Table 3. Comparison of sensitivity among multiplex and singleplex RT-qPCR and conventional RT-PCR.

Target	Multiplex RT-qPCR		Singleplex RT-qPCR		Conventional RT-PCR
	Copy number	RNA dilution	Copy number	RNA dilution	Copy number	RNA dilution
ASPV	102	10−4	102	10−4	105	10−2
ApMV	102	10−4	102	10−4	105	10−2
ASGV	103	10−4	102	10−4	106	10−1

Sensitivity of multiplex RT-qPCR and comparison to those of RT-qPCR and conventional RT-PCR assays, as estimated using tenfold serially diluted standards of Apple stem pitting virus (ASPV), Apple mosaic virus (ApMV) and Apple stem grooving virus (ASGV), and tenfold serially diluted total RNA extracted from a naturally triple infected tree. Serial 10-fold dilutions were prepared into RNA extracted from virus-negative tested apple tissue.