Glossary

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pertaining to the absence of life; abiotic diseases are not caused by living organisms (pathogens), but by chemical and/or physical factors.

A cushion-like, spore-producing body of a fungus erupting from host tissue usually below the cuticle or epidermis.

Filamentous bacteria that produce several antibiotics and give soil its earthy smell.

the dikaryotic spore of a rust fungus produced in an aecium; in heteroecious rusts, a spore stage that infects the alternate host.

One of two kinds of plants on which a parasitic fungus (e.g., rust) must develop to complete its life cycle.

A temporay state of suspended animation or greatly reduced metabolism. Used in reference to nematodes.

Asexual stage of a fungus.

Disease caused by acervuli-forming fungi (order Melanconzales) and characterized by sunken lesions and necrosis.

Sycamore Anthracnose

A complex chemical substance produced by one microorganism that inhibits or kills other microorganisms (e.g., streptomycin).

A specific protein formed in the blood of warm­blooded animals in response to the injection of an antigen.

Any foreign chemical (normally a protein) that induces antibody formation in animals.

A substance that prevents, retards, or destroys microorganisms.

An open, cuplike, or saucer-shaped sexual fungal fruiting body containing asci.

Apothecium

a swollen, flattened portion of a fungal hyphae that adheres to the surface of a plant, providing anchorage for penetration into the tissue.

A group of fungi characterized by the production of sexual spores within an oval or tubular membranous sac called an ascus.

A saclike cell in which meiosis occurs and which generally contain eight spores each.

asci with ascospores of Anisogramma anomala

Vegetative; without sex organs, sex cells, or sexual spores, as the anamorph of a fungus.

The reduction in size of an organ by distributed metabolism.

The need of only one host for completing the life cycle of a rust.

autoecious

Any chemical or physical agent that kills or protects plants from bacteria.

Bactericide

Microscopic one-celled organism. Cell type lacks a distinct nucleus, sexual recombination, and chlorophyll. It does have cell walls and DNA.

A group of fungi characterized by the pro­duction of sexual spores on a club-shaped filament called the basidium.

A haploid spore formed externally on a basidium.

Short, club-shaped fungus cell on which basidiospores are produced.

the exploitation of the natural competition, parasitism and/or antagonism of organisms for management of pests and pathogens.

Any sudden, severe, and extensive spotting, discoloration, or destruction of leaves, flowers, stems, or entire plants, usually attacking young, growing tissues. (In disease names, often coupled with the name of the affected part of the host; e.g., leaf blight, blossom blight, shoot blight).

Tomato late blight

A blot or spot, usually superficial and irregular in shape and size, on leaves, shoots and fruit.

The condition in which the cells of the host become reddish or dark brown and collapse.

Camellia Sunburn

Parenchyma tissue that grows over a wound or graft and protects it against drying or other injury.

Outermost whorl of organs of a flower.

death of cambium tissue and loss and/or malformation of bark; or by the formation of sharply delineated, dry, necrotic, localized lesions on the stem; the term canker also may be used to refer to the lesion itself, particularly in woody plants.

Canker on apple

A plant or animal that carries a virus or other infective agent without showing symptoms.

Closed, usually spherical, ascus-containing structure of powdery mildew fungi, also known as a Cleistothecium. A sexual fruiting structure.

Chasmothecium

Treatment of disease by chemicals (chemotherapeutants) working internally. Chemical agent has toxic effect directly or indirectly on the pathogens without injury to the host plant.

A plant with several tissue sectors or layers differing in genetic or chromosomal constitution from the original plant.

A thick-walled asexual resting spore formed by the modification of a fungus hypha.

Chlamydospore

The abnormal plant color of yellowish-white or gray condition of plant parts resulting from the incomplete destruction of the chlorophyll.

Chlorosis

A curl-like tuft; a tendril-like mass or "spore horn" of forced-out spores.

Cirrus

Closed, usually spherical, ascus-containing structure of powdery mildew fungi, also known as a chasmothecium. A sexual fruiting structure.

Cleistothecia

to grow together into one body or spot.