Background: This study aimed to identify polyphenols in nettle (Urtica dioica L.) using Liquid Chromatography coupled with Tandem Mass Spectrometry (LC-MS/MS) and to evaluate the toxicity of leaf and root extracts against larvae of Tuta absoluta and adults of the mealy aphid Hyalopterus pruni. Extraction yields were determined after maceration and toxicity was assessed through LD50&nbsp;measurements. 
 
Methods: Fresh leaves of&nbsp;Urtica dioica&nbsp;were collected from the experimental farm of the University of Mostaganem, Algeria. The extraction process was carried out through maceration with pure methanol. Phytochemical profiling was conducted using LC-MS/MS analysis on a UHPLC Nexera system coupled with an 8040 triple quadrupole mass spectrometer. The biological activity was asses sedusing the direct contact method. Four concentrations of lea fextract (10%, 20%, 30% and 40%) and four concentrations of root extract (10%, 20%, 25% and 30%) were tested. 
 
Result: A total of 22 compounds were identified in the roots and 27 in the leaves, mainly phenolic acids including gallic acid, 4-hydroxybenzoic acid, 4-methylguaiacol and ferulic acid. Extraction yields reached 10.9% for leaves and 22.4% for roots. Both extracts showed comparable toxicity, with LD50&nbsp;values of 17.54% (leaves) and 13.19% (roots) against T. absoluta and 8.05% (leaves) and 9.42% (roots) against H. pruni. 
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LC-MS Analysis and Study of the Insecticidal Activity of Phenolic Extracts from the Leaves and Roots of Urtica dio&iuml;ca against Tuta absoluta M. (Lepidoptera: Gelechiidae) and Hyalopteruspruni (Hemiptera: Aphididae)