Managing fruit rots and fungicide resistance?
January 23, 2023
Fruit rots can ruin an otherwise marketable harvest. Botrytis in particular can sneak in whether it’s pre-harvest in blueberries, late season in grapes or post-harvest in strawberries. Several tools are available, but with shifts in fungicide sensitivity, how do we best manage these fruit rots?
What is meant by “know your groups”?
The Fungicide Resistance Action Committee (FRAC) has a great explanation of classification, mode of action, codes, and labelling.
For example, the top of the Miravis® Prime label indicates that it contains a Group 7 and Group 12 fungicide.
You know the code, now what?
The best long-term strategy is loss prevention – keep the tools we have around for as long as possible. Here's how:
- Know your groups
- Plan accordingly
- Participate in monitoring programs
This video from FRAC highlights general best practices:
Putting it all together
Here’s a quick hit to help you manage fungicide resistance in your small fruits:
| Switch® | Miravis® Prime | Inspire Super® |
|---|
| FRAC code | 9 | 12 | 7 | 12 | 3* | 9 |
| Resistance risk | Medium | Low to medium | Medium to high | Low to medium | Medium | Medium |
| Grapes | 0.31 to 0.39 kg/acre | 0.32 to 0.4 L/acre | 0.42 to 0.6 L/acre |
| Strawberries | 0.39 kg/acre | 0.4 L/acre | NR** |
| Blueberries (highbush) | 0.31 to 0.39 kg/acre | 0.32 to 0.4 L/acre | 0.42 to 0.6 L/acre |
| Blueberries (lowbush) | 0.31 to 0.39 kg/acre | NR** | 0.42 to 0.6 L/acre |
| Guidelines (Botrytis-specific) | Group 7: Two sequential applications permitted when mixed with a different robust partner (ex. Group 12); no more than 50% of the total applications when applied in mixture. Grapes only: Maximum three applications per year across all diseases. Group 9: One application when one to three treatments made per season, two applications if four to six applications per season. Group 12: Two sequential applications permitted when mixed with a different robust partner (ex. Group 9 or 7). |
* Difenoconazole has no activity against Botrytis.
**NR - this product is not registered in the crop listed.
Inspire Super® and Switch® both contain a Group 9.
Switch and Miravis® Prime both contain a Group 12.
For resistance management in Botrytis, specific management guidelines exist for some groups. To summarize:
- No more than two sequential applications of a Group 7 or 12 containing product should be used, and no more than 50% of applications should include a Group 7 when products are applied in a mixture and the mix partners provide similar levels of control.
- Group 9 fungicides should only be used once when one to three applications are planned, and only twice if four to six applications are planned.
Remember: It’s all about the group, not the brand.
Reach out to your Syngenta rep or retail partner if you’d like advice on building a Botrytis program with resistance management top of mind.
For more information including articles, resources and videos on resistance management, check out Manage Resistance Now. This is a collaborative effort of industry, academia and government experts, brought together by CropLife Canada, to raise awareness and promote the adoption of strategies to manage weed, insect and disease resistance.
Please check with your packer or exporter when using Miravis® Prime on berries destined for use outside of Canada. At time of print, Maximum Residue Limits (MRLs) had been established for the active ingredient pydiflumetofen for export markets in the United States. Please see the Bryant Christie Inc. Global MRL database for a complete list of MRLs. Should you need additional information on export market MRLs, please consult with Syngenta to receive the most up-to-date information.
Always read and follow label directions. Miravis®, Inspire Super®, Switch® and the Syngenta logo are trademarks of a Syngenta Group Company. © 2023 Syngenta.
