Abstract:
The invention relates to a synergistic fungicidal composition containing more active ingredients comprising benzimidazole-2-ylmethylcarbamate and the zinc and manganese complexes of (8-oxyquinolinate)-(dimethyl dithiocarbamate) as active ingredients, optionally solid and/or liquid carrier(s) and other excipient(s). 
     The composition is of value especially in the treatment of infections caused by ustilaginales, powdery mildew and fusarium species on cereals.

Description:
FIELD OF THE INVENTION 
     The invention relates to synergistic fungicidal compositions comprising several active ingredients used in the treatment of fungal diseases of cereals, especially infections caused by ustilaginales, powdery mildew and fusarium species. The invention also resides in a method for combatting or preventing fungal infections by applying the said composition to the locus of the infection. 
     BACKGROUND OF THE INVENTION 
     It is well known from the art, that the most important pathogenic fungi of cereals (e.g. wheat, barley) are as follows: 
     smut diseases, such as bunt smut of wheat (Tilletia foetida), loose smut of barley (Ustilago nuda) and the fusarium species (Fusarium spp.) which infect the plant in embryomic stage partly in the soil, partly internally in the seed; 
     powdery mildew species (e.g. Erypsiphe graminis) which attack the plant in several stages of growth; 
     cereal fusarium fungi (Fusarium graminearum) and rusts (e.g. Puccinia glumarum) which attack the corn after earing. 
     The infections of the plant seed are treated by seed-dressing, while the later fungal attacks are treated with foliar spray application of different kinds of fungicides. 
     So far mercury containing compounds have been used for seed-dressing of corn. However, these compounds have several disadvantages. The health-detrimental and accumulating effect of mercury containing compounds is well known and the compounds do not protect the seeds from internal infections. 
     The activity of benzimidazol-2-ylmethylcarbamate (BMC, trade name: carbendazime) against phytopathogenic fungi was first described by H. Hampel and F. Locher [Proc. Br. Insectic. Fungic. Conf. 7th, (1973) pp 127, 301], and the utility of this compound as an antifungal foliar spray was referred to in U.S. Pat. No. 3,657,443. 
     Powel reported on the protective fungicidal effect of the copper complex of 8-oxyquinoline the first time in the second half of the 1940&#39;s [Phytopathology, 36, p. 573, (1946)]. 
     In Hungarian patent specification No. 171,736 the very favorable fungicidal effect of the mixed liganded (8-oxyquinolinate)-(dimethyl dithiocarbamate) metal complexes is described. These metal complexes are always more effective--especially if the central atom is zinc, manganese, copper, magnesium, iron, cadmium etc.--than the metal complexes of either 8-oxyquinolinate or dimethyl dithiocarbamate comprising the same ligand. It is further reported, that a mixture containing 1 part by weight of zinc complex and 1 part by weight of manganese complex is preferred. 
     According to Polish patent specification No. 104,686 a mixture of the copper complex of (8-oxyquinolinate)-(dimethyl dithiocarbamate) and carbendazime of a weight ratio 1:1 possesses synergistic effect against the fungi Rhizoctonia solani, Phome betae and Helminthosporium gramineum. 
     SUMMARY OF THE INVENTION 
     The compostion according to the invention contains benzimidazol-2-ylmethylcarbamate and zinc and manganese complexes of (8-oxyquinolinate)-(dimethyl dithiobarbamate) as active ingredients in a weight ratio of 1:3 to 2:1 and the weight ratio of the two different metal complexes of (8-oxyquinolinate)-(dimethyl dithiocarbamate) is 1:1. 
     The composition preferably contains 5% to 90% by weight of active ingredients, as well as solid or liquid carriers and other excipients. 
     According to a second aspect of the invention, there is provided a method of treating fungal infections of plants which comprises applying to said plants a fungicidally effective amount of a fungicidal formulation as defined above. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The combinations of active ingredients defined in the above formulation are novel and have been found to be surprisingly effective in controlling or combatting fungal infections of cereals. 
     The composition exhibits synergistic effect in the range of a weight ratio of carbendazime and the metal complexes being 1:3 to 2:1. The preferred weight ratio of the two metal complexes is 1:1. 
     In the method of treating fungal infections the formulation can be applied by foliar application or it can be used as seed-dressing depending on the fungal attack to be treated. The amount and frequency of application is determined by the severity or expected severity of the fungal disease and, as is well known to those skilled in the art, by the age and condition of the crop. 
     In order to simplify manufacture, storage and transport, the combinations of the active ingredients are normally produced in a concentrate or powder form intended for dilution in a solvent to the degree necessary to enable the above mentioned application rates to be easily achieved. Such formulations are usually in the form of a wettable powder or dust, aqueous suspension, emulsifiable concentrate and granules. The concentrate formulations are intended for appropriate dilution prior to use. This formation of a dispersion can be carried out in conventional spray tanks suitable for the purpose. 
     Wettable powders or dusts comprise an intimate mixture of the active ingredients, one or more inert carriers and appropriate excipients. The inert carrier may be selected from the attapulgite clays, the montmorillonite clays, the diatomaceous earths, kaolins, micas, talcs and purified silicates. 
     Sufficient excipients may be found among the nonionic and ionic surfactants. E.g. sodium or calcium salts of polyacrylic acids and lignin sulphonic acid; the condensation of fatty acids or aliphatic amines or amides with ethylene oxyde and/or propylene oxide; fatty acid esters of glycerol, sorbitan, sucrose or pentaerythritol; condensates of these with ethylene oxide and/or propylene oxide; condensation products of fatty alcohols or alkyl phenols with ethylene oxide and/or propylene oxide; sulphates or sulphonates of these condensation products; alkali or alkaline earth metals of sulphuric or sulphonic acid esters; sodium alkylaryl sulphonates; polymers of ethylene oxide and copolymers of ethylene oxide and propylene oxide. 
     The composition according to the invention can be used most preferably in the form of an aqueous dispersion which active ingredient concentration depends on the manner of application, i.e. foliar application or seed-dressing. 
    
    
     SPECIFIC EXAMPLES 
     The invention is illustrated by the following, non-limiting examples. 
     Example 1 
     A seed-dressing suspension concentrate containing a film forming polymer is prepared with a total active ingredient concentration of 300 g/1000 ml by admixing the components given in Table 1. The solution containing solid particles is wet-milled until the diameter of the solid particles is less than 4 micron. 
     The combination can preferably be used for wet seed-dressing. 
     
                       TABLE 1______________________________________         Amount of the compound addedCompound      to the composition (g)______________________________________Carbendazime  75      100    150    200  225(8-oxyquinolinate)-         112.5   100    75     50   37.5(dimethyl dithio-carbamate)Zn complex(8-oxyquinolinate)-(di-         112.5   100    75     50   37.5methyl dithiocarbamate)Mn complexethyleneglycol         90      90     90     90   90Ultrazine NA  50      50     50     50   50Hoe S 1494    12      15     15     15   17.5Pluriol PE 10 500         18      15     15     15   12.5Morwith DM 21 200     200    200    200  200Rhodamin 2BU Flu          5       5      5      5    5______________________________________ ion exchanged water completed to 1000 ml. 
    
     Example 2 
     A formulation containing a total 400 g/1000 ml of active ingredients is prepared. The combination of the composition is shown by Table 2. After the compounds are charged, the composition is filled with ion exchanged water to 1000 ml. and wet-milled until the particle size in the suspension achieves the size not higher than 5 micron. 
     The formulation is applied by foliar spray application after earing of corn. 
     
                       TABLE 2______________________________________         Charged amounts of theCompounds     compounds (g)______________________________________Carbendazime  100     133.4  200   266.8 300(8-oxyquinolinate)-         150     133.3  100   66.6  50(dimethyl dithio-carbamate)Zn complex(8-oxyquinolinate)-(di-         150     133.3  100   66.6  50methyl dithiocarbamate)Mn complexethyleneglycol         80      80     80    80    80Tensiofix XN6 30      30     30    30    30B 7425        15      15     10     5     5GG 21         15      15     20    25    25Rhodopol 23   0.1      0.1   0.1    0.1  0.1Ultrasil VN 3 0.1      0.1   0.1    0.1  0.2______________________________________ 
    
     Example 3 
     Wettable powder of 90% by weight of total active ingredients is prepared. The compounds are charged in an amount shown by Table 3, the composition is mixed, homogenized and milled until the size of the particles is 4 micron. 
     
                       TABLE 3______________________________________             Charged amounts of theCompounds         compounds (g)______________________________________Carbendazime      22.5   36       45  60a 1:1 mixture of Zn and             67.5   54       45  30Mn complexes of (8-oxyquinolinate)-(dimethyldithiocarbamate)Netzer IS          1.5   1.5      1.5 1.5Borresperse 3A     3.5   3.5      3.5 3.5Zeolex 444        5       5        5   5______________________________________ 
    
     Example 4 
     Wettable powder suitable for use in foliar application as well as seed-dressing were prepared. The amounts of the compounds charged are listed in Table 4. 
     The concentration of the active ingredients in the compositions were 5, 10, 15 and 20% by weight. The substances were homogenized and milled as described in Example 3. 
     
                       TABLE 4______________________________________Compounds     Amounts of the compounds charged (g)______________________________________Carbendazime  3        1.5   5      5    15a 1:1 mixture of Zn and         2        3.5   5      10   5Mn complexes of (8-oxyquinolinate)-(dimethyldithiocarbamate)Zeolex 444    15       15    10     15   10Silica earth  72       72    72     62   62Netzer IS     1.5      1.5   2      2    2Dispersing agent 1494         2.5      2.5   3      3    3Sulfit lye powder         4         4    3      3    3______________________________________ 
    
     Example 5 
     This Example illustrates the typical synergistic activity observed when combinations of the invention are employed for control of fungal organisms. 
     NS-Rona 2 type winter wheat seeds infected with Fusarium spp. in 49.8 to 50.5% were infected with 0.2% by weight of Tilletia foetida spora calculated for the weight of the wheat. 
     The thus prepared seeds were seed-dressed with 2 l. of a combination containing 300 g/1000 ml. of active ingredients. 
     Further seed-dressing liquids were prepared containing only carbendazime or only zinc or manganese complexes of (8-oxyquinolinate)-(dimethyl-dithiocarbamate). The compositions were similarly prepared like in Example 1. As comparative formulation Dithane-M-45 was used in an amount of 600 g/t. This formulation contained 80% Mancoseb as active ingredient and is widely known and used. 
     A part of the infected seeds was not seed-dressed, it served as control in the experiments. 
     2×100 pieces of the treated and untreated seeds were incubated on Papavizas-type selective medium at 20° C. for 8 days and the Fusarium spp. infection was determined according to the developed sporulation and expressed in %. 
     Another part of the seeds was seeded on November 17 to plots of 2 m 2  prepared previously. 150 seeds were seeded to each line. 50 seeds were seeded into each plot and the plants emerged were counted on March 27. The extent of the Tilletia foetida infection was determined on July 2 in the period of complete maturity by counting the ears one by one. 
     The results obtained by randomized block design method in three replicates are listed in Table 5. 
     The results show, that the combinations exhibit synergistic activity in the range of a weight ratio of 1:3 to 2:1 of carbendazime and the metal complexes; they reduce the Fusarium spp. infection below 2%, while the Tilletia foetida infection is completely controlled. 
     
                                           TABLE 5__________________________________________________________________________                      Fusarium spp.               Rates of the                      infection                             Number of the                                     Number of the ears/plot      Dosage   active %      plants emerged                                         infected withTreatment  g/t      ingredients                      (laboratory)                             from 150 seeds                                     healthy                                         Tilletia foetida__________________________________________________________________________Carbendazime      600         -- -- --     34.0    96.6    984.6                                         0.3(8-oxyquinolinate)-         600            -- --     29.0   105.3   1111.5                                         0.8(dimethyl di-thiocarbamate) Zn(8-oxyquinolinate)-            600               --     24.5   109.0   1154.4                                         0.5(dimethyl di-thiocarbamate) Mnzinc and manganese      -- 150            450               1:3    19.0   116.2   1183.6                                         0.6complexzinc and manganese      -- 300            300               1:1    15.5   118.8   1196.5                                         0.4complexzinc and manganese      -- 450            150               3:1    21.2   112.3   1155.6                                         0.5complexCarbendazime +      150         225            225               1:3    0      138.6   1403.2                                         0zinc and   200         200            200               1:2    0      140.2   1452.4                                         0manganese  300         150            150               1:1     0.5   129.8   1310.2                                         0complexes  400         100            100               2:1     1.5   129.2   1302.5                                         0      450          75             75               3:1     9.0   117.6   1196.6                                         0infected with       --         -- -- --     50.5    84.7    859.7                                         92.7ustilaginalesControlNon-infected cont.      -- -- -- --     49.8    92.0    959.6                                         9.4Dithane M-45               48.3   100.0    972.3                                         6.1(80% MANCOSEB)      600__________________________________________________________________________ 
    
     Example 6 
     The test shows the protective activity of the combaintions on winter wheat against powdery mildew and earfusarium. The tested combinations were applied as foliar sprays in field tests. 
     NS-Rona 2 type wheat seeds were seeded on plots of 5 ha. on October 25th into the soil adequately prepared. 
     The well emerged plants saved from winterkill were weed controlled by a herbicide containing MCPA as active ingredient, generally used in cultivation of cereals by spraying by airoplane, thereafter a sulphur comprising formulation (Sulphur 900 FW) was applied as a foliar spray at the end of tillage (on 5th May) in order to supress the incipient powdery mildew infection. 
     Later the selected plots were treated the first time at the end of earing (on 26th May), the second time on 10th June by spraying by airplane. In the treatment carbendazime (BCM), Dithane M-45, zinc and manganese complexes of (8-oxyquinolinate)-(dimethyl dithiocarbamate) and the combination according to the invention were used in 400 FW formulation, described in Example 2. 50 l/ha. of water were used for spraying, the amount of the active ingredients applied was 0.25 to 1.0 kg/ha. 
     The efficiency of the combinations against powdery mildew of crop was evaluated after the second spraying on 28th June. 100 productive plants selected by randomised method from each plots were examined, and the infection index was determined according to the following scale: 
     0=symptom-free 
     1=the infection is 5% or less 
     2=the infection is within the range of from 6% to 10% 
     3=the infection is within the range of from 11% to 25% 
     4=the infection is within the range of from 26% to 50% 
     5=the infection is within the range of from 51% to 75% 
     6=the infection is within the range of from 76% to 100% 
     The percent of the infection expresses the rate of the healthy and infected leaf surfaces or the average coverage of the leaf surface of the four leaf nodes by mycelium. 
     The infection index was calculated from the data obtained according to the following formula: ##EQU1## wherein a i  stands for the infection values according to the above scale, f i  represents the frequency of a certain scale value, while n stands for the number of the plants examined. 
     The experimental results are listed in Table 6. 
     
                                           TABLE 6__________________________________________________________________________                     Number of the infected plants belonging            Rate of the                     to each scale valuesTreatment   Dosage kg/ha.            active ingredients                     0 1  2  3  4  5  6  F.sub.1__________________________________________________________________________Carbendazime   0.25      -- -- --       --                        64                          260                             76 -- -- -- 2.03   0.50      -- -- --       --                       284                          116                             -- -- -- -- 1.29   1.00      -- -- --       16                       272                          112                             -- -- -- -- 1.24zinc complex   -- 1.0         -- --       --                       -- -- 320                                200                                   152                                      18 4.38   -- 2.0         -- --       --                       -- -- 72 200                                    84                                      44 4.25manganese   -- -- 1.0            --       --                       -- -- 88 184                                    72                                      56 4.24complex -- -- 2.0            --       --                       -- -- 76 232                                    92                                      -- 4.04the mixture of   -- 0.25         0.75            1:3      --                       -- -- 48 132                                   100                                      -- 4.28the zinc and   -- 0.50         0.50            1:1      --                       -- 72 274                                 56                                   -- -- 2.96manganese   -- 0.75         0.25            3:1      --                       -- -- 88 180                                   112                                      20 4.16complexesthe composi-   0.25      0.38         0.37            1:3      72                       296                          16 16 -- -- -- 0.94tion according   0.33      0.34         0.33            1:2      76                       292                          32 -- -- -- -- 0.89to the inven-   0.50      0.25         0.25            1:1      68                       276                          56 -- -- -- -- 0.97tion    0.67      0.16         0.16            2:1      --                       332                          68 -- -- -- -- 1.17   0.75      0.12         0.12            3:1      --                       324                          74 -- -- -- -- 1.19untreated   -- -- -- --       --                       -- -- -- -- 160                                      240                                         5.60controlDithane 1.0               10                       183                          115                             92          1.72M-45__________________________________________________________________________ 
    
     The test results very expressively show that the combinations containing carbendazime and metal complexes at the weight ratio of 1:3 to 1:1 can adequately prevent the powdery mildew infection even at a dose of 1 kg of active ingredients/ha. and exhibit a synergistic effect in these ratios of the active ingredients. The results also show, that they are more effective than the well known and widely used Dithane M-45. 
     In the course of the examinations of Fusarium spp. infections 500 ears were infected with Fusarium spp. on each plot and after harvesting the yield by combine-harvester on 16th July, 500 seed samples were taken from each plot. 
     The Fusarium spp. infection of these seeds was examined by microscopic test after incubating them on Papavizas-type medium at 20° C. for 8 days. When the total infection was measured, the seeds were incubated without any surface disinfection, while in order to determine the internal infection of the seeds, the seeds were previously soaked in 1% Neomagnol solution for ten minutes then washed with sterile water on the surface. 
     The test results are listed in Table 7. 
     
                                           TABLE 7__________________________________________________________________________                    Rate of                    the ear                    infection                         Rate of the seed              Rate of                    with infection with              the active                    Fusarium                         Fusarium spp. (%)Treatment   Dosage kg/ha.              ingredients                    spp. (%)                         total                             internal__________________________________________________________________________Carbendazime   0.25      --  --  --    8.5  15.45                             13.58   0.50      --  --  --    6.5  11.95                             10.16   1.00      --  --  --    5.25 11.05                             9.34zinc    -- 1.00          --  --    6.5  10.52                             9.54complex -- 2.00          --  --    5.5   9.24                             8.33manganese   -- --  1.00              --    6.4  11.68                             10.06complex -- --  2.00              --    5.5  10.53                             9.31a mixture of   -- 0.25          0.75              1:3   5.5  10.78                             9.96zinc and   -- 0.50          0.50              1:1   5.25 10.25                             9.50manganese   -- 0.75          0.25              3:1   5.5  11.05                             9.84complexthe composition   0.25      0.38          0.37              1:3   0.50  5.50                             4.40according to   0.33      0.34          0.33              1:2   0.65  5.84                             4.58the invention   0.50      0.25          0.25              1:1   2.50  7.36                             6.25   0.67      0.16          0.17              2:1   2.75  7.73                             6.43   0.75       0.125           0.125              3:1   3.25  7.90                             6.67control -- --  --  --    11.50                         38.78                             31.25Dithane 1.0      --  --        6.3  16.25                             13.82M-45__________________________________________________________________________ 
    
     The experimental results expressively show, that the combinations containing carbendazime and metal complexes in a weight ratio of 1:3 to 1:2 exhibit a synergistic activity even when a dose of 1 kg. of active ingredients/ha. is used for the treatment, and assure a significant protection against the infection of the ears as well as the internal and external infection of the seed. Comparing with Dithane M-45 which is well known and widely used in agriculture, it is also demonstrated that the combinations according to the invention are more effective. 
     Example 7 
     Spring barley was treated against powdery mildew, helminto-sporium and smut infection according to Example 6. The combinations described in Example 4, and an 1:1 mixture of the widely known Agrocit (comprising 50% of Benomyl) and Dithane M-45 (comprising 80% of Mancoseb) were used for powdering the stand. The infection indexes were calculated according to Example 6. The results are summarized in Table 8. 
     
                       TABLE 8______________________________________       Rate of the               Infection index                            us-     Dosage  active          helminto                                    tilagi-Treatment kg/ha.  ingredients                       mildew                             sporium                                    nales______________________________________Carbendazime     2.0               1.98  0.33   3.30zinc complex     2.0               4.12  0.60   4.08manganese 2.0               4.00  0.56   3.97complexa mixture of     2.0     1:3       4.06  0.57   4.53the zinc and     2.0     1:1       3.14  0.48   4.21manganese 2.0     3:1       3.96  0.52   4.68complexescomposition     2.0     1:2       0.95  0.00   1.84according to     2.0     3:1       1.20  0.00   2.05the invention     2.0     1:1       1.00  0.00   1.98     2.0     1.5:1     1.04  0.00   2.00untreated --      --        5.80  0.70   5.30controlAgrocit + 1.0     +Dithane M-45     1,0     --        2.06  0.36   2.60______________________________________ 
    
     The data listed in Table 8 show very expressively, that the combinations according to the invention containing carbendazime and metal complexes in the weight ratio of 3:1 to 1:1, wherein the weight ratio of the zinc and manganese complexes is 1:1, give a sufficient protection against all the three kinds of fungal diseases, and the combinations exhibit a synergistic effect in these ratios of the active ingredients. The antifungal effect of the combinations according of the invention is significantly higher than the combination of Agrocit and Dithane M-45 applied in the same dose. 
     Example 8 
     Winder barley was seed-dressed against the infection of Fusarium spp., Aspergilus, Penicillium and Tilletia foetida. The experiments were carried out similarly to Example 5, the combinations described in Example 3 were used and Quinolate V-4X (15% of oxyquinolate copper complex+50% of carboxine) well known in the art was applied as control. 
     The experimental results are listed in Table 9. 
     The test results show, that the combinations according to the invention in the weight ratio of 1:3 to 2:1 of the active ingredients exhibit synergistic activity, they suppress the Fusarium spp. and Aspergilus infection below 2%, while completely control the Penicillium and Tilletia foetida infection. Their antifungal effect is significantly higher than that of Quinolate V-4X widely used as fungicide. 
     
                                           TABLE 9__________________________________________________________________________                     Infection                          Infection    Number of                                              Number of the ears                                              per               Rate of the                     with with  Infection with                                       the plants                                              plots               active                     Fusarium                          Aspergilus                                Penicillium                                       emerged from                                                  infected withTreatment    Dosage g/t ingredients                     spp. (%)                          (%)   (%)    150 seeds                                              healthy                                                  Tilletia__________________________________________________________________________                                                  foetidaCarbendazime    1800       --  --  --    35.3 21.4  18.3    96.8   983.7                                                  0.5(8-oxyquinolinate)-    -- 1800           --  --    27.1 17.3  15.2   103.4  1078.4                                                  0.7(dimethyl di-thiocarbamate)Zn complex(8-oxyquinolinate)-    -- --  1800               --    23.2 12.9  10.3   108.1  1125.3                                                  0.4(dimethyl di-thiocarbamate)Mn complexthe mixture of    -- 450 1350               1:3   18.7 9.3   8.1    118.7  1192.7                                                  0.7the zinc and    -- 900 900 1:1   13.0 7.5   6.5    120.3  1305.8                                                  0.5manganese    -- 1200           600 2:1   17.4 8.2   8.7    116.5  1181.9                                                  0.3complexesCarbendazime +     450       675 675 1:3   0    0     0      145.2  1496.0                                                  0zinc and  720       540 540   1:1.5                     0.98 0     0      143.1  1494.2                                                  0manganese     900       450 450 1:1   1.02 0.4   0      138.0  1491.3                                                  0complex  1200       300 300 2:1   1.43 0.84  0      123.8  1300.4                                                  0untreated    -- --  --  --    50.3 40.5  32.4    86.0   873.8                                                  10.8controlQuinolate V-4X    2000       --  --  --    8.0  14.4  6.0     94.0   975.0                                                  2.5__________________________________________________________________________