<p><i>Bemisia tabaci</i> is one of the most invasive and damaging pests on diverse crops globally. This notorious sap-sucking pest has direct and indirect impacts on crops. Due to <i>B. tabaci</i>’s high potential for resistance to many commonly used insecticides, chemical control is no longer an effective method. Spiropidion, as a chemical pesticide, and siltak, as a chemical preparation, are novel insecticides that act effectively against different sucking pests. Combining these two Products has great potential for the effective management of this pest. In this study, for the first time, lethal and sublethal effects of spiropidion were evaluated against <i>B. tabaci</i>. We also evaluated co-applications of spiropidion at sublethal concentrations (LC₁₀ and LC₃₀) with some dosage of siltak under greenhouse conditions. The obtained results demonstrated that, in contrast to the high toxicity of spiropidion against eggs (LC₅₀= 9.19&#xa0;mg/L) and second instar nymphs (LC₅₀= 3.57&#xa0;mg/L), this insecticide was found to be slightly toxic to <i>B. tabaci</i> adults. Sublethal concentrations of spiropidion (LC₁₀ and LC₃₀) significantly decreased fecundity by 15% and 70%, respectively, compared to the control group. Additionally, the net reproductive rate (<i>R</i>0), intrinsic rate of increase (<i>r</i>), and finite rate of increase (λ) of <i>B. tabaci</i> that were exposed to the sublethal concentrations of spiropidion were significantly lower than those of the control group. The combination of sublethal concentrations of spiropidion with siltak at concentrations of 3%, 5%, and 7% of the recommended dosage (250&#xa0;cc/1000L water), compared with single treatments of spiropidion, increased the mortality rates of <i>B. tabaci</i> second nymphal stage.</p>