University of Guilan Plant Pest Research 2538-6123 16 1 2026 05 22 Sublethal effects of Alpha-Cypermethrin and integration of Emamectin benzoate with Acetamiprid on biological parameters of Encarsia formosa Sublethal effects of Alpha-Cypermethrin and integration of Emamectin benzoate with Acetamiprid on biological parameters of Encarsia formosa 49 65 9690 10.22124/iprj.2026.33432.1685 FA Nazi Reshadat Department of Plant Protection, Faculty of Agriculture, Urmia University, Urmia, Iran Fariba Mehrkhou Department of Plant Protection, Faculty of Agriculture, Urmia University, Urmia, Iran Shahram Aramideh Department of Plant Protection, Faculty of Agriculture, Urmia University, Urmia, Iran Maryam Forouzan Natural Resources Research Center, Agricultural Research, Education and Extension Organization (AREEO), Urmia, Iran Journal Article 2026 05 02 Chemical insecticides are widely used to control of <em>Trialeurodes vaporariorum</em>, which may have sublethal effects on its dominant parasitoid, <em>Encarsia formosa</em>. In this study, the sublethal effects (LC₂₅) of alpha-cypermethrin and integration of emamectin benzoate with acetamiprid were evaluated on the population and reproductive parameters of <em>E. formosa</em>. The sublethal studies were conducted using the leaf-dipping method of tomato leaves containing parasitized third-instar nymphs of greenhouse whitefly (coincides with pupa stage of parasitoid), into sublethal concentrations of the insecticides. Life table data were analyzed based on the age–stage, two-sex life table. The results showed that the highest and lowest, female longevity, reproduction period and fertility were on control (5.16±0.19 d; 4.63±0.27 d, and 17.95±1.34 eggs) and alpha-cypermethrin (2.25±0.19 d; 1.29±0.13, and 2.00±0.27 eggs) treatments, respectively. Also, adult females of F₁ parasitoid that exposed to sublethal concentration of alpha-cypermethrin had a delayed entry into the adult pre-oviposition and total pre-oviposition period compared to emamectin benzoate + acetamiprid. The results obtained from population growth parameters (<em>R</em>₀, <em>r,</em> and <em>λ</em>) showed that the lowest rate of aforementioned parameters were related to alpha-cypermethrin treatment (1.31±0.24 offspring/female/day; 0.0147 day^-1, and 1.01±0.01 day^-1, respectively). The overall results showed that, alpha-cypermethrin had stronger sublethal effects on <em>E. formosa </em>compared to emamectin benzoate + acetamiprid which need to be used with more caution in integrated pest management programs of the greenhouse whitefly. Chemical insecticides are widely used to control of <em>Trialeurodes vaporariorum</em>, which may have sublethal effects on its dominant parasitoid, <em>Encarsia formosa</em>. In this study, the sublethal effects (LC₂₅) of alpha-cypermethrin and integration of emamectin benzoate with acetamiprid were evaluated on the population and reproductive parameters of <em>E. formosa</em>. The sublethal studies were conducted using the leaf-dipping method of tomato leaves containing parasitized third-instar nymphs of greenhouse whitefly (coincides with pupa stage of parasitoid), into sublethal concentrations of the insecticides. Life table data were analyzed based on the age–stage, two-sex life table. The results showed that the highest and lowest, female longevity, reproduction period and fertility were on control (5.16±0.19 d; 4.63±0.27 d, and 17.95±1.34 eggs) and alpha-cypermethrin (2.25±0.19 d; 1.29±0.13, and 2.00±0.27 eggs) treatments, respectively. Also, adult females of F₁ parasitoid that exposed to sublethal concentration of alpha-cypermethrin had a delayed entry into the adult pre-oviposition and total pre-oviposition period compared to emamectin benzoate + acetamiprid. The results obtained from population growth parameters (<em>R</em>₀, <em>r,</em> and <em>λ</em>) showed that the lowest rate of aforementioned parameters were related to alpha-cypermethrin treatment (1.31±0.24 offspring/female/day; 0.0147 day^-1, and 1.01±0.01 day^-1, respectively). The overall results showed that, alpha-cypermethrin had stronger sublethal effects on <em>E. formosa </em>compared to emamectin benzoate + acetamiprid which need to be used with more caution in integrated pest management programs of the greenhouse whitefly. https://iprj.guilan.ac.ir/article_9690_291b3a5ccddb332d3ae3b514220a127a.pdf