First report of Meloidogyne enterolobii infecting tomato (Solanum lycopersicum) in Texas, United States

Authors: RONDON, MARINA - Texas A&M Agrilife; BAUGH, BRANT - Texas A&M Agrilife; CHAGOYA, JENNIFER - Texas A&M Agrilife; Skantar, Andrea; Handoo, Zafar

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/17/2025
Publication Date: 10/17/2025
Citation: Rondon, M.N., Baugh, B., Chagoya, J., Skantar, A.M., Handoo, Z.A. 2025. First report of Meloidogyne enterolobii infecting tomato (Solanum lycopersicum) in Texas, United States. Plant Disease. 109:2230. https://doi.org/10.1094/PDIS-04-25-0740-PDN.
DOI: https://doi.org/10.1094/PDIS-04-25-0740-PDN

Interpretive Summary: Plant-parasitic nematodes are microscopic roundworms that feed on plant-roots, causing billions of dollars in damage annually. The guava root-knot nematode is one of the most aggressive and damaging root-knot species. It is steadily spreading to new areas of the United States from where it was first found in Florida. This nematode poses a significant threat to both vegetable and crop plants due to its ability to develop new disease causing abilities. This nematode was discovered for the first time from tomato growing in a residential garden in Texas and identified by examining microscopic and molecular traits. This discovery will help extension agents and research scientists track the spread of this damaging pest, as well as develop control methods that will help protect growers from economic losses due to this pathogen.

Technical Abstract: Tomato (Solanum lycopersicum) is widely grown across the U.S., both commercially and in home gardens. Root-knot nematodes (RKN, Meloidogyne spp.) are major soilborne pathogens affecting tomato, with M. enterolobii being particularly concerning due to its aggressiveness and lack of known resistance (Philbrick et al., 2020). This nematode is a federally regulated quarantine pest in the U.S., with confirmed reports in Florida, Georgia, Louisiana, and the Carolinas across various crops. Meloidogyne enterolobii represents a serious threat to sweet potato and other host crops in the United States (Rutter et al., 2019). In May 2024, a ‘Celebrity’ tomato plant purchased from a national retailer in a homeowner's backyard showed rapid decline and large RKN galls, leading to its discarding. The homeowner then purchased a ‘Beefsteak’ variety from another national retailer, but of the same brand, and planted it in the same location. By the end of the season, similar RKN galls were observed on the roots. In December 2024, the plant was submitted for nematode analysis, exhibiting symptoms consistent with Meloidogyne spp. Genomic DNA was extracted from individual females or juveniles, and PCR amplification was performed using species-specific primers MeF/MeR (Schwarz et al., 2020) and primers D2A/D3B of 28S rDNA (De Ley et al., 2005), 5S/18S for IGS rDNA (Blok et al., 1997), and primers C2F3/1108 for the mitochondrial interval between cytochrome oxidase II and 16S RNA (Powers and Harris, 1993). The 729-bp 28S rDNA fragment (GenBank Accession No. PV369531), was 100% identical to M. enterolobii sequences from the U.S. and China. The 745 bp IGS rDNA fragment (Accession No. PV423808) was 100% identical to several M. enterolobii sequences from the U.S. and China. The 616 bp COII-16S mitochondrial fragment (Accession number PV389576) was 99.84% (1 bp difference, 1 gap) similar to MW167108 from Thailand and several other M. enterolobii sequences from around the world. Morphological examination of adult females revealed perineal patterns with a high, rounded to ovoid dorsal arch, with mostly widely spaced fine striae, characteristic of M. enterolobii. Second-stage juveniles (J2s) exhibited vermiform shape, tapering at both ends with long narrow tail. J2 measurements (n = 15) averaged 470.00 µm in length, with a mean stylet and tail lengths of 11.50 µm and 57.00 µm, respectively, aligning with species descriptions (Yang & Eisenback, 1983). The morphology and morphometrics of J2 and females, including the nature of perineal patterns, further established the identity of the species as M. enterolobii. To confirm pathogenicity, a growth chamber experiment (28°C, 14-hour photoperiod) was conducted with ‘Tiny Tim’ and ‘Rutgers’ tomato seedlings (three replicates per variety) transplanted into sterilized soil and inoculated with 2 mL of a 2,500-egg M. enterolobii suspension per pot (200 cc soil). Control plants received 2 mL of sterile water. After 60 days, inoculated plants exhibited root galling, stunted growth, and reduced vigor, while control plants remained healthy and gall-free. Egg masses and juveniles were recovered from inoculated plants, confirming reproduction (reproduction factor [RF] = 1.6 for ‘Tiny Tim’ and 2.5 for ‘Rutgers’). PCR was performed as described and M. enterolobii was confirmed from inoculated roots, fulfilling Koch’s postulates. To our knowledge, this is the first report of M. enterolobii parasitizing tomato in Texas. The presence of an infected plant from major retailers with nationwide distribution suggests that M. enterolobii may have already spread to multiple states, posing a serious threat to tomatoes and other susceptible crops. Given its regulatory significance, urgent surveys, containment strategies, and grower education are needed to prevent further spread and mitigate potential damage.