The Fungicide Resistance Action Group (FRAG-UK)

Good resistance management is based on limiting the level of exposure of the target pathogen to the fungicide.

• Fungicide input is only one aspect of crop management and other integrated control measures should always be used, such as disease-free seed lots, good hygiene through disposal of crop debris and control of volunteers which may harbour disease
• Always aim to select varieties exhibiting a high degree of resistance to diseases known to be prevalent in your area, in addition to the main agronomic factors you desire
• Avoid growing large areas of any one variety, particularly in areas of high disease risk where the variety is known to be susceptible
• Only use fungicides in situations where the risk or presence of disease warrants treatment
• Use a dose that will give effective disease control and which is appropriate for the variety and disease pressure
• Make full use of effective fungicides with different modes of action in mixtures or as alternate sprays
• Ensure that mixing partners are used at doses that give similar efficacy and persistence
• Monitor crops regularly for disease and treat before the infection becomes well established
• Avoid repeated applications of the same product or mode of action and never exceed the maximum recommended dose or number of applications

Usually, fungicides control susceptible fungal strains effectively. However, any resistant strains present – through mutation or natural variation – are more likely to survive and reproduce.

This process of ‘selection’ makes each subsequent generation more difficult to control. In the absence of any fitness costs, resistant strains may come to dominate the population, causing disease control to fail.

From 2023, all UK plant protection products will include mode of action (MoA) information on their labels.

Access FRAG information published before 2016 via the National Archives.