Characterisation of apple replant disease under South African conditions and potential biological management strategies

2009 ◽  
Vol 119 (2) ◽  
pp. 153-162 ◽  
Author(s):  
L. van Schoor ◽  
S. Denman ◽  
N.C. Cook
Keyword(s):  
South African ◽  
Management Strategies ◽  
Apple Replant Disease ◽  
Replant Disease ◽  
Biological Management

scholarly journals Assessment of Agro-Ecological Apple Replant Disease (ARD) Management Strategies: Organic Fertilisation and Inoculation with Mycorrhizal Fungi and Bacteria

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 272
Author(s):  
Ulrike Cavael ◽  
Peter Lentzsch ◽  
Hilmar Schwärzel ◽  
Frank Eulenstein ◽  
Marion Tauschke ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Field Experiments ◽  
Management Strategies ◽  
Economic Effects ◽  
Biological Interactions ◽  
Apple Replant Disease ◽  
Plant Vigour ◽  
Current Form ◽  
Replant Disease ◽  
Organic Fertilisation

Apple replant disease (ARD) impacts the economic yield of orchards by physiological and morphological suppression of apple trees on replanted soils. The complexity of replant disease caused by a plethora of biological interactions and physical properties of the soil requires complex management strategies to mitigate these effects. Based on expert recommendations, we selected two management strategies linked to agroecological principles of (a) organic fertilisation with a specific mulch composition (MDK) and (b) biofertilisation with arbuscular mycorrhizal and bacterial strains (AMFbac), applied by a composition of existing products. For both management strategies we provide a proof-of-concept, by pot and field experiments. Both treatments have the potential to mitigate ARD effects on plant vigour. ARD effect was fully mitigated by MDK treatment in the short-term (one year) and was mitigated by up to 29% after seven years of MDK treatment (long-term). MDK provides an additional substrate for root growth. AMFbac has the potential to mitigate ARD effects on plant vigour but with non-replicable plant-beneficial effects in its current form of application. Thereby our results show a principal potential to mitigate economic effects but not to overcome replant disease inducing effects. While the MDK treatment is found resource intensive but reliable, the AMFbac treatment was found more user-friendly.

scholarly journals Comparative Field Efficacy of Management Strategies Containing Brassica napus Seed Meal or Green Manure for the Control of Apple Replant Disease

Plant Disease ◽  
2005 ◽  
Vol 89 (11) ◽  
pp. 1207-1213 ◽  
Author(s):  
Mark Mazzola ◽  
Kent Mullinix
Keyword(s):  
Brassica Napus ◽  
Tree Growth ◽  
Green Manure ◽  
Growth Response ◽  
Management Strategies ◽  
Soil Fumigation ◽  
Growth And Yield ◽  
Seed Meal ◽  
Apple Replant Disease ◽  
Replant Disease

Alternative management strategies to the use of preplant soil fumigation for the control of apple replant disease (ARD), including cover crops and strategies incorporating Brassica napus seed meal (rape seed meal [RSM]) amendment as the central component, were evaluated in the orchard. A 1-year wheat cover crop consisting of three short-term cropping periods with plant material removed at the end of each growth period and a 3-year B. napus green manure significantly enhanced vegetative growth and yield of Gala/M26. However, in each instance, the resulting disease control and growth response were inferior to that achieved through preplant methyl bromide soil fumigation. A 3-year bare fallow and 1- or 2-year B. napus green manure neither suppressed disease development nor enhanced tree growth. Preplant RSM amendment in conjunction with a postplant mefenoxam soil drench provided effective suppression of ARD, and the resulting tree growth and yield were comparable with that attained in response to 1,3- dichloropropene-chloropicrin fumigation in one orchard. At a second orchard, the growth response attained with the alternative treatment was inferior to preplant soil fumigation, which was associated with an apparent re-infestation of RSM-treated soils and tree roots by Pratylenchus spp. Application of RSM after wheat cropping or in conjunction with soil solarization provided an intermediate level of disease control and a corresponding reduction in growth and yield of apple relative to preplant fumigation at both sites.

scholarly journals Candidate Causal Organisms for Apple Replant Disease in the United Kingdom

2018 ◽  
Vol 2 (4) ◽  
pp. 261-274 ◽  
Author(s):  
Emma L. Tilston ◽  
Greg Deakin ◽  
Julie Bennett ◽  
Tom Passey ◽  
Nicola Harrison ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Management Strategies ◽  
Sampling Strategy ◽  
Soil Samples ◽  
Apple Replant Disease ◽  
The United Kingdom ◽  
Replant Disease ◽  
Lower Abundance ◽  
Lesion Nematodes ◽  
Root Lesion Nematodes

Continuous planting of apple in the same area leads to reduced growth vigor and subsequent crop losses, i.e., apple replant disease (ARD) syndrome. Several soilborne plant pathogens including Pythium, Fusarium, and Cylindrocarpon spp. are often proposed as candidate causal organisms for ARD. In addition, the presence of root lesion nematodes and the lack of beneficial groups of bacteria are believed to exacerbate or ameliorate the effects of the plant pathogens. The importance of these proposed causal and auxiliary agents seems to vary with site. Using a spatially explicit sampling strategy to minimize spatial variability we collected rhizosphere soil samples from neighboring pairs of healthy and putative ARD trees to identify candidate causal organisms of ARD. Amplicon-based metabarcoding was used to obtain community-level profiles of the bacteria, fungi, oomycetes and nematodes in the soil samples. Total bacterial and fungal biomass in each sample was estimated using qPCR to adjust the raw sequence reads data. The results suggested that ARD is not ameliorated by enhanced rhizosphere biodiversity per se. We identified 25 bacterial operational taxonomic units (OTUs), 16 fungal OTUs, 18 oomycetes OTUs, and one nematode OTU group with differential abundance between healthy and putative ARD trees. All 25 bacterial OTUs had lower abundance in samples from ARD symptomatic trees than from healthy trees. One AMF OTU had lower abundance in samples from ARD symptomatic trees. None of 13 fungal OTUs that had higher abundance in samples from ARD symptomatic trees is a known plant pathogen; but at least one Pythium OTU (probably Pythium intermedium) is a candidate for causing ARD. The abundance of one nematode OTU was much higher in samples from ARD symptomatic trees than in healthy trees. The results suggest that, apart from the use of broad spectrum fumigants, the complexity of ARD may necessitate the combined use of multiple management strategies with the success of these measures expected to vary considerably between sites because of the varying importance of ARD causal agents among sites.

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.

Fatigue-management strategies among women with endometriosis in South Africa: a qualitative study

2021 ◽  
pp. 008124632110201
Author(s):  
Zamafiso Nombulelo Sibande ◽  
Rizwana Roomaney
Keyword(s):  
South Africa ◽  
South African ◽  
Psychosocial Intervention ◽  
Public Hospital ◽  
Management Strategies ◽  
Cognitive Strategies ◽  
Secondary Symptom ◽  
Face To Face ◽  
Fatigue Management ◽  
Insight Into

Fatigue is a common, secondary symptom of endometriosis that has not been qualitatively explored. We conducted individual, face-to-face interviews with 25 women in South Africa about their experiences of endometriosis-related fatigue. Participants were recruited at a public hospital in Cape Town and through several South African endometriosis organizations. Interviews were conducted in English and Afrikaans and ranged from 30 min to 1 hr 16 min in duration. All interviews were audio recorded and transcribed. Interviews were analyzed using thematic analysis. We found that both the experience of fatigue and fatigue-management strategies were highly personalized. Participants reported using a variety of cognitive strategies, such as planning, pacing, and pushing through their fatigue to reduce the levels of fatigue. Participants also employed physical strategies such as rest, dietary changes, using supplements, and exercise. We found that while participants often tried fatigue-management strategies suggested to them by others, they struggled to maintain these strategies even when they were successful. There are currently no interventions aimed at reducing endometriosis-related fatigue. The findings of this study provide insight into the management of fatigue in women with endometriosis and may be used to develop a psychosocial intervention for fatigue among women with the disease.

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.

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