Abstract:
The present invention relates to synergistic arthropodicidal composition of several pyrethroidal active ingredients causing no damage to warm-blooded organisms comprising pyrethroides and piperonyl butoxide as active ingredient which comprises as pyrethroidal active ingredient 0.1-20% by weight of 1StransR-alpha-cyano-3-phenoxy-benzyl-3- (2,2-dichlorvinyl)-2,2-dimethyl/cyclopropane-cyrboxylate of the Formula I ##STR1## 0.05-10% by weight of cis-trans-tetramethrin (3,4,5,6-tetrahydrophthalimido-methyl(1RS)-cis-trans-chrysantemate) or trans-tetramethrin of the Formula II ##STR2## and a further pyrethroide, 0.1-40% by weight of piperonyl butoxide of the Formula III ##STR3##

Description:
FIELD OF THE INVENTION 
     The present invention relates to arthropodicidal compositions containing several pyrethroidal active ingredients. The invention particularly relates to synergistic arthropodicidal compositions containing several pyrethroidal active ingredients which are not toxic to warm-blooded organisms. 
     DESCRIPTION OF THE INVENTION 
     The compositions contain as a pyrethroidal active ingredient 1StransR-alpha-cyano-3-phenoxy-benzyl-3-(2,2-dichlorvinyl)-2,2-dimethyl-cyclopropane carboxylate of the Formula I ##STR4## and tetramethrin or trans-tetramethrin of the Formula II ##STR5## and optionally a further pyrethroidal substance as well as piperonyl butoxide of the Formula III and, optionally, additives. ##STR6## 
     The compound of the Formula I amounts to 0.1-20% by weight and the compound of the Formula II to 0.05-10% by weight and the piperonyl butoxide of the Formula III amounts to 0.1-40% by weight. The remaining amount up to 100% consists of additives. 
     The following abbreviations are used throughout the specification: 
     Alphamethrin=(S)-alpha-cyano-3-phenoxybenzyl-(1R,3R)-3(2,2-dichlorvinyl)-2,2-dimethyl-cyclopropane-carboxylate and (R)-alpha-cyano-3-phenoxy-benzyl-(1S,3S)-3(2,2-dichlorvinyl)-2,2-dimethyl-cyclopropane carboxylate 
     TET=tetramethrin=3,4,5,6-tetrahydro-phthalimido-methyl(1RS)-cis-trans-chrysanthemate 
     deltamethrin=(S)-alpha-cyano-3-phenoxy-benzyl(1R,3R)-3-(2,2-dibrombinyl)-2,2-dimethyl-cyclopropane carboxylate 
     trans TET=trans tetramethrin=3,4,5,6-tetrahydro-phthalimido-methyl(1RS)-trans chrysanthemate 
     TRX=transmix=a mixture of 1StransR-alpha-cyano-3-phenoxy-benzyl-3-(2,2-dichlorvinyl)-2,2-dimethyl cyclopropane carboxylate and 1RtransS-alpha-cyano-3-phenoxy-benzyl-3-(2,2-dichlorvinyl)-2,2-dimethyl-cyclopropane carboxylate 
     SF=synergistic factor 
     PBO=piperonyl butoxide 
     The composition according to the invention may be used in all those locations wherein only such substances may be applied which are substantially not toxic to warm-blooded organisms, such as agricultural and horticultural pests, i.e. pests occurring in the preserved food industry and refrigerating industry. Various parasitic arthropodal pests cause significant harm in stock breeding. By disquieting the animals the pests cause a reduction of their yield capacity, their gain in weight, they disturb their behavior and their technology tolerance, increasing thereby the number of compulsory slaughterings. Significant yield losses are caused by the storage arthropoda as well, and this is worsened by the fact that these crops are already produced (i.e. costs are already involved) and the protection is needed for the entire storing period during the utilization of the crops to avoid the presence of substances harmful to a man and animals. 
     During the protection against diseases propagated by various arthropoda such as malaria, yellow fever, sleeping fever, dysentery, plague, it is important that only such agents may be applied which are not toxic to warm-blooded organisms, are nontoxic dermally, and do not cause dermal irritation and allergy. 
     As the most widely used insecticides are neuroactive substances (nerve poison), the function of nerves is damaged in both lower and higher animals (F. Matsumura: Differential toxicities of insecticides and halogenated aromatics, Pergamon Press 1984). Consequently, the selectivity of most of the compositions is not sufficient. 
     The compositions according to the invention have an outstanding activity against the following pests: flies such as Hydrotaea irritans, Morellia simples, M. Horitorum, Haematobla spp., Stomoxys calcitrans, Musca domestica, M. autumnalis, Glossina app., Simulium spp., Culicoides, Phlebotomus spp., Tabanidae; fleas such as Xenopsylla spp., Pulex spp., Ctenocephalides app; bugs such as Cemex spp., Iriatoma spp., Rhodnius spp., Triatoma spp; lice such as Pediculus spp., Phthirius pubis, Damalinia, Haematophinus; ticks or mites such as Ixodes, Sporoptes spp., scabiei; mosquitoes such as Anopheles spp., Aedes spp., Culex spp., Mansonia spp.; cockroaches such as Blattella germanica, Blatta orientalis, Periplaneta americana, Periplaneta australasie, Supella longipalpa; various storage pests such as Iribolium spp., Trogoderma spp., Stegobium spp., Sitophilus spp., Ienebrio spplk, Stagobium paniceum, Sitotroga cerealella, Zaorotes subfasciatus, Rhyzopertha dominica, Ptinus spp., Cryzaephilus surinamensis, O. mercator, Lasioderma serricorne, Necrobia spp., dermestes spp., Carpopohilus spp., Dryptolestes spp., Mezium spp., Alphitobius diapersinus, A.laevigatus, Callosobruchus spp., Bruchus spp., Anthrenus verbasci, Ephestia spp., Plodia interpunctella, Acaris siro, Tyrophagus putres, T. centiale, T. longinor, Tyrolichus casei and; agricultural pests belonging to genera Lepidoptera, Coleoptera, Heteroptera, Homoptera, Hymenoptera, Diptera and Acariformes. 
     A preferred form of the composition according to the present invention contains as a further active ingredient 1RtransS-alpha-cyano-3-phenoxy-benzyl-3-(2,2-dichlorvinyl)-2,2-dimethyl-cyclopropane-carboxylate in an amount of 0.1-20% by weight. The ratio of 1StransR to 1RtransS amounts to 0.7-1.3:1.3-0.7, preferably 1:1. 
     We have now found that 1StransR isomer hitherto considered to be the least active of the 4 trans isomers of cypermethrin can be transformed to a synergistic active and stable composition when combined with tetramethrin and piperonyl butoxide. Thus the advantages of the very low toxicity against warm-blooded animals can be utilized and outstanding selective arthropodicidal composition may be prepared. The data relating to synergistic compositions are shown in Table 1. 
     
                       TABLE 1______________________________________Interaction of transmix isomers and piperonyl butoxideon house fly (Musca domestica) tested by topical method         activity without                      activity withisomers and  PBO           PBOactive ingredient        LD.sub.50M    (1:2).sup.xmixtures resp.        ng/fly        ng/fly   SF______________________________________1RtransS     5.78          4.58     1.261StransR     571.50        278.62   2.05TRX          6.70          3.76     1.78TRX + TET (10:1)        8.02          2.97     2.70TRX + TET (10:5)        8.41          2.87     2.93______________________________________ x = calculated to trans cypermethrins 
    
     As excipients anionic tensides, such as calcium alkyl aryl sulfonate, calcium dodecyl benzene sulfonate or non-ionic surfactants such as nonyl or dinonyl phenol ethoxylates (EO=16-20) are used. The composition may contain further non-ionic components such as tristyryl phenol ethoxylates (ED=20) etc. 
     As a filling agent the composition may contain solvents such as xylene, aromatic solvent mixture, aliphatic hydrocarbon mixtures, alkyl benzene, mineral or vegetable oil and solid carriers. 
     The formulation of the composition depends on the method of application. 
     In order to prepare emulsifiable compositions anionic tensides, non-ionic surfactants and other non-ionic components and solvents are preferable admixed to the mixture. As anionic tensides 2 to 5% by weight of calcium alkyl aryl sulfonate, and as non-ionic surfactant 1 to 2% by weight of nonyldinonyl phenol ethoxylates (EO=16-20) and as further non-ionic components 0.5-2% by weight of tristyryl phenol ethoxylates (EO=20) and as the solvent xylene may preferably be used. 
     A transparent emulsifiable composition may be prepared by using as anionic tenside 2.5-9% by weight of a calcium salt of alkyl aryl sulfonate, and as non-ionic surfactant 1.25-3.5% by weight of nonly-, dinonyl phenol ethoxylates (EO=16-20) and as further non-ionic component 0.7-3.5% by weight of tri-styryl phenol ethoxylates (EO=20) and as solvent preferably 5-10% by weight of xylene, 1-3% by weight of ethylene glycol and water up to 100% by weight. 
     Wettable powders can also be prepared by adding dispersing agents and carriers. According to a preferred feature as dispersing agent 1-2% by weight of dioctyl sulfosuccinate and 6-8% by weight of polymerized sodium naphthalene sulfonate and as carrier silicic acid and talc may be used. 
     Pests to be found at the waterside or in large fields, such as mosquitoes, can be combatted by using the composition according to the invention in ULV form by aeroplane or helicopter spraying. Such compositions contain apart from the active ingredient an aliphatic hydrocarbon mixture and mineral or vegetable oil at a ratio of 1:100-1:2 as filling agent. The composition of the invention can be formulated according to other methods as well, such as Hungarian Patent Applications Nos. 3245-87, 3246-87, 4975-87, 4974-87. 
     The active ingredients may be prepared by methods known per se such HU-PS 152 558 and EPA 86900 830 etc. 
     Known pyrethroidal combinations are e.g. mixtures of permethrin and decamethrin (EP No. 5826) and mixtures of permethrin and tetramethrin (HU-PS 184 614, DOS 2704 066). The compositions of the present invention are more efficient than the known compositions and are also active against certain strains which are resistant to said known compositions (See biological Example 3.). 
    
    
     SPECIFIC EXAMPLES 
     The details of the invention can be illustrated by the following non-limiting Examples. 
     I. Biological Examples 
     EXAMPLE 1 
     Test animal: In laboratory cultivated 3-5 day old female house fly (Musca domestica) WHO/SRS images. The active ingredient and n-butenol or ethoxy ethanol are dissolved in (cellosolve) and the solution is applied in 0.22 μl drops on the dorsal cuticule of the flies moderately narcotized with carbon dioxide. The treated flies are provided with sugar and water ad libitum in plastic glasses and evaluated after 24 hours. The ratio of killed flies is expressed in percentage (morality %). The LD 50  values are calculated from the obtained data by probit analysis. 
     The combinative interaction is given as a ratio of the expected activity (E) and the measured activity (M) calculated on the basis of the activity of the components per se. If the measured activity surpasses the expected activity then the activity is synergistic and if the activities are the same then the activity is additive, whereas if the measured activity does not achieve the expected activity then there is an antagonistic activity between the two components. 
     The expected value can be determined by harmonic average: ##EQU1## 
     The synergistic factor can be expressed as a ratio of the expected and measured values: ##EQU2## wherein SF stands for synergistic factor, 
     A and B stand for the amount of the components (or ratio thereof) and in the index they relate to the corresponding LD 50  values. 
     The obtained results show the outstanding synergistic activity of the 1:1 mixture of 1RtransS+1StransR (transmix) isomers compared to the different behavior of the various cypermethrin isomers (See Table 1). 
     In case of the piperonylbutoxide which itself is not very active the synergistic activity an be deduced from the decreasing number of the LD 50  values. 
     The effect of piperonyl butoxide on the activity of some cypermethrin isomers on the house fly (Musca domestica/SRS) measured by topical method is shown in the following table. 
     
                       TABLE 2______________________________________dose        activity          change of(ng × fly.sup.-1)       per se      with PBO.sup.x                             activity______________________________________1RcisS      MORTALITY %0.50        5           5         00.72        15          20        +51.03        30          30        01.47        50          65        +152.10        80          75        -5LD.sub.50   1.37        1.301RtransS    MORTALITY %1.56        10          10        02.59        20          30        +104.32        40          50        +107.20        60          65        +512.00       75          85        +10LD.sub.50   5.78        4.581StransR    MORTALITY %118         0           5         +5168         0           15        +15240         0           35        +35343         20          70        +50490         45          85        +40700         60          100       +401000        80          100       +20LD.sub.50   571.5       278.61RtransS+1StransR (1:1)       MORTALITY %1.56        0           15        +152.59        10          30        +204.32        30          55        +257.20        50          80        +3012.00       80          95        +15LD.sub.50   6.70        3.76______________________________________ .sup.x Ratio of pyrethroide and piperonyl butoxide = 1:2 
    
     EXAMPLE 2 
     Mixtures of transmix+tetramethrin of different ratio were tested by applying the above methods with piperonyl butoxide and without. The obtained results (Table 3) indicate a moderate antagonism in the case of simple combinations of two components: transmix and transmethrin. Table 4, however, shows an unexpected synergistic activity of the double combination admixed with piperonyl butoxide, which cannot be explained with any synergistic activity of the two pyrethroids per se and piperonyl butoxide. TET per se is ineffective at the used dose. 
     
                       TABLE 3______________________________________Effect of mixtures of transmix and tetramethrin of variousratio on house fly (Musca domestica/SRS) measuredby topical method                   TRX +dose (ngxfly.sup.-1)     TRX    TET    TET    expected ac-                                   change ofTRX   TET     measured activity                        tivity (%)                                 activity______________________________________TRX:TET = 10:1 MORTALITY %1.7   0.17    10     0     0     10       -102.4   0.24    25     0     0     25       -253.4   0.34    35     0    10     35       -254.8   0.48    45     0    20     45       -256.9   0.69    55     0    35     55       -209.8   0.98    80     0    70     80       -10LD.sub.50 5.16-8.49TRX:TET = 10:5 MORTALITY %1.7   0.82    10     0     0     10       -102.4   1.18    25     0     0     25       -253.4   1.68    35     0    10     35       -254.8   2.40    45     0    25     45       -206.9   3.43    55     0    35     55       -209.8   4.90    80     0    65     80       -15LD.sub.50 5.16-8.41______________________________________ 
    
     
                       TABLE 4______________________________________Total effect of piperonyl butoxide, transmix andtetramethrin on house fly Musca domestica/SRSmeasured by topical method                               expected                                      changedose (ng × fly.sup.-1)          TRX    TET  TRX + TET                               effect ofTRX  TET       measured  effect   (%)    effect______________________________________TRX:TET:PBO = 10:1:20 Mortality %1.7  0.17      10     0    15       10      +52.4  0.24      25     0    35       25     +103.4  0.34      35     0    60       35     +254.8  0.34      45     0    80       45     +356.9  0.69      55     0    95       55     +409.8  0.98      80     0    100      80     +20LD.sub.505.16-2.97TRX:TET:PBO = 10:5:20 Mortality %1.7  0.82      10     0    20       10     +102.4  1.18      25     0    40       25     +153.4  1.68      35     0    60       35     +254.8  2.40      45     0    80       45     +356.9  3.43      55     0    90       55     +359.8  4.90      80     0    100      80     +20LD.sub.505.16-3.0______________________________________ 
    
     EXAMPLE 3 
     Test of efficiency on resistant insects 
     House fly larvae (Musca domestica/NTR) collected from a pigfarm were bred to developed insects. The permethrin&#39;s activity was tested by enhanced increase of the LD 50  values, whereafter a great heterogenicity was observed, resulting in a levelling out of the dose-effect curve and in the enhanced increase of the LD 95 . In order to strengthen resistance and to ensure the homogenicity of the population and an appropriate amount of test insects, the collected fly population was subjected to selection pressure for 5 generations at a level of LD 60 , by treating 2000 male and 2000 female flies in each generation with the given dosage (LD 70 ) topically. The surviving flies gave the parent generation. The culturing was carried out by Sawicki as follows. 
     The insects were examined according to the method given in before Example 1 . The LD 50  values were obtained by probit analysis. 
     
                       TABLE 5______________________________________Efficiency of transmix: tetramethrin combinations onhouse fly (Musca domestica/NTR) tested by topical methodactive ingredients            LD.sub.50 (ngxfly.sup.-1)                        resistance factorand mixtures     P.sub.0 F.sub.6 LD.sub.50F.sbsb.6 /LD.sub.50P.sbsb.0______________________________________permethrin       28.5    290.7   10.2tetramethrin     450     &gt;5000   &gt;11TET + PBO (1:20) 310     1500    5.2transmix         8.6     17.5    2.2transmix + TET (10:1)            9.5     21.2    2.2transmix + TET + PBO            5.8     7.2     1.2(10:1:20)transmix + TET + PBO            5.3     7.1     1.3(10:1:40)transmix + transTET + PBO            4.9     5.9     1.2(10:1:20)______________________________________ P.sub.0 = parent generation F.sub.6 = offspring generation 
    
     The results indicate that the effect of transmix+tetramethrinpiperonyl butoxide mixtures on resistant flies is significant. 
     EXAMPLE 4 
     Emulsifiable concentrates prepared according to Examples 3 or 4 were diluted with 200-400-800-1600-3200-6400 fold water and the obtained emulsions were sprayed with a 2 layer pulverizer in 0.5 ml portions at a pressure of 2 bar into Petri-dishes of a diameter of 9 cm. After drying 3-5 days old female flies (Musca domestica/ SRS) were placed to Petri-dishes (10 to each dish) in 4 replicates for each dosage. After 60 minutes the knocked down flies were calculated and their ratio was expressed in percent (see Table 6). 
     
                       TABLE 6______________________________________      dilutioncomposition  200     400     800  1600 3200 6400______________________________________      knockdown (%)Emulsion of formu-        100     100     75   50   30   10lation Example 4Emulsion of formu-        100     100     85   60   35   10lation Example 3Stomosan ®        100      80     40   15    0    0______________________________________ Stomosan ® = Composition containing 200 g/l of commercially available permethrin 
    
     The table shows that the knock-down effect is considerable even at a great dilution. 
     EXAMPLE 5 
     Test insects: cockroaches (Blatella germanica) 
     20 male cockroaches obtained from a 1-2 weeks continuous laboratory culture were treated topically in a mild carbon dioxide narcosis with 0.22 μl n-butanol solution of the test-compounds of a suitable concentration. 
     3 days after the treatment the insects, which were provided ad libitum with water and commercially available dogfood in plastic glasses, were evaluated. The ratio of the killed insects was expressed in percent. The results are shown in Table 7. 
     
                       TABLE 7______________________________________          dosage (ngxcockroach.sup.-1)test components    4.5 9      18   39    78______________________________________          Mortality (%)TRX              0     0      35   60    90TET              0     0      0    0     0TET + PBO (1:20) 0     0      0    0     0TRX + TET (10:1) 0     5      30   60    90TRX + TET + PBO (10:1:20)            15    55     85   100   100______________________________________ 
    
     EXAMPLE 6 
     Test insect: flour beetle (Tribolium confusum) 
     20 images obtained from a 1-2 weeks continuous laboratory culture were treated for each dosage with 0.22 μl of n-butanol solution of the tested compounds topically. 
     The treated insects were held in a glass vial sealed with a cotton wool stopper. The percent of the killed insects after 24 hours is shown in Table 8. 
     
                                           TABLE 8__________________________________________________________________________      dose (ngxinsect.sup.-1)test compounds      0.78         1.56            3.13               6.25                  12.5                     25 50  100__________________________________________________________________________transmix (TRX)      0  0  15 25 45 60 70  85tetramethrin (TET)      0  0  0  0  0  0  0   0tetramethrin + PBO      0  0  0  0  0  0  0   0(1:20)transmix + PBO (1:2)      0  0  20 40 60 75 90  100TRX + TET + PBO      10 35 50 65 80 90 100 100(10:1:20)__________________________________________________________________________ 
    
     II Formulation Examples 
     EMULSIFIABLE CONCENTRATES (EXAMPLES 1-8) 
     Piperonyl butoxide, calcium salt of alkyl aryl sulfonate, nonyl phenol- and dinonyl phenol ethoxylate and tristyryl phenol ethoxylate are dissolved in 500 ml of xylene at 40° C. and the pyrethroides are added under stirring and the solution is completed to 1000 ml at 20° C. (See Table 9). 
     The compositions according to 1 to 8 in Table 9 were tested for stability in CIPAC A and D water at +30° C. in 0.2, 1 and 5 % by volume. 
     The samples were subjected to heat treatment for 14 days at 54°±2° C. and at the given temperature emulsion stability and redispersion tests were carried out in the above CIPAC waters. The 8 samples showed similar behavior within 10% standard deviation like the freshly prepared sample. 
     
                                           TABLE 9__________________________________________________________________________Emulsifiable concentrates        amounts in g/lExample numbers        1    2    3    4    5    6    7    8__________________________________________________________________________Transmix     20   20   50   50   10   10   10   10Tetramethrin 2    2    5    5    1    1    2    2PBO          40   80   200  100  20   40   20   40Nonylphenolethoxylate        10   5    20   15   6    6    8    4(EO = 20)Dinonylphenolethoxylate        20   10   20   15   10   10   15   12(EO = 16)Tristyrylphenolethoxylate        10   15   20   5    10   5    8    8Ca salt of alkyl-aryl-        40   35   50   45   20   30   25   20sulfonateXylene       1000 ml             1000 ml                  1000 ml                       1000 ml                            1000 ml                                 1000 ml                                      1000 ml                                           1000 ml__________________________________________________________________________ 
    
     TRANSPARENT SOLUTIONS 
     General Method 
     Piperonyl butoxide, calcium salt of alkyl aryl sulfonate, alkyl phenol ethoxylates and tristyryl phenol ethoxylate are dissolved in an aromatic solvent mixture of a suitable amount whereafter transmix and tetramethrin are added at 40° C. The obtained solution is poured into 500 ml of ion exchanged water containing 8% ethylene glycol and it is completed to 1000 ml at 20° C. with water containing 8% ethylene glycol (see Table 10, Examples 9-16). 
     
                                           TABLE 10__________________________________________________________________________Transparent solutionsamounts in g/lExample numbers        9    10   11   12   13   14   15   16__________________________________________________________________________Transmix     20   20   50   50   10   10   10   10Tetramethrin 2    2    5    5    1    1    2    2PBO          40   80   200  100  20   40   20   40Nonylphenolethoxylate        30   10   5    --   5    5    --   --(EO = 20)Dinonylphenolethoxylate        5    --   10   15   --   --   15   10(EO = 16)Tristyrylphenolethoxylate        20   30   45   55   80   60   55   45(EO = 20)Ca salt of alkyl-aryl-        60   60   70   60   45   45   60   60sulfonateAromatic solvent mixture        90   90   100  100  50   50   50   508% ethyleneglycol water        1000 ml             1000 ml                  1000 ml                       1000 ml                            1000 ml                                 1000 ml                                      1000 ml                                           1000 mlsolution__________________________________________________________________________ 
    
     The above transparent solutions were examined by the method described for the emulsifiable concentrates. The stability of the samples before and after the storage was found to be suitable. 
     EXAMPLE 17 (ULV) 
     20 g of piperonyl butoxide, 10 g of transmix and 1 g of tetramethrin were completely dissolved in 250 ml Solvesso 150 and it is completed to 1000 ml at 20° C. with paraffin oil. 
     EXAMPLE 18 (ULV) 
     10 g of piperonyl butoxide, 5 g of transmix and 1 g of tetramethrin are dissolved in 250 ml of Solvesso 150 whereafter it is completed with sunflower oil to 1000 ml at 20° C. 
     EXAMPLE 19 (WP) 
     In a two layer pulverizer laboratory fluidization drying equipment on 745 g of silicic acid at 40° C., under 2 bar liquid pressure and 3 bar air pressure a solution of 200 ml xylene, 100 g of piperonyl butoxide, 50 g of transmix and 5 g of tetramethrin is pulverized. To the dried powder 20 g of dioctyl sulfosuccinate and 80 g of polymerized sodium salt of alkyl naphthalene sulfonic acid are mixed. The homogeneous powder mixture is ground to a size below 20 micrometer by using an ultraplex mill. Moisturization time: 16 sec. Floatability according to CIPAC: 86%. 
     EXAMPLE 20 
     A solution of 150 ml of xylene, 20 g of piperonyl butoxide, 10 g of transmix and 1 g of tetramethrin is sprayed on 894 g of silicic acid according to Example 19. 15 g of dioctyl sulfosuccinate and 60 g of polymerized sodium alkyl naphthalene sulfonate are added to the dry powder mixture in a homogenizer, and the mixture is ground. Moisturization time of the powder mixture: 12 sec., floatability: 88%. 
     EXAMPLE 21 
     A solution of 75 ml of xylene, 2 g PBO, 1 g of transmix, and 0.1 g of tetramethrin is sprayed on 996 g of silicic acid by a method given in Example 19. The product can be used without grinding as a dusting agent. 
     EXAMPLE 22 
     A solution of 100 ml of xylene, 10 g of piperonyl butoxide, 5 g of transfix and 0.5 g of tetramethrin is applied to 985 g of silicic acid as given in Example 19. Dusting agent is obtained.