Research Research Interests Our research interests are directed toward understanding the factors that affect vector-virus interactions and vector transmission. In these years, our researches focus on insect-borne plant viruses to study vector-virus interactions and the mechanism of vector transmission. We use a variety of techniques including molecular biology, cell biology, immunohistology, and ecology to investigate this multidisciplinary subject. Interrelationship of a watermelon tospovirus and its insect vector Watermelon silver mottle virus (WSMoV) is only transmitted by the melon thrips (Thrips palmi) and mainly infects watermelon and melon. The epidemic of WSMoV seriously affects the yields of watermelon and melon productions resulting in great economic losses in Taiwan. Although WSMoV causes serious problems in fields, few researches focus on its vector transmission and thrips-virus interaction. We confirmed the transmission mode of WSMoV by T. palmi and studied the effect of WSMoV infection on the life history traits of T. palmi. Our results suggest that T. palmi transmits WSMoV in a persistent-propagative mode, and the virus is only transmitted when first instar larva acquires the virus and keeps the virus until emergence to adult. Ecological experiments demonstrated that WSMoV infection did not affect the survival, development, longevity, and fecundity of T. palmi directly. Further, WSMoV increased the developmental rate of T. palmi through host plant but did not affect its survival rate. Transmission biology of tomato begomoviruses Tomato yellow leaf curl disease can cause yield losses as high as 100% in tomato fields and is emerging as a serious threat to global tomato production. The disease is associated with a group of phylogenetically related viruses referred to as tomato yellow leaf curl viruses. These viruses are only transmitted by the sweet potato whitefly (Bemisia tabaci). A survey revealed the progressive displacement of Tomato leaf curl Taiwan virus (ToLCTWV) by Tomato yellow leaf curl Thailand virus (TYLCTHV) from 2005 to 2009 in tomato fields in Taiwan. We are interested in the cause of the displacement. Transmission experiments proved that B. tabaci transmitted both viruses with similar acquisition access periods and inoculation access periods. However, B. tabaci transmitted TYLCTHV more efficiently than ToLCTWV. We also discovered that B. tabaci transmitted TYLCTHV transovarially, and the offspring of B. tabaci remained infective. In contrast, no evidence showed that the transovarial transmission of ToLCTWV by B. tabaci occurred. Bemisia tabaci transmits TYLCTHV more efficiently, and this may contribute to the replacement of ToLCTWV by TYLCTHV in tomato fields in Taiwan within few years.