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.
