QuestionsHow to growVegetable GrowingPumpkins and squashSpraying for Potato Blight
I want to spray for Potato blight but would like to use the bluestone & washing soda remedy. How effective is this in comparison to newer remedies such as Ditane and do you know what the proportions of each (bluestone & washing soda)should be used?Many thanks
The old sprays, such as Burgundy mixture, which uses copper sulphate (bluestone) and washing soda, or Bordeaux mixtrure (bluestone and lime) are still effective. The heavy metal copper is the effective part.
Bluestone can be difficult to get and the solution must be used freshly made up. It needs to be repeated more often. About 100 grams of each is dissolved in 5 litres of water and the two slowly mixed and used right away.
Dithane contains mancozeb and it is an effective fungicide. It lasts better on the leaves than Burgundy mixture.