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Potato blight fungicide



  • barry islandbarry island Posts: 1,753

    I did a google search to try and find what the commercial growers use and found a paper which stated that as the commercial organic potato growers rely on copper fungicides that it was permissible for them to use a copper mixture and that the maximum amount of copper that can be applied per hectare is 6kg per year and yet they ban Bordeaux mixture for the general public’s use.

  • ItalophileItalophile Posts: 1,731

    It's one of the great conundrums. Copper is a naturally occurring substance so, technically, it's organic. Yet it's a metal that is known to stay in (well, on top of) the soil so it can build up. Organic growers choose not to use chemicals but use a metal that is known to build up in the soil. And have argued - obviously successfully - that there are no known organic alternatives.

    I think the difference for commercial growers is that the authorities have decided they - commercial growers - can be trusted not to poison themselves. Private growers apparently can't. 

  • barry islandbarry island Posts: 1,753

    I don't know what the amount of copper is in the small amount of Bordeaux mixture that I used to spray onto my 8 or 9 rows of spuds was but I reckon that its less than the equivalent of 6kg per hectare each year, I think that the EU believe that we spray the stuff just for fun but I only ever used it sparingly and did pay attention to the potato council blight warnings before spraying.

  • ItalophileItalophile Posts: 1,731

    You can always make your own BM. Copper sulphate, hydrated lime, water. Just get the ratios right. 

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