Effect of plant ethanolic extracts of Rosmarinus officinalis L. and Nerium oleander L. on mortality, biological parameters and reproduction of Aphis gossypii (Hom.: Aphididae)

Aphis gossypii Glover (Hom.: Aphididae( is one of the most important pests in greenhouse and field. Considering the importance of human health and the environmental protection, reduction in pesticide application has to be considered as an essential issue in the pest control program. In the present study, effects of ethanolic extracts of Rosmarinus officinalis L. and Nerium oleander and an insecticide, imidacloprid were evaluated against Aphis gossypii. Leaf dipping method was used in the laboratory conditions (temperature of 25 ± 1 °C, 65 ± 5% relative humidity and 16 h light: 8 h dark). After 72-h, LC50 values of imidacloprid, plant extracts from rosemary and oleander were estimated 0.004, 24.69 and 45.26 mg/ml, respectively. In this study, the effects of sublethal concentration (LC30) of each treatment was evaluated against A. gossypii. Longevity and the number of offspring were estimated per female per day. In this experiment, significant effects were observed on the life table parameters such as survival, intrinsic rate of increase, net reproductive rate, finite rate of population increase and mean generation time, for aphids fed on the leaves treated with ethanolic plant extracts and imidacloprid as compared to the related controls. This information provides further support for plant extracts of R. officinalis and N. oleander having a good potential to control the A. gossypii. However before claiming firm conclusions, trials under glasshouse and field related conditions are needed to verify the applicability of these two plant extracts in control of A. gossypii.