How do I control Downy Mildew in my vegetables?

The weather is humid and I've had some reports of Downy Mildew in Brassica Vegetables. Brassicas are terrific vegetables and easy to grow so long as you can control 2 significant problems: Grubs, mostly an issue in hot weather but constant observation and control measures are still important and Downy Mildew. I feel that Downy is mostly an issue for young seedlings, generally plants in the ground or established in pots are less dramatically affected.

The best control is cultural, make sure plants are in a sunny position and in a spot where air can move freely around the foliage. The other trick is to not allow the foliage to remain wet around mid morning. Apparently the Downy Mildew fungi germinates around this time of day and needs water to do so. So, water early, like 7.00 or 8.00am or in the early afternoon to restrict the development of the disease spores.


Chemical control is hard to avoid with this disease. Yates offers "Anti Rot" which looks quite safe. It is described as a "Phosacid systemic" fungicide so I guess it is closely related to the Phosphonic Acid we use in commercial quantities. Yates does recommend spraying at the first signs of disease but I suggest controlling Downy Mildew requires preventative sprays as it's really difficult to get rid of once established. Anti Rot is also a very good root rot disease control and I am more confident recommending this than Fongarid which has been the only option in retail packs until now. Don't quote me but I think this type of product is accepted under organic farming regulations, it is an acid though so make sure you dilute it properly. It is certainly certified as NON-Hazardous.

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PPS. Around Christmas I asked for contact details for Professional Gardeners willing, even enthusiastic about gardeing as distinct from lawn mowing or paving. I have finally posted a list on our web site, if you would like you name added, please let me know.