In 2016, less than 30% of virus-like symptoms such as chlorosis, necrosis and ringspots were observed in Hoya carnosa from commercial greenhouse in Eumseong, Korea. A total of 6 samples from Hoya carnosa were collected both symptomatic and asymptomatic plants and tested for virus infection by RT-PCR of 3 viruses known to infect Hoya spp. including Tomato spotted wilt virus (TSWV), Impatiens necrotic spot virus (INSV) and Tomato chlorotic spot virus (TCSV). Three symptomatic samples were positives for INSV. Also, it was not the virus detected in three asymptomatic samples. To further confirm the presence of INSV, complete nucleocapsid (N) gene of the virus were amplified and sequenced from two samples. BLAST analysis of the consensus sequence showed that two isolates (INSV-Hy1 and-Hy2) shared nucleotide sequence identities of 99% with each other and 97-99% with other INSV isolates available in the GenbBank. Phylogenetic analysis showed that these isolates closely related to the INSV isolates from ornamental from China. This is the first report of INSV on Hoya carnosa from Korea.

Tomato yellow leaf curl virus (TYLCV) is a viral disease causing severe economic losses on tomato. Practical prevention of the TYLCV disease is to control tabacco whitefly (Bemisia tabaci) or to cultivate TYLCV-resistant tomato cultivars, because no agrochemical products are available to control TYLCV. In this study, TYLCV resistance of the commercial tomato cultivars were evaluated using the DNA markers tightly linked to TYLCV resistance genes Ty-1 and Ty-3 and infection with the TYLCV clones mediated by Agrobacterium. In marker genotyping, resistance alleles were detected from 4 oval type tomato cultivars (Titichal, TY tinny, TY saengsaeng II, TY sense Q). Four cheery type cultiavrs (TY endorphin, TY smartsama, Tiara TY, Olleh TY) and 6 round type cultivars (TY kingdom, TY ace, TY homerun, TY altorang, Dotaerang TY winner, Styx TY). The seedling bioassay indicated that tomato cultivars of the oval type and cherry type showed consistancy in marker genotype and phenotype while slight disease symptom was observed from some round type cultivras (TY ace, TY homerun, Styx TY) with resistance marker genotype. For fruit yields, TY tinny was greater than its control cultivar Titichal in oval types, TY smartsama was greater than its control Smile in cherry type, and TY ace and TY kingdom were greater than their control Dabok. These cutliavrs can be a good choice for high-yielding TYLCVresistant tomato cultivars.