Resistance of pests to plant protection products

In the current context, in which official policy is to reduce agricultural inputs and promote sustainable development, it is essential for the experts to be able to study and monitor problems of resistance and thus obtain information vital for the rational use of plant protection products.
The study of the phenomena of resistance requires the implementation of a specific approach, consisting essentially of searching for resistant individuals (level and frequency of resistance, resistance mechanisms) in pest populations.

The Agency is taking the following steps in this regard

• as part of surveillance plans, it conducts in vitro biological tests to determine levels of resistance and frequency of resistant individuals in field populations subjected to selection pressure;
• it implements biomolecular tests for genotypic characterisation of the resistance observed;
• it develops and/or validates methods to assess the level of susceptibility in pest populations;
• it investigates and studies the mechanisms at work in resistant individuals.

All of these studies allow it to produce summaries of the main problems of resistance and contribute to the work of various specialised working groups, including in particular, the "Resistance" group of the European and Mediterranean Plant Protection Organization (EPPO) and the group monitoring pesticide side effects (ECOACS).

The main pests studied are

• arboriculture: apple and pear scab and codling moth, Monilinia in stone fruit, diseases affecting apples in storage, bacterial blight of walnut, Oriental peach moth;
• vines: mildew, powdery mildew, botrytis, flavescence dorée leafhopper, annual ryegrass (Lolium rigidum);
• major crops: eyespot in wheat, Sclerotinia and pollen beetle in rapeseed, green aphid.