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Guarding against botrytis

Scott Mathew, Syngenta Viticulture & Fruit Portfolio Lead

Last month we discussed light brown apple moth (LBAM) control, through the use of PROCLAIM® Opti insecticide and VOLIAM TARGO® insecticide. Managing LBAM is an important first step in helping safeguard against botrytis infections, along with a robust fungicide program. 

Botrytis is referred to as a weak pathogen and needs a wound site to infect the plant. Botrytis thrives in high humidity, still-air environments, where there’s decaying plant material. It can germinate in the presence of free water or in conditions with at least 98 per cent relative humidity for 15 hours. 

One of the most critical times to protect against botrytis infection is over flowering, when the caps fall off leaving micro-injuries and decaying tissue inside the developing bunch, making an ideal entry point for botrytis infection. Similarly, wounds caused by mechanical injury, birds, insects, other fungal pathogens, or berries split by rain or hail are ideal entry points. For these reasons, an application of a systemic botryticide at 80% cap fall is extremely important where there’s history of botrytis, rainfall is expected over the flowering period or even when extended periods of high relative humidity are likely. 

Through the course of the season, it is important to keep on top of your botrytis management plan, with pre-bunch closure being the other crucial timing. This is the last chance for good spray coverage inside the bunch. 

SWITCH® fungicide has, for many years, been globally recognised by growers as the ‘go to’ product for botrytis management. Its active ingredients cyprodinil and fludioxonil deliver robust and reliable botrytis control, even under high temperature and wet conditions.  

AMISTAR® 250SC controls powdery mildew, downy mildew, and botrytis in one pass, and regular readers will know it can now be used alone at key infection times like 80% capfall or E-L29 pepper-corn size (not > 4 mm diameter), for botrytis control. New research demonstrates that AMISTAR® 250SC is a very effective botryticide on its own, without the need for a mixing partner. If used alone though it should be used in strict rotation with fungicides from a different mode of action group. 

By using AMISTAR® 250SC and SWITCH® in a protectant program, growers can build a strong foundation for protection against the development of botrytis this season. Talk to your local Syngenta representative if you have any questions or visit 

Remember, always follow CropLife resistance management strategies. Details can be found at


Scott Matthew - Syngenta Portfolio Lead for Viticulture & Fruit
Twitter | @HortApplication
Email | [email protected]
Mobile | 0428 225 597



About Syngenta Australia
Syngenta is a leading agriculture company helping to improve global food security by enabling millions of farmers to make better use of available resources. Through world class science and innovative crop solutions, our 28,000 people in over 90 countries are working to transform how crops are grown. We are committed to rescuing land from degradation, enhancing biodiversity and revitalizing rural communities. To learn more visit and