was calculated 15.64, 9.38, and 35.76 (female/female/generation) for A. millefolium, M. pulegium, and control, respectively. Our results revealed that the plant EOs studied could be suggested to be used in the integrated A. gossypii management programs in greenhouses due to the high potential in fumigant toxicity and population decrease of this pest.
Biological effects of essential oils and extracts
E. Ostovar; S. Khodayari; Sh. Aramideh
Abstract
Annually a significant portion of agricultural products is destroyed by the stored products pests. The chemical pesticides are commonly used to control pests. The residual hazards of pesticides on the storage products as well as increase in the pest resistance necessitate the selection of safe and effective ...
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Annually a significant portion of agricultural products is destroyed by the stored products pests. The chemical pesticides are commonly used to control pests. The residual hazards of pesticides on the storage products as well as increase in the pest resistance necessitate the selection of safe and effective control methods. The plant compounds can be the subject of researches on the storage pests control with the low-risk methods. Therfore, this experiment was conducted to study the effects of peel essential oil from three Citrus spp. including Citrus limon L., C. sinensis L., and C. aurantium L. on the adults of Callosobruchus maculatus F., Sitophilus granarius L., and Tribolium confusum Duv. The probit analysis was performed after 24 and 48 hours to evaluate the effects of essential oils on the pests. After determining the LC50 and LC25, the combinations of C. limon LC25 + C. aurantium LC25, C. limon LC25 + C. sinensis LC25, and C. sinensis LC25 + C. aurantium LC25 were tested to evaluate the combined effects of essential oils. The treatments had three replications and each replicate was performed on ten two-days-old adult insects in a completely randomized design. Also, the essential oils were analyzed by GC/MS to evaluate their major constituents. The LC50 value (µl.l-1) of essential oils of C. limon, C. sinensis, and C. aurantium was 3.8, 2.65, and 3.11 after 24 hours and 2.48, 1.93, and 2.88 after 48 hours on the S. granaries adults, 0.23, 2.41, and 2.66 after 24 hours and 0.13, 1.38, and 2.35 after 48 hours on C. maculatus, and 5.33, 2.76, and 1.35 after 24 hours and 24.2, 2.49, and 0.89 after 48 hours on T. confusum, respectively. The study on the combined effects of essential oils showed that the C. limon LC25 + C. sinensis LC25 treatment was more effective than the effect of each essential oil alone on all three pests. According to the results of this study, the use of Citrus peel essential oil, especially C. limon, could be recommended in the production of bio-pesticides.
F. Senfi; M.H. Safaralizadeh; S.A. Safavi; Sh. Aramideh
Abstract
Nowadays, the application of plant essential oils has been highly considered as an alternative for synthetic insecticides especially in stored-product pests. One of the potential resources for development of new pesticides is plant materials, acting as repellents, antifeedants, oviposition deterrents ...
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Nowadays, the application of plant essential oils has been highly considered as an alternative for synthetic insecticides especially in stored-product pests. One of the potential resources for development of new pesticides is plant materials, acting as repellents, antifeedants, oviposition deterrents and toxic compounds. In this study, fumigant toxicity of essential oils extracted from Laurus nobilis L. and Myrtus communis L. was assessed on adults and eggs stage of Callosobruchus maculatus. This research was conducted in a completely randomized design at 30 ± 2°C and relative humidity of 60 ± 5 % in darkness. Each essential oil was tested in 3 replications and 5 concentrations. The LC50 values for L. nobilis and M. communis for adults of the beetle were calculated to be 71.782 and 44.138 micro liter per liter of air and the LC95 values were calculated to be 216.278 and 141.716 micro liter per liter of air, respectively. The LC50 values for L. nobilis and M. communis for eggs of the beetle were calculated to be 63.994 and 38.371 microliter per liter of air, respectively. It seems that essential oils can be used as a low-risk insecticide.
