and RR values. In adults, imidacloprid resistance in Jiroft approached ~ 60-fold, whereas thiamethoxam resistance reached ~ 24-fold. Second-instar nymphs showed lower RRs than adults but still exhibited meaningful resistance (imidacloprid RR ≈ 15-fold in Jiroft), and eggs also displayed elevated tolerance relative to the reference population. In adult biochemical assays, resistant populations showed increased cytochrome P450 monooxygenase and glutathione S-transferase activities and/or elevated carboxylesterase activity, consistent with a metabolic component to resistance. These results delineate a life-stage-resolved resistance profile within a single MEAM1 lineage and under the present assay framework, second-instar nymphs appeared to be the most operationally responsive stage for potential intervention, but are no longer fully susceptible in highly selected populations, underscoring the value of stage-explicit monitoring in intensive vegetable systems.
Havestin et al. (Wed,) studied this question.