We evaluated the effectiveness of thermotherapy at different temperatures, chemotherapy with different concentrations of ribavirin, and combinations of these two methods on virus elimination from apple. We used Malus cv. 'Xinhongjiangjun', an apple cultivar widely grown in China, infected with Apple chlorotic leaf spot virus (ACLSV), Apple stem grooving virus (ASGV), and Apple stem pitting virus (ASPV). The survival and regeneration of plants were evaluated, and the efficiency of virus eradication was determined by reverse-transcription polymerase chain reaction with two primer pairs for each virus. All of the plants treated with 15 and 25 lg/ml ribavirin survived, although their proliferation was slightly inhibited. Ribavirin treatments at 15 and 25 lg/ml resulted in virus elimination rates of 74.4 and 75.0 %, respectively. Higher temperatures significantly affected the growth and proliferation of plants, and almost no axillary shoots regenerated under the highest temperature (38 ± 0.5°C). The average virus elimination rate after 34-36°C treatments for 20 days was no more than 45 %. The virus elimination efficiency was enhanced by combining thermotherapy and chemotherapy treatments. A treatment combining ribavirin (25 lg/ml) and thermotherapy at 36°C (R25 ? T36) resulted in high virus eradication efficiency (95.0 %). Across all of the treatments, the average survival rate of apical shoots (176/273) was 12 % lower than that of axillary shoots (266/349); the average virus elimination efficiency was 65.3 % for apical shoots and 72.7 % for axillary shoots. The results also demonstrated that it was easier to eliminate ASPV than to eliminate ACLSV and ASGV.

The complete nucleotide sequences of two isolates of grapevine rupestris stem pitting-associated virus (LSL and JF) collected from grapevine of Xingcheng in Liaoning Province, China, were determined. The genomes of both LSL and JF were found to contain five open reading frames (ORFs). Sequence alignments showed that the genomic sequences of JF were 76.1 %-83.5 % identical to the other ten GRSPaV isolates that have been reported previously and that the nucleotide sequence identity of isolate LSL to other isolates was no more than 78 %. Phylogenetic analysis based on the complete genome sequence indicated that JF belongs to group III and that LSL belongs to a new group (group IV). The average genetic distances of the new genetic lineage from groups I, II and III were 0.34, 0.32 and 0.33, respectively.

A new variant of grapevine berry inner necrosis virus (GINV) was identified by sequencing of small RNA extracted from 'Beta' and Thompson seedless grapevines showing leaf mottle and ring spot symptoms. However, GINV was not found in symptomless samples used as a control. The complete genome sequences of two GINV isolates (KU234316-17) were determined, and these showed 75.76-89.74% sequence identity to the genome of a previously reported Japanese GINV isolate. The new variants appear to be evolutionarily distinct from the original GINV isolate. This is the first report of GINV outside of Japan.