Characterization of Root-Knot Nematode Populations Associated with Vegetables in New York State

The northern root-knot nematode (Meloidogyne hapla) causes significant damage on vegetables in New York State. This study was conducted to determine if other species of Meloidogyne are also present in New York vegetable fields and to better characterize the root-knot populations in order to facilitate the development of effective rotations for nematode management. Populations of Meloidogyne were collected from 18 vegetable fields across New York and maintained in the greenhouse on tomato cv. Rutgers as both field populations and single-female populations. For the purposes of species identification, nematodes from each population were examined using perineal pattern analysis, scanning electron microscopy, and cytological analysis. All techniques identified the presence of only Meloidogyne hapla in the collected samples. The host range of the populations of Meloidogyne that were collected was investigated using a modified form of the North Carolina Differential Host Test. While host ranges were variable among the collected populations, the host range of all populations closely corresponded to that of M. hapla. The internal transcribed spacer region (ITS1) of the collected populations was amplified and sequenced. All sequences from the collected populations corresponded to the published sequence of M. hapla. Based on these results, it was concluded that M. hapla is the only root-knot nematode species present in New York vegetable fields. Crop rotational strategies for management of the root-knot nematode on vegetables in New York should be devised to reflect this fact.