First Report of Infecting Tomato () in Texas, United States.

Tomato () is widely grown across the U.S., and root-knot nematodes (RKN, spp.) are major soilborne pathogens, with being particularly concerning due to its aggressiveness and lack of known resistance (Philbrick et al. 2020). This nematode is a federally regulated quarantine pest, with confirmed reports in Florida, Georgia, Louisiana, and the Carolinas posing a threat to sweet potato and other crops (Rutter et al. 2019). In May 2024, a 'Celebrity' tomato plant purchased from a national retailer and grown in potting mix in a homeowner's backyard was observed to have root galls before transplanting. Despite this, the plant was transplanted, later declined, and discarded. Large RKN galls were confirmed upon removal. A 'Beefsteak' variety from another national retailer of the same brand was then planted in the same location. By season's end, similar RKN galls were observed. In December 2024, the plant was submitted for nematode analysis, exhibiting symptoms consistent with spp. As the varieties were RKN-resistant, DNA was extracted from individual females, and PCR using species-specific primers MeF/MeR (Schwarz et al. 2020) confirmed . Morphological examination of adult females revealed perineal patterns with a high, rounded to ovoid dorsal arch, with mostly widely spaced fine striae, characteristic of . Second-stage juveniles (J2s) were vermiform, tapering at both ends with a long, narrow tail. J2 measurements (n = 15) averaged 447 µm in length, with mean stylet and tail lengths of 11.8 µm and 51.2 µm, respectively, aligning with species descriptions (Yang & Eisenback 1983). The morphology and morphometrics of J2s and females confirmed . Juveniles were submitted for DNA sequencing using primers D2A/D3B of 28S rDNA (De Ley et al. 2005), 5S/18S for IGS rDNA (Blok et al. 1997), and C2F3/1108 for the mitochondrial COII-16S RNA region (Powers and Harris 1993). The 729-bp 28S rDNA fragment (GenBank Accession No. PV369531) was 100% identical to sequences from the U.S. and China, as was the 745-bp IGS rDNA fragment (Accession No. PV423808). The 616-bp COII-16S mitochondrial fragment (Accession No. PV389576) was 99.84% (1 bp difference, 1 gap) similar to MW167108 from Thailand and several other sequences worldwide. To fulfill Koch's postulates, a growth chamber experiment (28°C, 14-hour photoperiod) using three replicates of 'Tiny Tim' and 'Rutgers' seedlings in 200 cc pots with sterilized soil and inoculated with 2 mL of a 2,500-egg suspension. Control plants received 2 mL of sterile water. After 60 days, inoculated plants developed root galls and stunted growth, while control plants were healthy and gall-free. Egg masses and juveniles were recovered from inoculated plants, confirming reproduction (RF = 1.6 for 'Tiny Tim' and 2.5 for 'Rutgers'). To our knowledge, this is the first report of parasitizing tomato in Texas. The circumstances under which the nematode was detected suggest the infected transplant was the most probable source of introduction, though other possibilities cannot be entirely ruled out. The detection of in a plant from a national retailer raises concern it has spread to other states, posing a serious threat to tomatoes and other crops. Given its regulatory significance, urgent surveys, containment strategies, and grower education are needed to prevent further spread.