according to the present invention , there is used a polymeric substance of the compound having the general formula ( i ) above described as an effective component to control plant virus diseases . in a compound the general formula ( 1 ), r 1 represents a hydrogen atom or a methyl group ; r 2 represents a linear or a branched alkylene group containing from 2 to 5 carbon atoms , preferably dimethylene , trimethylene , tetramethylene group or ethylene group having at least one side chain methyl group , such as iso - propyl group , tert - butyl group ; r 3 and r 4 may be same or different , represent a lower alkyl group , preferably an alkyl group containing from 1 to 3 carbon atoms , concretely a methyl group , a ethyl group or a propyl group ; r 5 represents a hydrogen atom or a lower alkyl group , preferably a hydrogen atom or a alkyl group containing from 1 to 3 carbon atoms , concretely a methyl group , a ethyl group or a propyl group ; x represents a halogen atom such as a chlorine atom , a bromine atom and an iodine atom , an inorganic acid radical such as no 3 and 1 / 2 ( so 4 ), a lower fatty acid radical such as hcoo , ch 3 coo and c 2 h 5 coo or a lower alkyl sulfuric acid radical such as ch 3 so 4 and c 2 h 5 so 4 , preferably a chlorine atom , a bromine atom , an iodine atom , an inorganic acid radical , a fatty acid radical containing from 1 to 3 carbon atoms or an alkyl sulfuric acid radical containing from 1 to 3 carbon atoms in the alkyl moiety thereof . in case of r 5 is a hydrogen atom , x is selected from a halogen atom , a inorganic acid radical and a lower fatty acid radical , and in case of r 5 is an alkyl group , x is selected from a halogen atom and a lower alkyl sulfuric acid radical . the following are examples of dialkylaminoalkyl acrylate derivatives or dialkylaminoalkyl methacrylate derivatives according to formula ( i ), dimethylamino ( α - methyl ) ethyl methacrylate hydrochloride , dimethylamino ( β - dimethyl ) ethyl methacrylate acetate , dimethylaminotrimethyl methacrylate sulfate , dimethylammonium ( β - dimethyl ) ethyl methacrylate methylsulfate , dimethylammonium ( β - dimethyl ) ethyl methacrylate bromide , diethylammonium ( α - methyl ) ethyl methacrylate chloride , dimethylammoniumethyl acrylate methylsulfate , dimethylaminoethyl methacrylate hydrochloride . it is known that the compound of formula ( i ) can be prepared by either quaterizing a compound expressed by the general formula ( ii ) ## str2 ## ( wherein r 1 , r 2 , r 3 and r 4 have the same meanings as defined in the foregoing formula ( i ), respectively ) with an alkyl halide such as methyl chloride , methyl bromide , methyl iodide , ethyl bromide or the like or with an alkylsulfuric acid such as dimethylsulfuric acid or diethylsulfuric acid , or neutralizing the compound of formula ( ii ) with an acid such as hydrochloric acid , sulfuric acid , nitric acid , sulfamic acid or acetic acid . the preparation of the polymer , an effective component of the chemical according to the invention , from the compound of formula ( i ) is feasible by any of known techniques . for instance , the polymer can be obtained by subjecting to polymerize the compound of formula ( i ) alone or in combination with at least one copolymerizable ethylenically unsaturated monomer in the manner of a precipitation or a suspension polymerization in the presence of a catalyst for the polymerization . examples of the ethylenically unsaturated monomers copolymerizable with the compound of formula ( i ) include nonionic monomers such as lower alkyl esters of unsaturated carboxylic acids , i . e ., methylacrylate , ethylacrylate , methylmethacrylate and the like , acrylamide , methacrylamide , vinylpyrrolidone , acrylonitrile , methacrylonitrile , vinylacetate , vinyl methyl ether , vinyl ethyl ether , ethylene , isobutylene and the like , cationic monomers such as vinyl pyridines , p - dimethylaminomethylstyrene and the like . of these , acrylamide and methacrylamide are preferred . when a copolymer is used as the effective component of the chemical of the invention , the content of the compound of formula ( i ) in the copolymer should be within a range of above 10 mol %, preferably above 30 mol %. a polymer and copolymer of this invention are water - soluble or water - suspensible , preferably water - soluble . therefore , when the ethylenically unsaturated monomers in the copolymer are water - insoluble , the rate of said monomer in a compound limited within a rage of from 1 to 20 mol %. the intrinsic viscosity of polymers may be within a rage of from 0 . 3 to 15 . the polymer or copolymer described above may be used , as it is , as the control agent but is generally admixed with adjuvants to use in the form of a wettable powder , a dust , an emulsion or a solution . in the case of the dust , a carrier and a surface active agent are employed to mix with the polymer . suitable examples of the carrier include kaolin , bentonite , talc , clay , white carbon and diatomaceous earth . these carriers may be used singly or in combination . when using in the form of a wettable powder , the surface active agents are employed so as to improve the dispersiveness of the chemical in water and to increase the extend effect when sprayed on plants . ( in this specification , the wettable powder means that which does not contain the carriers .) a wide variety of surface active agents including nonionic active agents and cationic active agents are usable for this purpose . suitable agents include nonionic active agents such as polyoxyethylene alkylallyl ether , polyoxyethylene sorbitan monoalorate , etc . these agents may be used singly or in combination , which depends on the purpose in end use of the wettable powder . further , when the chemical is used as an emulsion or solution , water and / or a solvent miscible with water is employed aside from the above - mentioned two types of adjuvants . such solvents include alcohols such as methyl alcohol , ethyl alcohol and ethylene glycol , ketones such as acetone , ether such as dioxane and tetrahydrofuran , amides such as dimethylformamide , and a mixture thereof . when the polymer is applied as the control agent in the form of a wettable powder , 70 - 99 parts by weight of the polymer and 1 - 30 parts by weight of a surface active agent are mixed in a suitable ratio . in application , the mixture is diluted with water to have a desired concentration and applied for the control . to apply the polymer in the form of an emulsion or solution , 10 - 60 parts by weight of the polymer , 20 - 90 parts by weight of a solvent and 1 - 20 parts by weight of a surface active agent are mixed in desired ratios . then , the mixture is applied by dilution with water similarly to the case of the wettable powder . in the case of the dust , 1 - 20 parts by weight of the polymer , 80 - 98 parts by weight of a carrier and 1 - 5 parts by weight of a surface active agent are uniformly mixed in desired ratios and applied . the chemical for the plant virus disease control according to the invention can effectively control an contagion of viruses such as tmv , cmv , cgmmv , etc ., by soil treatment or by spraying on stems and leaves of growing plants . with the case of the wettable powder , emulsion or solution , a solution having a concentration of the effective component ranging 500 - 5000 ppm is sprayed on plants or irrigated into soils in an amount of 50 - 3000 l per 10 ares . with the dust , it is admixed with soils in an amount of 300 - 10000 g / 10 ares as effective component . as a matter of course , the polymer may be used by mixing with other active components which do not impede the antiviral activity of the polymer , e . g ., fungicide , insecticide , miticide , etc . the chemicals of the invention are effective to the mosaic diseases by the following viruses , tmv , cmv , cgmmv , pvx , lmv , mnsv and the like , especially , tmv , cmv and cgmmv . the chemicals of this invention are effective to prevent the virus deseases from spreading over the plants belong to solanaceae , cucurbitaceae , luguminosae , rosaceae and cruciferae , concretely , tobacco , tomato , spanish paprika , potato , cucumber , melon , watermelon , cowpea , french bean , radish , chinese cabbage , strawberry and the like , especially , solanaceae such as tobacco , tomato and spanish paprika , and cucurbitaceae such as cucumber , watermelon and melon . the present invention will be particularly described by way of the following examples showing preparations of polymers and experiments of the chemicals using such polymers as effective component . these examples are for purposes of exemplification only and in no way are intended to limit the scope of the invention . 4 . 94 g of dimethylamino ( α - methyl ) ethyl methacrylate , and 10 . 04 g of water were introduced into a test tube , to which was added 3 . 02 g of 35 % concentrated hydrochloric acid under agitation to obtain an aqueous hydrochloride solution . then , 2 . 0 g of an aqueous 1 % ammonium persulfate solution was added to the aqueous solution and , after degassing , nitrogen gas was charged into the reaction system , followed by polymerization at 60 ° c . for 3 hours . thereafter , acetone was added to the reaction system to precipitate a gel , followed by a decantation and a removal of acetone and water thereby obtaining a polymer of the hydrochloride of dimethylamino ( α - methyl ) ethyl methacrylate ( compound no . 1 ). the above process was repeated using various salts of methacrylate derivatives and acrylate derivatives to obtain polymers ( compound nos . 2 - 14 , 16 - 23 and 26 ). the structural formulae and intrinsic viscosities of these compounds ( nos . 1 - 14 , 16 - 23 and 26 ) are indicated in table 1 . in table 1 , n and m independently represent a natural number . 1 . 23 g of dimethylaminopropyl methacrylate and 33 . 51 g of water were introduced into a test tube , to which was further added 0 . 75 g of 35 % concentrated hydrochloric acid under agitation to obtain an aqueous hydrochloride solution . to the aqueous solution were added 0 . 51 g of acrylamide and 2 . 0 g of an aqueous 1 % ammonium persulfate and , after degassing , the system was filled with nitrogen gas , followed by copolymerization at 60 ° c . for 3 hours . after completion of the copolymerization , acetone was added to the reaction system to precipitate a gel , followed by a decantation and a removal of acetone and water to obtain a copolymer ( compound no . 15 ). the above process was repeated using different starting materials to obtain a copolymer of a hydrochloride of dimethylaminoethyl methacrylate and acrylamide ( compound no . 24 ) and a copolymer of a hydrochloride of dimethylaminoethyl methacrylate and vinylpyridine ( compound no . 25 ). the structural formulae and intrinsic viscosities of these compounds ( nos . 15 , 24 and 25 ) are indicated in table 1 below . table 1__________________________________________________________________________compound intrinsic * no . structural formula viscosity remarks__________________________________________________________________________ ## str3 ## 0 . 982 ## str4 ## 0 . 803 ## str5 ## 1 . 074 ## str6 ## 1 . 655 ## str7 ## 1 . 266 ## str8 ## 1 . 157 ## str9 ## 0 . 828 ## str10 ## 1 . 959 ## str11 ## 1 . 2310 ## str12 ## 1 . 2411 ## str13 ## 1 . 7712 ## str14 ## 1 . 0013 ## str15 ## 1 . 2914 ## str16 ## 1 . 3715 ## str17 ## 2 . 0616 ## str18 ## 1 . 2917 ## str19 ## 1 . 1718 ## str20 ## 1 . 9 ( average degree of polymeri - zation of about 1000 ) 19 ## str21 ## 6 . 3 ( average degree of polymeri - zation of about 4000 ) 20 ## str22 ## 11 . 2 ( average degree of polymeri - zation of about 8000 ) 21 ## str23 ## 5 . 122 ## str24 ## 3 . 823 ## str25 ## 8 . 524 ## str26 ## 2 . 45 n / m = 125 ## str27 ## 1 . 58 n / m = 3 / 726 ## str28 ## 8 . 1__________________________________________________________________________ * in 1n nacl at 25 ° c . aqueous solutions containing 2 , 000 ppm and 1 , 000 ppm of each of the compounds ( nos . 1 - 17 ) indicated in table 1 were , respectively , sprayed over potted tobacco seedlings ( xanthi nc ) of leaf stages of 10 - 11 in an amount of 50 ml per seedling by means of a spray gun . after drying in air , each seedling was inoculated with a separately prepared purified tmv solution ( 0 . 25 × 10 - 6 g / ml ) by an ordinary carborundum method and then allowed to stand in a glasshouse for 3 - 4 days thereby causing local lesions to form on leaves . the number of the formed local lesions was checked for comparison with that obtained with non - treated seedlings to determine a rate of inhibiting formation of tmv lesions for each test solution . the purified tmv solution was prepared by isolating tmv from a sap of tmv - infected leaves and purifying it by means of an ultra - centrifuge . furthermore , chemical damage was observed by spraying 2 , 000 ppm of each of the compounds ( nos . 1 - 17 ) over tobacco seedlings ( bright yellow ) of leaf stages of 10 - 11 , with the result that neither withering of the seedling nor chemical spot was observed . table 2______________________________________compound rate of inhibiting formation of tmv lesion (%) no . 2000 ppm 1000 ppm______________________________________1 97 . 3 89 . 22 94 . 3 88 . 43 93 . 7 88 . 64 96 . 2 89 . 75 95 . 4 90 . 46 95 . 7 88 . 77 93 . 8 86 . 58 95 . 9 90 . 19 94 . 0 91 . 110 95 . 6 89 . 411 97 . 1 92 . 112 96 . 6 92 . 313 92 . 1 86 . 414 90 . 3 86 . 915 87 . 5 77 . 416 92 . 5 85 . 917 94 . 1 87 . 0non - treated 0 0______________________________________ rate of inhibiting formation of tmv lesion ## str29 ## the procedure of example 1 was repeated using the compound nos . 18 - 26 except that the concentrations of the chemical solutions of each compound were 2 , 500 ppm and 1 , 250 ppm , respectively , and the purified tmv solution has a concentration of 5 × 10 - 7 g / ml , thereby determining the inhibition rates of each compound at different concentrations . furthermore , chemical damage was observed by spraying a solution of each of the compound nos . 18 - 26 in a concentration of 2 , 500 ppm over tobacco seedlings ( bright yellow ) of leaf stages of 10 - 11 , with the result that neither withering of the seedlings nor chemical spot appeared . table 3______________________________________compound rate of inhibiting formation of tmv lesion (%) no . 2500 ppm 1250 ppm______________________________________18 96 . 9 90 . 619 98 . 7 92 . 120 99 . 2 94 . 121 98 . 5 93 . 022 97 . 7 92 . 423 97 . 5 92 . 224 96 . 5 91 . 825 95 . 8 90 . 526 95 . 4 91 . 7non - treated 0______________________________________ rate of inhibiting formation of tmv lesion ## str30 ## aqueous solutions of each of the compounds indicated in table 4 with concentrations of 2 , 000 ppm and 1 , 000 ppm were each sprayed over young cowpea plants growing for 10 days after seedling ( vigna sinenis var . sesguipendalis , cv kurodane sanjaku ) in an amount of 5 ml per plant by means of a spray gun . after drying in air , a separately prepared cmv inoculation solution ( with a concentration of 10 × 10 - 6 g / ml ) was inoculated into the plants by an ordinary carborundum method , followed by allowing to stand in a glasshouse for 3 - 4 days to cause local lesion to form on leaves of the plant . the number of the formed local lesions was checked and compared with that obtained with the non - treated plant to determine a rate of inhibiting formation of cmv lesions for each test solution . table 4______________________________________compound rate of inhibiting formation of cmv lesion (%) no . 2000 ppm 1000 ppm______________________________________1 96 . 7 92 . 33 95 . 8 90 . 54 97 . 2 93 . 45 96 . 2 93 . 66 92 . 4 89 . 99 91 . 5 87 . 110 94 . 8 90 . 611 95 . 8 92 . 214 90 . 2 85 . 4non - treated 0 0______________________________________ rate of inhibiting formation of cmv lesion =? ## str31 ## the compound nos . 18 - 26 were tested in the same manner as in example 3 except that the concentration of the solutions being sprayed were 2 , 500 ppm and 1 , 250 ppm , respectively , to determine the inhibition rate for cmv . table 5______________________________________compound rate of inhibiting formation of cmv lesion (%) no . 2500 ppm 1250 ppm______________________________________18 95 . 5 90 . 119 96 . 7 89 . 920 99 . 0 92 . 721 97 . 7 91 . 222 98 . 1 92 . 323 96 . 8 90 . 424 96 . 7 90 . 625 95 . 0 89 . 726 96 . 2 91 . 3non - treated 0______________________________________ rate of inhibiting formation of cmv lesion =- ## str32 ## tobacco seedlings of bright yellow to be a kind of systemic infection plant were used to examine the effect of the chemicals of the invention in a field artificially contaminated with tmv *. aqueous solution having a concentration of 2 , 000 ppm of the compound nos . 4 , 8 , 9 and 13 indicated in table 1 were each sprayed over the tobacco seedlings by means of a sprayer of a knapsack type in an amount of 50 ml per seedling . after drying in air , the sprayed seedlings were planted in the contaminated field . 14 days , 21 days and 28 days after the planting , the seedlings were observed to check how many seedlings were infected with the mosaic disease . table 6______________________________________compound infected seedlings / total of seedlingsno . 14 days 21 days 28 days______________________________________4 0 / 15 1 / 15 3 / 158 2 / 15 4 / 15 5 / 159 0 / 15 1 / 15 2 / 1513 1 / 15 3 / 15 5 / 15non - treated 12 / 15 15 / 15 15 / 15______________________________________ potted tobacco seedlings bright yellow to be a kind of systemic infection plant were used to examine the effect of the chemicals of the invention . aqueous solutions containing 2 , 500 ppm of the compound nos . 19 , 20 , 21 and 24 indicated in table 1 were each sprayed over the tobacco seedlings by means of a spray gun . after drying in air , the purified tmv solution having a tmv concentration of 2 × 10 - 7 g / ml was inoculated in the largest leaf of each of the seedlings in a size of 5 × 5 cm , followed by allowing to stand in a glasshouse . the seedlings which shows symptoms of the mosaic disease was regarded as infected seedlings . 14 days , 21 days and 28 days after the inoculation , the infected condition was observed with the results shown in table 7 below . table 7______________________________________compound infected seedlings / total of inoculated seedlingsno . 14 days 21 days 28 days______________________________________19 0 / 15 1 / 15 3 / 1520 0 / 15 0 / 15 2 / 1521 0 / 15 2 / 15 3 / 1522 1 / 15 2 / 15 3 / 15non - treated 14 / 15 15 / 15 15 / 15______________________________________ tomato seedlings ( kind : yuyake ) were used to examine the effect of the chemicals of the invention in a field artificially contaminated with tmv . an aqueous solution containing 2 , 000 ppm of each of the compounds corresponding to nos . 4 , 8 , and 10 indicated in table 1 was applied to the seedlings , prior to planting , in an amount of 50 ml per seedling and also to the planting hole in an amount of 500 ml by means of a sprayer of a knapsack type . after drying the seedlings in air , the seedlings were each planted in the hole . about 1 month after the planting , the seedlings which were infected with the mosaic disease were checked . the test results are shown in table 8 . note : the hole was charged with a soil which was mixed with a dry powder of tomato leaves attacked with tmv in an amount of 0 . 5 g per l of the soil . table 8______________________________________ preven - compound tiveno . infected seedlings / total of seedlins value (%) ______________________________________4 2 / 20 90 . 08 4 / 20 80 . 010 4 / 20 80 . 0non - treated 20 / 20 0______________________________________ preventive value =- ## str33 ## the procedure of example 7 was repeated using an aqueous solution containing 2 , 500 ppm of each of the compound nos . 19 , 24 and 25 indicated in table 1 . the test results are shown in table 9 below . table 9__________________________________________________________________________ preven - compound tiveno . infected seedlings / total of seedlings value (%) __________________________________________________________________________19 1 / 20 94 . 124 2 / 20 88 . 225 2 / 20 88 . 2non - treated 17 / 20 0__________________________________________________________________________ preventive value =- ## str34 ##
chemicals containing an effective amount of homopolymers of dialkylaminoalkyl acrylate derivatives or dialkylaminoalkyl methacrylate derivatives or copolymers of such derivatives with ethylenically unsaturated monomers copolymerizable therewith . the chemicals exhibit a remarkable effect of preventing agricultural plants from being infected with plant virus diseases . a method for controlling the plant virus diseases is also described .