Manipulating the ecosystem enables management of soilborne pathogen complexes in annual legume forage systems

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Abstract

Studies were undertaken to examine the potential for manipulating the ecosystem by altering forage species composition, intensity of grazing or by adding Rhizobium, to enhance productivity of subterranean clover (Trifolium subterraneum) forages affected by the soilborne pathogens Pythium irregulare and Rhizoctonia solani. Levels of tap and lateral root disease on clover and its productivity were differentially and significantly affected by the relative proportions of clover to annual ryegrass (Lolium rigidum). In the presence of P. irregulare, both tap and lateral root disease decreased as percentage clover composition increased (R-2 = 0.58, 0.59, respectively); there was no such significant effect in the presence of R. solani (R-2 = 0.08, 0.18, respectively). Increasing and maintaining high clover content in forage offers a means to both reduce root disease and increase productivity and forage legume stand persistence. With simulated grazing studies, continuous (i.e. intensive) grazing in the presence of P. irregulare resulted in the most severe tap and lateral root disease, poorest nodulation and smallest roots and shoots compared with intermittent grazing. Hence, reducing grazing intensity also offers potential for significantly increasing productivity of root-rot-affected clover forage. For Rhizobium studies, nodulation was reduced in the presence of P. irregulare or R. solani; the extent of this was dependent upon which pathogen and the clover variety. Overall, these different studies highlight significant potential for manipulating the ecosystem to better manage soilborne pathogen complexes and improve productivity and persistence in annual legume forage systems adversely affected by soilborne oomycete and fungal pathogens.

Original languageEnglish
Pages (from-to)454-469
Number of pages16
JournalPlant Pathology
Volume68
Issue number3
DOIs
Publication statusPublished - Apr 2019

Cite this

@article{362da7c296ca4db7866056d3f73643cb,
title = "Manipulating the ecosystem enables management of soilborne pathogen complexes in annual legume forage systems",
abstract = "Studies were undertaken to examine the potential for manipulating the ecosystem by altering forage species composition, intensity of grazing or by adding Rhizobium, to enhance productivity of subterranean clover (Trifolium subterraneum) forages affected by the soilborne pathogens Pythium irregulare and Rhizoctonia solani. Levels of tap and lateral root disease on clover and its productivity were differentially and significantly affected by the relative proportions of clover to annual ryegrass (Lolium rigidum). In the presence of P. irregulare, both tap and lateral root disease decreased as percentage clover composition increased (R-2 = 0.58, 0.59, respectively); there was no such significant effect in the presence of R. solani (R-2 = 0.08, 0.18, respectively). Increasing and maintaining high clover content in forage offers a means to both reduce root disease and increase productivity and forage legume stand persistence. With simulated grazing studies, continuous (i.e. intensive) grazing in the presence of P. irregulare resulted in the most severe tap and lateral root disease, poorest nodulation and smallest roots and shoots compared with intermittent grazing. Hence, reducing grazing intensity also offers potential for significantly increasing productivity of root-rot-affected clover forage. For Rhizobium studies, nodulation was reduced in the presence of P. irregulare or R. solani; the extent of this was dependent upon which pathogen and the clover variety. Overall, these different studies highlight significant potential for manipulating the ecosystem to better manage soilborne pathogen complexes and improve productivity and persistence in annual legume forage systems adversely affected by soilborne oomycete and fungal pathogens.",
keywords = "ecosystem disease management, ecosystem manipulation, Lolium rigidum, Pythium irregulare, Rhizoctonia solani, Trifolium subterraneum, PHYTOPHTHORA-CLANDESTINA RACES, CLOVER TRIFOLIUM-SUBTERRANEUM, ANNUAL MEDICAGO SPP., ROOT-ROT, DAMPING-OFF, PASTURE LEGUMES, PARASITIC NEMATODES, SOIL PASTEURIZATION, FUSARIUM-AVENACEUM, PYTHIUM-IRREGULARE",
author = "You, {M. P.} and Barbetti, {M. J.}",
year = "2019",
month = "4",
doi = "10.1111/ppa.12963",
language = "English",
volume = "68",
pages = "454--469",
journal = "Plant Pathology",
issn = "0032-0862",
publisher = "John Wiley & Sons",
number = "3",

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TY - JOUR

T1 - Manipulating the ecosystem enables management of soilborne pathogen complexes in annual legume forage systems

AU - You, M. P.

AU - Barbetti, M. J.

PY - 2019/4

Y1 - 2019/4

N2 - Studies were undertaken to examine the potential for manipulating the ecosystem by altering forage species composition, intensity of grazing or by adding Rhizobium, to enhance productivity of subterranean clover (Trifolium subterraneum) forages affected by the soilborne pathogens Pythium irregulare and Rhizoctonia solani. Levels of tap and lateral root disease on clover and its productivity were differentially and significantly affected by the relative proportions of clover to annual ryegrass (Lolium rigidum). In the presence of P. irregulare, both tap and lateral root disease decreased as percentage clover composition increased (R-2 = 0.58, 0.59, respectively); there was no such significant effect in the presence of R. solani (R-2 = 0.08, 0.18, respectively). Increasing and maintaining high clover content in forage offers a means to both reduce root disease and increase productivity and forage legume stand persistence. With simulated grazing studies, continuous (i.e. intensive) grazing in the presence of P. irregulare resulted in the most severe tap and lateral root disease, poorest nodulation and smallest roots and shoots compared with intermittent grazing. Hence, reducing grazing intensity also offers potential for significantly increasing productivity of root-rot-affected clover forage. For Rhizobium studies, nodulation was reduced in the presence of P. irregulare or R. solani; the extent of this was dependent upon which pathogen and the clover variety. Overall, these different studies highlight significant potential for manipulating the ecosystem to better manage soilborne pathogen complexes and improve productivity and persistence in annual legume forage systems adversely affected by soilborne oomycete and fungal pathogens.

AB - Studies were undertaken to examine the potential for manipulating the ecosystem by altering forage species composition, intensity of grazing or by adding Rhizobium, to enhance productivity of subterranean clover (Trifolium subterraneum) forages affected by the soilborne pathogens Pythium irregulare and Rhizoctonia solani. Levels of tap and lateral root disease on clover and its productivity were differentially and significantly affected by the relative proportions of clover to annual ryegrass (Lolium rigidum). In the presence of P. irregulare, both tap and lateral root disease decreased as percentage clover composition increased (R-2 = 0.58, 0.59, respectively); there was no such significant effect in the presence of R. solani (R-2 = 0.08, 0.18, respectively). Increasing and maintaining high clover content in forage offers a means to both reduce root disease and increase productivity and forage legume stand persistence. With simulated grazing studies, continuous (i.e. intensive) grazing in the presence of P. irregulare resulted in the most severe tap and lateral root disease, poorest nodulation and smallest roots and shoots compared with intermittent grazing. Hence, reducing grazing intensity also offers potential for significantly increasing productivity of root-rot-affected clover forage. For Rhizobium studies, nodulation was reduced in the presence of P. irregulare or R. solani; the extent of this was dependent upon which pathogen and the clover variety. Overall, these different studies highlight significant potential for manipulating the ecosystem to better manage soilborne pathogen complexes and improve productivity and persistence in annual legume forage systems adversely affected by soilborne oomycete and fungal pathogens.

KW - ecosystem disease management

KW - ecosystem manipulation

KW - Lolium rigidum

KW - Pythium irregulare

KW - Rhizoctonia solani

KW - Trifolium subterraneum

KW - PHYTOPHTHORA-CLANDESTINA RACES

KW - CLOVER TRIFOLIUM-SUBTERRANEUM

KW - ANNUAL MEDICAGO SPP.

KW - ROOT-ROT

KW - DAMPING-OFF

KW - PASTURE LEGUMES

KW - PARASITIC NEMATODES

KW - SOIL PASTEURIZATION

KW - FUSARIUM-AVENACEUM

KW - PYTHIUM-IRREGULARE

U2 - 10.1111/ppa.12963

DO - 10.1111/ppa.12963

M3 - Article

VL - 68

SP - 454

EP - 469

JO - Plant Pathology

JF - Plant Pathology

SN - 0032-0862

IS - 3

ER -