Glossary

• Abdomen - The third and rearmost region of the insect body.
• Aecium (pl. aecia) - One of the reproductive structures in the life cycle of a rust fungus. Aecia normally appear as blisters on the host plant.
• Aeciospores - Spores produced in an aecium.
• Alternate host - Host in the life cycle of a rust fungus on which the pycnial and aecial stages are formed.
• Ascospores - Spores produced in a saclike structure (the ascus). This structure is typical of a large group of fungi, the Ascomycetes.
• Basidiospore - A spore borne on the outside of the reproductive structure called a basidium. This structure is typical of the group of fungi called the Basidiomycetes.
• Cambium - A layer, one- or two-celled thick, between the xylem and phloem in higher plants. The cambium produces both of these tissues, resulting in diameter growth.
• Canker - A localized necrotic lesion of the cambium.
• Chlorosis (adj. chlorotic) - The loss of green pigment in a plant due to the plants inability to produce chlorophyll.
• Conk - A fruiting body of a wood decay fungus that bears basidia.
• Dormant - Having growth, development, or other biological activity suspended; resting, inactive.
• Dorsal - Of or relating to the back; belonging to or situated on or near the upper surface.
• Epicormic - Growing from a dormant bud that has been exposed to light and air.
• Frass - Solid larval excrement, as left by defoliators; wood fragments made by a wood-boring insect, usually mixed with excrement.
• Fruiting Bodies - Any structure formed of mycelia that contains spore bearing cells.
• Fungus (pl. fungi) - A nongreen plant with a vegetative body formed of tubular filamentous cells (hyphae). Fungi reproduce by spores.
• Generation - Period of time required to complete the life cycle of an insect.
• Gouting - Tumorlike swellings on boles, branches, or twigs, caused by feeding of sucking insects.
• Haustorium (pl. haustoria) - A specialized structure of a pathogen that is capable of direct penetration into, and nutrient absorption from, a host plant.
• Head - The first region of the insect body. Eyes, mouth parts, and antennae (where present) are attached in this region.
• Honeydew - A sweetish secretion produced by sucking insects, particularly aphids and scales.
• Host - A plant which provides nutrition for an invading parasite.
• Host Range - The various plants which a pathogen can infect.
• Infection - The establishment of a feeding relationship between a host and a parasite.
• Infection Court - Point of entry and establishment of a pathogen in the host organism.
• Instar - The life stages of an insect larva between molts.
• Larva (pl. larvae) - A young insect differing fundamentally in form from the adult (compare to nymph).
• Metamorphosis - Series of changes through which an insect passes in developing from egg to adult.
• Mycelium - A mass of fungal filamentous cells. It forms the vegetative body of the fungal plant.
• Mycoplasma - A group of microscopic organisms intermediate between bacteria and viruses.
• Necrotic - Dead.
• Nymph - Young stage of insect which does not fundamentally differ in form from the adult (compare to larva).
• Parasite - An organism that lives on or in, and obtains its food from, another organism (host).
• Parthenogenesis - Reproduction without male fertilization.
• Pathogen - An agent that causes disease.
• Perithecium (pl. perithecia) - A closed bulb- or ball-shaped fruiting body with a pore through which ascospores are extruded, usually in a gelatinous paste.
• Primary host - The host of a rust fungus on which the telial stage of the fungus is produced.
• Prothorax - Firstthoracicsegment bearing the first pair of legs but no wings.
• Pupa (pl. pupae) - The intermediate life stage between the larva and the adult.
• Pupate - To become a pupa; to pass through a pupal state.
• Resinosis - Exudation of pitch from a wound or infection on a conifer.
• Resistance - The ability of a host to slow the development of a disease.
• Resistance Breeding - The selection and deliberate propagation of those individuals in the population which display resistance to a specific pest.
• Rhizomorph - A thick strand of mycelium in which the hyphae have lost their individuality; similar in appearance to a small root.
• Saprophyte - Any organism which feeds on dead organic matter.
• Segment - A subdivision of an animal body or appendage.
• Sooty Mold - A dark or black velvety coating of mycelium of various fungi growing in insect honeydew on the leaves, fruit, or other exposed parts of plants.
• Spores - The reproductive unit of fungi. Spores function in the same way that seeds do for higher plants.
• Sporodochium (pl. sporodochia) - A cushion-shaped vegetative structure covered with spore bearing cells.
• Stroma (pl. stromata) - A compact vegetative structure on, or within which, fruiting bodies are formed.
• Telium (pl. telia) - Specialized fruiting structure of a rust fungus which produces teliospores. Generally, telia appear as hairlike filaments on the underside of leaves of the host.
• Teliospores - In a rust fungus life cycle these resting spores are the normal overwintering spore form. They germinate in the spring and generate basidiospores.
• Thorax (Adj. thoracic) - The second (middle) region of the insect body. The six true legs are normally attached in this region.
• Thoracic legs - True legs located on the second region of the insect body.
• Uredium (pl. uredia) - One of the five reproductive tissues in the complete rust life cycle. This tissue gives rise to a large number of spores on a continuous basis for an extended period of time.
• Urediospores - Spores produced in a uredium.
• Vector - Any organism that transmits a disease-causing organism.
• Ventral - Of or relating to the belly; belonging to or situated on or near the lower surface.
• Windthrow - The uprooting or overturning of trees by the wind.

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USDA Forest Service - Forest Health Protection, Southern Region
Last Modified: Friday, 11 January 2013 at 13:00:03 EST