&# 34 ; a lower alkyl carbamoyl &# 34 ; means a carbamoyl radical with an alkyl group having 1 to 6 carbon atoms of the formula -- conh -- r 1 wherein r 1 represents an alkyl group , for example , methyl carbamoyl , ethyl carbamoyl , n - butyl carbamoyl and n - hexyl carbamoyl radicals ; &# 34 ; a lower alkyl radical &# 34 ; means an alkyl radical having 1 to 4 carbon atoms such as methyl , ethyl and propyl radicals . the radical y may be a thiazolyl group , for example thiazol - 2 -, 4 - or 5 - yl group , a dihydrothiazolyl group , for example , 2 , 3 - dihydrothiazol - 2 -, 3 -, 4 - or 5 - yl group , and 4 , 5 - dihydrothiazol - 2 -, 4 - or 5 - yl group , a tetrahydrothiazolyl group , for example , tetrahydrothiazol - 2 -, 3 -, 4 - or 5 - yl group or a furyl group , for example , 2 - furyl . &# 34 ; acid addition salts &# 34 ; of the compound of formula ( i ) include , for example , sulfuric acid , phosphoric acid , nitric acid , hydrochloric acid , p - toluene sulfonic acid and acetic acid salts . preferred benzimidazole compounds of formula ( i ) include those wherein w and z are a hydrogen atom and y is a thiazole or furyl group . a compound of formula ( i ) wherein w is a hydrogen atom , y is thiazol - 4 - yl and z is a hydrogen atom , i . e ., 2 -( thiazol - 4 &# 39 ;- yl ) benzimidazole is called &# 34 ; thiabendazole &# 34 ; in the industry and is commercially available . a compound of formula ( i ) wherein w is a hydrogen atom , y is 2 - furyl and z is a hydrogen atom , i . e ., 2 -( 2 &# 39 ;- furyl ) benzimidazole is called &# 34 ; fuberiidazole &# 34 ; in the industry and is commercially available . in the above formula ( ii ), r 3 can be either methyl or ethyl . though from the chemical structure itself , the compounds of formula ( ii ) may not be considered relating to the benzimidazole compounds ( i ), it is recognized in the art that the compounds ( ii ) are related to benzimidazole fungicides because the former undergo decomposition and rearrangement within the crop plant to give rise to a benzimidazole compound . a particularly preferred compound under this category is a compound of formula ( ii ) wherein z is hydrogen and r 3 is methyl , i . e ., 1 , 2 - bis ( 3 &# 39 ;- methoxy - carbonyl - 2 &# 39 ;- thioureido ) benzene , which is called &# 34 ; thiophanate - methyl &# 34 ; in the industry and is commercially available . in the above formula ( iii ), r may be any alkyl radical containing 8 to 20 carbon atoms including decyl , dodecyl , tetradecyl , hexadecyl , octadecyl and eicosyl . these alkyl radicals may be derived from natural sources , for example from coconut oil , beef tallow oil or palm oil or from synthetic alcohols , for example ziegler alcohols or oxo alcohols . they may comprise a mixture containing the pyridinium salts with various carbon atoms . the pyridinium salt may contain , in addition to the alkyl pyridinium salt , alkenyl pyridinium salts such as oleyl pyridinium salt . preferred pyridinium salts have an alkyl radical with 12 to 18 carbon atoms , especially dodecyl , tetradecyl or hexadecyl radical . x may be any suitable monovalent anion including a halide , for example , chloride or bromide ; a sulfonic acid residue , for example , methane sulfonate , benzene sulfonate or p - toluene sulfonate ( tosylate ) group ; a sulfate acid residue , for example methyl sulfate , ethyl sulfate ; and acetate . the most preferred is dodecyl ( lauryl ) pyridinium chloride or bromide . the ratio of the two components in the composition may vary widely range so far as the fungicidal activity of the benzimidazole (- related ) compound is enhanced . preferably about 0 . 1 to 10 parts by weight of the alkyl pyridinium salt is incorporated in the composition or used in the field per part of the benzimidazole (- related ) compound , and more preferably about 1 / 3 to 3 parts by weight of the pyridinium salt is used . the composition of the invention may be in any suitable form for the fungicidal composition with a suitable carrier . it may be in a customary formulation , such as wettable powders , concentrated solutions , granules , emulsions and suspensions . these formulations may be prepared in known manner , for example by mixing the active compounds with carriers , optionally with the use of surface active agents ( or emulsifying agents ) which are compatible with the alkyl pyridinium salts . as a liquid carrier there may be mentioned water , an organic solvent such as aromatic hydrocarbons , chlorinated hydrocarbons , aliphatic or alicyclic hydrocarbons , alcohols , ketones , ethers and esters . as a solid carrier there may be mentioned ground natural minerals such as kaolins , clays , talc , chalk , quartz and diatomaceous earth and group synthetic minerals such as highly - dispersed silicic acid , alumina and silicates . as an emulsifying agent there may be mentioned non - ionic emulsifiers such as polyoxyethylene fatty alcohol ethers , polyoxyethylene alkyl phenol ethers and polyoxyethylene fatty acid esters . the formulation normally contains from 0 . 1 to 90 , preferably from 1 to 50 %, more preferably from 5 to 30 %, by weight of the active ingredient the ( benzimidazole or benzimidazole - related compound ). according to the invention , the fungicidal benzimidazole (- related ) compound and the alkyl pyridinium salt may be applied to fungi or habitat thereof in a usual manner . the active compound may be used in the form of the formulations commercially available or in the use form further diluted from the formulations . the active benzimidazole (- related ) compound content of the use form can vary within wide ranges , the preferred content is from 0 . 1 ppm to 100 , 000 ppm more preferred content is from 1 to 1 , 000 ppm and further preferred content is from 10 to 200 ppm . the amount of the active compound to be applied per unit area also varies depending on various conditions , for example , the kind of fungi intended , the stage of the development of the plant , the kind of plant to be protected , the temperature , the humidity and so on . in general the active ingredient benzimidazole is applied 0 . 01 to 50 kg / ha , and preferably 0 . 1 to 10 kg / ha . the following examples illustrate the invention , however these examples should not be regarded as limiting the invention . the alkyl pyridinium salts used in the following examples were synthesized by direct n - alkylation of the pyridine with the desired alkyl compound . the reaction is carried out with the addition of the alkyl chloride to an excess of pyridine and heating the reaction mixture to a temperature between 40 ° c . and the reflux point , for a length of time between 2 hours and 48 hours , depending on the alkyl reagent used . the product is purified by repeated recrystallizations from acetone or alcohol / ether solutions . the effects of dodecyl pyridinium chloride in combination with thiabendazole were studied on the conidia of botrytis cinerea . the fungicidal activities of dodecyl pyridinium chloride and thiabendazole were measured on the conidia of a benzimidazole - tolerant strain of botrytis cinerea . the test was designed to assess the fungicidal activity of the alkyl pyridinium alone and of thiabendazole alone and in their combinations and was replicated five times . compounds were incorporated into cooled , autoclaved 2 % pda ( potato dextrose agar ) medium and the medium was poured into 9 cm sterile petri dishes . conidia were dispersed on the surface of the cooled agar and the amount of germination was measured after 18 hours incubation at 8 ° c . results are shown in table i below . table i______________________________________germination (%) of conidia of benzimidazole - tolerant strains ofbotrytis cinerea on 2 % pdatreatment mean germination (%)( ppm ) strain 6 strain 9______________________________________control 94 . 2 ± 1 . 3 89 . 8 ± 3 . 125 aps12c * 86 . 8 ± 1 . 6 64 . 4 ± 5 . 725 thiabendazole 91 . 6 ± 1 . 8 83 . 4 ± 3 . 425 aps12c / 25 58 . 4 ± 3 . 8 40 . 4 ± 5 . 3thiabendazole50 aps12c 60 . 4 ± 3 . 2 34 . 8 ± 3 . 850 thiabendazole 85 . 8 ± 4 . 4 89 . 0 ± 2 . 250 aps12c / 50 7 . 4 ± 1 . 5 1 . 2 ± 1 . 1thiabendazole______________________________________ * aps12c = dodecyl pyridinium chloride the expected reductions in germination over controls for 50 ppm aps12c / 50 ppm thiabendazole , based on additive affects of each used alone , were 44 . 8 % and 62 . 2 % for strains 6 and 9 , respectively . the observed values were 92 . 1 % and 98 . 7 %. similar effects were seen for both strains at concentrations 25 ppm asp12 / 25 ppm thiabendazole . the cmc ( critical micelle concentration ) value for aps12c is reported to be 3 . 89 ( log ppm ) ( c . f . mukerjee , p . and k . j . mysels , 1971 . critical micelle concentrations of aqueous surfactant system , united states department of commerce , nsrds - nbs 36 . washington , d . c . pp . 222 ), that is a little less than 1000 ppm . from above table i , it will be apparent that the alkyl pyridinium compound at a concentration far below its cmc value synergistically increases the fungicidal activity of the benzimidazole compound against the benzimidazole - tolerant fungus . dodecyl pyridinium chloride was tested alone and in combination with thiophanate methyl against the conidia of two benzimidazole - tolerant strains of botrytis cinerea . test compounds were incorporated into 2 % pda and the conidia dispersed over the surface . the plates were incubated 14 h . at 14 ° c . and five replicates of 100 conidia each per treatment were assessed for germination . table ii______________________________________germination of conidia of 2 benzimidazole - tolerant strains ofbotrytis cinerea on 2 % pda . mean germinatedtreatment (%)( ppm ) strain 1 strain 2______________________________________control 98 . 0 ± 2 . 0 89 . 2 ± 2 . 650 aps12c * 55 . 0 ± 8 . 9 27 . 0 ± 4 . 850 thiophanate methyl 97 . 2 ± 1 . 8 84 . 8 ± 6 . 850 aps12c plus 50 thio - 18 . 6 ± 5 . 8 6 . 4 ± 1 . 5phanate methyl______________________________________ * aps12c = dodecyl pyridinium chloride . results showed that germination of conidia for the first benzimidazole - tolerant strain at 50 ppm aps12c plus 50 ppm thiophanate methyl was decreased by 81 . 0 % from control germination , while the expected reduction through additive effects would have been 44 . 6 % ( table ii ). a similar effect was seen for a second benzimidazole - tolerant strain of b . cinerea .
there is disclosed a fungicidal composition comprising a fungicidal compound selected from the group consisting of benzimidazole compounds of the formula ## str1 ## wherein w is h , or alkyl carbamoyl ; y is thiazolyl , dihydrothiazolyl , tetrahydrothiazolyl or furyl ; z is h , halogen or alkyl and benzimidazole related compounds of the formula ## str2 ## wherein r 3 is c 1 - 2 alkyl , and z is as defined above , and a synergist alkyl pyridinium salt of the formula ## str3 ## wherein r is an alkyl containing 8 to 20 carbon atoms ; and x is a monovalent anion .