TY - JOUR
T1 - Characterization of oomycete species associated with root and crown rot of english walnut in Chile
AU - Guajardo, Jeannette
AU - Saa, Sebastián
AU - Riquelme, Natalia
AU - Browne, Gregory
AU - Youlton, Cristian
AU - Castro, Mónica
AU - BESOAIN CANALES, XIMENA ALEJANDRA
PY - 2019/4/1
Y1 - 2019/4/1
N2 - 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 P5ARP 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.
AB - 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 P5ARP 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.
UR - http://www.scopus.com/inward/record.url?scp=85064722143&partnerID=8YFLogxK
U2 - 10.1094/PDIS-07-18-1160-RE
DO - 10.1094/PDIS-07-18-1160-RE
M3 - Article
C2 - 30789315
AN - SCOPUS:85064722143
VL - 103
SP - 691
EP - 696
JO - Plant Disease
JF - Plant Disease
SN - 0191-2917
IS - 4
ER -