بررسی حشره‌کشی عصاره‌های آبی، اتانولی‌ و اسانس‌روغنی گیاه گل‌مغربی ( Oenothera biennis L ) روی Bemisia tabaci

The whitefly (Bemisia tabaci Gennadius) with piercing-sucking mouthparts, is considered as one of the most destructive insect pests of vegetables and ornamental crops worldwide. In addition, it is a major natural vector of a large number of important plant viruses such as begomoviruses. The management of B. tabaci is mainly based on using chemical pecitides which their excessive use has caused to various challenges such as increasing production costs, significant environmental impacts and development of insect resistance biotypes. In recent decades, plant products have received a great deal of attention with researchers as natural sources for development of new insticides. In this study the insecticidal efficiency of aqueous, ethanolic extracts and essential oil of Oenothera biennis L were investigated against B. tabaci under greenhouse conditions. Bioassay was performed by spraying the extracts and essential oil of the plant mentioned on tomato seedlings followed by releasing five-day-old mature whiteflies on seedlings and estimating LC50 values were determined. Biometric test was by spraying the extracts and essential oils of the plant. Mortality of treatments was determined 24 hours post –releasing of whitefly on topical-sprayed tomato plants.. Comparison of LC50 lethal concentrations of the studied treatments in B. tabaci showed a significant difference between different treatments. The results showed that the treatment of Evening primrose essential oil resulted in the highest lethal effect on B. tabaci. Essential oil and aqueous extract of Evening primrose showed the lowest (1.37 μl / L) and highest (3.52 μL / L) LC50, respectively with comparison of that of value for the the ethanolic extract (2.64 μL / L). Finally, this plant can be used as effective bio-insecticide and Eco-friendly for the control of B. tabaci in integrated management of this insect.