VG04061 White Blister – Workshop 2007

White blister (Albugo candida) is the most important foliar disease of brassica crops in Australia.

The disease can affect all stages of plant growth, but its greatest impact is on infected flower heads, resulting in substantial losses to yield and higher costs in sorting.

This Horticulture Australia project aimed to evaluate fungicides for white blister control (Albugo candida) and to expedite the registration of suitable fungicides in Australia for white blister control on brassica and leafy brassica crops.


Hoong Pung Susan Cross
Ross Holding Paul Florissen
Rodney Burns Jane Floyed
Kate Williams Scott Winner
Elizabeth Fields  

Workshop Notes - White Blister 2007
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Conclusions :

  • In these studies, Ridomil Gold MZ and Ridomil Gold Plus at 2.5 kg/ha and 2.2 kg/ha, respectively, were effective for white blister control.
  • The systemic fungicides, Amistar and BAS 500 or Cabrio, were also effective ; however, Penncozeb, Bravo, Filan and phosphorous acid had no effect on the disease.
  • BAS 500 belongs to the same strobilurin chemical group as (Amistar), and therefore is not a suitable alternative to Amistar.

    As a result, the product manufacturer and distributor decided not to register Cabrio for use on brassicas against white blister in Australia.

  • Amistar SC at 0.25 and 0.5 L/ha appeared to be adequate for effective disease control, when disease pressure was low and/or when field conditions were not favourable for the disease.
  • Higher rates of Amistar SC at 1.0 and 2.0 L/ha gave better disease control, when the disease pressure was high and field conditions were favourable to the disease.
  • Amistar SC or Ridomil MZ must be applied early, at the first sign of infection, for effective disease control. Less effective control by Amistar SC or Ridomil MZ was noted when they were applied later, long after the onset of the disease.
  • Copper fungicides based on copper hydroxide or copper oxychloride tend to be less effective than the systemic fungicides in preventing leaf infection, but are effective in reducing head infections.
  • They should be considered for use on crops that are approaching maturity in order to prevent head infections, following early systemic fungicide applications.
  • In Tasmania and Victoria, favourable field conditions, consecutive plantings and multiple plantings combine to create a constant disease pressure over a prolonged period of time, as well as prolonged exposure of fungal populations to a fungicide.
  • The systemic fungicides, Amistar, Cabrio, Ridomil Gold MZ and Ridomil Gold Plus have a high risk of resistance development if they are exposed to constant disease pressure.
  • Failure to follow resistance management guidelines carefully will likely result in the loss of these new fungicides as effective control measures.
  • Growers should adopt an integrated disease management strategy that incorporates the use of fungicides, along with other management practices such as resistance cultivars, crop rotations and reducing multiple plantings, for long-term and sustainable disease control.

Acknowledments :

This project has been facilitated by Horticulture Australia Limited, and has been funded by voluntary contributions from Syngenta Crop Protection Pty Ltd and the Australian Government.

Nufarm Australia Limited and Agrichem Industries Pty Ltd also contributed voluntary contributions in the first year for preliminary screening of their fungicides.

The assistance of broccoli growers who provided the trial sites in Tasmania and Werribee South, Victoria, is gratefully acknowledged.

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