Glossary of forest protection
 Diagnosing Injury to Eastern Forest Trees. The Pennsylvania State
University, Pennsylvania, 1987. 122 p.
A - B - C -
D - E - F - G
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M - N - O - P
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U - W - Z
ABDOMEN - The third or posterior major division
of the insect body; consists normally of nine or ten apparent segments;
bears no functional legs in the adult stage, but may bear prolegs or
false legs in the larval stage. Fin.
ABIOTIC PATHOGEN - A nonliving, disease-causing
entity, e.g., drought, salt, air pollutants. Fin.
ACUTE INJURY - Injury, usually involving
necrosis, which develops within several hours to a few days after
a high dose exposure to a pollutant; expressed as fleck, scorch, bifacial
necrosis, etc. Fin.
AECIAL STAGE (aecium) - A spore stage
of the rust fungi; a cuplike structure bearing aeciospores. Fin.
ALTERNATE HOST - One of two taxonomically
different hosts required by a heteroecious rust fungus to complete
its cycle; also applies to some insects. Fin.
ANTERIOR - In front; before; opposite of
posterior. Fin. Swe.
ANTHOCYANOSIS - Presence of abnormal
red-purple coloration in foliage.
ASEXUAL STAGE - Vegetative; without
sexual organs or spores. Fin.
AUTOECIOUS - Completing entire life cycle
on one host; especially applied to the rust fungi. Fin.
BANDING - A foliar symptom characterized by a
limited zone of necrotic or discolored tissue traversing the leaf, e.g.,
the band of tissue on a pine needle injured by SO2 or 03.
BASIDIAL STAGE (basidium)- A spore
stage of the rust fungi; a specialized structure in the Basidiomycetes
bearing basidiospores. Fin.
BASIDIOCARPS - Sexual fruiting structure
in the Basidiomycetes; conks, sporophore, mushrooms, etc. Fin.
BIFACIAL NECROSIS - Death of plant
tissues, extending from the upper to the lower leaf surface.
BIOINDICATOR SPECIES - Species,
varieties, or cultivars sufficiently sensitive to a specific pollutant
to be useful as indicators for the presence of that pollutant.
BIOTIC PATHOGEN - A living organism
capable of inciting disease, e.g., fungi, bacteria, viruses, etc.
BLEACHING - Loss of normal color, tending
toward white, cream, or tan coloration. Fin.
BLIGHT - A common term for several different
diseases; usually applied to those where leaf damage is sudden and
severe. Fin. Swe.
BRONZING - A golden brown discoloration that
usually appears on the lower surface of leaves and is often an advanced
stage of the silvering or glazing typical of injury by PAN and other
oxidants; brown coloration on needles due to spider mite infestation.
CALLUS TISSUE - A protective tissue of thin-walled
cells developed on wound surfaces, often beginning at the edges of a
CANKER - A plant disease symptom characterized
by a sharply defined necrosis of cortical tissue, often sunken below
bark surface. Fin.
CHEWING INSECTS - Insects that consume
all tissues of leaves or portions of leaves, using robust mandibles
for chewing. Fin.
CHLOROSIS - Yellowing of plant tissue due
to failure of chlorophyll synthesis or to chlorophyll destruction.
CHLOROTIC DWARF - An abiotic disease
of Pinus strobus characterized by reduced growth, chlorosis and mottling
of the needles, and premature abscission of all but current needles.
CHRONIC INJURY - Injury which develops
after long-term or repeated low dose exposure to an air pollutant
expressed as chlorosis, bronzing, premature senescence, reduced growth,
CLONAL LINES - A group of plants originating
from buds or cuttings from the same individual.
CONK - The fruiting structure of a wood-rotting
fungus, especially of one of the Polyporaceae. Fin.
COCOON - A covering, composed partly or wholly
of silk or other sticky fiber, spun or constructed by many larvae
as a protection for the pupal stage. Fin.
CORNICLES - The posterior dorsal erect or
semi-erect tubules of aphids which secrete a waxy defensive liquid
to protect the insect against enemies; short, blunt horns or rounded
projections occurring on the abdomen.
CRAWLER - The first instar motile nymphal
stage of scale insects and mealybugs, which moves to a new feeding
site before settling down to a sessile existence for the rest of its
CRINKLING - Bending or twisting of foliage
without breaking; wrinkling. Fin.
CRYPTIC - Hidden or concealed. Fin.
DEFOLIATOR - Any chewing insect that consumes
the leaves or needles of plants. Fin.
DELIQUESCENT - To ramify into fine divisions,
such as abnormal numbers of buds, twigs, branches, or leaves, e.g.,
witches' broom development. Fin.
DORSAL - Of or belonging to the upper surface;
DORSOVENTRAL - From top to bottom; from
the upper surface to the lower surface.
DORSUM - The upper surface; top. Fin.
DOSE - A measured concentration of a toxicant
for a known duration of time (concentration per unit time).
EGG GALLERY - A long, narrow tunnel along
the sides of which eggs are deposited in small niches; the pattern of
construction is often diagnostic of a particular species of insect.
EGG MASS - Cluster of eggs, usually in a
matrix of body hairs or wing scales from the female adult and/or a
mucilaginous cementing secretion.
ELYTRA - The anterior leathery or chitinous
wings of beetles and leafhoppers; serve as coverings to the hind wings
and commonly meet at rest in a straight line down the middle of the
ENGRAVER - Beetle which feeds in the phloem-cambium
region of woody plants, often scoring or engraving adjacent sapwood
EPICORMIC BRANCHING - Branches
arising from buds in bark along mainstem, most commonly occurring
in trees under crown stress; also called watersprouts. Fin.
EPIDEMIC - A change, usually a sudden increase,
in a disease within a population. Fin.
FOREWINGS - Front pair of wings. Fin.
FLECK - White to tan necrotic lesions up to
a few millimeters in length or diameter, usually confined to the upper
surface of leaves. Fin.
FRASS - Solid larval insect excrement; mixed
with wood fragments in woodboring or bark-boring insects. Fin.
FRUITING BODY - A specialized structure,
often macroscopic, on or in which spores are produced. Fin.
FUMIGATION - The natural or controlled
exposure of plants to toxic gases or volatile substances. Fin.
GALL" - A swelling or outgrowth of tissue induced
by a pathogen or insect on a slant. Fin.
GENERATION - The successive developmental
stages from reproduction to reproduction, e.g., egg, larva, pupa,
adult. Fin. Swe.
GIRDLING - Destruction of tissue in a ring
around a twig, branch, or stem. Fin.
GOUT - Formation of swellings at nodes or at
the base of buds.
GREGARIOUS - Living in groups or communities.
GRUB - An insect larva; a term loosely applied,
usually to larvae of Coleoptera; larva is thick-bodied with well-developed
thoracic legs but no abdominal prolegs. Fin.
HETEROECIOUS - Requiring two taxonomically
different hosts to be able to complete the entire life cycle, as in
the rust fungi. Fin.
HONEYDEW - A sweetish excretion produced
through the anus by certain insects, notably aphids and scale insects.
HOST - A living organism serving as a food source
for a parasite. Fin.
HYSTEROTHECIUM - A sexual fruiting
structure of the Ascomycete fungi, usually football-shaped or elongate
in appearance and occurring on infected needles. Fin.
INSTAR - The insect itself during the time between
molts in the larva or nymph, numbered to designate the various periods;
i.e., the first instar is the insect between the egg and first molt.
INTERVEINAL - Between veins. Fin.
INTRAVEINAL - Associated along or within
LARVA(plural = larvae) - The immature instars, between
the egg and pupal stages, in an insect having a complete metamorphosis
(egg, larva, pupa, adult). Larvae feed and grow but cannot fly, nor
can they reproduce. Fin.
LESION - A wound; a well-marked, but limited,
diseased area; a break or rupture through a tissue, especially a surface
LOOPER - A caterpillar in which some or all
of the middle abdominal prolegs are wanting and which moves by placing
the posterior part of the abdomen next to the thorax, forming a loop
of the intervening segments, then extending the anterior part of the
body forward. Fin.
MIDDORSAL - In the middle of the upper side
MIMICKING SYMPTOMS - Symptoms similar
to those caused by pollutants but induced by other abiotic or biotic
MINER - The larval stage of an insect which
makes galleries or burrows between the upper and lower surfaces of
leaf tissue. Fin.
MITE(S) - Small, often minute, arthropods in
the order Acarina of the class Arachnida, which includes spiders,
scorpions, and related forms. Mites have four pairs of legs vs. three
pairs in insects. Fin.
MOLT - To cast off the outgrown skin or cuticle
in the process of insect development; changing from one instar to
the next. Fin.
MOTTLE - Irregular, diffuse patterns of chlorotic
areas interspersed with normal green leaf tissue. Fin.
MOSAIC - A diseased condition where different
portions of a leaf vary in amounts of chlorophyll, thus giving the
leaf a mottled appearance; usually caused by viruses. Fin.
MYCELIUM - A mass or aggregate of hyphae;
vegetative stage of fungi. Fin.
NAKED - Larva devoid of body hairs or setae; pupa
not enclosed in a cocoon or other covering.
NECROSIS - Death. Fin.
NYMPH - The immature stage of insects, following
hatching, which does not have a pupal stage, i.e., incomplete metamorphosis
(egg, nymph, adult). Late instar nymphs may have nonfunctional rudimentary
wings and/or genitalia. Fin.
OVIPOSITION - The act of depositing the eggs.
OVIPOSITOR - The egg-laying apparatus;
the extended genitalia of a female insect. Fin.
PARASITE - An organism which lives on or in another
living organism and obtains part or all of its nutrients from that other
living organism. Fin.
PATHOGEN - Any agent of the environment capable
of inciting disease. Fin.
PERITHECIUM" - A sexual fruiting structure
of the Ascomycetes with an opening called the ostiole at or near its
POSTERIOR - Hind or hindmost; opposite of
PREDISPOSITION - The weakening of an
organism by some factor(s) of either the physical or biotic environment
so as to render the organism more susceptible to a pathogen. Fin.
PROLEG - Any process or appendage that serves
the purpose of a leg; specifically, the fleshy, unjointed, ventral
abdominal projections of caterpillars and certain sawfly larvae.
PUPA - The resting, inactive, nonfeeding instar
in all holometabolous insects; the stage intermediate between the
larva and the adult. Fin.
PYCNIAL STAGE (pycnium) - A flaskshaped
spore stage of the rust fungi; oozes out spores in a sticky matrix.
PYCNIDIUM - An open-pored, flaskshaped fruiting
structure in which asexual spores called conidia are produced.
RASPING - A type of feeding by insects which rub
or grate the leaf surfaces with their mouthparts to obtain particles
for consumption. Fin.
RESINOSIS - Resin flow through bark or from
wounds or cankers on conifers. Fin.
RHIZOMORPH - A thread- or cordlike fungal
structure made up of hyphae. Fin.
RINGSHAKE - Peripheral cracks in woody tissues
of stems. The pattern of damage is concentric with the annual rings.
RINGSPOT - A circular area of chlorosis with
a green center.
SAPROPHYTE - An organism living on dead organic
SCORCH - Appearing as if tissues were burned
by heat; usually affecting marginal portions of leaves. Fin.
SENESCENCE - Aging of tissues; growing
old. Fin. Swe.
SESSILE - Attached or fastened; incapable
of moving from place to place. Fin.
SETA (plural = setae) - Slender, hairlike or
bristly projections arising from the epidermal layer on any part of
the body of an insect. Fin.
SEXUAL STAGE - Reproductive stage of
the life cycle of an organism. Fin.
SHOTHOLES - Small holes in a leaf caused
by feeding activity and giving the appearance of injury via a shotgun.
SIGN - The actual presence of the causal organism
in association with the disease symptoms.
SKELETONIZER(S) - Insects which consume
leaf tissue, often from the lower side of the leaf, leaving the upper
epidermis and vascular tissues intact.
SPORE - A specialized structure consisting of
one or few cells and serving any or all of the following three functions:
(i) reproduction, (ii) dissemination. (iii) survival. Fin.
SPOROPHORE - A spore-producing or supporting
STADIUM (plural = stadia) - The period of
time between two successive molts. Fin.
STAGE - One of the successive principal divisions
in the life cycle of an insect, e.g., egg, nymph, larva, prepupa,
pupa, adult. Fin. Swe.
STAGHEAD - Death of limbs and main branches
of a tree in the upper crown, giving the appearance of antlers.
STIPPLE - Pigmented spots up to a few millimeters
in diameter, often on the upper surface of leaves.
STYLET - A small, stiff, needlelike tube inserted
into a food source to obtain liquid food.
SUCKING INSECTS - Insects that insert
their mouthparts into plant tissues and withdraw nutrients and fluids
through stylets. Fin.
SUSCEPT - Any organism that can be attacked
by a biotic pathogen.
SYMPTOM - Visible or measurable manifestation
that an organism is diseased; a change in the organism itself.
TELIAL STAGE (telium) - A stage of the rust
fungi; a fruiting structure usually appearing as fine, hairlike projections
from lower surfaces of infected leaves. Fin.
THORACIC - Belonging or attached to the thorax.
THORAX - The body region behind the head, which
bears wings and true (jointed) legs if present. Fin.
TUFT - Bunching of twigs or needles. Fin.
TYLOSIS - Outgrowth of a cell membrane from
a ray or axial parenchyma cell through a pit in a xylem vessel wall
into the vessel, partially or completely blocking the lumen of the
UREDIAL STAGE (uredium) - A stage of the
rust fungi; a fruiting structure usually appearing as a pustule bearing
the repeating spore stage that leads to disease increase. Fin.
WATER-SOAKED - A dull green coloration of
diseased tissues due to membrane leaking of cellular contents into intercellular
spaces. Fin. Swe.
WILT - A common symptom of disease due to a loss
of turgor and resulting in subsequent drooping and collapse of the
foliage or succulent tissues. Fin.
WITCHES' BROOM - A massed proliferation
of the branches of a woody plant. Fin.
ZONE LINE - Narrow brown or black lines in decayed
or decaying wood.