Susceptibility of the common pistachio psyllid (Agonoscena pistaciae Burkhardt and Lauterer) to several plant extracts in laboratory

The common pistachio psylla, Agonoscena pistaciae Burckhardt and Lauterer (Hem.: Aphalaridae), is one of the most important pests of pistachio orchards in Iran. In this study, the effect of ethanol extracts of Thymusv ulgaris L., Rosmarinus officinalis Save., Ricinus communis L. and Sophopra alopecuriodes L. were studied on the mortality of this pest in vitro. The bioassay experiments were done within 8-cm-diameter Petri dishes, containing pistachio leaf disks and fifth instar nymphs of common pistachio psylla. Different concentrations of extracts were sprayed on nymphs, by using the spray tower, and distilled water and ethanol were used as control. Nymphal mortality was calculated at 36 and 48h post-treatment. The experiment was conducted in a CRD design with three replications for each concentration of each treatment. According to the obtained results, the effect of different concentrations of all treatments was significant on the mortality of pest at 36 and 48h after treatment. The LC50 values for T. vulgaris, R. officinalis, R. communis and S. alopecuriodes (flowers) and S.alopecuriodes (leavs)at 36hafter treatmentwere calculated to be 386.642, 322.207, 314.338, 94.367 and 25.127 g/l, respectively. Based on the toxicity of extract used in this study at 24 and 48 hours after treatment, T. vulgaris and S. alopecuriodes extracts hadthe lowest and highest insecticidal effect on common pistachio psylla, respectively. The extract of S. alopecuriodes flowers and leaves was more effective and it could be used as an effective and environmentally friendly compound candidate in controlling this pest.