Characterization of Oomycete Species Associated With Root and Crown Rot of English Walnut in Chile

Guajardo, Jeannette; Saa, Sebastián; Riquelme, Natalia; Browne, Gregory; Youlton, Cristian; Castro, Mónica; Besoain, Ximena

Abstract

English (Persian) walnut (Juglans regia) trees affected by root and crown rot were surveyed in five regions of central Chile between 2015 and 2017. In each region, nine orchards, ranging from 1 to 21 years old, were randomly selected and inspected for incidence and severity of tree decline associated with crown and root rot. Soil and symptomatic crown and root tissues were collected and cultured in P(5)ARP semiselective medium to isolate potential oomycete pathogens, which were identified through morphology and molecularly using ITS sequences in the rDNA gene and beta tubulin gene. The most frequently isolated species was Phytophthora cinnamomi. Pathogenicity tests were conducted with representative oomycete isolates. P. cinnamomi, P. citrophthora, and Pythium ultimum were all pathogenic in J. regia. Nevertheless, only P. cinnamomi and P. citrophthora were pathogenic to English walnut. Py. ultimum caused limited levels of root damage to English walnut seedlings. Our research indicates that as the Chilean walnut industry has expanded, so have walnut crown and root rots induced by oomycetes.

Más información

Título según WOS: Characterization of Oomycete Species Associated With Root and Crown Rot of English Walnut in Chile
Título según SCOPUS: Characterization of oomycete species associated with root and crown rot of english walnut in Chile
Título de la Revista: PLANT DISEASE
Volumen: 103
Número: 4
Editorial: AMER PHYTOPATHOLOGICAL SOC
Fecha de publicación: 2019
Página de inicio: 691
Página final: 696
Idioma: English
DOI:

10.1094/PDIS-07-18-1160-RE

Notas: ISI, SCOPUS