Efficacy of several insecticides against western flower Thrips Frankliniella occidentalis by introducing its Two new effectiveness indices in greenhouse cucumber

Western flower thrips (Frankliniella occidentalis) is one of the most important plant pests with a wide range of hosts that causes damage in most parts of the world. In this study, the efficacy of four insecticides including Gracia® (fluxametamide EC 10%) 0.3 and 0.5 ml/l, imidacloprid (SC 35%) 0.5 ml/l, cypermethrin (EC 40%) 0.5 ml/l and Proteus® (thiachlopride + deltamethrin 11% OD) 0.7 ml/l against this pest was based on a randomized complete block design with four replications in a cucumber greenhouse in 2019. The regression relationship between post-spraying intervals and the western flower thrips population was fitted with a quadratic model.  The results of analysis of variance of Western flower thrips mortality by treatments on days 3, 7 and 14 after spraying were significant (P <0.05). Also, two effectiveness indices of chemical compounds on this pest were presented and a significant difference was observed between them. The relationship between the population density of western flower thrips per flower and the density of thrips hunted on each blue card was also determined and their conversion coefficients were obtained. In general, fluxametamide with the highest percentage of mortality and control index and the lowest damage index among the tested treatments is recommended as a suitable insecticide to control this pest in greenhouse conditions.