488 Effect of Oat Extract on Pea Root Rot Pathogen Aphanomyces euteiches

Pea root rot is a serious economic threat to pea production in the Great Lakes region. The primary causal organism is Aphanomyces euteiches Drechs., which is responsible for an estimated 10% annual crop loss. A fall oat (Avena sativa) rotation before spring pea planting reduces disease severity. To better understand the beneficial effect of oat on A. euteiches, isolated individual pathogen lifecycle stages of zoospores, mycelium, and oospores were treated in culture with oat extract. Resulting mycelial mats were dried and weighed. Treatment with 90%, 70%, 50%, and 30% oat extract resulted in significant spore germination and mycelial growth of A. euteiches. In the presence of nutrient solution, oat extract concentrations of 90%, 70%, 50%, and 30% significantly enhanced spore germination and mycelial growth of the pathogen. These results demonstrate that the use of oat extract results in dosage dependent germination and growth of A. euteiches.

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Aphanomyces euteiches. [Descriptions of Fungi and Bacteria].

IMI Descriptions of Fungi and Bacteria ◽

10.1079/dfb/20056400600 ◽

1978 ◽

Author(s):

D. J. Stamps

Keyword(s):

Population Dynamics ◽

Geographical Distribution ◽

Root Rot ◽

Aphanomyces Euteiches ◽

Conifer Seedlings ◽

Alternative Hosts ◽

Pea Root ◽

Pea Root Rot ◽

Sweet Pea

Abstract A description is provided for Aphanomyces euteiches. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Pea, Arabis, pansy, sweet pea, clover, bean, lupin, vetch, lucerne, Melilotus, barley, oats, Echinodorus brevipedicellatus. Conifer seedlings and other hosts were infected by inoculation. DISEASE: Root rot of pea. GEOGRAPHICAL DISTRIBUTION: Asia (Japan); Australia (Tasmania); Europe (UK, Denmark, France, Norway, Sweden, USSR); N. America (USA). (CMI Map 78, ed. 3, 1977). TRANSMISSION: Soil-borne, persisting in the soil for many years. Studies in Wisconsin suggested that A. euteiches may live as a weak parasite in the roots of many plants and occur naturally in some virgin soils (6, 523). Oospores were indicated to be the primary inocula for new outbreaks of pea root rot, zoospores the primary infective agents (39, 646). Survival between pea crops depended on oospore durability and possible alternative hosts, not saprophytic activity (41, 689). Studies were made of population dynamics in the soil (48, 2067) and penetration and infection of roots by zoospores (42, 287).

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Response of Aphanomyces euteiches mycelia, zoospore, and oospore to oat extract

Canadian Journal of Plant Science ◽

10.4141/p03-007 ◽

2004 ◽

Vol 84 (2) ◽

pp. 687-690

Author(s):

M. A. Chandler ◽

V. A. Fritz ◽

R. R. Allmaras

Keyword(s):

Pisum Sativum ◽

Root Rot ◽

Green Manure ◽

Mycelial Growth ◽

Late Summer ◽

Aphanomyces Euteiches ◽

Economic Threat ◽

Pisum Sativum L ◽

Production Research ◽

Reduce Disease Severity

Root rot (Aphanomyces euteiches Drechs.) is a serious economic threat to pea (Pisum sativum L.) production. Research has shown a late-summer-seeded oat (Avena sativa L .) crop can reduce disease severity. A. euteiches was exposed to extracts of oat cvs. Bay and Ogle. Oat extract significantly enhanced mycelial growth of the pathogen. Key words: Root rot, biological control, green manure, Pisum sativum

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Concentration- and Time-Dependent Effects of Isothiocyanates Produced from Brassicaceae Shoot Tissues on the Pea Root Rot Pathogen Aphanomyces euteiches

Journal of Agricultural and Food Chemistry ◽

10.1021/jf501776c ◽

2014 ◽

Vol 62 (20) ◽

pp. 4584-4591 ◽

Cited By ~ 7

Author(s):

Shakhawat Hossain ◽

Göran Bergkvist ◽

Kerstin Berglund ◽

Robert Glinwood ◽

Patrick Kabouw ◽

...

Keyword(s):

Root Rot ◽

Time Dependent ◽

Aphanomyces Euteiches ◽

Pea Root ◽

Pea Root Rot

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Arbuscular Mycorrhizal Fungi Reduce Development of Pea Root-rot caused by Aphanomyces euteiches using Oospores as Pathogen Inoculum

European Journal of Plant Pathology ◽

10.1023/b:ejpp.0000021070.61574.8b ◽

2004 ◽

Vol 110 (4) ◽

pp. 411-419 ◽

Cited By ~ 46

Author(s):

Karin Thygesen ◽

John Larsen ◽

Lars Bødker

Keyword(s):

Arbuscular Mycorrhizal Fungi ◽

Root Rot ◽

Mycorrhizal Fungi ◽

Arbuscular Mycorrhizal ◽

Aphanomyces Euteiches ◽

Pea Root ◽

Pea Root Rot

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Assessment of Soil Suppressiveness to Aphanomyces Root Rot of Pea

Plant Disease ◽

10.1094/pdis.1999.83.12.1108 ◽

1999 ◽

Vol 83 (12) ◽

pp. 1108-1112 ◽

Cited By ~ 29

Author(s):

L. Persson ◽

M. Larsson-Wikström ◽

B. Gerhardson

Keyword(s):

Root Rot ◽

Field Experiments ◽

Disease Suppression ◽

Root Tissue ◽

High Yield ◽

Aphanomyces Euteiches ◽

Talcum Powder ◽

Soil Suppressiveness ◽

Pea Root ◽

Pea Root Rot

The ability of field soils to suppress pea root rot caused by Aphanomyces euteiches was assessed in field soil samples in a greenhouse bioassay and in field experiments sown with pea in monoculture for four years. In the bioassay, an inoculum of oospores in talcum powder was added to the test soils 1 week prior to sowing of pea seeds. The rate of infection was assessed 4 weeks after sowing. The field experiments were placed in six localities with varying degrees of soil suppressiveness to pea root rot and the pea yield and number of oospores of A. euteiches in root tissue were measured each year. A large variation in disease suppression was found in 24 arbitrarily chosen soils, sampled in the vining pea growing area in southern Sweden, and some soils were found to be strongly disease suppressive. The pea root rot development was also clearly different between the field experiments, depending on the soil. In an experiment on a soil showing low disease suppressiveness in the greenhouse bioassay, the crop failed in the second year, the number of oospores in root tissue increased rapidly over time, and no yield at all could be taken the fourth year. In contrast, on a soil with a high disease suppressiveness in the bioassay, the pea monoculture led to a slow build-up of oospores in root tissue and a steady high yield of 5,300 kg/ha the fourth year.

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Inoculation with Nonpathogenic Fusarium solani Increases Severity of Pea Root Rot Caused by Aphanomyces euteiches

Plant Disease ◽

10.1094/pdis.2002.86.4.411 ◽

2002 ◽

Vol 86 (4) ◽

pp. 411-414 ◽

Cited By ~ 15

Author(s):

R. D. Peters ◽

C. R. Grau

Keyword(s):

Disease Severity ◽

Fusarium Solani ◽

Root Rot ◽

Aphanomyces Euteiches ◽

Disease Symptoms ◽

Pea Root ◽

Pea Seedlings ◽

Pea Root Rot

Aphanomyces euteiches is an important root-rotting pathogen of pea. When recovering isolates of A. euteiches from infested soils in Wisconsin using pea as a bait host, isolates of Fusarium solani often were recovered. Experiments were established to compare disease symptoms of pea seedlings inoculated with isolates of A. euteiches and F. solani alone or in combination. Inoculation of pea seedlings with either of two isolates of A. euteiches produced typical root rot symptoms. However, inoculation of pea seedlings with an isolate of F. solani resulted in no disease symptoms, indicating that the isolate was nonpathogenic to pea. Co-inoculation of pea seedlings with A. euteiches and the nonpathogenic isolate of F. solani resulted in significantly (P = 0.05) greater disease severity than inoculation with A. euteiches alone. Both A. euteiches and F. solani could be reisolated, individually or together, from pea seedlings following individual or co-inoculations, respectively. Although the mechanisms of interaction between these two species are unknown, the synergism documented in this study indicates that the interactions of pathogens with nonpathogens may affect development of disease symptoms.

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Root Rot of Pea and Faba Bean in Southern Sweden Caused by Phytophthora pisi sp. nov.

Plant Disease ◽

10.1094/pdis-09-12-0823-re ◽

2013 ◽

Vol 97 (4) ◽

pp. 461-471 ◽

Cited By ~ 13

Author(s):

F. Heyman ◽

J. E. Blair ◽

L. Persson ◽

M. Wikström

Keyword(s):

Faba Bean ◽

Root Rot ◽

Phytophthora Sojae ◽

Distribution Data ◽

Aphanomyces Euteiches ◽

Southern Sweden ◽

Common Vetch ◽

Crop Species ◽

Pea Root ◽

Pea Root Rot

A root rot disease of pea and faba bean caused by a Phytophthora sp. was observed in fields and field soil samples in southern Sweden. Observations of the disease in pea root rot greenhouse assays were systematically recorded, and incidence and geographic distribution data were compared with the pea root rot caused by Aphanomyces euteiches. Following one successful isolation of the pathogen, isolation procedures and selective media were optimized to retrieve more isolates. Phylogenetic analysis showed that the isolates belong to a novel lineage, closely related to Phytophthora sojae, and proposed here as a new species, P. pisi sp. nov. In a collection of 13 isolates from separate fields, intraspecific variation was detected in both nuclear and mitochondrial loci. Pathogenicity tests on a range of crop plants and wild legumes suggest that the host range of the pathogen is restricted to a group of legumes closely related to pea which, in addition to pea, include the crop species faba bean, lentil, common vetch, and chickpea. Morphology, growth requirements, and pathogenicity traits indicate that the species may be identical to the organism previously described as P. erythroseptica var. pisi. The work characterizes a novel Phytophthora sp. causing root rot of legume crops.

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