Plant growth regulation compositions and methods using gibberellin biosynthesis inhibitor combinations

Abstract

Described are plant growth regulation compositions and methods utilizing combinations of Class A and Class B gibberellin biosynthesis inhibitors. Preferred methods and compositions involve the combination of trinexapac-ethyl with either or both of flurprimidol and paclobutrazol, in particular to provide a synergistic effect in the regulation of the growth of turfgrass.

1 . A method for regulating plant growth, comprising:
 applying to a plant a Class A gibberellin biosynthesis inhibitor; and   applying to the plant a Class B gibberellin biosynthesis inhibitor;   wherein said Class A and Class B gibberellin synthesis inhibitors exhibit synergism in regulating growth of the plant.   
     
     
         2 . A method according to  claim 1 , wherein:
 said Class A gibberellin synthesis inhibitor is encompassed by the formula:   
       
         
           
           
               
               
           
         
         wherein 
         A is an —OR 2  or —NR 3 R 4  radical, 
         R is C 3 -C 6  cycloalkyl, 
         R 2 R 3  and R 4  are each independently hydrogen, C 1 -C 6  alkyl, C 1 -C 6  haloalkyl, C 2 -C 10  alkoxyalkyl, C 2 -C 10  alkylthioalkyl, C 3 -C 6  alkenyl, which is unsubstituted or substituted by halogen, C 1 -C 4  alkoxy or C 1 -C 4  alkylthio; C 3 -C 6  alkynyl; phenyl or C 1 -C 6  aralkyl, wherein the phenyl nucleus is unsubstituted or substituted by halogen, C 1 -C 4  alkyl, C 1 -C 4  alkoxy, C 1 -C 4  haloalkyl, nitro or cyano; one of R 3  and R 4  is methoxy; or 
         R 3  and R 4 , together with the nitrogen atom to which they are attached, form a 5- or 6-membered heterocyclic ring system which may contain an additional oxygen or sulfur atom in the ring; and the metal or ammonium salts thereof. 
       
     
     
         3 . A method according to  claim 2 , wherein the Class A gibberellin synthesis inhibitor is trinexapac-ethyl. 
     
     
         4 . A method according to  claim 1 , wherein the Class B gibberellin synthesis inhibitor is encompassed by the formula: 
       
         
           
           
               
               
           
         
         wherein 
         R 5  is alkenyl, alkynyl or optionally substituted aralkyl; 
         Y is ═N— or ═CH—; 
         R 6  is cycloalkyl, alkyl or haloalkyl; and 
         R 7  is hydrogen, methyl or alkenyl, or an ester, an ether, an acid addition salt or a metal complex thereof. 
       
     
     
         5 . A method according to  claim 4 , wherein the Class B gibberellin synthesis inhibitor is paclobutrazol. 
     
     
         6 . A method according to  claim 1 , wherein:
 the Class B gibberellin synthesis inhibitor is encompassed by the formula:   
       
         
           
           
               
               
           
         
         wherein 
         R 8  is 2-pyrazinyl, 3-pyridyl, or 5-pyrimidinyl; 
         R 9  is phenyl, pyridyl, C 1 -C 12  alkyl, or C 3 -C 8  cycloalkyl; 
         R 10  is trifluoromethoxyphenyl, tetrafluoroethoxyphenyl, pentafluoroethoxyphenyl, 3,4-(difluoromethylenedioxy)phenyl, or 2,2,4,4-tetrafluoro-1,3-benzodioxanyl; 
         X is hydrogen, hydroxy, lower alkoxy, lower alkylthio, or lower alkanoyloxy; 
         or an acid addition salt thereof. 
       
     
     
         7 . A method according to  claim 6 , wherein the Class B gibberellin synthesis inhibitor is flurprimidol. 
     
     
         8 . A method according to  claim 1 , wherein the Class A and Class B gibberellin biosynthesis inhibitors are applied together. 
     
     
         9 . A method according to  claim 1 , wherein the Class A and Class B gibberellin biosynthesis inhibitors are applied separately. 
     
     
         10 . A method according to  claim 1 , wherein the plant is turfgrass. 
     
     
         11 . A method according to  claim 10 , wherein the Class A gibberellin biosynthesis inhibitor is trinexepac-ethyl, and wherein the trinexepac-ethyl is applied at a level of about 0.02 to about 0.7 pounds of active ingredient per acre. 
     
     
         12 . A method according to  claim 11 , wherein the Class B gibberellin biosynthesis inhibitor is flurprimidol, and wherein the flurprimidol is applied at a level of about 0.05 to about 1.5 pounds of active ingredient per acre. 
     
     
         13 . A method according to  claim 11 , wherein the Class B gibberellin biosynthesis inhibitor is paclobutrazol, and wherein the paclobutrazol is applied at a level of about 0.05 to 1.0 pounds of active ingredient per acre. 
     
     
         14 . A method according to  claim 10 , wherein the Class A and Class B gibberellin biosynthesis inhibitors are applied together. 
     
     
         15 . A method according to  claim 10 , wherein the Class A and Class B gibberellin biosynthesis inhibitors are applied separately. 
     
     
         16 . A method according to  claim 14 , wherein the turfgrass comprises one or more grasses selected from as Bahiagrass ( Paspalum notatum ); Bermudagrass ( Cynodon dactylon ); Buffalograss ( Buchloe dactyloides ); Carpetgrass ( Axonopus affinis ); Centipedegrass ( Eremochloa ophiuroides ); Kikuyugrass ( Pennisetum cladestinum ); Seashore paspalum ( Paspalum vaginatum ); St. Augustinegrass ( Stenotaphrum secundatum ); Zoysiagrass ( Zoysia matrella  ( japonica )); Annual ryegrass ( Lolium multiflorum ); Bentgrass ( Agrostis  spp.); Fescue ( Festuca  spp.); Kentucky bluegrass ( Poa pratensis ); Perennial ryegrass ( Lolium perenne ); and  Poa annua.    
     
     
         17 . A method according to  claim 14 , wherein the turfgrass comprises one or more grasses selected from Bermudagrass ( Cynodon dactylon ); Annual ryegrass ( Lolium multiflorum ); Bentgrass ( Agrostis  spp); Kentucky bluegrass ( Poa pratensis ); and Perennial ryegrass ( Lolium perenne ). 
     
     
         18 . A composition for regulating plant growth, comprising:
 a Class A gibberellin biosynthesis inhibitor; and   a Class B gibberellin biosynthesis inhibitor;   wherein said biosynthesis inhibitors exhibit synergism in the regulation of plant growth.   
     
     
         19 . A composition according to  claim 18 , wherein:
 said Class A gibberellin synthesis inhibitor is encompassed by the formula:   
       
         
           
           
               
               
           
         
         wherein 
         A is an —OR 2  or —NR 3 R 4  radical, 
         R is C 3 -C 6  cycloalkyl, 
         R 2 R 3  and R 4  are each independently hydrogen, C 1 -C 6  alkyl, C 1 -C 6  haloalkyl, C 2 -C 10  alkoxyalkyl, C 2 -C 10  alkylthioalkyl, C 3 -C 6  alkenyl, which is unsubstituted or substituted by halogen, C 1 -C 4  alkoxy or C 1 -C 4  alkylthio; C 3 -C 6  alkynyl; phenyl or C 1 -C 6  aralkyl, wherein the phenyl nucleus is unsubstituted or substituted by halogen, C 1 -C 4  alkyl, C 1 -C 4  alkoxy, C 1 -C 4  haloalkyl, nitro or cyano; one of R 3  and R 4  is methoxy; or 
         R 3  and R 4 , together with the nitrogen atom to which they are attached, form a 5- or 6-membered heterocyclic ring system which may contain an additional oxygen or sulfur atom in the ring; and the metal or ammonium salts thereof. 
       
     
     
         20 . A composition according to  claim 18 , wherein the Class A gibberellin synthesis inhibitor is trinexapac-ethyl. 
     
     
         21 - 32 . (canceled)