First report of Meloidogyne incognita infecting white Pitahaya plants

Primeiro relato de Meloidogyne incognita em Pitaia-branca

Abstract

In July 2020, during a survey carried out in a small farm located in Laranjal Paulista, state of São Paulo (Brazil), more than 20 white pitahaya plants [Hylocereus undatus (Haw.) Britton and Rose (syn. Selenicereus undatus (Haw.) D.R. Hunt] were found with stunting symptoms and showing chlorotic-yellowish stems, some of them already decaying. Roots exhibited numerous galls, indicating Meloidogyne sp. infection. Nematodes were recovered from 200 cm³ and 7 g of roots: 1.7 Meloidogyne juveniles (J2) per cm³ of soil and 954 eggs + J2 per g of roots were found. The perineal pattern of 10 females pointed to M. incognita. Additionally, esterase phenotype was obtained through isozyme electrophoresis, using another 10 females, which identified M. incognita. To our knowledge, this is the first report of M. incognita infesting pitahaya plants (Hylocereus spp.) and, based on our results, M. incognita could be a potential threat to the crop.

Index terms
Diagnosis; dragon fruit; Hylocereus undatus; root-knot nematode; morphology; esterase phenotype