P-662 - REPRODUCTIVE POTENTIAL AND PATHOGENICITY OF MELOIDOGYNE ENTEROLOBII ON ONION

Meloidogyne enterolobii, an aggressive and emerging root-knot nematode in the southern U.S., was first detected in Georgia within the state's world-renowned Vidalia onion growing region. However, the host status of onion to M. enterolobii has not been previously evaluated. This study assessed the nematode’s reproduction and potential yield suppression on onion cultivars commonly grown in Georgia. Six Vidalia cultivars (‘Rio del Sol’, ‘Sapelo’, ‘Sweet Magnolia’, ‘Tania’, ‘Vidora’, and ‘NUN 1011’), three red cultivars (‘Red Duke’, ‘Red Halen’, and ‘Red Maiden’), and one white cultivar (‘Monjablanca’) were evaluated. Each plant was inoculated with 8,000 eggs in a replicated greenhouse trial with six replications. Twelve weeks post-inoculation, plants were harvested to assess reproduction factor (Rf = final population / initial inoculum) and reductions in bulb and shoot weights. All cultivars tested were susceptible to M. enterolobii (Rf > 1), although significant differences were observed among them. ‘Vidora’ and ‘Tania’ exhibited the highest galling indices and Rf values, whereas ‘Sweet Magnolia’ and ‘Sapelo’ recorded the lowest. All red onion cultivars showed significant reductions in both bulb and shoot weights, while among Vidalia cultivars, only ‘NUN 1011’ displayed notable reductions. These findings confirm that onion is a suitable host for M. enterolobii, and that cultivar-specific differences influence nematode reproduction and yield suppression. Further field-based studies are needed to better understand the nematode’s impact under commercial growing conditions.