First Report of Meloidogyne enterolobii Infecting Myrica rubra in Fujian Province, China

Chinese bayberry (Myrica rubra) is an economically important subtropical fruit tree in China. In September 2025, stunting, canopy thinning, leaf yellowing, and multiple root galls associated with root-knot nematodes (RKN) were observed on M. rubra cv. Dongkui in approximately 1.87-ha commercial orchard (24°22′12″N, 117°55′12″E) located in Fugong Town, Longhai District, Zhangzhou City, Fujian Province, China. Disease incidence was approximately 28% with severely affected trees exhibiting canopy dieback. Severely infected roots were malformed and cracked, with discolored and rotting tissues. One to several females of Meloidogyne sp. within each gall, and egg masses were embedded inside the galls without protruding. Males were rarely observed. Females and egg masses were dissected, and the egg masses were incubated in distilled water at 25℃ to obtain second-stage juveniles (J2s). Perineal patterns of 20 females and morphology of 20 J2s matched the original description of M. enterolobii (Yang and Eisenback 1983). Perineal patterns were oval, with moderate to high dorsal arches that were usually rounded to square in outline. Striae varied from fine to coarse; lateral lines are faint or indistinct. The J2 had a slender tail with a broad, bluntly rounded tip, and a clearly defined hyaline tail terminus; measurements of J2s included L= 441 ± 22.2 (410–473) μm, stylet = 13.9 ± 1.07 (11.8–16.5) µm, tail = 65.0 ± 6.44 (54.4–75.6) μm, and hyaline tail terminus = 18.0 ± 1.26 (16.3–20.9) μm. rDNA-ITS and 28S rDNA were amplified using primers V5367 and 26S (Vrain et al. 1992), and the 28S rDNA region using primers D2A and D3B (De Ley et al. 2005) respectively. The ITS and 28S sequences were 765 bp (GenBank accession nos. PZ619244 and PZ619245), and 759 bp (PZ631814 and PZ631815), respectively. BLAST analysis revealed 99%–100% with corresponding sequences of M. enterolobii available in GenBank. Species identification was further confirmed using M. enterolobii-specific primer pair Me-F/Me-R (Long et al. 2006), which amplified a product of approximately 240-bp, a fragment reported to be specific to M. enterolobii, no amplicon from M. incognita controls. For pathogenicity tests, 20-cm-high M. rubra cv. Dongkui seedlings grown in sterilized sandy soil in 20-cm-diameter plastic pots. Six replicate seedlings were each inoculated with 3000 J2s of the collected population of M. enterolobii, while another six non-inoculated seedlings served as controls. After 90 days, all inoculated seedlings developed root galls identical to those observed in the field, and the nematode reproduction factor (RF = final population / initial population) reached 20.3. The non-inoculated control seedlings grew well without any galling. To our knowledge, this is the first report of M. enterolobii infecting Myrica rubra (Myricaceae) in China. M. enterolobii is considered one of the most damaging RKN species, owing to its wide host range, high pathogenicity, and ability to reproduce on many crops possessing resistance genes (Castagnone-Sereno 2012). In China, Myrica rubra is primarily sold and distributed as grafted and cuttage seedlings, which are susceptible to M. enterolobii infection. Therefore, this report provides important implications for the management and dissemination control of M. enterolobii.