490:. Resistant cultivars have been identified in alfalfa, bean, pea and red clover. Breeding for resistance has been successful in alfalfa and beans, however in beans it has been difficult to establish resistant cultivars that also meet consumer needs. The efficacy of chemical suppression is dependent on environmental factors such as temperature and soil moisture. Before widespread fungicide use, control consisted mainly of avoiding fields with high disease risk based on a field indexing procedure developed in 1958 by Sherwood and Hagedorn. Management practices should also include good soil drainage and
37:
564:) is the crop where Aphanomyces causes the greatest economic damage. Aphanomyces root rot can account for yearly losses of about 10% in the fields where it occurs, and may cause losses of entire fields in conditions that are favorable to the pathogen. In agricultural regions that produce large amounts of susceptible crops and have favorable weather conditions for
576:) factories to relocate, a considerable threat for local economies. In fact, prevalence of Aphanomyces root rot has ultimately shifted pea production in the United States from being predominantly in the Midwest and Eastern parts of the country to drier states such as Idaho, Washington, and Oregon where
599:
had been known as a pathogen of pea since the 1920s, in alfalfa it was often confused with other pathogens. It was not until the 1980s that scientists from the
University of Wisconsin confirmed it as a significant pathogen of alfalfa. Since then, Aphanomyces root rot has been an emerging concern in
477:
stage, and when temperatures are between 22 and 28 degrees
Celsius. Because zoospores require water for mobility, standing water in the soil increases host infection by making it easier for zoospores to move to host cells. After infection, though, the development of symptoms is favored by warm and
409:
is oospores, which can be found either in the soil or in infected plant debris from previously infected host plants. Oospores germinate as a response to chemical signals detected from the roots of new hosts plants. Germination can either be direct or indirect. Either way, infecting begins at the
333:
tend to progress up the plant tissue, starting with the epicotyls and moving to the hypocotyls, eventually extending above the soil. Lesions on pea epicotyls turn black, eventually creating a pinched region above the cotyledons as the result of pinched tissue. Lesions on beans, on the other hand,
621:
in prevalence in fields where alfalfa is grown. Due to these diseases, conventional advice was to avoid growing alfalfa in any wet soils. However, with the development of ARR- and PRR-resistant varieties, wet soil conditions have become less of a concern for alfalfa production, at least as far as
556:
was commonplace in pea production for processing, for decades. The pathogen has since been recorded in Europe, Australia, New
Zealand, Japan, and throughout the United States, suggesting that the disease may have already been widespread at the time of its discovery.
801:
Munkvold, G.P., W. M. Carlton, E. C. Brummer, Meyer, J. R., Undersander, D. J., and C.R. Grau. 2001. Virulence of
Aphanomyces euteiches isolates from Iowa and Wisconsin and benefits of resistance to A. euteiches in alfalfa cultivars. Plant Disease. 85,3:328-333.
198:
root rot is an important agricultural disease in the United States, Europe, Australia, New
Zealand, and Japan. Management includes using resistant crop varieties and having good soil drainage, as well as testing soil for the pathogen to avoid infected fields.
296:
occur on roots and stem tissue below the soil line. Infected roots often appear gray and water-soaked, eventually becoming soft and honey-brown or blackish-brown in appearance. Infection causes a reduction in root volume and function, including reduced
329:(high clay content), or excessive wetness due to irrigation or rainfall. Symptoms are generally similar among infected legumes, however timing and pattern of disease can differ among hosts and between annuals and perennials. In both peas and beans,
393:
Aphanomyces root rot is an example of a monocyclic disease, causing only one infection cycle per season. This is in contrast to polycyclic diseases, which can infect new hosts and produce multiple disease cycles within a single season.
852:
Thygesen, Karin, John Larsen, and Lars Bødker. 2003. Arbuscular mycorrhizal fungi reduce development of pea root-rot caused by
Aphanomyces euteiches using oospores as pathogen inoculum. European Journal of Plant Pathology 110: 411–419.
325:, and wilting of foliage. Some symptoms can differ among hosts. Infected plants and patterns of infection in the field often correspond to areas in the field with poor soil drainage, which can be the result of soil compaction,
513:
abundance is less severe when the infected plant also has significant mycorrhizal development. Excessive use of nitrogen and phosphorus fertilizers, and repeated tillage can reduce mycorrhizal development.
410:
cell in the root tips of the host plant. In direct germination, the oospore produces hyphae which directly penetrate host cells at the plant's root tips. In indirect germination, the oospore produces
334:
have a characteristic water-soaked appearance, are grayish-green in color, and are firm to the touch. In alfalfa symptoms include chlorotic cotyledons which may eventually become necrotic.
568:, careful monitoring is of paramount importance. Such regions include the American Midwest, particularly the Great Lakes region. In areas where peas are grown for processing, widespread
789:
Malvick, D.K. and C. R. Grau. 2001. Characteristics and
Frequency of Aphanomyces euteiches Races 1 and 2 Associated with Alfalfa in the Midwestern United States. 85,7:740-744
461:
can result in symptoms within 10 days, and oospores can be formed between 7 and 14 days. Oospores become dormant after being formed, and can survive for more than 10 years.
1199:
502:, however because oospores can survive for up to 10 years in the soil, rotation is not an effective means of eradicating the inoculum. Therefore, once high levels of
1099:
681:
454:
are not needed for sexual reproduction. The antheridium fertilizes an oogonium, which then develops into a single oospore, which is 20-35 micrometers in diameter.
190:
can infect a variety of legumes. Symptoms of the disease can differ among hosts but generally include reduced root volume and function, leading to stunting and
1138:
1008:
281:, which is responsible for pea root rot and is the most economically damaging form of pea root rot. In North America, genetically distinct populations of
909:
746:
301:, leading to decreased water and nutrient up-take, which lead to above-ground secondary symptoms. Symptoms in the above-ground plant tissue can include
473:
does best in warm, wet soil conditions, but can survive at a range of moderate temperatures. Infection is most prevalent when host plants are in the
958:
1073:
876:
Heyman, Frederik. 2008. Root Rot of Pea Caused by
Aphanomyces euteiches. Doctoral thesis. Swedish University of Agricultural Sciences, Uppsala.
713:
Heyman, Frederik. 2008. Root Rot of Pea Caused by
Aphanomyces euteiches. Doctoral thesis. Swedish University of Agricultural Sciences, Uppsala.
363:
root rot rarely results in seed rot and/or pre-emergent damping-off. The characteristic lesions caused by the different pathogens also differ.
878:
715:
842:
405:
can potentially infect hosts at any point in the growing season, infection usually begins during seedling emergence. The primary source of
617:
was identified as an economically significant alfalfa pathogen in other states as well. In
Wisconsin, Iowa and Kentucky it often exceeds
775:
Schwartz, Howard F., David H. Gent, Martha Mikkelson, and Jack Rieggelman. 2007. Aphanomyces Root Rot of Pea. Published on BugwoodWiki,
1209:
583:
In addition to fresh peas, alfalfa is another crop where Aphanomyces root rot (ARR) causes significant economic damage. Whereas in peas
469:
Aphanomyces is a soil-borne disease, and the entire lifecycle is completed in the host root and surrounding soil. The pathogen
955:
Malvick, Dean. Root and Crown Rots and Virus Diseases in Alfalfa and Clover. From University of Wisconsin Extensions website:
677:
Hughes, Teresa J., and Craig R. Grau. 2007. Aphanomyces root rot or common root rot of legumes. The Plant Health Instructor.
1125:
944:
species and their root diseases in pea and sugarbeet: A review. United States Department of Agriculture, Washington, D.C.
678:
945:
426:
colonize host tissue through inter- and intra-cellular growth. For sexual reproduction, hyphae develop male and female
864:
Brady, NC and RR Weil. 2010. Elements of the Nature and Properties of Soil. 3rd Ed. Prentice Hall, Boston, MA. p. 345
36:
1143:
622:
disease pressure is concerned. Today, modern alfalfa varieties are required to have both PRR and ARR resistance.
1214:
609:
760:
1204:
418:. The zoospores then encyst on the host plant cells, and germinate. After direct or indirect germination,
976:
956:
525:, another important alfalfa pathogen which causes Phytophthera root rot. In this case, colonization by
150:
506:
have been identified in a field, growers should abstain from planting susceptible hosts in that field.
341:
can be difficult to distinguish from symptoms caused by other root-infecting plant pathogens (such as
1153:
1065:
1034:
885:
722:
447:
117:
803:
790:
240:
31:
1104:
814:
Teasdale, J. R., R. G. Harvey, and D. J. Hagedorn. 1979. Mechanism for the suppression of pea (
1161:
1021:
903:
740:
1176:
779:
486:
The most effective management technique available to farmers is the use of disease-resistant
1166:
613:, which causes Phytophthora root rot (PRR) in alfalfa. After initial studies in Wisconsin,
962:
759:
Agrios, George N. 2005. Plant Pathology. 5th ed. Elsevier Academic Press, Burlington, MA.
685:
600:
alfalfa crops in the United States and Canada, and is considered widespread in Wisconsin.
275:
216:
854:
1060:
819:
322:
107:
74:
61:
1193:
1013:
679:
http://www.apsnet.org/edcenter/intropp/lessons/fungi/Oomycetes/Pages/Aphanomyces.aspx
495:
224:
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demonstrate host specificity, but such specificity has not been observed in Europe.
326:
264:
212:
87:
1026:
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451:
443:
431:
427:
406:
349:
298:
127:
999:
922:
Jones, F. R. and C. Drechsler. Boot rot of peas in the United States caused by
398:
is not usually a saprophyte in nature, but can be grown in culture in the lab.
411:
256:
1047:
549:
491:
419:
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248:
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48:
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In alfalfa, there is evidence that another interaction can occur between
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232:
1091:
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330:
220:
970:
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837:
Jacobsen, B. J., H. J. Hopen. 1981. Influence of herbicides on
804:
http://apsjournals.apsnet.org/doi/pdf/10.1094/PDIS.2001.85.3.328
791:
http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.2001.85.7.740
587:
usually occurs alone, in alfalfa it often occurs in conjunction
1039:
974:
446:
the antheridium and oogonium arise from the same hypha and are
822:
herbicides. Weed Science Society of America. 27, 2:195-201.
548:
of root rot in peas. At the time, the disease had plagued
367:
infection results in black or reddish vascular tissue, and
776:
182:, plant pathogen responsible for the disease Aphanomyces
595:, two other root rot-causing pathogens. Thus although
544:
was first described by Drechsler in 1925 as the causal
457:
When growing under optimal conditions, an infection of
385:
can be seen in root tissue with a compound microscope.
983:
580:is still common but conditions are less favorable.
498:can be implemented to slow the rate of build-up of
940:Papavizas, George C. and William A. Ayers. 1974.
371:infection results in sunken, cankerous lesions.
8:
936:
934:
932:
607:is especially damaging in conjunction with
971:
833:
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771:
769:
767:
20:
872:
870:
673:
671:
669:
667:
665:
663:
661:
659:
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655:
359:), there are some distinct differences.
1200:Water mould plant pathogens and diseases
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908:: CS1 maint: archived copy as title (
901:
745:: CS1 maint: archived copy as title (
738:
292:is a root-infecting pathogen, primary
7:
1154:448a1da1-c80a-4e7d-be2f-c37c5fe365e3
377:exhibits no macroscopic signs, but
14:
16:Species of single-celled organism
572:infection can cause processing (
552:and the American Midwest, where
337:Although the symptoms caused by
35:
841:root rot of peas. 65, 1:11-16.
529:may make it more difficult for
241:snap bean and red kidney bean (
1:
824:www.jstor.org/stable/4043003
271:. Of particular concern is
494:to avoid infested fields.
1231:
1210:Protists described in 1925
156:
149:
32:Scientific classification
30:
23:
926:(n. sp.). 30, 4:293-325.
610:Phytophthora medicaginis
509:A study indicates that
537:History and importance
430:called, respectively,
985:Aphanomyces euteiches
924:Aphanomyces euteiches
542:Aphanomyces euteiches
478:dry soil conditions.
440:Aphanomyces euteiches
273:Aphanomyces euteiches
209:Aphanomyces euteiches
188:Aphanomyces euteiches
178:is a water mould, or
175:Aphanomyces euteiches
160:Aphanomyces euteiches
25:Aphanomyces euteiches
450:, meaning separate
223:family, including:
961:2011-06-14 at the
684:2013-05-04 at the
259:Trifolium pratense
243:Phaseolus vulgaris
203:Hosts and symptoms
1187:
1186:
1162:Open Tree of Life
977:Taxon identifiers
171:
170:
142:A. euteiches
1222:
1215:Oomycete species
1180:
1179:
1170:
1169:
1157:
1156:
1147:
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1131:BMSSYS0000001546
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884:. Archived from
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267:Trifolium repens
166:Drechsler (1925)
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879:"Archived copy"
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716:"Archived copy"
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448:self-compatible
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235:Medicago sativa
205:
167:
164:
158:
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118:Leptolegniaceae
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11:
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1228:
1226:
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1205:Saprolegniales
1202:
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975:
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966:
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845:
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820:dinitroaniline
818:) root rot by
816:Pisume sativum
807:
794:
782:
763:
752:
689:
630:
629:
627:
624:
619:P. medicaginis
538:
535:
533:to take hold.
531:P. medicaginis
523:P. medicaginis
483:
480:
466:
463:
414:which release
390:
387:
265:white clover (
204:
201:
186:. The species
169:
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154:
153:
147:
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139:
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133:
132:
125:
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108:Saprolegniales
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85:
78:
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65:
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62:Diaphoretickes
59:
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46:
42:
41:
28:
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949:
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905:
891:on 2011-08-14
887:
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742:
728:on 2011-08-14
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581:
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562:Pisum sativum
558:
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551:
547:
543:
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512:
507:
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497:
496:Crop rotation
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389:Disease cycle
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227:Pisum sativum
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151:Binomial name
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88:Stramenopiles
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893:. Retrieved
886:the original
860:
848:
838:
815:
810:
797:
785:
755:
730:. Retrieved
723:the original
618:
615:A. euteiches
614:
608:
604:
603:In alfalfa,
602:
597:A. euteiches
596:
592:
588:
585:A. euteiches
584:
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578:A. euteiches
577:
569:
566:A. euteiches
565:
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527:A. euteiches
526:
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519:A. euteiches
518:
516:
511:A. euteiches
510:
508:
504:A. euteiches
503:
500:A. euteiches
499:
492:soil testing
485:
471:A. euteiches
470:
468:
459:A. euteiches
458:
456:
452:mating types
439:
424:A. euteiches
423:
403:A. euteiches
402:
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396:A. euteiches
395:
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375:A. euteiches
374:
373:
368:
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354:
348:
342:
339:A. euteiches
338:
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327:soil texture
290:A. euteiches
289:
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283:A. euteiches
282:
278:
272:
266:
258:
257:red clover (
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159:
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141:
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128:
81:
68:
55:
24:
18:
1087:iNaturalist
942:Aphanomyces
839:Aphanomyces
605:A. eutiches
593:Pythium spp
570:Aphanomyces
554:monoculture
465:Environment
444:homothallic
438:. Because
369:Rhizoctonia
361:Aphanomyces
350:Rhizoctonia
249:faba bean (
196:Aphanomyces
129:Aphanomyces
1194:Categories
895:2010-11-30
732:2010-11-30
626:References
482:Management
432:antheridia
428:gametangia
422:hyphae of
420:coenocytic
319:hypocotyls
307:cotyledons
299:nodulation
251:Vicia faba
217:perennials
194:foliage.
550:Wisconsin
488:cultivars
416:zoospores
412:sporangia
401:Although
315:epicotyls
303:chlorosis
233:alfalfa (
207:Hosts of
192:chlorotic
136:Species:
49:Eukaryota
1113:MycoBank
1105:10869011
1061:Fungorum
1014:60016562
1009:AusFungi
1000:Q4779503
994:Wikidata
959:Archived
904:cite web
741:cite web
682:Archived
589:Fusarium
546:pathogen
475:seedling
407:inoculum
383:oospores
365:Fusarium
356:Fusarium
323:stunting
311:necrosis
294:symptoms
288:Because
184:root rot
180:oomycete
114:Family:
98:Oomycota
94:Phylum:
45:Domain:
1177:1275922
1079:3202941
574:canning
436:oogonia
379:oogonia
344:Pythium
331:lesions
317:and/or
313:of the
305:of the
219:in the
213:annuals
211:can be
124:Genus:
104:Order:
1174:uBio:
1167:908526
1151:NZOR:
1144:100861
1118:264411
1092:381260
1066:264411
1053:APHAEU
1040:189674
353:, and
263:, and
221:legume
1100:IRMNG
889:(PDF)
882:(PDF)
726:(PDF)
719:(PDF)
560:Pea (
276:f.sp.
225:pea (
82:Clade
69:Clade
56:Clade
1139:NCBI
1074:GBIF
1048:EPPO
1027:FBG8
910:link
747:link
591:and
521:and
434:and
381:and
309:and
279:pisi
1126:NBN
1035:EoL
1022:CoL
442:is
215:or
75:SAR
1196::
1164::
1141::
1128::
1115::
1102::
1089::
1076::
1063::
1050::
1037::
1024::
1011::
996::
931:^
906:}}
902:{{
869:^
830:^
778:.
766:^
743:}}
739:{{
692:^
634:^
347:,
321:,
255:,
247:,
239:,
231:,
84::
71::
58::
912:)
898:.
749:)
735:.
269:)
261:)
253:)
245:)
237:)
229:)
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