What influences residue levels?

What influences pesticide residues in food?

The amount of a pesticide residue in a food is dependent on:

  • The proper use of the pesticide.
  • The amount of the pesticide used.
  • When the pesticide was used.
  • How the pesticide is metabolised by plants and animals.
  • How the pesticide breaks down in the environment.
  • Contamination (small amounts of pesticide that remain in the environment after legitimate use).


What influences pesticide residues in general?

  • Properties of the active ingredient and formulation – All plant protection products degrade with time.  Different active ingredients and formulations lead to different degradation rates.
  • Regional cultivation and site conditions – Factors like hours of sunlight, temperature and rainfall influence degradation and thus residue levels.
  • Period of time – More time between the application of a plant protection product and the harvest usually means more time for degradation resulting in reduced residue levels.
  • Type of crop – The type of crop is also an important factor.  For example, the roots of potatoes and carrots are protected from direct spraying as they are below the surface of the soil.
  • Pest infestation – Pest infestation influences the timing and rate of applications.
  • Plant health – Higher residues are likely to occur if the crop does not develop properly (e.g. due to drought).