Invasive plant Conyza canadensis exacerbates wheat susceptibility to aphids and pathogens under drought and nitrogen addition

This study investigates how the invasive plant Conyza canadensis alters wheat (Triticum aestivum) growth, biochemical defense traits, and susceptibility to aphids and pathogens under drought and nitrogen deposition. Through a common garden experiment, we demonstrate that C. canadensis suppresses wheat biomass and key defensive metabolites (cellulose, DIMBOA, phenolics), while enhancing oxidative stress, thereby promoting higher aphid infestation and pathogen damage. Drought stress further weakens wheat resistance, whereas nitrogen enrichment improves growth but compromises defense allocation. These findings highlight the dual threat of invasive plants and global change drivers in agroecosystems, emphasizing the importance of integrating invasion biology into sustainable crop protection strategies.