Plant-protection treatment of plant and compositions which can be used for this purpose

Abstract

To increase the effectiveness of a cupric plant-protection composition and therefore to reduce the dose of copper used per hectare, a copper source, in non-chelated form, is combined with a sparingly soluble calcium and/or zinc and/or manganese chelate. This combination makes it possible to obtain, in situ, the gradual release of a soluble copper chelate.

1 . Process for the plant-protection treatment of plants, characterized in that it consists in combining a copper source, in non-chelated form, and a sparingly soluble calcium and/or zinc and/or manganese chelate in order to obtain, in situ, the gradual release of the soluble copper chelate.  
     
     
         2 . Plant-protection composition comprising a copper source, in non-chelated form, and at least one chelate of an α-hydroxycarboxylic, diphosphonic, polyphosphonic or α-hydroxyphosphonic acid and of calcium and/or of zinc and/or of manganese.  
     
     
         3 . Plant-protection composition according to  claim 2 , characterized in that it comprises a sufficient amount of at least one calcium and/or zinc and/or manganese chelate to chelate at least a portion of the Cu 2+  ions originating from the copper source.  
     
     
         4 . Composition according to  claim 2  or  3 , in which the copper source is a Bordeaux mixture, copper carbonate, copper hydroxide, copper oxychloride, cuprous oxide or a copper hydroxide sulphate.  
     
     
         5 . Composition according to  claim 2  or  3 , in which the copper source is a Bordeaux mixture in which virtually all the copper is in the brochantite state and which, in the dry state, does not comprise more than 20% by weight of bassanite.  
     
     
         6 . Composition according to one of  claims 2  to  5 , in which the α-hydroxycarboxylic acid is chosen from citric, glycolic, tartronic, gluconic, lactic, malic, tartaric and saccharic acids, it being possible for the final five to be in the L, D or DL form.  
     
     
         7 . Composition according to one of  claims 2  to  5 , in which the sparingly soluble chelate is calcium citrate or calcium malate.  
     
     
         8 . Composition according to one of  claims 2  to  7 , in which the chelate/copper molar ratio is between 0.005 and 10, preferably between 0.01 and 5 and more particularly between 0.05 and 1.  
     
     
         9 . Composition according to one of  claims 2  to  8 , in the form of an aqueous suspension, of a powder or of granules.  
     
     
         10 . Composition according to one of  claims 2  to  9 , additionally comprising at least one organic fungicide.  
     
     
         11 . Process according to  claim 1 , in which a composition according to one of  claims 2  to  10  is applied on the plant at a dose such that the amount of copper in g/ha is between 30 and 3000, preferably between 300 and 3000 and more particularly between 500 and 2500.