The elm leaf beetle, Xanthogaleruca luteola (Müll). (Col: Chrysomelidae) is one of the most important pests on elm trees in Iran. Due to environmental issues of synthetic insecticides, biorational agents have been advised in control management programms of elm leaf beetle in urban green spaces. The susceptibility of adults and 3rd instar larvae of this pest was evaluated to Bithiran® (Bacillus thuringiensis var. tenebrionis) and NeemAzal®-T/S (Neem based insecticide) using elm leaves dipped in aqueous insecticidal solutions. The mortality was recorded 24 h after treatment. The LC50 values for the third instar larvae and adults were respectively estimated to be 106.83 and 57.6 ppm for BT and 357.17, 107.61 ppm for Neem. Bithiran® was more effective against X. luteola larvae and adults when compared to NeemAzal®-T/S. Further research on these biorational agents is recommended in field conditions before making any decision on their incorporation in control management programs.

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