The posterior part of the adult body in arthropods, comprising ten segments in insects.
A small, dry, single-seeded fruit (q.v.) that does not split open.
Plants: Roots or buds arising from an unusual position on a stem.
Needing free oxygen or air to live/function/work. The opposite of anaerobic.
See also: Aerobic
Not needing free oxygen or air to live/function/work. The opposite of aerobic.
The non-sexual form of fungi.
Flowering plant producing a covered seed.
A state of suspended animation characterised by nearly complete loss of all water; organisms in anhydrobiotic condition will revive after rehydration.
An atom or molecule carrying one or more surplus electrons, and therefore having a negative charge.
Plants completing their lifecycle in one year or less. The plant dies after flowering or maturity.
Main male reproductive structure, in which pollen are formed and stored.
The period of flowering, from the opening of the flower-bud to the setting of the seed.
Common name of plant diseases characterised by black lesions, usually sunken, caused by certain imperfect fungi that produce conidia in acervuli, e.g. Colletotrichum, Gloeosporium and some closely-related Sphaceloma spp.
It is recommended that the term be used only as the common name for diseases caused by Colletotrichum lindemuthianum on Phaseolus, C. coffeanum on coffee, and Gloeosporium limetticola on lime, Citrus aurantifolia. The disease of raspberry and loganberry caused by Elsinoë veneta is better known as 'cane spot'. (BSPP)
The tendency for a plant's apical meristem to be more active than its lateral or axial meristems. It is particularly evident in young trees, and is due to production of auxins in the apical meristem.
A fleshy structure or skin on a seed used to attract ants or birds to disperse the seed
A type of simple fruit having a fleshy exocarp, mesocarp, and endocarp. Example: tomato.
Biological pest control
The use of organisms that do not compete with the crop to control populations of crop competitors.
Having a male and female parent.
British Society for Plant Pathology.
Insect-toxic bacterial protein (from Bacillus thuringiensis), produced by a gene that has been cloned and introduced into various crops to provide transgenic insect protection.
Plant essential micronutrient, usually found in the soil in a borate anionic form.
A scion with one bud used in grafting.
A type of graft in which the scion is a bud.
A type of modified subterranean storage stem/bud consisting of overlapping fleshy leaf bases or scales. Example: garlic and onions.
Outermost floral whorl, consisting usually of modified leaves known as sepals.
Parenchymatous cell mass that forms over plant wounds and is commonly seen growing as white, undifferentiated cells from cultured plant cells or tissues.
Cambium layer; Cambial
A thin layer of meristematic cells found between the wood and bark of woody plants. Often called the 'inner bark'. Every year the cambial cells divide to produce new cells on each side, the many large inner layers becoming wood cells or xylem, and the small outer layers becoming bast or phloem. Outside the bast, a small bark-cambium grows an outer layer of bark cells each year to form the protective bark (q.v.).
Plants: A sunken necrotic lesion of main root, stem or branch arising from disintegration of tissues outside the xylem cylinder, but sometimes limited in extent by host reactions which can result in more or less massive overgrowth of surrounding tissues; concentric zonation may indicate successive host responses to advancing infection. In a perennial canker, infection and host responses continue for more than one season. Because no new wood is formed under such cankers the lesions appear to penetrate deep into the wood: this is because continued growth outside the limits of the lesion tends to bury it. Infection normally continues to be restricted mainly to the bark tissues. A hold-over canker is one in which the pathogen survives the winter/dormant season and from which it may re-infect healthy tissues in the spring/growing season. A term particularly used of fireblight cankers caused by Erwinia amylovora. (BSPP)
i. Antennae with enlarged terminal segments forming a knob.
Cation exchange capacity (CEC)
The ability of a soil's colloids to attract and hold onto its cations. Soils high in humus and expanding clays tend to have the highest CECs.
A sprinkler irrigation system consisting of a mobile line attached to a fixed central well, resulting in a cultivated field arranged within a circle.
Partial or complete absence of normal green colour in plants, where the affected organs become yellow-green, yellow or white. The condition may result from reduction in size or number of chloroplasts, destruction of chlorophyll, or from a failure of synthesis of chlorophyll as in iron deficiency. Failure to produce chlorophyll can be the result of genetic factors (albinism) or chimaeral growth or growth of plants in darkness (etiolation). (BSPP)
The complete cultivation or removal of all plant residues from the soil surface.
Point in time when fruit can be harvested and still ripen to maximum quality.
Insect order that includes beetles and weevils, which damage plants mainly by chewing plant parts. Examples of economically-important species: Rhinoceros beetle, longhorn beetle, bean weevil, cucumber beetle. The lady bird beetle (lady bug) is an important biological control organism for aphid infestations, particularly in greenhouses.
Insoluble soil microparticles including clays and humus. These soil colloids have a net negative charge.
A flower having all four floral whorls: stamens, pistils, petals, and sepals.
Asexual spores produced on conidiophores other than sporangiospores and chlamydospores.
An enlarged, compressed, underground modified stem, often with scaly leaves.
A tubular organ on the abdomen of an aphid, from which a waxy fluid is secreted as a pheromone when the insect is attacked.
Second of the four floral whorls moving inward, containing the modified leaves known as petals.
(Regional Plant Protection Organization)
Caribbean Plant Protection Commission
The active first instar (q.v.) of a scale insect.
Plants of the mustard family (Brassicaceae). The term "crucifer" comes from the cross-shaped configuration of the four flower petals. Ex., broccoli, cabbage, canola, turnips.
Plants of the cucumber/melon family (Cucurbitaceae). Ex., cantaloupe, cucumber, squash, watermelon, etc.
The stem of a monocotyledonous plant, e.g. grasses, cereals.
See also: Variety; Strain
i. 'An assemblage of cultivated individuals which is distinguished by any characters (morphological, physiological, cytological, chemical or others) significant for the purposes of agriculture, forestry or horticulture and which, when reproduced (sexually or asexually), retains its distinguishing features'. (Cult. Code, Art. 5). (BSPP)
iii. Strain, e.g. barley 'Balder'. A cultivar may be a clone (Solanum tuberosum 'King Edward VII') or a line (Tbriticum aestivum 'Marquis'). Plant pathologists should use this useful term in the sense of the Code, e.g. for cultivars (varieties) of the cultivated mushroom. Use of the term in the sense of R. H. Stover (Canadian Journal of Botany 37: 245-255, 1959) 'a distinct group of isolates that have some common morphological or physiological characteristics but which may consist of one or more clones or races', e.g. Fusarium oxysporum (cultivar) 'Inodoratum' (clone) B, is to be deprecated. (BSPP)
The turning of surface soil to prepare a seedbed, aerate, and/or eliminate weeds.
The outer protective envelope of any living organism. In the case of mammals or arthropods, the alternative names 'skin' or 'integument' are often used. However, cuticle is always used with regard to green plants. Plant cuticle is a macromolecular structure of predominantly paraffinic composition over-lying cellulose and pectin.
An inflorescence in which the central terminal flower comes to perfection first.
Collapse and death of seedling plants resulting from the development of a stem lesion at soil level. This is a growers term, apparently deriving from the damp conditions among seedlings crowded in a box, which favour the attack and spread of such pathogens as Pythium spp. Pre-emergence damping-off is the death of seedlings, as a result of disease, before they have emerged above the surface of the soil or other medium. (BSPP)
The removal of leaves or portions of leaves from a plant.
Dehiscence (variety form) Dehiscent (variety form) Dehiscing (variety form)
To split open along a natural line, especially when associated with discharge of contents, as in the opening of seedpods or the freeing of pollen by the anther.
Die-back (variety form)
Necrosis of a shoot, starting at the apex and progressing downwards towards the main stem. (BSPP)
Plant species having male (staminate) and female (pistillate) flowers on separate plants. Examples:sago palm, asparagus and some fig varieties
Insect order consisting of true flies. Important plant pests include the cabbage root maggot, Oriental fruit fly and Cucurbit fruit fly.
The period of plant growth inactivity. May be in the seed or in the whole plant.
The fruit of certain plants, having a thin exocarp, fleshy or leathery mesocarp, and a hard, stony endocarp. Examples: mangoes and rambutan.
A parasitoid that lives on the external surface of its host, feeding on it and killing it in the process
One of a pair of hard upper wings in Coleoptera and Dermaptera.
A parasitoid that lives in another organism, feeding on it and killing it in the process.
A plant which grows on the surface of another organism without causing any harm to that organism.
OEPP (variety form) (Regional Plant Protection Organization)
European and Mediterranean Plant Protection Organization
A plant growth-regulating gas, naturally produced in ripening fruit as well as other parts of the plant, responsible for promoting ripening and involved in abscission and other plant processes.
See also: Chlorosis
Internode extension and the lack of green colour that result from growth of a plant in insufficient light or complete darkness. (BSPP)
A substance that oozes out from animal or plant pores.
Exuvia (plural) Exuviae (plural)
The cast skin of arthropods after moulting/ecdysis.
A plant derived from a sexual cross between two homozygous but different parents.
See also: Parasite
One able to live as a saprophyte and to be cultured on laboratory media (not obligate). (BSPP)
Practice of leaving a field unplanted during a growing season, usually to conserve moisture and nutrients.
Plant taxonomic category consisting of a group of related subfamilies, tribes (as in grasses), or genera. Examples: Fabaceae (legume family), Poaceae (grass family), Solanaceae (nightshade family).
A threadlike root, as in grasses.
The point at which all excess gravitational water has drained from a soil.
Microbiology: A whip-like organ of motility found on bacteria, flagellates and zoospores.
Entomology: That part of an insect's antenna beyond the pedicel.
The waste of wood-boring insects and caterpillars. Contains a high proportion of plant fragments.
A fungous structure that contains or bears spores, e.g. a mushroom.
Generic (adjective) Genera (plural)
A taxonomic grouping of organisms having common characteristics distinct from those of other genera, usually containing one or more species and being one of a series of genera constituting a taxonomic family.
A phloem-disruption method of inducing reproductive bud development. All of the cambium except for small patches are severed in a ring around the stem, thus causing a localised increase in the carbohydrate/nitrogen ratio in the upper portion of the plant. This method is often used in seedless grape production.
Hairless or bald. The opposite of pubescent or hirsute.
The union of two different plant parts to create a single new plant.
Tending to move in or form a group with others of the same kind.
Emission of gum from a tissue or organ; production of gum may be external, constituting a characteristic symptom, as in cherry bacterial canker (Pseudomonas mors-prunorum) and cucumber gummosis (Cladosporium cucumerinum), or it may be internal, resulting in the filling of lysigenous cavities in xylem or phloem, or occlusion of vessels as a response to wounding or infection by vascular pathogens. (BSPP)
Hemolymph (variety form)
Lymph-like nutritive fluid in insects and other arthropods which is the equivalent of blood in vertebrates.
Gradual exposure of nursery plants to warmer temperatures, drier conditions, increased light, or reduced fertility in preparation for transplanting in the field.
A simple or complex structure formed by an interaction between a branch of a fungal hypha and a host cell into which it has penetrated without causing lethal injury, generally assumed to provide a means by which a fungus absorbs nutrients from the host cells. (BSPP) Haustoria are also found in parasitic plants which grow on trees, where they perform the same function.
i. A plant that contains little woody tissue above ground and which usually dies back to ground level during the dormant season.
ii. A term also applied to aromatic plants used to flavour dishes of food.
Chemical that destroys plant life. Categories include narrow vs. broad spectrum; systemic or translocated vs. contact; persistent vs. non-persistent; and preplant, preemergence, and postemergence types.
Bisexual. In a flowering plant, having both stamens and carpels in the same flower; in an animal, producing both male and female gametes.
Insect order consisting of phloem-sucking insects, including whiteflies and aphids. Economically important species include the green citrus aphid, melon aphid and whiteflies.
Liquid waste with high sugar content discharged from the anus of some Homoptera and settling on surrounding vegetation as thin, sticky droplets.
A given soil layer in a soil profile. Horizons are designated as A, B, C, or D, with the A horizon being the surface layer, usually.
i. An organism harbouring a parasite (BMS). A living organism harbouring another organism or virus dependent on it for existence (APS). The individuals of a species which are capable of harbouring a parasite, even though a particular individual or population of that species may not at the time be parasitized, can also be described as hosts; however, in these circumstances it is preferable to refer to the organism as a potential host. The term is used commonly in preference to suscept (q.v.) to denote an organism harbouring a pathogen. Nevertheless, it must be stated that the conceptual parallel of 'host and parasite' is 'suscept and pathogen'. (BSPP)
ii. The plant on which a pest feeds, i.e. the food- or hostplant.
The series of plants that a particular pathogen can infect or parasitise.
Dark brown, decomposed, colloidal organic matter found in soils. Humus usually has a beneficial effect on aeration and soil structure due to its ability to flocculate, or aggregate, multivalent cations.
Transparent. Used when referring to a transparent or translucent spot devoid of scales on the wing of a butterfly or moth, or the whole wing of some insects, e.g. Odonata, Hymenoptera.
The superior phenotypic characteristics of an F1 hybrid when compared with its two distinct, homozygous parents.
See also: Parasite
A parasite or parasitoid attacking another parasite within a host organism. For example, a hyperparasite of a fruitfly attacking a parasite within the fruitfly larva or pupa.
A single thread of fungal mycelium.
The successive loss of population vigour with each generation of selfing of an F1 hybrid. It is often seen in outcrossing, vegetatively-propagated, and/or heterozygous autotetraploid plants.
To eat or swallow.
Larval instar (synonym) Stadium (synonym)
A stage in the development of a larva between two moults; a stadium.
The planting of two different crops together in the same field.
Plants: The stem structure between two nodes or joints.
IPM Integrated pest management, a strategy for controlling crop pests using a combination of tactics, including crop management practices, pesticides, biological competitors, etc.
Larval (adjective) Larvae (plural) Worm (synonym)
i. The growing, worm-like stage of insects with a complete metamorphosis; the caterpillar, 'worm', maggot or grub.
ii. The newly hatched six-legged stage of mites and ticks.
Root induction on stem tissue in order to eventually sever the tissue for propagating a new individual plant.
Gravitational movement of water, dissolved, and colloidal substances from the surface or upper horizons to lower horizons in a soil.
Order of chewing insects that have a caterpillar or worm stage and a flying adult stage. Examples: Diamondback moth, armyworm, codling moth, rambutan fruit borer, citrus leafminer.
i. A localized area of diseased or disordered tissue. (BSPP)
ii. Any break in the epidermis of a plant or animal caused by a disease or disorder.
Plants of the pea family (Fabaceae) that form characteristic elongated seed pods and fix atmospheric nitrogen through symbiotic interaction with soil bacteria of the genera Rhizobium and Bradyrhizobium. Ex., beans, peas, peanuts, soybeans, tamarind, etc.
A white/brown, corky, raised 'breathing' pore on a woody shoot.
Plants: The cavity of an anther which contains the pollen, or the chamber of an ovary which contains the ovules.
Fungi: A cavity in the stroma containing asci.
Specific place on a chromosome or genetic map where a gene and its alleles are found.
When plants fall over and lie flat on the soil surface, especially cereal grain crops, often due to wind, hail, and/or excessive stem growth.
Secondary macronutrient critical for plant growth, as it is the central metal in chlorophyll. Magnesium forms a divalent soil cation.
Micronutrient critical for plant growth, usually found as the manganous oxide anion in soil.
The brown, torpedo-like faecal pellets excreted by parasitic Hymenoptera prior to pupation.
Parenchymatous, photosynthetic cell layers within the leaf, consisting usually of palisade and spongy mesophyll tissues.
Power-producing organelles of the cell, site of catabolic aerobic respiration. Mitochondria contain their own chromosome of DNA, which are generally maternally inherited through the egg.
Plants having separate male and female flowers on the same plant. Examples: banana and corn.
Leaf mottling and yellowing symptoms, typical of certain viral diseases.
Mold (variety form) Grey mould (sub-term) Sooty mould (sub-term)
A mycelial microfungus or a visible growth of such a fungus. Blue mould or green mould is caused by Penicillium spp.; grey mould, by Botrytis cinerea; sooty mould is caused by one of the Capnodiaceae but the term has been used incorrectly for growth of Cladosporium spp. and other fungi on foliage, etc. (Mold in the USA). (BSPP)
Molt (variety form)
The shedding of skin of arthropods and reptiles in the process of growth. (Molt in the USA).
The nutrient-seeking fibres (hyphae) of a fungus.
Primary plant macronutrient and a major component of proteins and nucleic acids. Inert atmospheric dinitrogen gas must be converted to soluble forms in the soil. A major way it is converted is through the action of nitrogen-fixing bacteria symbiotically associated with the roots of leguminous plants. Common soluble soil forms are the ammonium monovalent cation and the nitrate monovalent anion.
Plants: The joint on a stem from which roots, leaves and branches have their origin.
The growing stage (instar) of an insect with an incomplete metamorphosis, e.g. immature locusts are called nymphs or hoppers.
adj.: used to qualify a parasite, to distinguish those which cannot live outside their hosts. Most parasites are obligate in nature. The word is sometimes restricted to those which cannot be cultured in the laboratory, i.e. in vitro.
(Regional Plant Protection Organization)
Organismo Internacional Regional de Sanidad Agropecuaria. Members: Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama
Oospore (variety form)
A resting spore produced by sexual reproduction in downy mildew and related fungi.
Soil fraction consisting of live, dead, and decomposed organisms or parts thereof.
Insect order that includes grasshoppers, crickets, and locusts.
Female floral structure located at the base of the style, containing the ovule(s).
An organ, present in many female insects, specialized for depositing eggs in plant structures or in the ground.
Parasitoid (variety form)
i. Entomology: An organism that grows and feeds in or on a host without killing it. A parasitoid is a parasite (usually of insects) which kills its host. The latter are often used in biological control programs to suppress pest populations. True parasites tend not to be used as they rarely have much effect upon the pest status of a pest.
ii. Pathology: An organism or virus existing in intimate association with a living organism from which it derives an essential part of the material for its existence while conferring no benefit in return (BMS). An organism or virus existing within or attached to or in intimate association with another living organism, from the functioning tissues of which it derives part or all of the material for its nutrition. An organism or virus for which the tissues of another living organism serve as substratum and source of nutrition (APS). The essential characteristic of a parasite is that it is wholly or partly dependent for its nutrition on the function ingtissues ofa living organism with which it lives in intimate association; the BMS addendum, that the parasite confers 'no benefit in return', is difficult to establish in practice, and was presumably added to enable a distinction to be made be tween parasitic and symbiotic relationships. However, there seems no reason why, for example, a mycorrhizal fungus should not be regarded as a parasite having a symbiotic relationship with its host. The terms 'parasite' and pathogen' are not necessarily interchangeable; both may be applicable to a given organism, but 'parasite' indicates its mode of existence, whereas 'pathogen' relates to its ability to cause disease. (BSPP)
Plant tissue type composed of relatively undifferentiated (non-specialised) cells. Found primarily in leaf (mesophyll), cortex, and also in conductive tissues.
Fruit production due to enlargement of the ovary without fertilisation, ie, seedless fruit. Examples: bananas, cucumbers, and oranges.
A spreading type of inflorescence or seed-head, as in oats and rice.
Disease agent (synonym) Pathogenic agent (synonym)
An organism or virus able to cause disease in a particular host or range of hosts. The term can be applied to genera, species and sub-specific taxa of fungi, bacteria, etc., and to strains etc. of viruses. It indicates a general disposition within the taxon, but does not preclude the possibility that a particular race, strain, isolate etc. may be unable to cause disease in a given host; such an exception can be distinguished as a non-virulent (or avirulent) race, strain or isolate of the pathogen, distinct from others of high, intermediate or low virulence in respect of the same host. Similarly, the use of the term is not precluded if a particular host does not become diseased because it is tolerant of the pathogen.
Type of berry-fruit consisting of an exocarp rind, fleshy mesocarp, and watery endocarp. Example: cantaloupe and other cucurbits.
A plant that lives longer than 2 years from time of germination.
Modified leaves of the second floral whorl moving inward, or corolla.
What the plant looks like, ie, its morphology.
Plant vascular tissue composed of specialised cells that conduct photosynthate throughout the plant body.
A primary plant macronutrient, usually found in slow-leaching soil forms, that is a main component of nucleic acids, including energy-transmitting ATP, as well as phosphoproteins and phospholipids.
Toxic to plants or plant growth. The threshold dose at which injury occurs is termed the Dosis toxica.
Female flower parts: stigma, style, ovary. Also, the innermost floral whorl, or gynoecium.