Abstract
Satsuma dwarf virus (SDV) causes serious damage to citrus production by reducing the quality and yield of fruit. SDV in young shoots of citrus trees is usually detected using an enzyme-linked immunosorbent assay (ELISA); however, such tests can only be performed during several weeks in the spring and are time-consuming. To overcome these issues, we developed an all-season, rapid detection method using an immunochromatographic assay (ICA) kit. The results obtained using this system showed that petals, stigmas, and ovaries sampled from SDV-infected plants during the spring gave positive results that were comparable to those obtained using shoots. In the summer and autumn, the virus was detected from the flavedo of fruits of SDV-infected plants at a high frequency and more frequently detected in the flavedo of fruits from inside the tree crown than in fruits from the exterior of the crown. In the winter, flavedo from fruits stored at ambient temperature for 3 months also tested positive. The frequency of detection was sometimes lower in fruits obtained in the summer or stored at ambient temperature for 1–3 months. We therefore recommend that more samples should be taken from fruits for SDV diagnosis using ICA. SDV diagnosis of citrus scions in the winter is more effective using young leaves and flower buds that have been sprouted by soaking the cut shoot under controlled conditions such as a growth chamber at approximately 27°C. These results showed that all-season diagnosis of SDV is feasible using samples from young shoots, flower buds, fruits in the summer, stored fruits in the winter, and from samples sprouted from scions during the winter.
