Identification of apple mosaic virus (ApMV) (A), prunus necrotic ringspot virus (PNRSV) (B), and apple necrotic mosaic virus (ApNMV) (C) by RT-PCR. (A) Detection of ApMV. Numbers 11/12/13, 24/25/26, and 37/38/39 indicate samples collected from Yanyuan county, Weining county, and Zhaotong city, respectively. (B) Detection of PNRSV. Samples are the same as (A). (C) Detection of ApNMV. H, healthy leaf as a negative control. AS, asymptomatic leaves from trees with mosaic leaves. S, symptomatic leaves from trees with mosaic leaves. Each sample has two lanes, the left one indicates the product of ACTIN, and the right one corresponds to ApMV or ApNMV. Arrows indicate position of RT-PCR products of ApMV, ApNMV, and ACTIN, severally. M, DNA size marker. The mark ‘x’ indicates none of band at corresponding position. All primer pairs used here were listed in Table S2.