[A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] [Y] [Z]
F distribution
The sampling distribution of the ratio of two independent quantities
each of which is distributed like a sample variance from a normal distribution.
F1
The first filial generation, or the first-generation offspring of a
given mating.
F2
The second filial generation. It is in this generation that segregation
first occurs.
Facets
The visual units that compose the compound eye.
Facette
Funnel-shaped opening through the inner membrane complex of the egg
of a pentastomid; it receives the product of the dorsal organ.
Facial (artery)
The artery which runs along the groove of the jaw bone and the lower
edge of the jaw.
Facitious host
An easily grown plant or animal species used as a host for the mass
culture of a natural enemy in the insectary but which is not attacked by
this enemy in nature.
Factor
An independent variable under examination in an experiment as a possible
cause of variation.
Factor comparison
A job evaluation method where each job is ranked in a job hierarchy
and a payment hierarchy to derive a ranking of all jobs and wage rates.
Factorial experiment
An experiment designed to examine the effect of one or more factors,
each factor being applied at two or more levels. The experiment utilises
every combination of factor levels as treatments in the experimental design.
Facultative
The ability of an organism to grow either in the presence of absence
of an environmental factor (e.g. facultative aerobe, facultative psychrophile).
Facultative agents
Used by Howard & Fiske to describe agents of destruction which
increase their percentage of destruction as population density rises; synonymous
with density-dependent factors.
Facultative parasite
An organism that is usually saprophytic but which under certain conditions
may become parasitic e.g. a fungus capable of operating at two trophic
modes - decomposer and consumer.
Facultative saprophyte
An organism that is usually parasitic but which may also live as a
saprophyte.
Facultative symbiont
When facultative, a symbiont is an opportunist, establishing a relationship
with a host only if the opportunity presents itself; it is not physiologically
dependent on doing so.
Facultative weed
A weed found growing both wild and in association with man.
Fallow
Cropland left idle to restore productivity, primarily through accumulating
water or nutrients or both. The soil is tilled for at least one growing
season to destroy weeds, to encourage moisture storage, and to promote
decomposition of plant residues.
Fan nozzle
See nozzle v.
Farmyard manure
Cattle droppings (faeces) mixed with straw or similar material used
as bedding in sheds, barns or night yards. If heaped to rot well before
use, farmyard manure does not cause crop burn, increases most crop yields
and water-retaining properties of soils.
Fasciation
Hyperplastic symptom characterised by a fusing (and flattening) of
such plant organs as stems.
Fasicle
Stylet bundle or combination of mouthparts used to pierce the skin
in a blood-feeding arthropod; composition of a fasicle varies according
to group.
Fasiculation
Hyperplastic symptom characterised by a clustering of such plant organs
as shoots into such structures as 'witches-brooms'.
Fat-corrected milk
Gaines' s formula is an attempt to relate the energy required to produce
milks of different fat contents by adjusting the yield to that of a 4%
butterfat milk: FCM = 0.4M + 15F(M = milk yield, F = butterfat yield:
all in the same units, e.g. all as kg)
Feasibility study
A study, not necessarily quantitative, to determine if an investment
proposal can meet corporate objectives.
Fecundity
Reproductive capacity of an organism.
Feedback inhibition
Inhibition by an end product of the biosynthetic pathway involved in
its synthesis.
Feedback (loop)
The use of information produced at one stage in a series of operations
as input at another, usually earlier, stage.
Feedlot
An area of land, used to accommodate animals (very commonly beef cattle)
at a very high density, not contributing at all to the production of animal
feed (all of which has therefore to be brought to the animals from outside
the feedlot).
Feekes scale
Scale expressing stages in cereal seedling development.
Femoral (artery)
The large artery running down the centre of the inner aspect of the
thigh.
Femur
Counting from the body, the third and usually the heaviest segment
of an insect's leg.
Feral
A domesticated animal which has returned to the wild state.
Fermentation
The process of growing a selected organism, usually a bacterium, mould
or yeast, on substrate so as to bring about a desired change or to generate
products of the cells' metabolism (e.g. ethanol and carbon dioxide from
yeast fermentation). The term is also used to describe biochemical conversions
and catabolic reactions producing ATP.
Fermenter
A large vessel (5,000 to 50,000 gallons) in which industrial fermentations
are carried out.
Ferrodoxin
An electron carrier of low reduction potential; small protein containing
iron.
Fertile
Capable of producing offspring.
Fertility
Actual capability of an organism to produce living offspring.
On a herd basis, best expressed as the number of calves born per year
as a percentage of the number of females exposed to the bull in the previous
year. May also be expressed as the number of conceptions confirmed by
pregnancy diagnosis or the calving percentage of services or inseminations.
It may be expressed as the percentage of non-returns (i.e., cows which
did not come on heat after insemination) but obviously this is not a satisfactory
method.
Fertilisation (plant and animals)
The union of the male gamete or sperm and the female gamete or egg
and of their nuclei to form a zygote.
Fertilisation (soil)
The application of nutrients (fertiliser) to soil in order to promote
growth and development of plants.
Festoons
Sclerites on the posterior margin of the opisthosoma of certain hard
ticks.
Fetch
In an airstream - is the length of its traverse across an area which
modifies its properties.
Fetotoxin
A substance that can poison an unborn foetus.
Fibrin
The protein which composes blood clots; formed from the blood protein
fibrinogen.
Fibrinous pericarditis
An inflammation of the heart sac characterised by the excess accumulation
of a straw-coloured or haemorrhagic fluid containing fibrin, a whitish
insoluble protein derived from the blood.
Fibrous root
A thread-like root, as in grasses.
Fibrous root system
Composed of profusely branched roots with many lateral rootlets but
with no main or tap root development.
Fidelity
Degree of regularity or 'faithfulness' with which a species occurs
in certain plant communities, expressed on a five-part scale: (5) exclusive,
(4) selective, (3) preferential, (2) companion, indifferent, (1) accidental,
strangers.
Field capacity
The water content of the soil immediately after all 'free water' has
been drained by the force of gravity (Hillel, 1980). Typical values range
from 10-40 vol% with the lower range generally found in sandy soils and
the upper range often associated with clay-type soils.
Field recording form
A form used in collecting field information. Usually in a format
compatible with data base management systems, statistical calculations
etc.
Field resistance
Resistance observed in the field (usually on mature plants, but not
under experimental conditions (usually on seedlings)). A term best avoided,
since resistance of this type can now easily be produced experimentally,
by using plants of appropriate age under appropriate environmental conditions.
Field scout
A person who samples fields for pest infestations.
Filamentous
Thread-like; many times longer than wide.
Filiform
Thread-like; filamentous.
Filler
Inert component of pesticide dust or granular formulation that acts
as a diluent.
Fimbria
Tube-like protein structures on the exterior of some bacteria, which
may be involved in attachment to surfaces and the formation of pellicles
but are not involved in motility.
Finance budget
A budget showing the borrowings which are needed and interest and principal
repayments.
Financial accounting
The recording of financial transactions leading to the preparation
of global financial statements, e.g. profit and loss account or balance
sheet.
Financially discrete
Characteristic of a R & D project component which makes it easy
to calculate costs.
Fine granule
A granule in the particle size range from 300 to 2,500 µm.
Fine spray
A dispersion of drops of 100 to 200 µm volume median diameter.
See spray v.
Finite difference
A method in which a derivative is approximated by a difference between
a function values over a small finite time difference.
First-best optimum
The absolutely optimal allocation of resources, where all prices are
set equal to marginal social cost.
First in first out
A stock valuation system where goods are priced and issued to work
in progress on the assumption that the first stock received is issued first.
First-order difference transformation
A first-order difference transformation (Vyt) is a series developed
by computing the differences between adjacent values (yt - yt-1) in a time
series.
First order process
A chemical process where the rate of reaction is directly proportional
to the amount of chemical present.
First-pass effect
Biotransformation of a xenobiotic before it reaches the systemic circulation.
The biotransformation of an intestinally absorbed xenobiotic by the liver
is referred to as a hepatic first-pass effect.
Fiscal year
That twelve-month period which the government has determined shall
be the basis for budgeting all government activities. It may, or may not
coincide with the January-December calendar year. It may, or may not coincide
with the fiscal year of any other organisation, e.g. a R & D client
in the private sector.
Fishbone diagram
A graph used in quality control to identify possible problem causes.
Also called an Ishikawa diagram after its inventor.
Fission
Transverse splitting in two of bacterial cells, asexual.
Fixed assets
Physical assets kept by an organisation to carry out its business,
e.g. buildings and vehicles.
Fixed budget
A budget which remains unchanged irrespective of the actual level of
output.
Fixed capital
Land, buildings, irrigation equipment etc. which cannot easily be moved.
Fixed coppers
Insoluble copper fungicides whose copper is in a combined form. Usually
finely divided, relatively insoluble powders.
Fixed overhead absorption rate (FOAR)
A calculation that divides the total fixed overheads of a cost centre
by a measure of output such as units, volume, labour hours or machine hours.
Fixed (overhead) costs
Costs which must be met and are not affected by the size of the activities
in the farm operations.
Fixed overhead expenditure variance
The difference between the actual cost and the budgeted cost of fixed
overheads.
Fixed overhead volume variance
The under- or over-recovery of fixed overheads caused by the actual
level of activity varying from the budgeted level used to set the standard
absorption rate.
Flacherie
A term used to describe the flaccid condition (flaccidity) seen in
silkworm larvae suffering from dysentery.
Flacherie viral
An infectious flacherie of silkworm larvae caused by a small non-occluded
virus.
Flagellae
Plural of flagellum.
Flagellate
Having one or more flagella.
Flagellosis
Infection with a flagellate protozoan.
Flagellum
A whip-like filament projecting from a bacterium or zoospore and functioning
as an organ of locomotion. Also called a cilium.
Flagging
The loss of rigidity and drooping of leaves and tender shoots preceding
the wilting of a plant.
Flag stage
(Also knee stage in onions). The early post-emergence stage of onion
seedlings between the crook stage and the emergence of the first true leaf.
The bent tip of the seed leaf resembles a flag attached to a staff. Also
used to designate the stage of development in cereals and other grasses
at which the sheath and leaf have been produced.
Flame gun: Flame thrower
Device producing tongue of flame, used to kill weeds and brushwood.
Flammable
Readily ignitable.
Flammable liquid
A liquid having a flash point of 21°C or more but less that 55°C
as determined by a closed cup method.
Flash point
The lowest temperature at which a material forms a flammable vapour/air
mixture under standard conditions.
Flat storage
Mainly bag type storage, but could be bulk storage.
Flavonoid
Any number of compounds, including plant pigments, related to or similar
in chemical structure to flavone C15H10O2.
Flavoprotein
A protein containing a derivative of riboflavin, which acts as an electron
carrier in the electron-transport system.
Fleck
A minute spot.
Flesh fly
Any member of the dipteran family Sacrophagidae.
Flexible budget
A budget which is designed to change in accordance with the actual
level of activity achieved.
Flexuous
Full of bends and curves.
Flint
A maize (Zea mays indurata) having usually rounded kernels with
a hard outer layer.
Flocculation
Joining together of particles in suspension.
Flo-dust (GP)
Special form of dustable powder for pneumatic application in greenhouses.
Floor spray
See spray vi.
Floret
Lemma and palea with the enclosed flower, they may be bisexual and
perfect, or unisexual and male or female or infertile.
Individual small flower, as in grasses or composites.
Flow
The rate of transfer of material between compartments or state variables.
Flow diagram
The diagrammatic representation, usually with conventional symbols,
of the structure of a system in terms of physical and information flows
between compartments.
Flowability
Property of flowing possessed by dusts, colloids or liquids.
Flowable
A type of pesticide formulation in which a very finely divided pesticide
is mixed in a liquid carrier.
Flowable concentrate for seed treatment
A stable suspension for application to the seed either directly or
after dilution.
Flowable powders
Contain the finely divided herbicide mixed with surface active agents
and a small volume of water. Like wettable powders they are diluted with
water before use.
Fluorescein
A fluorescent substance adsorbed to antibodies in order to facilitate
their detection and location on a tissue.
Fluorescent
Having the ability to emit light of a certain wavelength when activated
by light of another wavelength.
Fluorescent antibody
Immunoglobulin molecule which has been coupled with a fluorescent dye
so that it exhibits the property of fluorescence.
Fluorescent tracer
Fluorescent material added to spray to aid assessment of deposit on
plant material.
Flux
A flow of matter or energy of which direction, rate and density can
be determined.
Flux density
The amount of energy or matter passing through a unit area perpendicular
to the stream per unit time.
Flying herd
A dairy herd where calves are not reared, replacement down-calving
heifers may be brought in. Most commonly met where land values and milk
prices are high so that the price of milk does not justify its being fed
to calves, and other uses of the land pay better than rearing heifers.
An example of stratification.
Foaming agent
A chemical that causes a pesticide preparation to produce a thick foam,
which aids in reducing drift.
Foci
A small group of cells occurring e.g. in the liver, distinguishable,
in appearance or histochemically, from the surrounding tissue. They are
indicative of an early stage of a lesion which may lead to the formation
of neoplastic nodules or hepatocellular carcinomas.
Focus
The site of local concentration of infection of infestation from which
secondary spread may occur.
Fodder
Coarse grasses, such as maize and sorghum, which are harvested whole
and cured in an erect position for animal feed.
Foetus
The young of mammals when fully developed in the womb. In human beings,
this stage is reached after about 3 months of pregnancy. Prior to this,
the developing mammal is at the embryo stage.
Fog treatment
The application of a pesticide as a fine mist for the control of pests.
Foliage-acting
A herbicide which is active when applied to foliage.
Foliage applied herbicides
Compounds penetrate the outer waxy cuticle and are absorbed into the
leaf tissue, where they may or may not be translocated basipetally in the
phloem.
Foliar spray fertilisers
Nutrients sprayed in solution on to leaves.
Foliar application
Application of a pesticide to the leaves or foliage or plants.
Fomite
An article or substance, other than food, which can harbour and carry
micro-organisms and transmit them from one animal to another, thus disseminating
a disease.
Food
Those commodities which people normally eat: the weight of wholesome
edible material, measured on a moisture-free basis, that would normally
be consumed by humans. Inedible portions of the crop, such as stalks,
hulls and leaves are not food. A useful but arbitrary distinction is often
made between 'food', consumed by man, and 'feed', consumed by or fed to
animals.
Food chain
Sequence of species within a community, each member of which serves
as food for the species next higher in the chain e.g. plants, herbivores,
carnivores.
Food infection
Illness arising from ingestion of food containing pathogenic organisms
such as some salmonella which grow in the gastrointestinal tract.
Food loss
Any change in the availability, edibility, wholesomeness or quality
of food that reduces its value to humans.
Food poisoning
Illness arising from ingestion of food containing toxins from the growth
of organisms such as some staphylococci or clostridia.
Food web
A complex of branching, joining or diverging food chains that connect
together the various populations in an ecosystem.
Foot rot
Rotting involving the lower part of the stem-root axis, but not the
distal parts of the roots.
Forage
Vegetable matter, fresh or preserved, utilised as feed for animals.
Forb
A non-grass-like herb of the range. Small grass-like plant.
Forecasting
Method for extrapolating the future from analysis of available data
of the past. Most often applied in statistical analysis of time series.
Foreign matter
Other things, such as stones, sand, chaff, straw or other seeds mixed
with the crop product e.g. rice grain.
Form
A subdivision within a species or variety.
Formal reaction
An equation describing an electrochemical reaction in which electrons
are included as reactants.
Forma specialis
Special form: a biotype (or group of biotypes) of a species of pathogen
that differs from others in the ability to infect selected genera or species
of susceptible plants. (usually abbreviated as f. sp.). A subspecific
taxon usually denoting the host genus of which the organism is a parasite
e.g. tritici to denote wheat in Puccinia graminis f. sp. tritici.
Formamidine insecticide
An insecticide with a mode of action that is highly effective against
insect eggs and mites.
Formulant
Any substance other than technical material(s) incorporated in a formulation.
Formula pricing
A pricing method based on a cost calculation plus a percentage for
profit.
Formulation
Way in which basic pesticide is prepared and sold for use. It contains
the active ingredient(s) includes dusts, baits, fumigants, aerosols, granules.
Emulsifiable concentrates, wettable powders and suspension concentrates.
Forrester diagram
Model compartment diagram including information about factors controlling
flows.
Fossorial
Modified for digging; in the habit of digging or burrowing.
Foster-mother
A cow used to suckle one or more calves in addition to her own.
Foundation seed
The progeny of breeder's seed and the first major increase of seed
of an improved strain or variety, handled so as to maintain its superior
genetic qualities.
Fractile
Let _ be between 0 and 1. In a set of observations of a variable the
_ fractile is the number for a fraction _ of the observations is less than
this number. The fraction is often given in percent; the term percentile
may then be used.
Fractional factorial design
An experiment design in which parameters are studied at several levels
with only a fraction of the possible parameter-level combinations included
in the experiment.
Fractional sterilisation
A process in which some material is made sterile by several brief applications
of heat over a period of time.
Frame
A list of sampling units.
Frame shift
Since the genetic code is read three bases at a time, if reading begins
at either the second or third base of a codon, a faulty product usually
results. This is called a frame shift (the reading frame refers to the
pattern of reading).
Frame shift mutation
A change in the structure of DNA such that the transcription of genetic
information into RNA is completely altered because the start point for
reading has been altered i.e. the reading frame has been altered.
Frass
Refuse and excrement, left by insects larvae particularly borers.
Free energy
Energy available to do useful work.
Free-living
Growing outside of and not directly dependent on other organisms e.g.
a pathogen living in the soil, outside of its host.
Freeze-drying
A technique used in the preservation of living material, whereby water
is removed under vacuum while the tissue remains frozen.
Frequency distribution
A specification of the way in which the frequencies of members of a
population are distributed according to the values they exhibit.
Freund's incomplete adjuvant
A substance containing an emulsifier and mineral oil, which is mixed
with a virus before it is injected into the muscles of an animal to produce
anti-serum. The adjuvant allows slow release of the virus following injection.
Friability
The tendency of a granule to crumble, breaking down into smaller particles.
Friable
Crumbly; a desirable condition in a soil.
Friction polisher
Type of whitener using the friction between the rice grains to remove
the bran layer.
Friedman test
A non-parametric test to compare t > 2 treatments when the randomised
block design has been used. The data are ranked within each block, and
the rank sums for each of the t treatments are used in the Friedman test
statistic, X2.
Fringe benefits
Personal compensation for work done, usually given in the form of insurance,
paid leave, housing, transport or some other perquisite.
Fructification
Spore production by fungi; or, a structure in or on which spores are
formed. Also a fruiting body.
Fruit
The developed ripened ovary of a seed plant, e.g. pea pod, nut, tomato.
The ripened ovary with adnate parts.
Fruit-bud stages
i) breaking. Stage at which scales of fruit tree blossom buds begin
to separate at bud apex
ii) burst. Stage at which fruit tree blossom buds show separated leaf
tips emerging from bud apex
iii) cot-split. Stage shortly after petal-fall in plum when dead calyx
splits to reveal small fruitlet
iv) fruitlet. Stage in some fruit development 2-3 weeks after petal-fall
v) grape. Blossom-bud stage in black currants at which unopened flowers
are revealed in tight clusters
vi) green - flower (green - cluster). Blossom-bud stage of tree fruits
at which unopened flower buds are tightly clustered within a rosette of
opened leaves
vii) mouse-ear. Stage of development of apple fruit bud when partially
expanded rosette leaves protrude about 5 mm from bud apex
viii) petal-fall. Stage of tree fruits at which 80% of petals have
fallen
ix) pink-bud. Stage at which blossom-buds of apple have well-developed
and coloured petals, but flowers are still unopened
x) white-bud. Blossom stage in pears when petals show boldly but flowers
are still unopened
Fruiting body
A complex structure that bears fungal spores, e.g. sporangia, coremia,
sporodochia, acervuli, pycinidia, apothecia, perithecia.
Fugacity
(1) The tendency for a substance to transfer from one environmental
medium to another
(2) Analogous to chemical potential as it pertains to the tendency
of a chemical to escape from a phase e.g. from water.
Full-coverage spray
Spray applied thoroughly over a crop to the point of runoff or drip.
Full-sib
Having both parents in common.
Fumigant
Liquid or solid chemical that forms vapours that kill organisms. Particularly
used in the treatment of areas difficult to penetrate with sprays or other
pesticidal formulations, e.g. soils.
Fumigation
The application of a fumigant for disinfestation of an area.
Functional group
A group of species that are assumed in a model to function in a similar
fashion by having the same parameter values for process equations. These
are lumped together in the model as a single entity.
Functional response
Term used to describe the relationship between the number of prey attacked
per parasitoid (or predator) at different prey densities and the numerical
response between predator numbers and prey density.
Fundatrice
A viviparous parthenogenetic female aphid produced on a primary host
plant from an overwintering fertilised egg.
Fundatrigeniae
Progeny of the fundatrix; often applied to all spring generations following
the fundatrix of a heteroecious aphid on its primary host.
Fundatrix
Parthogenetic females which produce sexual females; in heteroecious
aphids, the return migrants to the primary host in autumn.
Fungi
All non-chlorophyll-bearing thallophytes (i.e. all non-chlorophyll-bearing
plants of a lower order than mosses and liverworts) that often show mycelial,
spreading growth e.g., rusts, mildews, moulds and yeasts.
Fungicidal
Killing fungal spores of mycelium.
Fungicide
Chemical or physical agent that kills or inhibits development of fungus
spores or mycelium (or when used in a broad sense bacteria).
The term 'fungicide' includes all preparations intended for preventing,
destroying, repelling or mitigating any fungi. Fungi includes all such
organisms as rusts, smuts, mildews, moulds, yeasts, viruses and bacteria,
except those on or in living man and other animals.
Fungicide resistance
A decrease in sensitivity to a fungicide due to selection or mutation
following exposure o the compound.
Fungi Imperfecti
A form class erected to contain those fungi whose sexual reproduction
is unknown.
Fungistasis
The prevention of fungal growth; the effect is reversible, if the inhibitor
is removed or diluted, growth is resumed.
Fungistatic
Able to inhibit germination of fungus spores or development of mycelium
without causing death of fungus.
Furrow application
Placement of pesticides with seed in furrow at time of sowing.
Futile cycling
The generation of superoxide of peroxide anions through the cyclic
activation of molecular oxygen by the cytochroms P-450 when these combine
with a difficulty-oxygenated substrate (e.g. phenobaritone) and are reduced
by cytochrome P-450 reductase and NADPH. Mixed-function oxidation by the
cytochromes P-450 generally reduces molecular oxygen to give the oxygenated
chemical substrate plus water; in futile cycling molecular oxygen is reduced
to super-oxide or peroxide and the chemical substrate is left unchanged.
