A copper pesticide is a copper compound used as a pesticide or fungicide. In the UK the Soil Association (one of the organic certification authorities) permits farmers to use some copper fungicides on organic land used for the production of certified organic crops only if there is a major threat to crops.  The compounds permitted are copper sulfate, copper hydroxide, cuprous oxide, copper oxychloride, copper ammonium carbonate (at a maximum concentration of 25 g/l), and copper octanoate. According to the Soil Association the total copper that can be applied to organic land is 6kg/ha/year. This limit is designed so that the amount of copper in the soil does not exceed the limits specified in the Soil Association standards for heavy metals.