scholarly journals Elucidation of the Microbial Complex Having a Causal Role in the Development of Apple Replant Disease in Washington

1998 ◽  
Vol 88 (9) ◽  
pp. 930-938 ◽  
Author(s):  
Mark Mazzola
Keyword(s):  
Damage Threshold ◽  
Threshold Level ◽  
Parasitic Nematodes ◽  
Minor Role ◽  
Disease Development ◽  
Apple Replant Disease ◽  
Relative Contribution ◽  
Replant Disease ◽  
Microbial Groups ◽  
Soil Pasteurization

Systematic studies were conducted to elucidate the role of different soil microbial groups in the development of apple replant disease. Populations of targeted microorganisms were reduced by the application of semiselective biocides and soil pasteurization. Bacteria were not implicated in the disease, because application of the antibiotic chloramphenicol reduced soil populations of bacteria but failed to improve growth of apple transplants, while enhanced growth was achieved at pasteurization temperatures that did not alter attributes of the bacterial community recovered from apple roots. Populations of Pratylenchus penetrans were below the damage threshold level in eight of nine orchards surveyed, and nematicide applications failed to enhance apple growth in four of five replant soils tested, indicating that plant parasitic nematodes have a minor role or no role in disease development. Application of the fungicide difenconazole or metalaxyl enhanced growth of apple in all five replant soils, as did fludioxinil in the two soils tested. Soil pasteurization enhanced growth of apple and resulted in specific changes in the composition of the fungal community isolated from the roots of apple seedlings grown in these treated soils. Cylindrocarpon destructans, Phytophthora cactorum, Pythium spp., and Rhizoctonia solani were consistently isolated from symptomatic trees in the field and were pathogenic to apple. However, the composition of the Pythium and Rhizoctonia component and the relative contribution of any one component of this fungal complex to disease development varied among the study orchards. These findings clearly demonstrate that fungi are the dominant causal agents of apple replant disease in Washington state.

Alleviation of Nematode-Mediated Apple Replant Disease by Pre-Cultivation of Tagetes

2021 ◽  
Author(s):  
Xorla Kanfra ◽  
Taye Obawolu ◽  
Andreas Wrede ◽  
Bernhard Strolka ◽  
Traud Winkelmann ◽  
...  
Keyword(s):  
Parasitic Nematodes ◽  
Tagetes Patula ◽  
Plant Parasitic Nematodes ◽  
Apple Rootstocks ◽  
Base Diameter ◽  
Free Living ◽  
Apple Replant Disease ◽  
Severe Problem ◽  
Replant Disease ◽  
Shoot Base

Apple replant disease (ARD) is a severe problem in orchards and tree nurseries caused by yet unknown soil biota that accumulate over replanting cycles. This study tested the contribution of nematodes to ARD, and cultivation of Tagetes as a control option. In a pot experiment, Tagetes patula or Tagetes tenuifolia were grown in ARD soil, incorporated or removed. Nematodes extracted from untreated ARD soil and washed on 20 µm-sieves induced ARD symptoms when inoculated to apple saplings growing in a sterile substrate. In contrast, nematodes from Tagetes treated ARD soil did not reduce root growth compared to uninoculated plants, irrespective of Tagetes species and incorporation. In plots of five apple tree nurseries or orchards, either Tagetes or grass was grown on ARD soil. Nematodes extracted from the grass plots and inoculated to apple saplings significantly reduced plant growth compared to nematodes from Tagetes plots for all five farms. Apple rootstocks showed overall a significantly higher increase in shoot base diameter when grown on Tagetes-treated plots compared to grass plots, while this effect differed among farms. Plant-parasitic nematodes were too low in abundance to explain plant damage. In conclusion, the free-living nematodes involved in ARD can be controlled by Tagetes.

scholarly journals Alleviation of Nematode-Mediated Apple Replant Disease by Pre-Cultivation of Tagetes

Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 433
Author(s):  
Xorla Kanfra ◽  
Taye Obawolu ◽  
Andreas Wrede ◽  
Bernhard Strolka ◽  
Traud Winkelmann ◽  
...  
Keyword(s):  
Parasitic Nematodes ◽  
Tagetes Patula ◽  
Plant Parasitic Nematodes ◽  
Apple Rootstocks ◽  
Base Diameter ◽  
Apple Replant Disease ◽  
Severe Problem ◽  
Replant Disease ◽  
Control Option ◽  
Shoot Base

Apple replant disease (ARD) is a severe problem in orchards and tree nurseries caused by yet unknown soil biota that accumulate over replanting cycles. This study tested the contribution of nematodes to ARD, and cultivation of Tagetes as a control option. In a pot experiment, Tagetes patula or Tagetes tenuifolia were grown in ARD soil, incorporated or removed. Nematodes extracted from untreated ARD soil and washed on 20-µm sieves induced ARD symptoms when inoculated to apple plantlets growing in a sterile substrate. In contrast, nematodes from Tagetes treated ARD soil did not reduce root growth compared to uninoculated plants, irrespective of Tagetes species and incorporation. In plots of five apple tree nurseries or orchards, either Tagetes or grass was grown on ARD soil. Nematodes extracted from the grass plots and inoculated to apple plantlets significantly reduced plant growth compared to nematodes from Tagetes plots for all five farms. Apple rootstocks showed overall a significantly higher increase in shoot base diameter when grown on Tagetes-treated plots compared to grass plots, while this effect differed among farms. Plant-parasitic nematodes were too low in abundance to explain plant damage. In conclusion, Tagetes alleviated ARD by changing the nematode community in soil.

scholarly journals Screening Malus Germplasm for Field Resistance to Apple Replant Disease and Root-lesion Nematodes

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 618f-618
Author(s):  
D.K. Isutsa ◽  
I.A. Merwin ◽  
B.B. Brodie
Keyword(s):  
Cover Crops ◽  
Dry Mass ◽  
Parasitic Nematodes ◽  
Screening Methods ◽  
Apple Replant Disease ◽  
Replant Disease ◽  
Lesion Nematodes ◽  
Root Necrosis ◽  
Root Lesion Nematodes ◽  
Plant Dry Mass

Apple replant disease (ARD) is a serious problem in fruit production, and none of the major clonal rootstocks are resistant to ARD. We have screened Malus domestica clones and species accessions from the USDA Malus Germplasm Repository at Geneva, N.Y., including M. angustifolia-2375.03 (MA), M. coronaria-2966.01 (MC), M. fusca-3031.01 (MF), M. ioensis-3059.01 (MI), M. sieversii-3530.01 (MS), and M. kirghisorum-3578.01 (MK), for resistance to ARD and root-lesion nematodes (RLN, Pratylenchus spp.), in a composite soil collected from 11 New York orchards with known ARD. Plant dry mass and height, root necrosis, and nematode populations in different apple species and clones were compared after 60 days growth in steam-pasteurized (PS), RLN-inoculated (IS), and naturally infested field (FS) soils with 1200 RLN per 100 cm3. More severe stunting, reduced plant dry mass, and root necrosis occurred in FS seedlings compared with those in PS, but M. angustifolia seedlings were substantially more resistant or tolerant to RLN and ARD than the other species tested. Plant dry mass ranked MK>MS>MA>MI>MF>MC, and these differences were significant at the 5% level. RLN root populations were negatively correlated with plant dry mass, and accounted for about 10% of its variation, with nematode populations in roots ranking MC>MF>MK>MI>MS>MA. Useful resistance to ARD and parasitic nematodes apparently exists within Malus germplasm collections, and can be identified by testing more genotypes, developing rapid resistance screening methods, and comparing RLN host preferences among Malus genotypes and various orchard cover crops.

Root exposure to apple replant disease soil triggers local defense response and rhizoplane microbiome dysbiosis

2021 ◽  
Author(s):  
Alicia Balbín-Suárez ◽  
Samuel Jacquiod ◽  
Annmarie-Deetja Rohr ◽  
Benye Liu ◽  
Henryk Flachowsky ◽  
...  
Keyword(s):  
Gene Expression ◽  
Plant Defense ◽  
Defense Response ◽  
Soil Column ◽  
Soil Layer ◽  
Soil Microbiome ◽  
Control Soil ◽  
Apple Rootstocks ◽  
Apple Replant Disease ◽  
Replant Disease

Abstract A soil column split-root experiment was designed to investigate the ability of apple replant disease (ARD) causing agents to spread in soil. ‘M26’ apple rootstocks grew into a top layer of Control soil, followed by a barrier-free split-soil layer (Control soil/ARD soil). We observed a severely reduced root growth, concomitant with enhanced gene expression of phytoalexin biosynthetic genes and phytoalexin content in roots from ARD soil, indicating a pronounced local plant defense response. Amplicon sequencing (bacteria, archaea, fungi) revealed local shifts in diversity and composition of microorganisms in the rhizoplane of roots from ARD soil. An enrichment of OTUs affiliated to potential ARD fungal pathogens (Ilyonectria and Nectria sp.) and bacteria frequently associated with ARD (Streptomyces, Variovorax) was noted. In conclusion, our integrated study supports the idea of ARD being local and not spreading into surrounding soil, as only the roots in ARD soil were affected in terms of growth, phytoalexin biosynthetic gene expression, phytoalexin production, and altered microbiome structure. This study further reinforces the microbiological nature of ARD, being likely triggered by a disturbed soil microbiome enriched with low mobility ARD-causing agents that induce a strong plant defense and rhizoplane microbiome dysbiosis, concurring with root damage.

Formation and exudation of biphenyl and dibenzofuran phytoalexins by roots of the apple rootstock M26 grown in apple replant disease soil

2021 ◽  
Vol 192 ◽  
pp. 112972
Author(s):  
Belnaser A. Busnena ◽  
Till Beuerle ◽  
Felix Mahnkopp-Dirks ◽  
Traud Winkelmann ◽  
Ludger Beerhues ◽  
...  
Keyword(s):  
Apple Rootstock ◽  
Apple Replant Disease ◽  
Replant Disease

Induction and diagnosis of apple replant disease (ARD): a matter of heterogeneous soil properties?

2018 ◽  
Vol 241 ◽  
pp. 167-177 ◽  
Author(s):  
Felix Mahnkopp ◽  
Margaux Simon ◽  
Eva Lehndorff ◽  
Stefan Pätzold ◽  
Andreas Wrede ◽  
...  
Keyword(s):  
Soil Properties ◽  
Apple Replant Disease ◽  
Replant Disease ◽  
Heterogeneous Soil

scholarly journals Ozonated water electrolytically generated by diamond-coated electrodes controlled phytonematodes in replanted soil

2021 ◽  
Author(s):  
Xorla Kanfra ◽  
Ahmed Elhady ◽  
Hendrik Thiem ◽  
Sven Pleger ◽  
Markus Höfer ◽  
...  
Keyword(s):  
Energy Efficient ◽  
Greenhouse Experiment ◽  
Soil Nematodes ◽  
Pratylenchus Penetrans ◽  
Yield Losses ◽  
Management Options ◽  
Apple Replant Disease ◽  
Replant Disease ◽  
Coated Electrodes ◽  
Ozonated Water

AbstractPhytonematodes cause severe yield losses in horticulture, partly because they are difficult to manage. Compact, energy-efficient generators that electrochemically produce ozonated water by utilizing diamond-coated electrodes have become available. In this study, the application of on-site generated ozonated water to inactivate soil nematodes and to mitigate nematode-mediated apple replant disease was tested. Pratylenchus penetrans was highly susceptible to dissolved ozone (LC50 0.6 mg L−1). In one greenhouse experiment, treatment of P. penetrans in soil with ozonated water (0.27 mg ozone L−1 soil) reduced subsequent invasion of the nematodes into roots by 60%. Growth of apple saplings in soil that was affected by apple replant disease (ARD) was significantly improved following a treatment with 1/10 volume ozonated water compared to the control. In a second greenhouse experiment, one-time drenching of ARD soil with ozonated water was followed by improved growth of apple plants similar to that in autoclaved soil. A second application of ozonated water did not further improve plant growth. The number of active nematodes in replanted soil that moved through a Baermann filter was significantly reduced by all tested concentrations of ozone (0.12–0.75 mg L−1 soil). A fraction of 19–36% of the nematodes survived and slightly recovered after four weeks. In conclusion, on-site generated ozonated water has potential to mitigate nematode problems in horticulture and to expand management options.

scholarly journals Optimizing Safe Approaches to Manage Plant-Parasitic Nematodes

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1911
Author(s):  
Mahfouz M. M. Abd-Elgawad
Keyword(s):  
Crop Yields ◽  
Abiotic Factors ◽  
Alternative Methods ◽  
Soil Microbiome ◽  
Parasitic Nematodes ◽  
Control Mechanisms ◽  
Plant Parasitic Nematodes ◽  
Safe Alternative ◽  
Microbial Groups ◽  
Plant Parasitic

Plant-parasitic nematodes (PPNs) infect and cause substantial yield losses of many foods, feed, and fiber crops. Increasing concern over chemical nematicides has increased interest in safe alternative methods to minimize these losses. This review focuses on the use and potential of current methods such as biologicals, botanicals, non-host crops, and related rotations, as well as modern techniques against PPNs in sustainable agroecosystems. To evaluate their potential for control, this review offers overviews of their interactions with other biotic and abiotic factors from the standpoint of PPN management. The positive or negative roles of specific production practices are assessed in the context of integrated pest management. Examples are given to reinforce PPN control and increase crop yields via dual-purpose, sequential, and co-application of agricultural inputs. The involved PPN control mechanisms were reviewed with suggestions to optimize their gains. Using the biologicals would preferably be backed by agricultural conservation practices to face issues related to their reliability, inconsistency, and slow activity against PPNs. These practices may comprise offering supplementary resources, such as adequate organic matter, enhancing their habitat quality via specific soil amendments, and reducing or avoiding negative influences of pesticides. Soil microbiome and planted genotypes should be manipulated in specific nematode-suppressive soils to conserve native biologicals that serve to control PPNs. Culture-dependent techniques may be expanded to use promising microbial groups of the suppressive soils to recycle in their host populations. Other modern techniques for PPN control are discussed to maximize their efficient use.

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