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Glossary of Terms

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Bacillary bands
Lateral zones in the body wall of some nematodes, that consists of glandular and non-glandular cells of unknown function

Shaped like a rod.

A rod-shaped bacterium.

Crossing (mating) 'offspring' (a hybrid) with its parent to reinforce or increase the gene frequency of a desired characteristic.

Checking the validity of a forecasting method by retrospectively making a 'forecast' for a period for which the outcome is already known.

The presence of bacteria in the hemolymph of blood of invertebrates and other animals, without production of harmful toxins or other deleterious effects.

Microscopic procaryotic organisms, which commonly have a spherical, rod, or spiral shape but are sometimes more complex.

Any substance that is toxic to bacteria.

A pigment similar to chlorophyll, used by purple and green bacteria during photosynthesis.

Proteins synthesised by bacterial species that are toxic when absorbed by bacteria belonging to sensitive strains (King & Stansfield, 1990).

An ultra-microscopic organism, similar to a virus, that replicates in bacteria, causing lysis of cells.

A chemical or physical agent that inhibits the growth of, but is not lethal to bacteria. Bacteroid An enlarged branched bacterium surrounded by a membrane that is of host origin, especially the irregular-shaped bodies of the bacterial genus Rhizobium, which carry out nitrogen fixation within root nodules on the roots of leguminous plants.

A major class of microscopic (0.5-2.0 micron) motile or non-motile, unicellular organisms, the smallest living things able to reproduce themselves, achieved mainly by each cell dividing into two. The genetic code is carried in a tangled coil of DNA known as the bacterial chromosome.

Baer's disc
Large, ventral sucker of an aspidogastrean trematode.

Bag storage
Storing of grain or other produce in bags, usually made of jute (gunny) or polyethylene.

The crushed stalks of sorghum and sugar-cane after extracting the juice by heavy grooved rollers.

A formulation, including attractants, toxicants, and/or mechanical devices used as a lure for killing pests or for sampling populations.

Bait concentrate
A solid or liquid intended for dilution before use as a bait.

The state of an insect population in which large deviations from population oscillations do not occur.

A basidiospore that is forcibly shot away from the basidium.

Four inflated areas within the 'head' of nematodes of the family Gnathostomatidae.

Band application
An application of either sprays or granules to a continuous restricted area such as a band of soil in row-crops, usually in or along plant rows.

Band seeding
A method of seed and fertiliser placement in which grass and legume seed are placed at exact depths directly above a concentrated band of fertiliser.

Banding (of fertilisers)
The placing of fertilisers in the soil in continuous narrow bands or ribbons, usually at specific distances from the plants or seeds.

Bar chart
(or Gantt chart)
A planning tool which shows the start date, stop date and duration of research and development tasks which comprise a project by means of a two dimensional array which depicts tasks on the vertical axis and time on the horizontal.

Gossypium barbadense, Sea Island, Egyptian, Pima or long-staple cottons.

Having sharp points or hooks such as those on awns of wheat or barley.

Barrier cream
Protectant skin ointment for spray operators.

Basal area
The area of a breast high cross-section of a tree or of all trees in a forest stand.

Basal body
Centriole from which an axoneme arises; also called a kinetosome or blepharoplast.

Basaltic derived soils
Soils developed from basalt rocks.

Basal treatment
An application to the stems of plants at or just above the level of the soil.

An alkaline, usually nitrogenous organic compound.

Base pairing
The linking of the complementary pair of polynucleotide chains of nucleic acids by means of hydrogen bonds between the opposite purine and pyrimidine pairs.

Basic chromosome number
Closely related species have the same number of haploid chromosomes (x) of a multiple of the common basic number.

Basic research
Fundamental scientific inquiry to understand the unknown and contribute to improved general knowledge (cf. with applied research).

Fruiting body of the Basidiomycete fungi in or on which basidia are produced.

A class of fungi characterised by exogenous production of spores (basidiospores) on club-shaped organs of meiosis (basidia).

Small sexually produced spores, borne on a basidium or stalk as in the Basidiomycetes (rusts, smuts and mushrooms).

A spore-producing, club-shaped, hypha usually giving rise to four Basidiospores (see Basidiocarp).

Basin listing
Tillage that dams lister furrows at regular intervals to create small basins.

Successively from apex to base.

Basis (basipodite)
Joint of a crustacean appendage between the coxa and the exopod and endopod.

h A defined quantity of material produced in a single series of operations by a non-continuous or continuous process.

Batch costing
A type of job costing where a batch of identical products is treated as an individual job with unit cost found by dividing the total batch cost by the number of units produced.

Bat fly
Parasitic fly of the family Streblidae.

Bat fly spider
Parasitic dipteran of the family Nycteribiidae.

Bayes' Law
If A is some event that occurs if and only if either B or B occurs, then P(B\A) = [P(A\B)P(B)] / [P(A\B)P(B)+P(A\B)P(B)] = P(AB)/ P(A)

B cells
Type of lymphocyte that, on stimulation with an appropriate antigen, differentiates into a 'blast' cell, which gives rise to plasma cells that liberate antibody to the antigen of primary importance in humoral immune response.

Beaumont period
Period of weather required for potato blight Phytophthora infestans infection.

A narrow flat-topped ridge on which crops are grown with a furrow on each side for drainage of water or an area in which seedlings or sprouts are grown before transplanting.

Beetle mites
Mites of the suborder Cryptostigmata.

Beneficial insect
An insect that serves the best interest of man, eg. insect pest predators and parasitoids and pollinating insects.

A gain.

Benefit:cost ratio
The ratio of the present value of an enterprise over the present value of costs incurred.

Contained and unable to invade surrounding tissue (contrast with malignant).

Biota that live on or near the bottom of a water body.

A collodial clay (hydrated aluminium silicate that has the property of forming viscous suspensions (gels) with water) that is used as a carrier in pesticide dusts to increase their adhesive properties.

A group of chemical compounds occurring in maize and having an allomonic effect on the European corn borer Ostrinia nubilalis.

Bettlach May disease
A paralysis of adult honey bees caused by poisonous substances in the pollen of Ranunculus species.

Plants completing their life-cycle within two years. The first year it produces leaves and stores food while the second year it produces fruit and seeds.

Having two flagella.

Disease caused by the parasite Schistosoma spp. Also called schistosomiasis.

Accessory pigment for photosynthesis; phycobilin.

A machine which cuts and binds a crop in bundles.

Binary fission
Simple asexual division of a cell, especially bacteria. A cell wall forms across the cell and the two halves separate to become individual cells.

Binomial distribution
A calculation that measures the likelihood of events taking place where the probability is measured between 0 (the event will certainly not occur) and 1 (the event is absolutely certain).

Binomial experiment
An experiment consisting of n independent trials in which the outcome at each trial is a 'success' with probability p or a 'failure' with probability (1-p). Interest is in x, the number of successes observed during the n trials.

Binomial nomenclature
The method of scientifically naming plants and animals in descriptive Latin terms. The first term identifies the genus, the second the species to which an organism belongs. The first letter of the generic name is capitalised and both names are italicised. The name (often abbreviated) of the author responsible for naming the organism may follow the Latin binomial. When another author transfers a species to another genus, the name of the first author is placed in parentheses and the name of the second author follows. Thus, the scientific name of the fungus that causes brown rot of peach is written Monilinia fructicola (Wint.) Honey.

Binomial probability distribution
A probability distribution giving the probability of x, the number of successes observed during the n trials of a binomial experiment: p(x) = Cnxpx(1-p)n-x x = 0,1,2, ..., n

Determination of chemical effects in tests on living organisms. Also a term applied to a method for determining insecticidal residues employing previously established dosage mortality figures for a given compound on a suitable test organism. Although extremely sensitive, this method does not distinguish and identify residues of different classes of insecticides.

Biochemical Oxygen Demand
The amount of oxygen required by micro-organisms, usually in polluted water, slurry or industrial effluent, for oxidation processes. Generally measured as mg of O2 taken up by 1 litre of the sample when incubated at a standard temperature (20°C) for 5 days.

Biochemical mechanism
A chemical reaction or series of reactions (usually enzyme catalysed) which produce a given physiological effect in a living organism.

A synonym for chemicals that are toxic to a wide range of species e.g. insects, snails, birds, people. A term not commonly used.

The uptake and retention of chemicals by organisms from their immediate environment. When a chemical increases in concentration at each succeeding link in the food chain.

The microbial conversion of a chemical to a compound of economic importance.

Capable of being broken down by micro-organisms which utilise the substance as a source of energy and bring about its destruction. Usually referred to biological processes in soil, water, sewage but also to man-made organic compounds such as pesticides.

Biodegradable polymers
Used as formulating agents in controlled-release systems. Composed of macro-molecules that show appreciable breakdown in biologically active environments, no residues of the polymer remain in the environment. If formulated with a short lived pesticide no residues of the pesticide remain following completion of the treatment.

A thin layer of living cells, usually micro-organisms, coating a surface.

Biogeochemical cycle
The conversion of a micro-organism from its oxidised to its reduced form (or vice versa).

Branch of biology that deals with the geographic distribution of plants and animals.

Biological assay
Measurement of the potency of any stimulus, physical, chemical or biological by means of the reactions which it produces in living matter.

Biological control
The regulation of plant and animal numbers by natural enemies. It is the aim of biological control to manipulate natural enemies (parasitoids, predators, pathogens) in an attempt to reduce the pest numbers and keep them at much reduced levels. The 'manipulation' can involve the introduction of natural enemies into a region where they previously did not exist to counter accidentally introduced pests of crops (classical biological control). Also manipulation can involve the use of indigenous natural enemies to augment existing populations or to alter the environment to improve conditions for enhanced natural enemy activity.

The use of one biological agent to control another, generally by predation or parasitism (Spedding, 1975).

The use, by man, of living organisms to control (usually meaning to suppress) undesirable animals and plants; certain non-organismal biological factors, such as metabolic and genetic diseases, when used in control may be included (Cantwell, 1974).

Control of pests using natural enemies (usually predators and parasites) (Stiling, 1985).

The regulation of plant and animal populations by natural enemies. The term is also applied to the practice of using natural enemies to control pests (van den Bosch, 1980).

Control of pests by means of predators, parasites and disease-producing organisms (Parry, 1990).

The reduction of the amount of the amount of inoculum or disease-producing activity of a pathogen accomplished by or through one or more organisms (antagonists) other than man (Parry, 1990).

Pest control by living organisms (Marsh, 1969).

Biological control agent
Any biological agent that adversely affects pest species.

Biological half-life (t_)
The time taken for the concentration of a chemical in a body fluid or tissue to fall by half by a first-order process.

Biological monitoring
Analysis of the amounts of potentially toxic substances or their metabolites present in body tissues and fluids in order to assess levels of exposure and to aid timing of preventative action. Also the assessment of the biological status of populations and communities of organisms that are at risk in order to protect them and to provide an early warning of possible hazards.

Biological system
A system consisting essentially of biological processes.

Biologically compatible mixture
A mixture of formulations or chemicals (usually pesticides) which under defined conditions retain their separate activity and which does not have any unwanted biological side effects when used.

Light produced by living organisms.

The increase in concentration of a persistent pollutant along a food chain e.g. persistent organochloride insecticides and their metabolites accumulating up a food chain.

The total mass of material resulting from the growth of an organism or weight of living organisms per unit area.

Bionomic strategy
A strategy that will have evolved to maximise the fitness of the organism in its environment in terms of its size, longevity, fecundity, range, migration habit.

Long chain molecules synthesised by living organisms e.g. proteins, cellulose and starch.

Biorational pesticides
Pesticides based on bacteria, viruses, fungi or protozoa; includes pest control agents, and chemical analogues of naturally occurring biochemicals (pheromones, insect growth regulators, etc.). They are generally considered more environmentally friendly than synthetic chemical pesticides.

The whole earth ecosystem i.e. all living organisms on earth.

The synthetic reactions of cell metabolism (see anabolism).

Species of animals and plants occurring in a given habitat.

Any technique that uses living organisms, or substances from those organisms to make or modify a product, to improve plants or animals, or to develop micro-organisms for specific uses (OTA, 1989). Traditional biotechnology covers well established and widely used technologies based on the commercial use of living organisms e.g. biotechnologies used in brewing, food fermentation, conventional animal vaccine production. Modern biotechnology encompasses technologies based on the use of: recombinant DNA technology; monoclonal antibodies and new cell and tissue culture techniques (Persley, 1992).

Biotic agent
A living organism that is the cause of damage.

Biotic factors
The influence of plants or animals on the environment (opposite of abiotic factors).

Biotic insecticide
A pathogen usually an entomopathogen that is applied in the same manner as a conventional insecticide to control pest species (see biorational pesticide and microbial pesticide).

Biotic potential
Reproductive potential of a species.

Obligate parasite i.e. an organism which is entirely dependent upon another living organism as a source of nutrients.

Entirely dependent upon another living organism as a source of nutrients.

In entomology, an individual or a population that is distinguished from the rest of its species by criteria other than morphology, e.g. a difference in parasite ability (Maxwell & Jennings, 1980).

A population or group of individuals composed of a single genotype (Watson, Moore & Wave, 1976).

A group of individuals with the same genetic constitution (Kipps, 1970).

Sub-group within a species differing in some respect from the species, such as a sub-group that is capable of reproducing on a resistant variety (Ware, 1978).

Biotype specific resistance
Resistance that is effective only for a given biotype of the pest species. The resistance is often, but not necessarily, vertical.

The taking up of a stain at either end of a micro-organism while the central part remains clear. Members of the genus Pasteurella commonly exhibit bipolar staining.

Bird scarers
Devices to repel birds from crops.

Having both sexes present and functional in the same organism e.g. flower.

Biting midges
Insect species in the family Ceratopogonidae.

Black fly fever
A combination of symptoms resulting from sensitisation to bites by black flies (Simuliidae).

A disease of turkeys caused by the protozoan Histomonas meleagridis. Also called histomoniasis or infectious enterohepatitis.

The flat portion of a grass leaf above the sheath that extends outward from the stem.

Blanket application
(see broadcast application)

A plant disease similar to blight.

A symptom of plant disease characterised by shedding of unopened buds; classically the failure to produce fruit or seed.

A systemic fungal disease originating in the lungs, caused by Blastomyces dermatitidis.

A homogeneous mixture of two or more substances.

A granule at the base of a flagellum in protozoans that is apparent when stained. Also called a basal body or kinetosome.

Common name for a number of different diseases on plants characterised by the rapid death of plant tissue e.g. leaf blight, blossom blight, shoot blight.

Blind cultivation
Cultivation that is undertaken before a crop emerges.

Excessive accumulation of gases in the rumen of an animal.

Blood serum
The clear liquid which separates from the blood when it is allowed to clot.

Bloom period
The period during which flowers are opened.

Blossom stage
From the time the first blossoms open until the petals fall.

A disease of plants characterised by large, necrotic and irregular in shape, spots or blots on leaves, shoots and stems.

Blue disease
A rickettsial disease of the larvae of the Japanese beetle, Popillia japonica, and of other related scarab larvae by Rickettsiella popilliae.

Blue-green algae
See cyanobacteria.

Blue stain
A deep-seated discoloration of wood owing to fungal attack, usually bluish.

Virus disease of ruminants transmitted by the biting midges Ceratopogonidae.

Boiling range
The range of temperatures over which a mixture or an impure compound boils.

Boot stage
See growth stages of grain crops.

The spherical shaped fruits of cotton and flax.

A lightweight, horizontal or vertical frame carrying a number of regularly spaced spray nozzles. The boom is often hollow, serving also as a supply tube for the spray liquid.

Boom and bust cycle
Refers to crop cultivars that after a period of widespread cultivation of a variety having major gene resistance (boom), it succumbs to disease or infestation and its popularity among farmers declines (bust).

The sheath and partially opened blade of the upper leaf in grasses. 'Booting' is the stage at which the inflorescence expands the boot.

Botanical composition (percentage)
The proportion of pasture made up by different botanical species

Botanical pesticide
A pesticide produced from naturally occurring chemicals found in some plants e.g. nicotine, pyrethrum, strychnine and rotenone. Toxicity to vertebrates in this group is highly variable.

Bot fly
Member of Gasterophilidae family of flies whose maggots are parasitic in the stomach of mammals, especially equids.

Muscular lappet on the dorsal or ventral side of the scolex of a tapeworm; bothridia are often highly specialised, with many types of adaptations for adhesion.

Dorsal or ventral grove, which may be variously modified, on the scolex of a cestode.

Like the narrow neck of a bottle through which all contents must pass, a 'bottle-neck. In planning terms it is that time in a project when many activities coincide so that resources, e.g. labour, are severely taxed. In genetic terms, a population with reduced genetic variation due to exposure to limited conditions.

The conceptual limits of a system, penetrated by outputs and inputs but not by feedback loops.

Boundary layer
A general term for the layer of air adjacent to a surface.

Bounded rationality
A form of behaviour associated with uncertainty where individuals do not examine every possible option open to them, but simply consider a number of alternatives which happen to occur to them.

Box-Jenkins forecasting procedure
A four-stage procedure for the development of a forecasting model that combines an auto-regressive component (involving past observed values) with a moving average component (involving current and past error terms).

Box plot
A graphical display that allows for the assessment of asymmetry and the detection of outliers in a data set.

Brace root
Aerial roots that extend downward from lower above-ground nodes. On coming in contact with the soil, true roots then develop and function as support and feeder roots.

A bacterial disease of certain Malacosoma species (tent caterpillars), caused by Clostridium brevifaciens and Clostridium malacosomae.

Having short wings that do not cover the abdomen e.g. some aphids.

A modified leaf of the flower or the branch of a flower, i.e. glumes and lemmas.

Small stage in various coccidia of the protozoan Isopora group that develops in a zoitocyst.

The pericarp, testa and usually the aleurone layer of cereal seeds which are removed in milling.

A lateral stem.

Branch and bound
An algorithm for solving dynamic programming problems.

The name, number, trademark or designation of a pesticide. Each pesticide that differs in the ingredient statement, analysis, manufacturer or distributor, name, number or trademark is considered a distinct and separate brand.

Attaching a brand mark or brand name to a product in order to distinguish it from other product variants.

Breakbone fever
Another name for dengue, a virus disease transmitted by mosquitoes.

Breakdown of resistance
The inability of a cultivar to maintain resistance when attacked by a pest biotype that has a gene for virulence at every locus corresponding to a gene for resistance in the host (see Biotype and Vertical resistance).

Break even graph
A graph that plots the total revenue and total cost functions for a specific product.

Break even model
A decision making technique that determines the effect on profit if cost, price or output are altered.

Break-even point
The level of output, or sales value, at which total cost equals total revenue.

Separation of phases from a pesticide emulsion e.g. an oil and water emulsion.

Broken emulsion
(see breaking)

A solid block designed for controlled release of active ingredients of plant protection products.

Broadcast application
Application over an entire area rather than only on rows, beds or middles (also referred to as blanket application).

Broad-leaved plants
In general, those that are not mosses or grass-like plants.

In general, a pesticide with activity against a wide range of pests e.g. a non-selective fungicide affects a wide range of pathogens.

Pieces of the rice kernel that are less than 3/4 the size of the full kernel.

The two main branches of the trachea.

Generally used to refer to offspring of birds or insects of approximately the same age arising from a single species of animal.

Broom, spray
T-shaped spray lance with nozzles on cross-piece.

Brownian motion
Vibratory, haphazard motion observed in microscope preparations (as distinguished from true motility).

Brown rice
Dehusked paddy, often referred to as unpolished rice.

A method of feeding by herbivores, in which the leaves and peripheral shoots are removed from trees and shrubs.

Brush control
Control of woody plants.

Plant in the phylum Bryophyta comprising of the mosses, liverworts and hornworts.

Swollen lymph node.

Buccal cone
Portion of the mouthparts of acarines composed of hypostome and the labrum.

A method of vegetative propagation of plants by implantation of buds from the mother plant onto a rootstock, or in cell biology the process of cell division in which the mother cells retains its identity, and the daughter cell forms by growth of a new cell upon one part of the mother cell..

A detailed statement of a plan which describes both costs involved and the returns expected.

Budgetary control
The process of comparing the actual performance of an aspect of farm production against planned performance.

Budget cost allowance
A set of cost control figures that are calculated when the actual level of output is known in a flexible budgeting system. In a fixed budgeting system the BCA figures are determined during the planning phase.

The process of anticipating the costs, and planning the expenditure of financial resources for the execution of on-farm research and development tasks, projects and programmes.

Budget variance
The difference between the planned and actual cost or revenue figures.

Common name in USA for various tortricid larvae eg. the tomato budworm.

Technically, an insect of the order Hemiptera, but in popular language an insect of almost any kind, and for other creepy-crawly cryptic things too.

An underground storage organ with a much-shortened stem bearing fleshy leaf bases or scale leaves enclosing the next year's bud.

Bulb bath
Container in which flower bulbs are subjected to heat treatment by immersion in water for purposes of de-infestation, usually as a quarantine measure.

Bulk or bin storage
Storing of grain in loose form in a large solid container, without the use of bags.

Non-living structure serving as an anchor to which the maxillae are permanently attached. It is secreted by the head and maxillary glands of female copepods in the family Lernaeopodidiae.

A grass that grows in clumps of tussock with a clear boundary around the plant. It has no prominent stolons or rhizomes.

Lateral circular extensions present at the posterior end of males of some nematodes.

A low thick shrub without a distinct trunk.

Bush-fallow system
A system of retiring land from cultivation.

By-product costing
A costing system for relatively low value output from a production process.