By Lisa Beirn, Ph.D., technical services manager for Syngenta

General Principles | Fungicides | Herbicides | Insecticides | Explore Modes of Action

Whether applying alone or tank mixing, it's essential to have knowledge of modes of action to help prolong product efficacy for fungicides, insecticides and herbicides. Modes of action, represented as Fungicide Resistance Action Committee (FRAC) codes, Insecticide Resistance Action Committee (IRAC) codes and Herbicide Resistance Action Committee (HRAC) codes, are typically listed on product labels.

Mixing products with different modes of action can help lessen the chance your application will lead to disease, insect or herbicide resistance:

• Tank mixing:
  • Ensures complete activity against target pathogens by using multiple active ingredients
  • Improves disease control when multiple pathogens are present
• Pre-mixed combinations:
  • Offer convenience of multiple active ingredients in one jug and less container waste (e.g., Posterity^® XT fungicide combines ADEPIDYN^® technology for dollar spot control and the strength of Headway^® fungicide active ingredients for broad-spectrum disease control)
  • Economical option for both common and difficult-to-control diseases

• For example, one application of Acelepryn^® insecticide (group 28) or Acelepryn Xtra insecticide (group 4 and 28) in spring is effective for season-long control of masked chafer white grubs, among other species.
• Insects that reproduce rapidly, have multiple generations per season and are repeatedly exposed to the same active ingredient are more likely to develop levels of resistance (e.g., southern chinch bugs, annual bluegrass weevil)
• Strategies for preserving control options:
  • Use resistant turfgrass species or cultivars
  • Reduce treatment frequency
  • Rotate modes of action
  • Apply control measures specific to target insect through correct identification, monitoring and action thresholds

• Tank mixing: Broadens weed control spectrum. 
  • Example: Pennant Magnum^® herbicide (group 15) + Barricade^® 65WG herbicide (group 3) for warm-season turf in heavy weed pressure regions
• Post-emergent control: Use products like Monument^® 75WG herbicide (group 2), Tenacity^® herbicide (group 27) or Manuscript^® herbicide (group 1) for weeds that escape herbicide applications, depending on turf type
• Employ an integrated strategy: 
  • Herbicides may not always have the same mode of action or activity on the same weed
  • Use all available herbicide options (pre- and post-emergent)
  • Include non-selective and mechanical (hand removal) methods

• Carefully read each product label.
• Products that belong to the same FRAC, IRAC or HRAC group, may not necessarily control the same diseases, insects or weeds. 

Resistance management is an important consideration used in the development of Syngenta agronomic programs. These proven programs help turf become fit before the season, provide exceptional turf quality for players and recover from stress like insects, disease, heat, drought, aerification and traffic. To find an agronomic program that can assist in managing resistance for your area, visit ConditionPerformRecover.com.

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