DOCSLIB.ORG

Non-Fumigant Alternative Soil Management Practices for Mitigating Replant Disease of Fruit Trees

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

NON-FUMIGANT ALTERNATIVE SOIL MANAGEMENT PRACTICES FOR MITIGATING REPLANT DISEASE OF FRUIT TREES: MECHANISMS CONTRIBUTING TO PRATYLENCHUS PENETRANS SUPPRESSION by Tristan Tanner Watson B.Sc. (Honours), The University of British Columbia, 2013 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE COLLEGE OF GRADUATE STUDIES (Biology) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) April 2018 © Tristan Tanner Watson, 2018 The following individuals certify that they have read, and recommend to the College of Graduate Studies for acceptance, a dissertation entitled: NON-FUMIGANT ALTERNATIVE SOIL MANAGEMENT PRACTICES FOR MITIGATING REPLANT DISEASE OF FRUIT TREES: MECHANISMS CONTRIBUTING TO PRATYLENCHUS PENETRANS SUPPRESSION submitted by Tristan Tanner Watson in partial fulfillment of the requirements of the degree of Doctor of Philosophy . Dr. Louise Nelson, Irving K. Barber School of Arts and Sciences Co-supervisor Dr. Thomas Forge, Agriculture and Agri-Food Canada Co-supervisor Dr. Melanie Jones, Irving K. Barber School of Arts and Sciences Supervisory Committee Member Dr. José Úrbez-Torres, Agriculture and Agri-Food Canada Supervisory Committee Member Dr. Paul Shipley, Irving K. Barber School of Arts and Sciences University Examiner Dr. Mario Tenuta, Faculty of Agricultural and Food Sciences, University of Manitoba External Examiner ii Abstract Replant disease presents a significant barrier to the reestablishment of orchards. In the Okanagan Valley, Canada, the root-lesion nematode, Pratylenchus penetrans, is widely distributed and implicated in poor growth of newly planted fruit trees. Restrictions on soil fumigants have generated interest in alternative management strategies for disease control. Using a combination of greenhouse and field experiments, this dissertation evaluated the effects of composts, bark chip mulch, biocontrol inoculation, and two different irrigation systems (drip emitter and microsprinkler) on the establishment of apple and sweet cherry trees in old orchard soil, P. penetrans population dynamics, as well as biotic and abiotic factors that may have contributed to enhanced plant growth and nematode suppression. In the first greenhouse experiment, compost amendments, but not biocontrol inoculation, improved growth of apple and sweet cherry seedlings in old orchard soil, suppressed P. penetrans, enhanced soil populations of total bacteria, 2,4- diacetylphloroglucinol-producing (DAPG+) bacteria, pyrrolnitrin-producing (PRN+) bacteria, and altered the composition of the soil microbial community. In the field experiment, compost amendment and surface application of bark chip mulch increased trunk diameters of sweet cherry trees planted at an old orchard site as well as suppressed P. penetrans populations. Compost enhanced rhizosphere populations of total bacteria, DAPG+ bacteria, and PRN+ bacteria, soil microbial activity, soil biological suppressiveness, and root colonization by arbuscular mycorrhizal fungi (AMF). Bark chip mulch enhanced rhizosphere populations of total fungi, soil microbial activity, and soil biological suppressiveness. Drip irrigation promoted greater trunk diameters and fruit yield, suppressed P. penetrans populations, and trees had greater root colonization by iii AMF relative to microsprinkler irrigation. In the second greenhouse experiment, compost amendments increased plant growth relative to that of untreated soil in six out of twelve of the orchard soil x compost type combinations evaluated, and suppressed P. penetrans in four out of twelve treatment combinations. Inoculation with antagonistic Pseudomonas isolates provided minor plant growth promotion and P. penetrans suppression in orchard soil. Overall, preplant incorporation of composts and surface application of bark chip mulch, alongside the use of drip irrigation resulted in the best establishment of sweet cherry trees in old orchard soil. iv Lay Summary Replant disease is responsible for the poor growth of fruit trees planted into soil previously used for tree-fruit production, and has been linked to elevated populations of plant-parasitic nematodes in soil, among other possible causes including fungal pathogens. Recent restrictions on use of soil fumigants are increasing the interest in alternative soil management strategies that can provide similar levels of disease control. Using a combination of greenhouse and field experiments, the goal of this research was to evaluate the effects of compost amendments, bark chip mulch, inoculation with potential biocontrol microbes, and choice of low-volume irrigation system (drip emitter versus microsprinkler) on the establishment of fruit trees planted into old orchard soil. This research demonstrated that preplant incorporation of composts and surface application of bark chip mulch, alongside the use of a drip irrigation system provided the best establishment of fruit trees replanted into old orchard soil. v Preface Chapter 2 is work that was conducted by myself under the guidance of Dr. Tom Forge and Dr. Louise Nelson. Segmented flow-injection analysis of soil mineral N content and combustion analysis of soil organic C and N contents were conducted by Dr. Denise Neilsen's research technician, Shawn Kuchta, at the Summerland Research and Development Centre. Optimization of the real-time polymerase chain reaction (PCR) assay for quantification of total fungi was performed in collaboration with Dr. Louise Nelson's Master of Science student, Paige Munro, at the University of British Columbia - Okanagan Campus. Optimization of the real-time PCR assay for quantification of total bacteria was performed by Dr. Tanja Vogel, at the University of British Columbia - Okanagan Campus. I designed and conducted the greenhouse experiment, collected the data, performed all other analyses, and conducted data analysis and interpretation. Chapter 3 is work that was conducted by myself, Dr. Tom Forge, Dr. Denise Neilsen, and Dr. Gerry Neilsen. Segmented flow-injection analysis of soil mineral N content, combustion analysis of soil organic C and N contents, and inductively coupled plasma-optical emission spectroscopy of leaf nutrient concentrations were performed by Dr. Gerry Neilsen's research technician, Lana Fukumoto. Set-up of time-domain reflectometry (TDR) equipment and subsequent monitoring of soil volumetric water contents in sub-plots were performed by Dr. Denise Neilsen's research technicians, Shawn Kutcha and Istvan Losso. From 2014 through 2016, nematodes were extracted from soil and root samples by Dr. Tom Forge's research technician, Paul Randall. Experimental design was decided upon by Dr. Tom Forge, Dr. Denise Neilsen, and Dr. Gerry Neilsen prior to my involvement in the project. I collected the samples, performed vi all other analyses, as well as conducted data analysis and interpretation. A portion of Chapters 2 and 3 has been published: Watson, T.T., Nelson, L.M., Neilsen, D., Neilsen, G.H., Forge, T.A. (2017) Organic soil amendments influence P. penetrans populations, beneficial rhizosphere microorganisms, and growth of newly planted sweet cherry. Applied Soil Ecology 117-118: 212-220. I wrote the manuscript with guidance and input from Dr. Tom Forge, Dr. Louise Nelson, Dr. Denise Neilsen, and Dr. Gerry Neilsen. I independently designed and conducted the greenhouse experiment. For the field experiment, I collected the soil samples, quantified nematodes from samples, quantified rhizosphere/soil microorganisms, and performed plant growth measurements. A portion of Chapter 3 has been published: Forge, T.A., Neilsen, D., Neilsen, G., Watson, T. (2016) Using compost amendments to enhance soil health and replant establishment of tree-fruit crops. Acta Horticulturae 1146: 103-108. I collected the soil samples, quantified nematodes from samples, and performed plant growth measurements. Chapter 4 is work that was conducted by myself under the guidance of Dr. Tom Forge and Dr. Louise Nelson. I designed and conducted the experiment, collected the data, performed all other analyses, and conducted data analysis and interpretation. A portion of Chapter 4 has been accepted for publication: Watson, T.T., Nelson, L.M., Neilsen, D, Neilsen, G.H., Forge, T.A. (XXXX) Evaluation of composts as a non- fumigant alternative to promote the establishment of fruit trees at old orchard sites. Acta Horticulturae (in press). I wrote the manuscript with guidance and input from Dr. Tom Forge and Dr. Louise Nelson. I independently designed and conducted the greenhouse experiments, as well as performed data analysis and interpretation. vii Table of Contents Abstract ............................................................................................................................. iii Lay Summary .................................................................................................................... v Preface ............................................................................................................................... vi Table of Contents ........................................................................................................... viii List of Tables .................................................................................................................. xiv List of Figures ................................................................................................................ xvii List of Abbreviations ..................................................................................................
Recommended publications
  • Apple Replant Disease – Theory Versus Practice, an Overview of Known Controlling Methods

    Apple Replant Disease – Theory Versus Practice, an Overview of Known Controlling Methods

    Apple Replant Disease – Theory versus practice, an overview of known controlling methods By H. Meints & A. Toma Summary In the past decades, several researchers focused their attention on identifying the causes of Apple Replant Disease, along with finding new strategies to prevent and control this important threat to fruit production. From leaving the land fallow, using rotation and control crops to soil fumigation and organic amendments, all has been considered over time. Nowadays, there is a visible tendency on using environmental friendly solutions, along with an increase in banning regulation regarding the chemical products used in EU agriculture sector. Therefore, solutions such as Brassica seed meal soil amendments developed by Mark Mazzola, or Herbie invented by Thatchtec in The Netherlands are the proof that alternatives exist and can be efficient. Field trials have resulted in an almost 100% pathogen suppression and significant yield increase. However, in the case of Herbie and particularly in the trials conducted at Fleuren Tree Nursery in Baarlo, experiments are pushed to their extremes trying to monitories the method’s efficiency and limitations, regarding time frames, larger range of temperature and dosage. What differentiate this later trial from the ones conducted by Mark Mazzola in the US, is that at Fleuren, testing lots are bigger. So far, the results obtained give a positive trend and special attention should be paid not only to the unpredictable weather conditions and temperature from the last period (that are obviously different from the usual values) that can affect the trials, but also try to observe and monitor the soil biodiversity along the tests, complementary to the plant behavior.
  • Description of Pratylenchus Dunensis Sp. N. (Nematoda: Pratylenchidae

    Description of Pratylenchus Dunensis Sp. N. (Nematoda: Pratylenchidae

    Nematology, 2006, Vol. 8(1), 79-88 Description of Pratylenchus dunensis sp.n.(Nematoda: Pratylenchidae), a root-lesion nematode associated with the dune grass Ammophila arenaria (L.) Link ∗ Eduardo DE LA PEÑA 1, , Maurice MOENS 1,2, Adriaan VA N AELST 3 and Gerrit KARSSEN 4,5 1 Agricultural Research Centre, Crop Protection Department, Burg. van Gansberghelaan 96, 9820, Merelbeke, Belgium 2 Gent University, Laboratory for Agrozoology, Coupure 653, 9000 Gent, Belgium 3 Wageningen University & Research Centre, Laboratory of Plant Cell Biology, Arboretumlaan 4, 6703 BD Wageningen, The Netherlands 4 Plant Protection Service, Nematology Section, P.O. Box 9102, 6700 HC Wageningen, The Netherlands 5 Wageningen University & Research Centre, Laboratory of Nematology, Binnenhaven 5, 6709 PD Wageningen, The Netherlands Received: 4 April 2005; revised: 7 November 2005 Accepted for publication: 7 November 2005 Summary – A root-lesion nematode, Pratylenchus dunensis sp. n., is described and illustrated from Ammophila arenaria (L.) Link, a grass occurring abundantly in coastal dunes of Atlantic Europe. The new species is characterised by medium sized (454-579 µm) slender, vermiform, females and males having two lip annuli (sometimes three to four; incomplete incisures only visible with scanning electron microscopy), medium to robust stylet (ca 16 µm) with robust stylet knobs slightly set off, long pharyngeal glands (ca 42 µm), lateral field with four parallel, non-equidistant, lines, the middle ridge being narrower than the outer ones, lateral field with partial areolation and lines converging posterior to the phasmid which is located between the two inner lines of the lateral field in the posterior half of the tail, round spermatheca filled with round sperm, vulva at 78% of total body length and with protruding vulval lips, posterior uterine sac relatively short (ca 19 µm), cylindrical tail (ca 33 µm) narrowing in the posterior third with smooth tail tip and with conspicuous hyaline part (ca 2 µm).
  • <I>Heterodera Glycines</I> Ichinohe

    <I>Heterodera Glycines</I> Ichinohe

    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Theses, Dissertations, and Student Research in Agronomy and Horticulture Agronomy and Horticulture Department Summer 8-5-2013 MULTIFACTORIAL ANALYSIS OF MORTALITY OF SOYBEAN CYST NEMATODE (Heterodera glycines Ichinohe) POPULATIONS IN SOYBEAN AND IN SOYBEAN FIELDS ANNUALLY ROTATED TO CORN IN NEBRASKA Oscar Perez-Hernandez University of Nebraska-Lincoln Follow this and additional works at: https://digitalcommons.unl.edu/agronhortdiss Part of the Plant Pathology Commons Perez-Hernandez, Oscar, "MULTIFACTORIAL ANALYSIS OF MORTALITY OF SOYBEAN CYST NEMATODE (Heterodera glycines Ichinohe) POPULATIONS IN SOYBEAN AND IN SOYBEAN FIELDS ANNUALLY ROTATED TO CORN IN NEBRASKA" (2013). Theses, Dissertations, and Student Research in Agronomy and Horticulture. 65. https://digitalcommons.unl.edu/agronhortdiss/65 This Article is brought to you for free and open access by the Agronomy and Horticulture Department at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Theses, Dissertations, and Student Research in Agronomy and Horticulture by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. MULTIFACTORIAL ANALYSIS OF MORTALITY OF SOYBEAN CYST NEMATODE (Heterodera glycines Ichinohe) POPULATIONS IN SOYBEAN AND IN SOYBEAN FIELDS ANNUALLY ROTATED TO CORN IN NEBRASKA by Oscar Pérez-Hernández A DISSERTATION Presented to the Faculty of The graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy Major: Agronomy (Plant Pathology) Under the Supervision of Professor Loren J. Giesler Lincoln, Nebraska August, 2013 MULTIFACTORIAL ANALYSIS OF MORTALITY OF SOYBEAN CYST NEMATODE (Heterodera glycines Ichinohe) POPULATIONS IN SOYBEAN AND IN SOYBEAN FIELDS ANNUALLY ROTATED TO CORN IN NEBRASKA Oscar Pérez-Hernández, Ph.D.
  • Growing Young Fruit Trees in Old Orchard Sites Introduction

    Growing Young Fruit Trees in Old Orchard Sites Introduction

    A P a c i f i c N o rt h west Ext e n s i o n Pu b I i c at i o n • WASHINGTON • IDAHO • OREGON • Mike Willett, Robert Stevens and Tim Smith Growing Young Fruit Trees in Old Orchard Sites Introduction The orchard replant problem is any situation in which the replanted trees do not grow to the grower's expectations. If you have lowered your expectations due to a previous lack of success, the replant problem may result in an unprofitable orchard. In Pacific Northwest orchards, the problem has been most obvious when apples were planted after apples. The apple replant problem has been identified in virtually every fruit growing region in the world and similar problems have been documented for many fruit crops. Moreover, throughout agricultural history there are cases where growth of a particular crop has been reduced or prevented by continuously cropping it in the same field. The reasons for these yield reductions or failures are the changes that the crop and its production practices cause in the soil. These include chemical, physical and biological changes. Some examples are toxic spray residues such as lead arsenate, low soil pH caused by nitrogen fertilizer application, soil compaction caused by heavy equipment, poor water management, buildup of soil organisms that damage tree roots or a combination of these. Older orchards have extensive root systems and are apparently more resistant to these soil changes. They show fewer ill effects than new trees. However, decline in the vigor and performance of older orchards has been attributed to some of these factors.
  • JOURNAL of NEMATOLOGY Intraspecific Variation in Phenotypic

    JOURNAL of NEMATOLOGY Intraspecific Variation in Phenotypic

    JOURNAL OF NEMATOLOGY Article | DOI: 10.21307/jofnem-2020-102 e2020-102 | Vol. 52 Intraspecific variation in phenotypic and phylogenetic features among Pratylenchus penetrans isolates from Wisconsin, USA Kanan Saikai and Ann E. MacGuidwin* Abstract Department of Plant Pathology, University of Wisconsin–Madison, Pratylenchus penetrans is a common and important agricultural pest 484 Russell Laboratories, 1630 in Wisconsin, a USA state with a diverse agriculture. We compared Linden Dr., Madison, WI, 53706. populations from around the state to each other and to data published for populations around the world to gain insight on the variability of *E-mail: [email protected] features important for identification of this cosmopolitan species. This paper was edited by Thirteen isolates from samples collected in soybean fields in ten Zafar Ahmad Handoo. Wisconsin counties were established in monoxenic cultures. Analysis of morphological features revealed the least variable feature for all Received for publication isolates collectively was vulva percentage. Features less variable within August 3, 2020. than among isolates were body width, lip region height, and stylet length. Some isolates showed only the smooth tail tip phenotype and others had a mix of smooth and annulated tail phenotypes. A suite of features provided sufficient pattern to group isolates into four clusters according to hierarchical agglomerative clustering and canonical discriminative analyses, but not with enough distinction to be useful for classification. Haplotype analysis based on the COI mitochondrial gene of the 13 cultured isolates, 39 Wisconsin field populations, and published sequences representing five additional USA states and six countries revealed 21 haplotypes, 15 of which occurred in Wisconsin.
  • Cordoba Biology Society (Sociedad De Biología De Córdoba)

    Cordoba Biology Society (Sociedad De Biología De Córdoba)

    BIOCELL ISSN 0327 - 9545 2004, 28(2): 171-199 PRINTED IN ARGENTINA Cordoba Biology Society (Sociedad de Biología de Córdoba) Abstracts from the XIV Annual Scientific Meeting Edited by Lic. Ana Laura Correa & Dra. Graciela Racagni August, 7-9, 2003 Villa General Belgrano, Córdoba, Argentina 172 ABSTRACTS BIOCELL, 28(2), 2004 Board of the Society 2001-2003 PRESIDENT Dr. Ismael E. di Tada VICEPRESIDENT Dr. Mario Guido SECRETARY Dra. Graciela Racagni TREASURER Dr. César Casale MEMBERS Dra. Stella Castro Dr. Carlos Coronel Dra. Mónica Garrido Dra. Edith Taleisnik Dr. Guillermo Yudosky Dra. Silvia Milrad Dra. Mirta Koncurat Dr. Marcelo Doucet Dra. María Ester Cobe Dra. Adriana Vivas Dr. Luis Patrito GOVERNAMENTAL SPONSORS Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Agencia Córdoba Ciencia Sociedad del Estado (ACC SE) Universidad Nacional de Río Cuarto (UNRC) Secretaría de Ciencia y Técnica de la Universidad Nacional de Río Cuarto (SCyT-UNRC) Facultad de Ciencias Exactas Físico-Químicas y Naturales UNRC (FCEFQyN-UNRC) Universidad Nacional de Córdoba (UNC) ACKNOWLEDGMENTS Asociación de Biología de Tucumán Sociedad de Biología de Cuyo Sigma Xi, The Scientific Society PRIVATE SPONSORS Carl Zeiss Argentina SA Papelería Gassó Copiacentro H. D. Zanini BIOCELL, 28(2), 2004 ABSTRACTS 173 1. 2. PHOTODYNAMIC STUDIES OF CATIONIC PORPHYRIN STUDIES PHARMACOKINETIC AND PHOTOTHERA- 5-(4-TRIMETIHYL AMMONIUM PHENYL) - 10, 15, 20 - PEUTIC OF CP AND CF3 PORPHYRINS IN VIVO: APPLI- TRIS (2, 4, 6 – TRIMETHOXY PHENYL) PORPHYRIN: BIO- CATION OF PHOTODYNAMIC THERAPY LOGICAL CONSEQUENCES IN A HUMAN CARCINOMA Alvarez MG, Rumie Vittar NB, Principe F, Milanesio ME, Durantini CELL LINE EN, Bertuzzi M, Rivarola V.
  • Nematode Control Alternatives

    Nematode Control Alternatives

    Nematodes: ATTRA Alternative Controls A Publication of ATTRA - National Sustainable Agriculture Information Service • 1-800-346-9140 • www.attra.ncat.org By Martin Guerena This publication provides general information on the tiny worm-like organisms called nematodes. It NCAT Agriculture contains detailed descriptions of the genera of nematodes that attack plants, as well as various methods Specialist to diagnose, discourage, and manage plant parasitic nematodes in a least toxic, sustainable manner. © 2006 NCAT Contents Introduction Introduction ..................... 1 ematodes are Symptoms and tiny, worm-like, Sampling .......................... 4 Nmulticellular Preventing Further animals adapted to liv- Spread of Nematodes ....................... 4 ing in water. The num- ber of nematode species Managing Soil Biology ............................... 5 is estimated at half a Crop Rotations and mil lion, many of which Cover Crops ...................... 6 are “free-living” types Botanical found in the oceans, Nematicides ..................... 9 in freshwater habitats, Biocontrols ...................... 10 and in soils. Plant-par- Plant Resistance ............11 asitic species form a Red Plastic Mulch ......... 12 smaller group. Nema- www.insectimages.org Solarization .................... 13 todes are common Flooding .......................... 13 in soils all over the Root-knot nematode—Meloidogyne brevicauda Loos Summary ......................... 13 world (Dropkin, 1980; ©Jonathan D. Eisenback, Virginia Polytechnic Institute and State University References ..................... 14 Yepsen, 1984). As a commentator in the early Further Resources ........17 twentieth cen tury wrote: genera and species have particu lar soil and Web Resources ..............17 climatic requirements. For example, cer- Suppliers .......................... 18 If all the matter in the universe except the tain species do best in sandy soils, while nematodes were swept away, our world would oth ers favor clay soils.
  • Determining the Occurrence of Replant Disease in British Columbia Orchard and Vineyard Soils by Pasteurization1 R.S

    Determining the Occurrence of Replant Disease in British Columbia Orchard and Vineyard Soils by Pasteurization1 R.S

    . .. Canadian Plant Disease Survey 68:2,1988 149 Determining the occurrence of replant disease in British Columbia orchard and vineyard soils by pasteurization1 R.S. Utkhede and Thomas S.C. Li Experiments were conducted to determine by response to soil pasteurization what sequence of fruit trees or grapevines will grow without damage by replant disease after removing a particular fruit tree or grapevine crop. Apple seedlings developed replant disease in apple, peach, cherry, pear, and grape soils. Peach trees may be planted after any fruit tree or grapevine crop. Plums will grow normally when planted after grapes or any fruit trees except peach. Testing of orchard and vineyard soil is required for the proper diagnosis and treatment of replant disease. Can. Plant Dis. Surv. 68:2, 149- 151, 1988. On a realis6 des experiences afin de dbterminer, en se fondant sur la reaction B la pasteurisation du sol, quelle sequence d'arbres fruitiers ou de vignes ne serait pas endommagee par la maladie de la replanta- tion aprbs avoir bliminb une culture particulibre d'arbres fruitiers ou de vignes. Les plantules de pommiers plantees dans des sols ou l'on avait antbrieurement cultive des pommiers, des pachers, des cerisiers, des poiriers et des vignes ont Bt6 frappbes par la maladie de la replantation. En outre, les pachers peuvent 6tre plantes dans un sol ou a poussb n'importe quel arbre fruitier ou n'importe quelle vigne. Les pruniers croitront normalement s'ils sont plantbs apres des cultures de vignes ou d'un arbre fruitier, B I'exception du pacher. II est necessaire d'analyser les sols de vergers et de vignobles afin d'etablir un diagnostic exact et de determiner le traitement des plantes atteintes de la maladie de la replantation.
  • Pests and Diseases Guide

    Pests and Diseases Guide

    Pests and Diseases Pests and Diseases - It used to be that you could look along rows upon rows of chemicals to kill or cure all manner of plant ills. This was a hangover from the second world war when anything that hindered the nation’s food supply had to be got rid of at any cost. Today thankfully we have woken up to the possible long term effect of indiscriminate use of chemicals and so our choice of product has been greatly reduced. If our arsenal of weapons against the onslaught of marauding pests and diseases has been so depleted you may well ask yourself what hope is there to have a healthy garden. Let us go back a step and think about dealing with the cause rather than the symptoms of plant health issues. First let us agree on the principle that nature abhors a void, so as one species or variety is displaced another comes in, sometimes more problematic to take its place. That would suggest that the compromise would be to have a balanced approach and to work towards creating a harmonious situation between our desires for perfection and natures vagaries. Why do plants suffer from pests and diseases? We might apply the same logic as we would do to ourselves. Sometimes it can be a genetic disposition to a certain illness but often in less severe cases it can be due to stress or failing to take adequate care of ourselves. So let us look at some possible causes before we reach for the chemicals. Stress Right from the onset are we working with nature or trying to persuade a plant that it must grow in a particular spot rather than considering whether it is suitable for such a growing position.
  • Genus Pratylenchus Filipjev: Multientry and Monoentry Keys and Diagnostic Relationships (Nematoda: Tylenchida: Pratylenchidae)

    Genus Pratylenchus Filipjev: Multientry and Monoentry Keys and Diagnostic Relationships (Nematoda: Tylenchida: Pratylenchidae)

    © Zoological Institute, St.Petersburg, 2002 Genus Pratylenchus Filipjev: multientry and monoentry keys and diagnostic relationships (Nematoda: Tylenchida: Pratylenchidae) A.Y. Ryss Ryss, A.Y. 2002. Genus Pratylenchus Filipjev: multientry and monoentry keys and diag- nostic relationships (Nematoda: Tylenchida: Pratylenchidae). Zoosystematica Rossica, 10(2), 2001: 241-255. Tabular (multientry) key to Pratylenchus is presented, and functioning of the computer- ized multientry image-operating key developed on the basis of the stepwise computer diagnostic system BIKEY-PICKEY is described. Monoentry key to Pratylenchus is given, and diagnostic relationships are analysed with the routine taxonomic methods as well as with the use of BIKEY diagnostic system and by the cluster tree analysis using STATISTICA program package. The synonymy Pratylenchus scribneri Steiner in Sherbakoff & Stanley, 1943 = P. jordanensis Hashim, 1983, syn. n. is established. Con- clusion on the transition from amphimixis to parthenogenesis as one of the leading evolu- tionary factors for Pratylenchus is drawn. A.Y. Ryss, Zoological Institute, Russian Academy of Sciences, Universitetskaya nab. 1, St.Petersburg 199034, Russia. Identification of nematode species is difficult diagnostic system, and by the cluster tree analy- because of relative poverty and significant sis using STATISTICA program package intraspecific variability of diagnostic characters. (STATISTICA, 1995). The genus Pratylenchus Filipjev is an example of a group with large number of species (49 valid Material and the basic information sources species, more than 100 original descriptions) and complicated diagnostics. The genus has a world- The collections of the following institutions wide distribution and economic importance as were used in research: Zoological Institute, Rus- its species are the dangerous parasites of agri- sian Academy of Sciences; Institute for Nema- cultural crops.
  • Prof. Dr. Hrotkó Károly Raising Grafts

    Prof. Dr. Hrotkó Károly Raising Grafts

    Raising grafts and trees in the nursery Aims of raising grafts . Propagation trees and shrubs difficult to propagate by autovegetative means . Production of composite plants with traits determined by more than one genom . Production of trees and shrubs with special growth habits (sphaeroid, compact, hanging, shrubs on high trunks, combi-trees, trained forms) Raising grafts Prof. Dr. Hrotkó Károly 2 Stages of graft raising . Raising of rootstock: until the required size - for bench grafting in previous years - grafting in root collar 6 – 12 month - for topworking 2-4 years . Creation the graft - during rootstock raising: budding in autumn, grafting in spring as the rootstock reached the required height - separate process: bench grafting on bareroot or potted rootstocks . Raising grafts until the required size and quality: Raising grafts Prof. Dr. Hrotkó Károly 3 Classification of fruit trees by ENA standards . One year grafted trees (maidens) . Feathered fruit tree (2-3 years) - minimum two years cultivation at wide spacing, - side branches may have been pruned appropriate to species/cvs . Pyramid fruit tree - pyramidal appearance, straight leading shoot - regularly distributed main branches not lower than 30 cm from graft . Bush fruit tree: same as pyramid but no leading shoot . Branched fruit tree (Knipboom) - one year graft cut back at min. 40 cm from soil level - well distributed 3-4 shoots on the new growth between 50-100 cm from soil level . Standard trees: dwarf, short, half, full standard . Trained forms: horizontal cordons (one or two arms), oblique palmet (single or two stage), single or double U, two stage U, horizontal espalier, fan. Raising grafts Prof.
  • UC Riverside UC Riverside Electronic Theses and Dissertations

    UC Riverside UC Riverside Electronic Theses and Dissertations

    UC Riverside UC Riverside Electronic Theses and Dissertations Title Investigations into Peach Replant Disease and Nematophagous Fungi Permalink https://escholarship.org/uc/item/2249179h Author Yang, Jiue-in Publication Date 2012 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA RIVERSIDE Investigations into Peach Replant Disease and Nematophagous Fungi A Dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Plant Pathology by Jiue-in Yang September 2012 Dissertation Committee: Dr. James Borneman, Chairperson Dr. Jörn Ole Becker Dr. Michael D. Coffey Copyright by Jiue-in Yang 2012 The Dissertation of Jiue-in Yang is approved: ___________________________________________________ ___________________________________________________ ___________________________________________________ Committee Chairperson University of California, Riverside ABSTRACT OF THE DISSERTATION Investigations into Peach Replant Disease and Nematophagous Fungi by Jiue-in Yang Doctor of Philosophy, Graduate Program in Plant Pathology University of California, Riverside, September 2012 Dr. James Borneman, Chairperson The research described in this dissertation examined peach replant disease and two nematode biological control systems using traditional plant pathology methods and molecular microbial ecology methods. In Chapter 1, the experiments identified microbes associated with peach replant disease in soils with various levels of disease symptoms. To identify bacteria, fungi and oomycetes associated with the replant disease, culture and culture-independent analyses were performed on DNA extracted from plant roots. Among the most abundant bacterial operational taxonomic units, 27 were negatively correlated with peach top weights while 10 were positively correlated. Among the most abundant fungi and oomycetes, negative and positive associations were identified between P.