Continued foliar herbivory by the red spider mite <i>Tetranychus macfarlenei</i> on <i>Plumbago zeylanica</i> severely reduces the levels of a medicinally important metabolite in the roots

<div><p>Red spider mite, <i>Tetranychus macfarlanei</i>, was identified as a causative parasite for <i>Plumbago zeylanica</i> in India. Present study was undertaken to evaluate the detrimental role of <i>T. macfarlanei</i> on <i>P. zeylanica</i>. The relative change in biomass, stem length, stem diameter, and leaf number was significantly reduced by mite infestation as compared with uninfected plants. A significant reduction of chlorophyll a, chlorophyll b, and total chlorophyll was observed in mite-infested plants. Mite infestation significantly hampered the normal physiological process of the plant, namely, CO<sub>2</sub> assimilation, stomatal conductance, electrolyte leakage, cell membrane injury, and carboxylation efficiency. A significant increase in tissue H<sub>2</sub>O<sub>2</sub> and lipid peroxidation coupled with depletion of antioxidant enzymes, namely superoxide dismutase and catalase indicated augmented oxidative stress associated with biotic interaction. Finally, a significant reduction of root-specific secondary metabolite, plumbagin, production highlighted the potential damage of <i>T. macfarlanei</i> in <i>P. zeylanica</i>. The experimental outcome could conclude that the aboveground symptoms due to mite infestation could also exert profound detrimental effect in the belowground tissues.</p></div>