Glossary of phytopathology

This is a glossary of some of the terms used in phytopathology. Phytopathology is the study of plant diseases. It is a multi-disciplinary science since prerequisites for disease development are the presence of a susceptible host species, a pathogen and the appropriate environmental conditions.

• 2Blades – A nonprofit organization focused on promoting durable genetic resistance in crops against plant pathogens through advanced research and strategic partnerships.
• Abiotic – Non-living environmental factors, such as temperature or pollutants, that can cause plant disorders or mimic pathogen-induced diseases.
• Acid precipitation – Rainfall with low pH due to air pollution, which can damage plant tissues and alter soil chemistry.
• Acid rain – A form of acid precipitation resulting from atmospheric sulfur and nitrogen compounds, affecting plant health and soil ecosystems.
• Acropetal – A directional term indicating movement from the base toward the apex, such as nutrient or toxin movement in plants.
• Actinomycetes – A group of filamentous, gram-positive bacteria known for producing antibiotics and contributing to the suppression of soil-borne plant diseases.
• Acute toxicity – The adverse effects of a toxic substance after a single or short-term exposure.
• Acute – Refers to symptoms that appear rapidly and are often severe in nature.
• Aeciospore – A type of spore produced in aecium structures of rust fungi during their life cycle.
• Aecium – A cup-like structure in rust fungi that produces aeciospores.
• Aflatoxin – A toxic secondary metabolite produced by certain Aspergillus species, commonly found in stored grains and nuts.
• Agar – A gelatinous substance derived from red algae, widely used as a culture medium for microbial growth in labs.
• Aggressiveness – The quantitative ability of a pathogen to colonize and cause damage to a host, distinct from virulence.
• Agreement on the Application of Sanitary and Phytosanitary Measures – An international treaty under the World Trade Organization that sets guidelines for protecting human, animal, and plant health while preventing unjustified trade barriers.
• Air pollution – Contaminants in the atmosphere that can contribute to abiotic plant injuries or increase susceptibility to pathogens.
• Alkaloids – Naturally occurring plant compounds that often have defensive properties against herbivores and pathogens.
• Allele – One of two or more versions of a gene that may influence disease resistance or susceptibility in plants.
• Allelopathy – The chemical inhibition of one plant species by another due to the release of bioactive compounds.
• Alternate host – A different plant species required by certain pathogens to complete their life cycle, such as rust fungi.
• Alternative hosts – Plant species that can harbor a pathogen but are not the primary host in the life cycle.
• American Phytopathological Society – A professional society dedicated to the advancement of plant pathology research and education, primarily in North America.
• Amphid – A sensory organ in nematodes used for navigation, essential in host-finding by parasitic species.
• Amphigynous – A type of oogonium arrangement where the male gametangium encircles the female in certain Oomycetes.
• Amphimixis – Sexual reproduction involving gamete fusion, leading to genetic recombination.
• Amphimobile – Describes a substance or signal that can move in both upward (acropetal) and downward (basipetal) directions within a plant.
• Anaerobic – Environments or organisms that operate in the absence of oxygen; some anaerobic conditions promote disease development.
• Annual Review of Phytopathology – A leading peer-reviewed journal that publishes comprehensive review articles in the field of phytopathology.
• Antagonism (phytopathology) – An interaction where one microorganism inhibits or suppresses the growth of another, often used in biological control strategies.
• Anthracnose – A general term for plant diseases characterized by dark, sunken lesions, typically caused by fungi in the Colletotrichum genus.
• Antibiotic – A substance produced by a microorganism that inhibits or kills other microorganisms, sometimes used in biological control.
• Antibody – A protein produced by animals in response to antigens; used in ELISA assays for pathogen detection.
• Antigen – A substance recognized by the immune system, often used in diagnostics to detect pathogens in plants.
• Antiseptic – An agent that inhibits or destroys microorganisms on living tissues; less commonly used in plant pathology.
• Apothecium – An open, cup-shaped fruiting body typical of some Ascomycota fungi, producing ascospores.
• Arbuscule – A highly branched fungal structure within plant root cells formed during arbuscular mycorrhizal symbiosis, facilitating nutrient exchange.
• Asci – Plural of ascus; sac-like structures in which sexual spores (ascospores) develop in Ascomycetes.
• Ascogenous – Refers to the hyphal cells in Ascomycetes that give rise to asci during sexual reproduction.
• Ascomycetes – A large division of fungi characterized by the formation of spores in sac-like structures called asci; includes many plant pathogens.
• Ascospore – A sexual spore produced within an ascus, typical of Ascomycota fungi.
• Ascus (pl. asci) – A sac-like cell in Ascomycetes that typically contains eight ascospores.
• Aseptate – Lacking septa or cross-walls; used to describe certain fungal hyphae, such as those of Zygomycetes.
• Asexual reproduction – The formation of offspring identical to the parent through methods like spore production, binary fission, or budding.
• Asexual – Reproduction not involving the fusion of gametes, common in fungi and some bacteria.
• Atrophy – The degeneration or wasting of plant tissues, often due to disease or nutrient deficiency.
• Attract-kill pattern – A pest management technique that uses attractants to lure pests to a location where they are then neutralized or eliminated.
• Australasian Plant Pathology Society – A regional society supporting plant pathology research, education, and collaboration in Australia, New Zealand, and surrounding areas.
• Australasian Plant Pathology – A scientific journal publishing research related to plant diseases in the Australasian region and beyond.
• Autoecious – Describes fungi that complete their entire life cycle on a single host species (e.g., some rust fungi).
• Autotroph – An organism capable of synthesizing its own food from inorganic sources using light or chemical energy.
• Axenic – A culture containing only a single species or strain of organism, free from contamination.
• Bacilliform – Rod- or cylinder-shaped, often used to describe the shape of certain bacterial or viral particles.
• Bacterial streaming – The movement of bacteria from cut plant tissue, used diagnostically to identify bacterial infections.
• Bactericide – A chemical substance capable of killing bacteria, used in disease management.
• Bacteriocin – A protein produced by bacteria that inhibits or kills closely related bacterial strains.
• Bacteriophage – A virus that infects and replicates within bacteria; being explored for controlling bacterial plant pathogens.
• Basidiomycetes – A class of fungi that includes rusts, smuts, and mushrooms, characterized by producing spores on specialized cells called basidia.
• Blue stain fungi – A group of fungi that colonize wood, often after insect damage, and produce characteristic blue or gray staining, but typically do not cause structural damage.
• Borlaug Global Rust Initiative – A global effort to combat wheat rust diseases through coordinated research and deployment of rust-resistant cultivars.
• British Society for Plant Pathology – A UK-based professional organization promoting plant pathology through publications, events, and advocacy.
• Discomycetes – An obsolete grouping of ascomycete fungi known for their cup-like fruiting bodies, now classified under various ascomycete orders.
• Disease management (agriculture) – Strategies and practices used to prevent or control plant diseases to ensure healthy crop production.
• Disease suppressive soils – Soils that naturally reduce the incidence or severity of specific plant diseases due to their microbial composition and activity.
• Electrical penetration graph – A technique used to study the feeding behavior of piercing-sucking insects, such as aphids, on plant tissues by measuring electrical resistance.
• Gene-for-gene interactions in rust fungi – A genetic model describing how specific resistance genes in plants correspond to avirulence genes in rust fungi.
• Gene-for-gene relationship – A framework for understanding host-pathogen interactions, where resistance in the host is activated only when a matching gene is present in the pathogen.
• Glossary of phytopathology – A compiled list of terms and definitions commonly used in the field of plant pathology and phytopathological research.
• Horizontal resistance – A type of disease resistance controlled by multiple genes, providing partial but broad-spectrum resistance across pathogen races.
• Hypersensitive response – A rapid, localized cell death at the infection site in plants, serving as a defense mechanism to limit pathogen spread.
• ISPM 15 – An International Standard for Phytosanitary Measures that mandates treatment of wood packaging material to prevent the spread of pests and diseases across borders.
• Integrated pest management – An ecological approach to managing pests and diseases through a combination of biological, cultural, mechanical, and chemical practices.
• International Cocoa Quarantine Centre – A research center in the UK responsible for safely exchanging and quarantining cocoa plant material to prevent disease spread.
• International Society for Plant Pathology – A global organization dedicated to advancing the science of plant pathology and fostering international collaboration.
• International Year of Plant Health – A campaign by the FAO and the United Nations (2020) to raise awareness about the importance of protecting plant health to ensure food security.
• Koch's postulates – A set of four criteria established by Robert Koch used to prove that a specific pathogen causes a particular disease.
• Molecular Plant Pathology – A journal focusing on the molecular biology of plant-microbe interactions and mechanisms of plant disease.
• Mycelia sterilia – A group of fungi that do not produce recognizable spores, making them difficult to identify through traditional taxonomic methods.
• Pathosystem – The dynamic relationship between a host plant, a pathogen, and the environment in which disease development occurs.
• Photoassimilate – Organic compounds produced by photosynthesis in plants, often redirected to infection sites or consumed by pathogens.
• Phycomycete – An outdated term previously used for several groups of lower fungi, such as Oomycetes, that share similar morphological characteristics.
• Phytopharmacology – The study of the effects and mechanisms of plant-derived substances in biological systems, especially for their role in plant disease control.
• Phytosanitary certification – Official documentation verifying that plants or plant products are free from regulated pests and meet the phytosanitary requirements of an importing country.
• Phytosanitary quarantine – Regulatory practices to isolate and restrict the movement of plants or plant materials to prevent the spread of pests and diseases.
• Plant Pathology (journal) – A leading international journal that publishes research on all aspects of plant pathology, including epidemiology and molecular biology.
• Plant disease epidemiology – The study of disease incidence, distribution, and control in plant populations over time and space.
• Plant disease forecasting – The use of models and environmental data to predict disease outbreaks and guide management decisions.
• Plant disease resistance – The inherent ability of plants to prevent or mitigate infection by pathogens, often classified as vertical or horizontal resistance.
• Plant pathology – The scientific study of plant diseases caused by pathogens and environmental conditions, encompassing diagnosis, prevention, and management.
• Plant quarantine – The enforcement of legal restrictions on the movement of plants to prevent the introduction and spread of harmful pests and diseases.
• Plant-induced systemic resistance – A plant defense response that is triggered by a prior infection or treatment, leading to enhanced resistance throughout the plant.
• Puccinia pathway – A conceptual and geographic route describing the northward movement of wheat stem rust in the U.S., named after the pathogen genus Puccinia.
• Research Plot 2 – A historically significant field research plot used for long-term plant disease and agronomic studies.
• Research Plot 30 – Another notable experimental plot, possibly used in longitudinal phytopathological research, especially in cereal crops.
• Sanitary and phytosanitary measures and agreements – Regulations and protocols under WTO designed to protect human, animal, and plant life while ensuring fair trade practices.
• Sporodochia – A cushion-like mass of fungal tissue that bears conidia, often seen in coelomycetes.
• Sporodochium – The asexual fruiting body of certain fungi, from which masses of spores (conidia) are produced.
• Systemic acquired resistance – A whole-plant resistance response activated after an initial localized infection, enhancing future defense capabilities.
• Vertical resistance – Resistance governed by single genes, often providing strong but race-specific immunity against particular pathogen strains.
• Vertifolia effect – A phenomenon where breeding for vertical resistance leads to loss of horizontal resistance, resulting in increased vulnerability when resistance genes are overcome.
• Zygomycetes – A former phylum of fungi characterized by zygospore formation; now reclassified into newer groups like Mucoromycota.