Pesticides: code of practice for using plant protection products in Scotland

The code is aimed at all professional users of plant protection products (pesticides) in Scotland.

Annex C: glossary of terms used in this code

This glossary defines words used in this code and of application equipment and methods.

Glossary of terms used in this code and of application equipment and methods.

The definitions in this glossary are for guidance only. They are not legally binding, unless it specifically states that the definition is that set by law.

Glossary 1

This glossary defines words used in this code.

Active ingredient

The part of a pesticide product which gives it its pesticidal properties. 'Active substance' is often used to mean the same thing.

Active substance

Any substance or micro-organism (including a virus) that has a general or specific action against harmful organisms or on plants, parts of plants or plant products. 'Active ingredient' is often used to mean the same thing.


A substance (other than water) without significant pesticidal properties and which, when added to a pesticide before it is applied, improves or is intended to improve the effectiveness of the pesticide.

Aerial application

Applying a pesticide from an aircraft (either fixed-wing or helicopter) in flight.

Agricultural vehicle

Any agricultural or forestry tractor or agricultural machinery.

Anti-cholinesterase compounds

A class of chemicals that includes many insecticides, such as parathion or carbaryl. They prevent the action of cholinesterase, which can in turn lead to a variety of symptoms such as nausea, vomiting, blurred vision, stomach cramps, and rapid heart rate.


All pesticide products must be approved before they can be advertised, stored, sold, supplied or used. The company wanting to sell a pesticide will usually apply for the approval. It will only be given when all the necessary evidence and information on the safety, effectiveness and, where relevant, the humaneness of the pesticide have been evaluated and considered acceptable. You can find full details of the approvals process on the PSD website.

Biobed (lined biobed)

A lined pit, 1 to 1.3 metres deep, filled with a mixture of straw, soil and peat-free compost and then turfed over. When correctly used, biobeds are effective at locking in and breaking down pesticide residues resulting from drips and splashes. In certain circumstances, a lined biobed may also be used to dispose of dilute pesticide from tank washings.

Biodiversity (or biological diversity)

The richness, abundance and variety of plant and wildlife species. Both the number of species and the number of individuals within each species are important in considering the biodiversity in an area.

Biological agents

Bacteria, viruses, fungi, other micro-organisms and their associated toxins. They can affect human health in a variety of ways, ranging from relatively mild, allergic reactions to serious medical conditions, even death. They are everywhere in the natural environment - in water, soil, plants, and animals. Because many microbes reproduce quickly and need very little to survive, they are a potential danger in a wide variety of occupational settings.

Biological monitoring

Measuring and assessing levels of chemicals or their 'metabolites' (substances the body converts the chemical into) in the breath, urine or blood of exposed workers. This monitoring may investigate either the level of exposure to an active substance or look for chemical signs of a reaction to exposure.


Any person who is in or near the area where a pesticide is being or has been used but is not directly involved in using the pesticide.


The area of land which water flows from (by run-off, movement through the soil or drainage) to surface water or groundwater.


An enzyme found primarily at nerve endings. It is important in sending nerve impulses in the body.

Closed-transfer system

A way of transferring the necessary amount of a pesticide from its container to the equipment applying it in a closed system to avoid the need for pouring and measuring and so reducing the risk of contamination. Some systems are designed for use with returnable containers.

Commodity substance

Substances with an approved pesticidal use which also have other non-pesticidal uses. Approval is given only for using the substance, not for selling, supplying, storing or advertising it. There is no approval holder or approved pesticide product label. You must read, understand and follow the approved conditions of use in the approval. You can look at the approval on the PSD website.


The detailed rules under Part III of the Food and Environment Protection Act 1985 are set out in what are known as 'consents' to be found in the Schedules to the Control of Pesticides (Amendment) Regulations 1997 and the Plant Protection Products (Basic Conditions) Regulations 1997. These consents are issued by Ministers and permit pesticides to be advertised, sold, stored, supplied and used, subject to certain conditions. these conditions set out general conditions for all pesticide users.

The term 'consent' is also used to describe the regulatory regime in place under the Control of Pollution Act 1974. It is the main legislative vehicle for point source pollution control, and provides a system whereby discharges of pollutants are subject to consent by SEPA.

Cross compliance

Standards and requirements which farmers and crofters have to meet as a condition of receiving their single farm payment. These requirements and measures concern the promotion of a more environment-friendly and sustainable approach to farming in Scotland.

Following crop

The next crop grown in the treated area, including when it is a treated perennial.


All water which is below the surface of the ground in the saturation zone (the soil lying immediately under the top layer of soil) and in direct contact with the ground or subsoil.

Landfill site

Defined in the Landfill (Scotland) Regulations 2003 as 'a waste disposal site for the deposit of the waste onto or into land'. This applies to both landfill sites receiving waste from a range of external sources and also internal waste disposal sites used by producers to dispose of waste at the site where it is produced.


The movement of pesticide residues through the soil by water filtering through the ground.

Local Environment Risk Assessment for Pesticides (LERAP)

For certain pesticides you must leave 'buffer zones' (untreated areas) to protect water and anything living in it when you are applying pesticide with a ground crop sprayer or a broadcast air-assisted sprayer. In some circumstances, the size of the buffer zone needed, as stated on the product label, can be adjusted to suit individual situations by carrying out a LERAP. Details of the LERAP schemes for ground crop sprayers and broadcast air-assisted sprayers are on the PSD website.

Maximum exposure limit (MEL)

The maximum concentration of a substance in the air, averaged over a set period, which people at work can be exposed to under any circumstances. The MEL for each substance that has one is given in Schedule 1 of the COSHH Regulations. These are now referred to as Workplace Exposure Limits.

Mixer or loader

A person who is involved in mixing or loading pesticides into the tank or hopper of any application equipment.

Occupational Exposure Standard (OES)

The concentration of a substance in the air, averaged over a set period, at which, according to current knowledge, there is no evidence that it is likely to harm a person at work who repeatedly breathes in that concentration. These are now referred to as Workplace exposure limits.

Parallel import

An imported pesticide which is identical to a product already approved in the UK. A parallel import also has to get a UK approval before it can be sold, supplied, stored, used or advertised.

Personal Protective Equipment (PPE)

Any device or appliance, which meets the appropriate standards, designed to be worn or held by a person to protect them from one or more health and safety risks.


Any substance, preparation or organism that is prepared or used for controlling any pest.


Any organism that is harmful to plants, wood or other plant products, any unwanted plant, or any harmful creature.

Pesticide approved for agricultural use

A pesticide (other than one with methyl bromide or chloropicrin as one of its active ingredients) approved for use:

  • in agriculture and horticulture (including amenity areas)
  • in forestry
  • in or near water (other than by householders)
  • as an industrial herbicide (such as weedkillers for use on land that is not intended for producing any crops)

Plant protection product

an active substance or preparation that contains one or more active substances (in the form in which it is supplied to the user) which is intended to:

  • protect plants or plant products against all harmful organisms or prevent the action of those organisms
  • influence the life processes of plants other than as a nutrient (for example, as a growth regulator)
  • preserve plant products (except for substances or products which are controlled under European union law on preservatives)
  • destroy unwanted plants
  • destroy parts of plants or control or prevent the undesired growth of plants

Reduced-volume spraying

Applying a pesticide in a lower volume of water than the minimum volume recommended on the label for that dose.

Respiratory protective equipment (RPE)

Any respiratory or breathing apparatus, which meets the appropriate standards and is designed to prevent or control contamination from breathing in a substance.

Special waste

Any waste which is hazardous waste as defined by Article 1(4) of the Hazardous Waste Directive (91/689/ EEC).

Specific Off-Label Approval (SOLA)

Other approved uses of a pesticide product (possibly on a minor crop or in an uncommon situation) as well as the uses described on the product label. If you use a pesticide under a SOLA you must read, understand and follow the approved conditions of use set out in the notice of approval for that SOLA. You can view the approval on the PSD website.

Spray quality

A classification reflecting the size of droplet in a spray, normally expressed in terms of the 'volume median diameter (VMD)'. Under the British Crop Protection Council (BCPC) Scheme, the following categories are used:

Volume median diameter

Size classification

less than 25µm

Fine aerosol ('fog' or 'very fine spray')

26 to 50µm

Coarse aerosol ('fog' or 'very fine spray')

51 to 100µm

Mist ('very fine spray')

101 to 200µm

Fine spray

201 to 300µm

Medium spray

More than 300µm

Coarse spray

Substance hazardous to health

Any substance (including any preparation) which:

  • is listed in Part I of the Approved Supply List as dangerous within the meaning of the Chemical (Hazard Information and Packaging) Regulations 1993, and which is classified as 'very toxic', 'toxic', 'harmful', 'corrosive' or 'irritant'
  • has a maximum exposure limit specified in Schedule 1 of the COSHH regulations or the Health and Safety Commission has approved an 'occupation exposure standard' for
  • is a biological agent
  • is a dust of any kind when present at a substantial concentration in the air
  • not mentioned in the list above, but which creates a similar danger to the health of any person


A broad shallow drain used as part of sustainable urban drainage schemes (SUDS).

Tank mix

A spray solution, prepared by the user, containing a mixture of two or more pesticide products.


Person or persons who use pesticides professionally in the course of their job or business: on farms and holdings; in horticulture; on amenity areas, industrial areas and sports grounds; and in forestry.

Water abstraction

Removing water, either permanently or temporarily, from any source including groundwater (for example, wells and boreholes) or surface water (rivers, streams, lakes and coastal waters). In the UK, the main water abstractors are statutory water supply undertakers, households, irrigated agriculture, industry and energy generators.

Workplace Exposure Limit (WEL)

New terminology for Maximum Exposure Limit (MEL), see entry under MEL.

Glossary 2

The definitions in glossary 2 relate to equipment and methods of applying pesticides. they are loosely based on the NPTC assessment schedules for certificates of competence in using pesticides safely.

Air assistance

Using forced air to carry spray droplets to their intended target (see 'Broadcast air-assisted spraying' and 'Downward placement air-assisted spraying').

Air-inclusion (air-induction) nozzle

A type of hydraulic nozzle with an air inlet so that the flow of liquid through the nozzle sucks in air which mixes with the spray liquid. These nozzles usually produce a coarse spray with many droplets containing one or more bubbles of air.

Broadcast air-assisted spraying

Using any equipment which broadcasts spray droplets, in an air stream produced by forced air, which carry upwards and outwards from the source of the spray.

Controlled Droplet Application (CDA)

CDA means producing only the optimum sizes of spray droplet for the particular application. This is achieved by using a rotary atomiser. See also entry for 'rotary atomiser'.

Deflector (flooding, anvil, impact) nozzle

A nozzle of either the 'hydraulic' or 'twin-fluid' type which produces a fan-shaped spray pattern when a cylindrical jet of liquid passes through a relatively large hole and hits a smooth, angled surface at a high speed. Generally, for hydraulic types, these nozzles produce relatively large droplets and are used at low pressures.

Downward placement air-assisted spraying

Using a forced stream of air to force the pesticide downwards (for example to help it to penetrate a crop canopy or reduce off-target drift).

Electrostatically charged

Material which has had an electrostatic charge added to help deposit the pesticide on target.


A space treatment using a droplet with a volume median diameter of less than 50µm, and with more than 10% of the spray volume having a droplet diameter smaller than 30µm. This includes both thermal fogs produced in a very hot air flow and cold fogs produced by a whirling mass of air.


An operation in which the pesticide acts as a gas, although it may not be applied in the form of a gas, to control or kill pests or other undesirable organisms.

Granule applicator

Any equipment, possibly air-assisted, which applies pesticides in granule form.

Ground crop sprayer

Any equipment of the spray boom type which applies pesticides using a horizontal boom.

Hand-held applicator

Any equipment carried by a person or where the pesticide delivery nozzle or outlet is supported directly by the user.

Hydraulic nozzle

A device though which spray liquid is given out, broken up into droplets and scattered using the pressurised liquid as the energy source.

Induction bowl or hopper

Metal, plastic or fibreglass hoppers attached to the side of the sprayer or the nurse tank that allow pesticides to be added to the mix tank without the person climbing onto the spray rig. Pesticides are poured into the bowl and water is added to flush out the bowl and carry the pesticide to the spray tank. A rinse nozzle is often mounted inside the bowl for rinsing out empty pesticide containers.


A space treatment using a droplet with a volume median diameter of 51 to 100µm, and with less than 10% of the volume of the spray having a droplet diameter smaller than 30µm.

Mounted equipment

Any pesticide application equipment which is mounted on, attached to or which forms a permanent part of the prime mover.

Pedestrian-controlled equipment

Any equipment which is supported by a mechanical carriage controlled by a person who does not ride in or on the carriage.

Pre-orifice nozzle

A hydraulic nozzle which incorporates a second hole upstream of the outlet. This decreases the pressure through the nozzle and so reduces the proportion of small droplets.

Prime mover

Any self-propelled vehicle used by a person who rides in or on the vehicle.

Roller table equipment (conveyor-belt mounted equipment, planter-mounted equipment and so on)

Application equipment which is mounted on, attached to, or forms a permanent part of a treatment system.

Rotary atomiser

A device in which a rotating solid surface, such as a cup, disc, wheel or cage, is the main source of energy used to produce a spray.

Seed-treating equipment

Any equipment, either mobile or static, which applies pesticides on cereal grains, pulses and other small seeds.

Shrouded boom sprayer

A horizontal boom sprayer, that is mounted on a vehicle, trailed or pedestrian-controlled, and which incorporates a shroud designed to prevent, or reduce, off-target drift. The shroud could be with a flexible skirt in contact with the target.


A space treatment using a device to produce smoke containing the pesticide's active substance.

Spray train

Any vehicle running on rails that has equipment for applying pesticides to the track, trackside or nearby areas and which is mounted on or attached to the vehicle or forms a permanent part of the vehicle.


Any equipment used to apply sprays that have droplets within limits described by the British Crop Protection Council (BCPC) nozzle classification scheme as 'coarse', 'medium', 'fine' and 'very fine'.

Sub-surface liquid applicator

Any equipment, except pedestrian-controlled equipment, which is designed to apply liquid pesticides below the surface of the ground.

Trailed equipment

Any application equipment which is trailed behind the prime mover.

Twin-fluid nozzle

A nozzle in which air under pressure is mixed with the spray liquid before it reaches the nozzle's hole.

Variable geometry sprayer

Any equipment which applies pesticides using a boom which can be positioned horizontally or vertically to suit the target.

Vehicle-mounted kerb sprayer

Any equipment which is mounted on, fixed to, or forms part of any vehicle for applying pesticides on roadside kerbs.

Water volume (application volume)

The volume of a spray liquid, including all pesticides, diluents, adjuvants, carriers and other components of the spray solution, applied in each unit area, normally expressed as litres per hectare.

Wick applicator or weed wiper

Any equipment which applies pesticides to the target by direct contact with an impregnated absorbent surface (wick, pad or roller).

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