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How it works:

Powdery mildew overwinters in the vineyard either as hyphae in dormant buds or as cleistothecium containing ascospores.  As temperatures warm in early spring these two life forms of powdery mildew infect vines and start to produce the spores that are the inoculum leading to infection of the rest of the vineyard.

Karbyon should be applied prior to bud burst onward to attack the overwintering fungal hyphae and thereby prevent infection taking hold in the vineyard.  Apply Karbyon at 2.5 kg/ha (diluted 1:100) as a preventative measure to kill powdery mildew spores and break the fungal life cycle.



Figure 1. In most of Australian viticulture, powdery mildew develops from infected buds and sometimes, also from cleistothecia. Both lead to the production of new infection sites in the canopy from where the disease spreads steadily. (Sourced from Managing Powdery Mildew, Peter A. Magarey, Research Plant Pathologist, Magarey Plant Pathology, Australia.


Biostart Karbyon is a new, fast-acting fungicide for the prevention and curative treatment of Powdery Mildew. Dr Jerome Demmer, R & D Director for Biostart explains how the product works “Karybon’s active ingredient is potassium bicarbonate, a well known product used to control powdery mildew, which is thought to disrupt the potassium or sodium ion balance within the fungal cell, causing the cell walls to collapse. Potassium bicarbonate is a contact fungicide so complete coverage is essential for the most effective results and Karbyon has been formulated to microencapsulate potassium bicarbonate to improve crop coverage (no other wetting agents are needed). “ 

Geoff Warmouth, Biostart’s Vitacultural Territory Manager says “A trial application of Karbyon at a Wairau Valley vineyard in September 2013, followed by their conventional powdery mildew program, resulted in no powdery mildew infection up to harvest. In previous years incidences of powdery mildew were detected throughout the season. To avoid developing spray resistance in your vineyard, your powdery mildew control programme should use a combination of different control products that are alternated with each other. Karbyon can be used to kick-start your program and can be incorporated strategically throughout the season”.

Contact Geoff Warmouth on  021 794 276 for more information.

Karbyon has a 7 day withholding period and can be used through-out the season up to harvest.

If infection has occurred or disease pressure is high then apply Karbyon at heavier rates and shorten the spray frequency. 

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