Abstract:  Plant viruses can induce changes in plant morphology and physiology, which may affect the performance of the insect vectors and parasitoids. However, the impact of plant viruses has been rarely considered in the research of this type of plant-vector-parasitoid interactions. In this study, we tested and analyzed the effects of the begomovirus, tomato yellow leaf curl virus (TYLCV), on the leaf trichome density of tomato and the foraging performance and fitness of the whitefly parasitoid, Eretmocerus hayati Zolnerowich and Rose. Our results showed that viral infection of tomato led to a significant increase of leaf trichome density, which in virus-infected plants was 1.8 times as high as that in uninfected plants. The host handling time and patch residence time of the parasitoid on virus-infected plants were 2- and 1.5-fold as high as that on uninfected plants, respectively. However, the parasitism rates, emergence rates and developmental durations of the parasitoid on infected and uninfected plants were similar. This is the first report of begomovirus-induced increase of plant leaf trichomes and its effects on a parasitoid, and it provides new data for understanding the interactions between plants, begomoviruses, whiteflies and parasitoids.