Ecology Of Root Pathogens

Collection of soil samples. Isolation of groups of microorganisms from soil. Enumeration and observation of microorganisms in situ. Microorganisms in the rhizosphere. Isolation of plant pathogens from soil. Isolation of plant pathogens from roots. Control of soil environment. Extraction of soil solutions. Respiration and enzyme activity. Growth and survival. Root exudates. Screening soil microorganisms for antagonism. Testing for antibiotic activity. Production, stability, and activity of antibiotics in soil. Biological control. Culture media.

Root disease epidemics, because much of the activity takes place in soil and out of sight, pose special challenges to growers who seek to manage them and to scientists who study them. All relevant topics of root disease epidemics and their management are presented: The critical aspects of specific disease components including inoculum, host roots, mycorrhiza and the soil environment are explored. Challenges of disease assessment and the temporal and spatial aspects of epidemic development are considered, and approaches to root disease management including host resistance, chemical, biological and cultural management are discussed in detail. The book fulfills the needs of researchers, teachers, and practitioners of plant pathology.

Ecology of Root Pathogens discusses the significance of fungi infecting the roots, and emphasizes the significant diseases of roots and their symptoms. This book also names the genera and species of fungi that cause diseases of roots, and classifies and characterizes the root and pathogen interaction in soil. The book describes the behavior of plant pathogenic bacteria, such as Agrobacterium, Corynebacterium, Xanthomonas, Pseudomonas, Erwinia, and Streptomyces. It also explores how plants and plant-produced stimuli affect the associated population of plant parasitic nematodes and how these plant parasitic nematodes affect higher plants in certain ways. In addition, this book discusses the morphology, classification, nomenclature, multiplication and translocation of viruses infecting the plants. It also describes the symptoms of the virus infection in roots. The book includes a discussion on the fundamentals of biological control, which include the pathosystem concept, the behavior of the soil microflora in the soil, the reservoirs for infection, the processes of pathogen decline, and the integrated effects on the decline of the pathogen. This discussion on biological control also presents the natural and artificially induced biological control. This book will be of great value to soil microbiologists and plant pathologists.

In the course of evolution, a great variety of root systems have learned to overcome the many physical, biochemical and biological problems brought about by soil. This development has made them a fascinating object of scientific study. This volume gives an overview of how roots have adapted to the soil environment and which roles they play in the soil ecosystem. The text describes the form and function of roots, their temporal and spatial distribution, and their turnover rate in various ecosystems. Subsequently, a physiological background is provided for basic functions, such as carbon acquisition, water and solute movement, and for their responses to three major abiotic stresses, i.e. hard soil structure, drought and flooding. The volume concludes with the interactions of roots with other organisms of the complex soil ecosystem, including symbiosis, competition, and the function of roots as a food source.

Root disease epidemics, because much of the activity takes place in soil and out of sight, pose special challenges to growers who seek to manage them and to scientists who study them. All relevant topics of root disease epidemics and their management are presented: The critical aspects of specific disease components including inoculum, host roots, mycorrhiza and the soil environment are explored. Challenges of disease assessment and the temporal and spatial aspects of epidemic development are considered, and approaches to root disease management including host resistance, chemical, biological and cultural management are discussed in detail. The book fulfills the needs of researchers, teachers, and practitioners of plant pathology.

The study of soilborne plant pathogens: changing outlook or more of the same?; Characteristics of trends in disease caused by soilborne pathogens with spring barley monoculture; Mycophagous amoebas from arable, pasture, and forest soils; Northern poor root syndrome of sugarcane in Australia; Effects of soil insects on populations and germination of fungal propagules; A technique to comapre growth in soil of Gaeumannomyces graminis var. tritici over a range of matric potentials; Use of aerial photography for assessing soilborne disease; Isolation and characterization of plasmid DNA in the fungus Rhizoctonia solani; Sharp eyespot of cereals and Rhizoctonia of potato; Saprophytic survival of Gaeumannomyces graminis var. tritici in the Victorian Mallee, Australia; The changing nature of stalk rot of maize caused by Gibberella zeae; Collar rot of passion fruit possibly caused by Nectria haematococca in Taiwan; Survival of Phytophthora cinnamomi in eucalyptus roots buried in forest soils; The Rhizoctonia disease complex of wheat; Population and survival of sclerotia of Rhizoctonia solani in soil; Rhizoctonia in South Australian wheat fields; Anastomosis groups of Rhizoctonia solani and binucleate Rhizoctonia; A study of pepper wilt in Northern Iraq; Rhizoctonia on small-grain cereals in Great Britain; Fungal invasion of clover and grass roots in New Zealand pasture soils; Pathogenic Rhizoctonia and orchids; Origin and distribution of Phytophthora cinnamomi; The biology of the rhizosphere; Mode of colonization of roots by Verticillium and Fusarium; Dynamics of root colonization by the take-all fungus; A mathematical model of vesicular-arbuscular mycorrhizal infection in roots of Trifolium subterraneum; Rhizoplane mycoflora of Gahnia radula and Isopogon ceratophyllus in soils infested and free from Phytophthora cinnamomi; Soils suppressive to Fusarium wilt: mechanisms and management of suppressiveness; Reduction of take-all by mycophagous amoebas in pot bioassays; Trichoderma as a biocontrol agent against soilborne root pathogens; Chemical factors in soils suppressive to Pythium ultimum; Influence of trichoderma on survival of Thanatephorus cucumeris in association with rice in the tropics; Biological control of Fusarium wilt of sweet potato with cross-protection by nonpathogenic Fusarium oxysporum; Integrated biological and chemical control of sclerotial pathogens; Yield depressions in narrow rotations caused by unknown microbial factors and their suppression by selected pseudomonads; Antagonistic behavior of root region microfungi of pigeon pea against Fusarium udum; Control of Verticillium dahliae by coating potato seed pieces with antagonistic bacteria; Application of fluorescent pseudomonads to control root diseases; The role of seeds in the delivery of antagonists into the rhizosphere; Interactions between microbial residents of cereal roots; Survival of fungal antagonists of Gaeumannomyces graminis var. tritici; Control of wheat take-all and ophiobolus patch of turfgrass by fluorescent pseudomonads; Role of plant breeding in controlling soilborne diseases of cereals; Phytophthora drechsleri causes crown rot and the accumulation of antifungal compounds in cucurbits; Changes in root tissue permeability associated with infection by Phytophthora cinnamomi; Stability of Verticillium resistance of potato clones and changes in soilborne populations with potato monoculture; Field resistance of wheat cultivars to crown rot (Fusarium graminearum group 1); Variability in Phytophthora cactorum in India; Glasshouse test for tolerance of wheat to crown rot caused by Fusarium graminearum group 1; Development of inoculation technique for Rhizoctonia solani and its application to screening cereal cultivars for resistance; Phytophthora cinnamomi; a study of resistance in three native monocotyledons that invade diseased victorian forests; Relative susceptibility of wheat, rye, and triticale to isolates of take-all; New inoculation technique for Gaeumannomyces graminis var. tritici to measure dose response and resistance in wheat in field experiments; Soil as an environment for the growth of root pathogens; Lethal temperatures of soil fungi; Relation between root infection with Phytophthora cinnamomi and water relations in susceptible and field-resistant Eucalyptus species; Effects of soil temperature, moisture, and timing of irrigation on powdery scab of potatoes; Influence of depleted oxygen supply on phytophthora root rot of safflower in nutrient solution; Pea root pathogen populations in relation to soil structure, compaction, and water content; Wax layers for partitioning soil moisture zones to study the infection of wheat seedlings by Fusarium graminearum; Effect of frost on Fusarium root rot of alfalfa and possibility of double trait selection; Reduction in infection of wheat roots by Gaeumannomyces graminis var. tritici with application of manganese to soil; Effect of parent materials derived from different geological strata on suppressiveness of soils to black root rot of tobacco; Effect of varied NPK nutrition and inoculum density on yield losses of wheat caused by take-all; Influence of environmental factors and sclerotial origin and parasitism of Sclerotinia sclerotiorum by Coniothyrium minitans; Impact of herbicides on plant diseases; Effects of soil application of fungicides on take-all in winter wheat; Use of fungicides to study significance and etiology of root rot of subterranean clover in dryland pastures of Victoria; Suppression of soilborne diseases of ornamental plants by tree bark composts; Effects of cropping sequences on saprophytic survival and carry-over of Gaeumannomyces graminis var. tritici; Susceptibility of apple trees to Phytophthora cactorum and effect of systemic fungicides; Enhanced suppression of take-all root rot of wheat with chloride fertilizers; Effect of tillage on Heterodera avenae in wheat; Effect of rotation and tillage on take-all and Rhizoctonia root rot in wheat; Activity of fungicides in soil against infection of wheat roots by Gaeumannomyces graminis var. tritici; Integrated control of root rot of soybean caused by Phytophthora megasperma f.sp. glycinea; Cropping practices and root diseases; Root rot of irrigated subterranean clover in Northern Victoria: Significance and prospects for control; Solar disinfestation of soils; Soil solarization: effects on Fusarium wilt of carnation and Verticillium wilt of eggplant; Evaluation of soil solarization for control of clubroot of crucifers and white rot of onions in Southeastern Australia; Relative efficiency of polyethylene mulching in reducing viability of sclerotia of sclerotium oryzae in soil; Proceedings of the first International Workshop on Take-all of Cereals; preface to the Take-all Workshop; Session 1: Culture and taxonomy; Session 2: Inoculum; Session 3: Pathogenic variation; Session 4: Growth regulators, pesticides, and herbicides; Session 5: Disease expression and measurement; Session 6: Grower observations and questions; Session 7: Nutrition and fertilizers; Session 8: Environmental factors; Session 9: Host-parasite interactions; Session 10: Microbial interactions; Session 11: Disease management; Session 12: Suppressive soils and take-all decline; Session 13: Bacterization and biological control.