Root and crown rot pathogens found on dry beans grown in Mozambique

Phytophthora tentaculata was detected for the first time in North America in 2012 in a nursery on sticky monkeyflower plant (Diplacus aurantiacus) and again in 2014 on outplanted native plants. At that time, this species was listed as a federally actionable and reportable pathogen by the USDA. As a result of these detections, California native plant nurseries were surveyed to determine the prevalence of Phytophthora species on native plant nursery stock. A total of 402 samples were collected from 26 different native plant nurseries in California between 2014 and 2016. Sampling focused on plants with symptoms of root and crown rot. Symptomatic tissue was collected and tested by immunoassay, culture, and molecular techniques (PCR). Identifications were made using sequences from the internal transcribed spacer (ITS) rDNA region, a portion of the trnM-trnP-trnM, or the atp9-nad9 mitochondrial regions. Phytophthora was confirmed from 149 of the 402 samples (37%), and from plants in 22 different host families. P. tentaculata was the most frequently detected species in our survey, followed by P. cactorum and members of the P. cryptogea complex. Other species include P. cambivora, P. cinnamomi, P. citricola, P. hedraiandra, P. megasperma, P. multivora, P. nicotianae, P. niederhauserii, P. parvispora, P. pini, P. plurivora, and P. riparia. A few Phytophthora sequences generated from mitochondrial regions could not be assigned to a species. Although this survey was limited to a relatively small number of California native plant nurseries, Phytophthora species were detected from three quarters of them (77%). In addition to sticky monkeyflower, P. tentaculata was detected from seven other hosts, expanding the number of associated hosts. During this survey, P. parvispora was detected for the first time in North America from symptomatic crowns and roots of the nonnative Mexican orange blossom (Choisya ternata). Pathogenicity of P. parvispora and P. nicotianae was confirmed on this host. These findings document the widespread occurrence of Phytophthora spp. in native plant nurseries and highlight the potential risks associated with outplanting infested nursery-grown stock into residential gardens and wildlands.

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First Report of Neopestalotiopsis clavispora Causing Root and Crown Rot on Strawberry in Italy

Plant Disease ◽

10.1094/pdis-03-19-0673-pdn ◽

2019 ◽

Vol 103 (11) ◽

pp. 2959-2959 ◽

Cited By ~ 1

Author(s):

G. Gilardi ◽

F. Bergeretti ◽

M. L. Gullino ◽

A. Garibaldi

Keyword(s):

Crown Rot ◽

First Report ◽

Root And Crown Rot

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Genetic Determinants of Wheat Resistance to Common Root Rot (Spot Blotch), Fusarium Crown Rot, and Sharp Eyespot

10.1101/2020.07.30.228932 ◽

2020 ◽

Author(s):

Jun Su ◽

Jiaojie Zhao ◽

Shuqing Zhao ◽

Mengyu Li ◽

Xiaofeng Shang ◽

...

Keyword(s):

Root Rot ◽

Spot Blotch ◽

Crown Rot ◽

Genetic Determinants ◽

Common Root ◽

Fusarium Crown Rot ◽

Common Root Rot ◽

Sharp Eyespot ◽

Root And Crown Rot ◽

Moderate Resistance

Due to the field soil changes, high density planting, and straw-returning methods, wheat common root rot (spot blotch), Fusarium crown rot (FCR), and sharp eyespot have become severe threatens to global wheat productions. Only a few wheat genotypes show moderate resistance to these root and crown rot fungal diseases, and the genetic determinants of wheat resistance to these devastating diseases have been poorly understood. This review summarizes the recent progress of genetic studies on wheat resistance to common root rot, Fusarium crown rot, and sharp eyespot. Wheat germplasms with relative higher resistance are highlighted and genetic loci controlling the resistance to each of the disease are summarized.

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Fusarium Root and Crown Rot: A Disease of Container-Grown Hostas

Plant Disease ◽

10.1094/pdis.2000.84.9.980 ◽

2000 ◽

Vol 84 (9) ◽

pp. 980-988 ◽

Cited By ~ 15

Author(s):

B. Wang ◽

S. N. Jeffers

Keyword(s):

South Carolina ◽

Crown Rot ◽

Undescribed Species ◽

Fresh Weight ◽

Fusarium Spp ◽

Disease Symptoms ◽

Leaf Yellowing ◽

Oat Seeds ◽

Root And Crown Rot ◽

Fusarium Sp

A previously unreported disease was observed on 11 cultivars of container-grown hosta plants at five wholesale nurseries in South Carolina between 1997 and 1999. Symptoms included leaf yellowing, plant stunting, rotting of and vascular discoloration in roots, and necrosis in the crowns. Fusarium spp. consistently were isolated from symptomatic hosta plants. Four species were recovered: F. solani, F. oxysporum, F. proliferatum, and an undescribed species designated Fusarium sp.; F. solani and Fusarium sp. were recovered most frequently. To demonstrate pathogenicity, four methods were used to inoculate hosta plants with representative isolates of F. solani, F. oxysporum, and Fusarium sp. Two types of inoculum, colonized oat seeds and conidium suspensions, were used to inoculate wounded and nonwounded plants. Disease symptoms occurred consistently only on hosta plants inoculated by dipping wounded roots and crowns into suspensions of conidia. Symptoms were most severe on plants inoculated with Fusarium sp. and much less severe on plants inoculated with F. solani or F. oxysporum. Disease severity increased and fresh weight of inoculated plants decreased when the concentration of inoculum of Fusarium sp. was increased over the range of 1 × 103 to 1 × 107 conidia per ml. Isolates of Fusarium sp., F. solani, and F. oxysporum varied in virulence when Hosta ‘Francee’ plants were inoculated. This study demonstrated that Fusarium root and crown rot of container-grown hostas is caused primarily by Fusarium sp. but that it also can be caused by F. solani and F. oxysporum. Fusarium sp. appears to be taxonomically distinct from other species, and its identity currently is under investigation.

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