Resistance to plant protection products
Introduction
Plant protection products are used to control diseases, pests, and weeds in almost all agricultural and horticultural crops. It has been known for decades that fungi, insects, and weeds can develop resistance to plant protection products. Since the first cases of resistance emerged, research has been conducted and measures developed to prevent or delay the development of resistance, as well as to manage resistance that had already developed. Manufacturers of crop protection products establish international guidelines for such measures within the Fungicide Resistance Action Committee (FRAC), the Insecticide Resistance Action Committee (IRAC) and the Herbicide Resistance Action Committee (HRAC). These measures are also referred to as resistance management (see sidebar Resistance management). In a number of countries, including the Netherlands, regional groups known as Resistance Action Groups (RAGs) have been established to address the issue of resistance to plant protection products.
Resistance Action Group - The Netherlands (RAG-NL)
A regional fungicide resistance working group has been active in the Netherlands since 2004, addressing all aspects of fungal resistance to fungicides in the Netherlands. Working groups focused on insecticide resistance and herbicide resistance (later merged into the Weed management working group) were also established around that time. These working groups have been affiliated with the KNPV since 2014. In November 2025, the fungicide resistance working group broadened its scope to include insecticide and herbicide resistance and is continuing under the name Resistance Action Group. The Insecticide Resistance and Weed management working groups have been disbanded. The Resistance Action Group comprises representatives from plant protection product manufacturers, the Ctgb, the NVWA, and HAS Green Academy, as well a number of researchers.
Objectives
The working group has the following objectives:
• to be alert to reduced sensitivity of diseases, pests and weeds to plant protection products;
• to exchange information on resistance and reduced sensitivity among plant protection product manufacturers, government bodies and independent research institutions;
• to reach a consensus in the Netherlands regarding resistance to plant protection products and its management and to enter resistance cases into the EPPO Resistance Cases Database;
• to develop a national strategy for situations where key active substances are no longer available;
• to promote practical guidelines for resistance management in the Netherlands (based on RAC guidelines wherever possible);
• to produce information materials for advisors and growers regarding resistance to plant protection products and its management.
Contact
For more information, please contact the Secretary (Ivonne Elberse, or, until the end of November 2026, the Chair (Erno Bouma, ). The position of chair will be vacant from December 2026.
Resistance managementFor detailed information, please consult the RAC websites. General recommendations include: Use of good crop protection practices: Application of plant protection products: |