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Fruit rots and foliar pathogens can ruin an otherwise marketable crop. In vegetables, Stemphylium, anthracnose, Alternaria, early blight, and gummy stem blight are some of the usual suspects. In small fruits, Botrytis and anthracnose (Colletotrichum spp.) are often to blame. We only have so many tools available to manage these tough diseases, so how do we steward products to maintain their effectiveness as long as possible? 

Know your diseases 

Disease management is more than just fungicides. Know your diseases and understand their biology to better implement all available management practices.

Know your region 

Consider the history of fungicide resistance in your growing region, and when available, participate in local monitoring programs that assess current fungicide sensitivity.  

Know your tools 

The Fungicide Resistance Action Committee (FRAC) has a great explanation of fungicide classification and modes of action. Watch this short clip about codes and labelling. 



Understand which products are available to you to use, which diseases they suppress or control, and how they are classified by mode of action.



 

FRAC code	9	12	7	3	11	3	7	29
Ginseng	Botrytis grey mould, white mold		Alternaria leaf blight, Botrytis blight		Not registered		Not registered	Rhizoctonia root rot, Alternaria blight, Botrytis blight
Tomato	Botrytis grey mould		Early blight, Alternaria canker and rot, powdery mildew, anthracnose, Septoria leaf spot, Botrytis grey mould*, white mould*, Cercospora leaf spot		Early blight, anthracnose, Septoria leaf spot, powdery mildew		Early blight, anthracnose, Septoria leaf spot, powdery mildew	Not registered
Pepper	Anthracnose, grey mould							Phytophthora blight
Brassica	Alternaria leaf blight*		Alternaria leaf blight, powdery mildew		Alternaria leaf blight, powdery mildew		Not registered	Clubroot
Onion	Botrytis leaf blight, purple blotch*		Purple blotch, Botrytis leaf blight*, Stemphylium leaf blight*		Purple blotch, Botrytis leaf blight, leaf blotch*, Stemphylium leaf blight*		Purple blotch, Stemphylium leaf blight*	Purple blotch*, Botrytis leaf blight*, Stemphylium leaf blight*
Cucurbit	Not registered		Powdery mildew, Alternaria leaf spot, anthracnose, gummy stem blight, Alternaria blight*		Powdery mildew, Alternaria leaf blight, anthracnose, gummy stem blight*		Powdery mildew, Alternaria leaf blight and spot, anthracnose, Cercospora leaf spot, gummy stem blight	Downy mildew*, gummy stem blight*, Alternaria leaf spot

*Cabbage and crop group 5B only 


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FRAC code	9	12	7	12	3	9	29**
Grapes	Botrytis bunch rot		Botrytis grey mould, powdery mildew		Powdery mildew, Botrytis bunch rot, black rot, Alternaria rot, foliar anthracnose		Dead arm, Botrytis grey mould, anthracnose*
Strawberries	Grey mould, powdery mildew*, anthracnose		Grey mould, anthracnose		Botrytis grey mould, anthracnose**		Not registered
Blueberries (highbush)	Anthracnose, Botrytis fruit rot, mummyberry		Botrytis fruit rot		Monilinia blight, mummyberry, rust*, anthracnose, Alternaria leaf spot		Botrytis grey mould, mummyberry*, Phomopsis fruit rot*, fruit anthracnose*
Blueberries (lowbush)	Anthracnose, Botrytis fruit rot, mummyberry, sclerotinia berry drop*		Botrytis fruit rot, anthracnose				Botrytis grey mould, mummyberry*, Phomopsis fruit rot*, fruit anthracnose*, Valdensinia*

*Suppression 
**Wine grapes only 

Know the rules 

Next, review the specific guidelines for each mode of action group. Remember that mixtures can serve two purposes – to broaden spectrum, or to serve as a resistance management tool. An effective mix partner for resistance management provides effective control on its own – if the mix partner isn’t effective on the target disease, treat the application as a solo. 



For some medium and high-risk pathogens, there are more specific guidelines about alternation, mixing, and the total number of applications in a season. Here’s an example for Botrytis: 

Putting it all together 

Using what you know, map out a management plan for the season. Remember to also consider pre-harvest intervals, restricted entry intervals, maximum applications per season on the product label, and other label restrictions, which vary crop by crop. 

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. 

Does this seem overwhelming? Reach out to your Syngenta rep or retail partner if you’d like advice on building a crop protection program with resistance management top of mind. 

For more information contact our Customer Interaction Centre at 1-87-SYNGENTA (1-877-964-3682). 

Please check with your exporter when using any Syngenta product on ginseng destined for use outside of Canada. At time of print, Maximum Residue Limits (MRLs) had been established for the active ingredients cyprodinil, fluazinam, and pydiflumetofen for export markets in the United States and fludioxonil for export markets in the United States and Codex. Please see the Bryant Christie Inc. Global MRL database at https://www.globalmrl.com/db#query 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. 

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.​​​​​​​

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