Plant protection

Thresholds of the economic harmfulness of pests

A detailed vetting should be carried out to determine the severity of agrophages before chemical crop protection measures are applied.

Knowledge of damage thresholds is required before decisions on chemical control can be made. The economic damage thresholds determine when chemical pest control becomes cost-effective, i.e. at what pest abundance the damage caused by the pest exceeds the cost of chemical control. Identification of treatment needs to be based on crop-specific integrated pest management methodologies and decision-support systems that allow accurate risk and timing of treatments. Economic damage thresholds are developed for some agrophages, while for others indicator data are available to describe possible losses at emergence (

The occurrence of pests often varies and depends on the climatic conditions of the region, the nature of the soil and the history and environment of the field. The basis of cultivation measures for effective pest reduction is accurate identification of agrophages. This applies to locally important weed species as well as to pests and fungi, whose sources of infection may be within or outside the field. The need for chemical treatment must be based on an analysis of the current need for action to protect against agrophages that are not met by other, non-chemical methods of reducing or controlling them. The fact that action is needed should be based on an assessment of the actual threat level of the pest, its developmental stage and the conditions under which the treatment is carried out.

The decision should take into account the subsequent course of climatic conditions, the variety of the crop, the developmental stage of the pest, as well as the presence of its natural enemies.

The reason for treatment, as well as the type of product and its dosage, must be documented in the records of plant protection treatments.


One very effective and selective method of reducing the harmfulness of certain agrophages is seed treatment. In this case, very small amounts of plant protection products placed closest to the site of pathogen emergence work most effectively. Seed and seed potato treatments are applied on the basis of knowledge of the expected occurrence of the targeted agrophages, such as fungal diseases of cereals, potatoes, or pests feeding on emerging plants, exceeding the damage thresholds.