abaxial: on the side facing away from the axis or stem (dorsal)

acervulus (pl. acervuli): a sub-epidermal, saucer-shaped, asexual fruiting body that produces conidia on short conidiophores

adaxial: on the side facing the axis or stem (ventral)

aeciospore: a dikaryotic rust spore produced in an aecium

aecium: a cup-shaped fruiting body of the rust fungi which produces aeciospores

alternate host: one of two kinds of plants on which a parasitic fungus (e.g. rust) must develop to complete its life-cycle

anamorph stage: the part of the life cycle of a fungus in which no sexual spores are produced; also called imperfect stage

anastomosis: the union of one hypha with another resulting in the intercommunication of their contents

appressorium (pl. appressoria): the swollen tip of a hypha or germ tube that facilitates attachment and penetration of the host by the fungus

ascocarp: the fruiting body of ascomycetes bearing or containing asci

ascomycetes: a group of fungi that produce their sexual spores, ascospores, within asci

ascospore: a sexually produced spore borne in an ascus

ascus (pl. asci): a sac-like cell of a hypha in which meiosis (part of gamete formation process consisting of joining of chromosomes and two cell divisions) occurs and which contains the ascospores

asexual reproduction: any type of reproduction not involving the union of gametes or meiosis

autoecious fungus: a parasitic fungus that can complete its entire life cycle on the same host

basidiomycetes: a group of fungi producing their sexual spores, basidiospores, on basidia

basidiospore: a sexually produced spore borne on a basidium

basidium (pl. basidia): a special form of sporophore (spore-bearing hypha) on which the sexual spores are borne

biological control: total or partial destruction of pathogen populations by other organisms

blight: a disease characterized by general and rapid killing of leaves and culms

blotch: a disease characterized by large, irregular spots or blots on leaves, shoots and/or stems

canker: a necrotic, often sunken lesion on a stem, branch or minor branch of a plant

canopy: the uppermost leafy layer of a tree or a forest

caryopsis: the fruit of a grass in which the outer layer (testa) of the seed proper is fused to the ovary wall

culm: the main ascending axis (stem) of bamboo

culm sheath: the sheath of the culm leaf, borne singly at each node of the culm proper, below the level at which the sheaths of foliage leaves take their place

curing (open-air): traditional method for preserving bamboo culms in which harvested culms with branches and leaves still attached are left in open air for some time to reduce the starch content of the culms by continued transpiration of the leaves

cellulase: an enzyme that breaks down cellulose

cellulose: a polysaccharide (a carbohydrate containing more than three monosaccharide -- carbohydrate unit that does not break down on hydrolysis -- units per molecule) composed of hundreds of glucose molecules linked in a chain and found in the plant cell walls

chlamydospore: a thick-walled asexual spore formed by the modification of a cell of a fungus hypha

chlorosis: yellowing of normally green tissue owing to chlorophyll destruction or failure of chlorophyll formation

coalesce: to unite so as to form one mass

conidiophore: a specialized hypha on which conidia are produced

conidium (pl. conidia): asexual fungus spore formed from the end of a conidiophore

culture: to artificially grow microorganisms on a prepared food material; a colony of microorganisms maintained on such food material

damping-off: destruction of seedlings near the soil line, resulting in the seedlings falling over on the ground

die-back: progressive death of shoots, branches, and roots generally starting at the tip

dikaryotic: mycelium or spores containing two sexually compatible nuclei per cell, common in the basidiomycetes

disease: any malfunctioning of host cells and tissues that results from continuous irritation by a pathogenic agent or environmental factor and leads to development of symptoms

disease cycle: the chain of events involved in disease development, including the stages of development of the pathogen and the effect of the disease on the host

disinfectant: a physical or chemical agent that frees a plant, organ or tissue from infection

epicormic: sprouts arising on stem or branch in response to infection or injury

epidemic: a widespread and severe outbreak of a disease; a drastic increase in disease-affected population

epidemiology: the study of factors affecting the outbreak and spread of infectious diseases

epidermis: the superficial layer of cells, occurring on all plant parts

epiphytic: existing on the surface of a plant or plant organ without causing infection

erumpent: projecting from or bursting through
(host tissue)

etiology: causes or origin of a disease and their relations to the host; the study of the causal factors of a disease

fruit: the ripened ovary of a seed plant with its contents and accessory parts

fructification: production of spores by fungi; also, a fruiting body

fruiting body: a complex fungal structure containing spores

fungicide: a compound toxic to fungi

genus (pl. genera): the smallest natural group containing distinct species

germ tube: the early growth of mycelium produced by a germinating fungus spore

haustorium (pl. haustoria): a projection of hyphae into host cells which acts as an absorbing organ

heteroecious: requiring two different kinds of
hosts to complete its life cycle; pertaining particularly to rust fungi

heterokaryosis: the condition in which a mycelium contains two genetically different nuclei per cell

hilum: the mark or scar on a seed produced when it separates from its stalk

hyaline: something glassy or transparent

hypha (pl. hyphae): a specialized threadlike element of the mycelium

hyphopodiate: having a specialized hyphal branch, composed of one or two cells, serving for attachment and the absorption of food

imbricate: overlapping, like tiles

inflorescence: the arrangement and mode of development of the flower on the floral axis

internode: the portion of the culm between two nodes

imperfect stage: see anamorph stage

incubation period: the period of time between penetration of a host by a pathogen and the first appearance of pathogenic symptoms on the host

infection: the establishment of a parasite within a
host plant

infectious disease: a disease that is caused by a pathogen, which can spread from a diseased to a healthy plant

infested: containing great numbers of insects, mites, nematodes, etc. as applied to an area or field; also applied to a plant surface or soil contaminated with bacteria, fungi, etc.

injury: see wound

inoculation: the arrival or transfer of a pathogen onto a host

inoculum: the pathogen or its parts that can cause infection; the portion of individual pathogens that are brought into contact with the host

integrated control: an approach that attempts to use all available methods of control of a disease, or of all the diseases and pests of a crop plant, for best control results but with the least cost and minimum damage to the environment

intracellular: within or through the cells

invasion: the introduction of a pathogen into the host

isolate: a single spore or culture and the subcultures derived from it; also used to indicate collections of a pathogen made at different times

isolation: the separation of a pathogen from its host and its culture on a nutrient medium

lamina: the blade or expanded portion of a leaf

lemma: the lower of the two membranous bracts enclosing the flower in grasses; the lower of the two glumes that surround each floret in the spikelet of grasses

lenticel: a body of cells formed on the stem surface of a plant as a lens-shaped spot, and serving as a pore

leptomorph: a term coined to designate a slender, elongated type of rhizome

lignin: a colloidal polymer of varying chemical structure that forms secondary wall material in xylem vessels, tracheids and sclerenchyma fibres

ligule: a thin, membranous outgrowth characteristic of most grasses

linear: long and narrow with parallel sides

leaf spot: a self-limiting lesion on a leaf

lesion: a localized area of discoloured, diseased tissue

life cycle: the stage or successive stages in the growth and development of an organism that occur between the appearance and reappearance of the same stage (e.g. spore) of the organism

locule: a small chamber or compartment

lodicule: one of the specialized scales at the base of the ovary certain grass flowers

midrib: the main vein of a leaf which is a continuation of the petiole

mesophyll: the parenchyma, usually containing chlorophyll, that forms the interior parts of a leaf

mosaic: symptoms of certain viral diseases of plants, characterized by intermingled patches of normal and light green or yellowish colour

mould: any profuse or woolly fungus growth on damp or decaying matter or on plant tissue surfaces

mycelium: the hypha or mass of hyphae that make up the body of a fungus

mycoplasma-like organism (MLO) : a microorganism found in the phloem and phloem parenchyma of diseased plants, and assumed to be the cause of
the disease; it resembles mycoplasma (a parasitic
microorganism, lacking a true cell wall and able to survive without oxygen) in all respects except that it cannot yet be grown on artificial nutrient media

mycorrhiza (pl. micorrhizae): a symbiotic association of a fungus with the roots of a plant

necrosis: a localized and rapid destruction of cell structures and consequent death of the protoplasts

necrotic: discoloured and dead

node: the point on the stem or branch at which a leaf or branch is borne

non-infectious disease: a disease that is caused by an environmental factor, not by a pathogen