Root-Knot Nematode Species Associated with Horticultural Crops in the Island of Azores, Portugal

Plant-parasitic nematodes (PPN) are an economically important group of plant pests present throughout the world. In particular, root-knot nematodes (RKN), sedentary endoparasites of a wide variety of economically important hosts with the ability to survive in temperate regions. During 2020-2021 an extensive survey of Meloidogyne spp. was undertaken on the island of Sao Miguel Azores, Portugal. A total of 80 samples comprising 23 species of plants were collected from 13 localities in 4 districts of the island. Samples included field and greenhouse vegetable crops. Bioassays were carried out to obtain females and juveniles for morphological and biochemical characterization of the isolates. The observed morphological features showed high similarity and consistency with previous descriptions of the genus. Concerning the biochemical characterization, the esterase (EST) phenotype displayed the patterns described for M. incognita, M. arenaria, and M. javanica. Meloidogyne incognita was found to be the most prevalent species with respect to both natural host range and geographical distribution, followed by M. arenaria and M. javanica. This is the first field survey that assesses the species of root-knot nematodes associated with horticultural crops in the Azores Island, contributing additional information on the distribution of this genus.

Automated summary

This study conducted an extensive survey on root-knot nematodes on Sao Miguel Island, Azores, Portugal. Through bioassays and morphological and biochemical characterization, the distribution of Meloidogyne species was determined. The results showed that M. incognita was the most prevalent root-knot nematode species on the island.