Pesticide active substances: introduction

 An active substance is a chemical, plant extract, pheromone or micro-organism that has action against plant pests, weeds or diseases. Examples include:

  • insecticides
  • herbicides
  • fungicides
  • molluscicides
  • plant growth regulators

Active substances can only be used within a plant protection product (PPP) if they are approved.

HSE is the assessing competent authority for GB and will evaluate the application for approval.

Types of active substances

Standard chemical

Active substances that are either organic or inorganic compounds.


Biopesticide active substances are:

  • microbials (such as a bacterium, fungus, protozoa, virus, or viroid)
  • plant extracts and botanicals
  • pheromones and semiochemicals, such as chemicals emitted by plants that evoke a behavioural or physiological response


There are several types of biostimulants some of which are covered by the Plant Protection Products Regulation (PPPR).

Basic substances

A basic substance is an active substance that is not placed on the market primarily as a plant protection product but which may be of value for plant protection.


Great Britain

Active substances in Great Britain must meet the requirements and conditions specified in retained Regulation (EC) No 1107/2009.

Northern Ireland

Pesticides in Northern Ireland are regulated by the Northern Ireland Protocol, which is subject to existing EU law, Regulation (EC) 1107/2009 as it has effect in Northern Ireland.

More on pesticide regulation

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Updated 2023-10-03