alkyl as used herein refers to straight chains , branched and cyclic forms and preferably contain one to four carbon atoms . r1 and r2 are preferably independently hydrogen , methyl or phenyl , more preferably r1 is hydrogen or methyl and r2 is hydrogen . r4 and r5 are preferably independently hydrogen or c1 - 3 alkyl , more preferably r4 is hydrogen or methyl and r5 is hydrogen or c1 - 3 alkyl , more preferably r4 is hydrogen or methyl and r5 is hydrogen . r6 and r7 are preferably independently hydrogen , c1 - 6 alkyl , benzyl optionally substituted by halogen , more preferably r6 is hydrogen or methyl and r7 is hydrogen . preferred compounds of the invention are the β - amino - butyric acids and the β - aminovaleric acids ; and most preferred is r - β - aminobutyric acid . the structures of various aminobutyric acids are shown in scheme 1 . ## str2 ## salt forms of the compound of formula ( i ) contemplated in this application include acid addition salts such as those obtained by the addition of hc 1 , cf 3 co 2 h , toluene sulfonic acid , methane sulfonic acid and ( co 2 h ) 2 ## str3 ## wherein y is the residue of the acid ; alkali metal salts such as those obtained by treatment with naoh , koh or lioh ## str4 ## wherein m is an alkali metal such as na , k or li ; and acid addition / amine salts such as those obtained by treatment with hci and an amine such as diethylamine , propyl amine , benzylamine . ## str5 ## wherein r a and r b are substituents . preferred crops in which the method of the present invention is applicable are cucumbers , melon , broccoli , cauliflower , kohlrabi , potatoes , sunflower , tobacco , grapes , cotton , maize , sorghum , cabbage , pearl millet , rice , onion and hop . most preferred are sunflower , grapes , cucumber , melon , broccoli , kohlrabi , cauliflower , potatoes , tobacco and maize . the novel compounds encompassed by the present application are structurally related to known compounds and can be easily prepared by either derivatising the known compounds or by modifying the procedures for preparing the known compound , as required . these procedures will be apparent to those skilled in the art . the following procedures are illustrative . compounds of the formula ( ia ) ## str6 ## wherein r 1 and r 4 - 7 are as previously defined and r 3 represents hydrogen or c 1 - 8 alkyl can be obtained from a compound of the formula ( iia ). ## str7 ## to prepare compounds of formula ( ia ) where r 6 is h and r 7 is as previously defined , the compound of formula ( iia ) is reacted with nr 7 h 2 , wherein r 7 is as previously defined . reactions of this type are described in the literature , e . g ., by a . zilkha and j . rivlin , j . org . chem . 1957 , 23 , 94 . to prepare compounds of formula ( ia ) where r 6 and r 7 are as previously defined but excluding hydrogen , the compound of formula ( iia ) is reacted with nr 6 r 7 li , wherein r 6 and r 7 are as previously defined but excluding hydrogen . reactions of this type are described in the literature , e . g ., by davies et al ., tetrahedron : asymmetry , vol . 2 , no . 3 , pp . 183 - 186 ( 1991 ). compounds of the formula ( iia ) are either known or obtainable from known compounds according to standard procedures . as can be appreciated , in such cases where r 4 and r 5 do not represent , the same substituent , the carbon atom to which they attach is chiral . procedures for preparing each enantiomer form are either specifically described in the literature , e . g ., in ep 0 144 980 or in davies , supra , or can be prepared according to analogous procedures . the present method was found to be effective against a variety of diseases . examples are late blight , downy mildew , blue mold , leaf spots , fusarium wilt , trunk rot , fruit brown rot , damping off , white rust , black shunk and phytophthoras root rots . the compounds of this invention will typically be applied to crops or their locus before or after the onset or after the initial signs of fungal attack and may be applied to the foliar surfaces of the crop . the amount of the active ingredient to be employed will be sufficient to induce the systemic resistance of the crop to control the fungi and will vary depending on such factors as the species of fungi to be controlled , the type of treatment ( for example , spraying dusting , seed treatment , soil drench ), the condition of the crop , and the particular active ingredient used . as an application to the corp or its locus , the compounds will be applied to the crops with a dosage rate of from 0 . 1 to 5 kg / ha , preferably from 0 . 2 to 2 kg / ha , with application being repeated as necessary , typically at intervals of every one to three weeks . depending on circumstances , the compounds of this invention may be used in association with other pesticides , e . g ., fungicides , insecticides , acaricides , herbicides , or plant growth regulating agents in order to enhance their activity or to widen their spectrum of activity . the compounds of this invention are conveniently employed as fungicidal compositions in association with agriculturally acceptable carriers or diluents . such compositions also form part of the present invention . they may contain , aside from a compound of formula ( i ) as active agent , other active agents , such as fungicides . they may be employed in either solid or liquid application forms e . g ., in the form of a wettable powder , an emulsion concentrate , a water dispersible suspension concentrate (&# 34 ; flowable &# 34 ;), a dusting powder , a granulate , a delayed release form incorporating conventional carriers , diluents and / or adjuvants . such compositions may be produced in conventional manner , e . g . by mixing the active ingredient with a carrier and other formulating ingredients . particular formulations to be applied in spraying forms such as water dispersible concentrates or wettable powders may contain surfactant such as wetting and dispersing agents , e . g ., the condensation product of formaldehyde with naphthalene sulphonate , an alkyl - aryl - sulphonate , a lignin sulphonate , a fatty alkyl sulphate an ethoxylated alkylphenol and an ethoxylated fatty alcohol . in general , the formulations include from 0 . 01 to 90 % by weight of active agent , said active agent consisting either of at least one compound of formula ( 1 ) or mixture thereof with other active agents , such as fungicides . concentrate forms of compositions generally contain between about 2 and 80 %, preferably between about 5 and 70 % by weight of active agent . application forms of formulation may , for example , contain from 0 . 01 % to 20 % by weight , preferably from 0 . 01 % to 5 % by weight , of active agent . 50 parts by weight of a compound of formula ( i ) are ground with 2 parts of lauryl sulphate , 3 parts sodium lignin the sulphonate and 45 parts of finely divided kaolininite until the mean particle size is below 5 microns . the resulting wettable powder so obtained is diluted with water before use to a concentration of between 0 . 01 % to 5 % active ingredient . the resulting spray liquor may be applied by foliar spray as well as by root drench application . 25 parts by weight of a compound of formula i , 65 parts of xylene , 10 parts of the mixed reaction product of an alkylphenol with xyleneoxide and calcium - dodecyl - benzene sulphonate are thoroughly mixed until a homogeneous solution is obtained . the resulting emulsion concentrate is diluted with water before use . onto 94 . 5 parts by weight of quartz sand in a tumbler mixer is sprayed 0 . 5 parts by weight of a binder ( non - ionic tenside ) and is thoroughly mixed . 5 parts by weight of compound of the formula ( i ) in powdered form are then added and thoroughly mixed to obtain a granulate formulation with a particle size in the range of from about 0 . 3 to about 0 . 7 mm . the granulate may be applied by incorporation into the soil adjacent the plants to be tested . 25 parts by weight of compound of the formula ( i ), 15 parts of dialkylphenoxy - poly -( ethylenoxy ) ethanol , 15 parts of fine silica , 44 parts of fine kaolin , 0 . 5 parts of a colorant ( e . g ., crystal violet ) and 0 . 5 parts of xantham gum are mixed and ground in a contraplex mill at approximately 10 , 000 rpm to an average particle size of below 20 microns . the resulting formulation is applied to the seeds or tubers as an aqueous suspension in an apparatus suitable for that purpose . where the compound of the formula ( i ) is liquid , it is first absorbed on the carriers , if desired with the air of a small amount of a volatile solvent such as acetone . the resulting powder is first allowed to dry if a solvent is used , then the other ingredients are added and the rest of the procedure is carried out . 2 parts by weight of compound of the formula ( i ) are dissolved in 1 , 000 parts of water . the resulting formulation is applied to plants by drip irrigation . as previously mentioned , the compounds of formula ( i ) are effective in activating or enhancing a crop &# 39 ; s defense system against fungal diseases caused by fungi . such activity can be demonstrated in using the general procedures of the following tests : test a : ipd in potato plants against phytophthora infestans . potato plants ( cultivar bintje ) are grown from tubers in pots filled with sandy loam , peat and perlite mixed in equal volumes , in the greenhouse ( 20 °- 22 ° c .). the plants are ready for testing when they have 6 or 7 compound leaves . tests are carried out with the metalaxyl - resistant isolate mr1 of phytophthora infestans , as well as the ms2 , ms3 , mr2 and mr3 isolates ( kadish and cohen , phytopathology , 78 : 912 - 9155 1988 ). the fungus is grown on potato tuber slices at 15 ° c . in the dark . fresh sporangia are harvested at 6 days after inoculating the slices into double distilled water ( 4 ° c .) and their concentration adjusted to 10 , 000 sporangia / ml before used for challenge inoculations . the compounds of this application are dissolved in water and sprayed on either the lower or upper leaf surfaces of the potato plants with a fine atomizer ( about 10 ml per plant ). the plants are left on the bench until the droplets dry and then are placed in a growth cabinet calibrated to 20 ° c . and 14 hours of light per 10 day . challenge inoculation with p . infestans is carried out at time intervals ranging from 30 minutes to 12 days after treatment with the compounds , by spraying a sporangial suspension on the upper leaf surfaces ( about 15 ml per plant ). in one experiment , inoculum droplets ( 10 containing about 100 sporangia ) are placed on the leaf surfaces , two droplets per leaflet , one on each side of the main vine . in another experiment the compounds are applied curatively , 24 hours after inoculation with p . infestans . inoculated plants are kept at 100 % rh in the dark for 24 hours at 18 ° c . and then returned to a growth cabinet maintained at 20 ° c . with 12 hours light per day . disease severity is monitored 4 - 8 days after inoculation by visually estimating the proportion or a leaf area covered by blight lesions . test b : ipd in tobacco plants against peronospora tabacina . tobacco plants ( cultivars ky - 14 or ky - 16 ) are grown from seek in pots in the greenhouse . when reaching the 10 - leaf stage or older the compounds of this application are injected into the stem of the plant . at 1 - 3 days before injection or at 1 - 10 days after injection plants are challenge - inoculated with conidia of the fungus peronospora tabacina adam which causes the blue mold disease . conidia are harvested from previously infected tobacco plants . inoculation is done with 10 , 000 - 100 , 000 conidia / ml , with approximately 50 ml per plant . the procedure described above for inoculation , maintaining and scoring the disease are also applicable here . while the invention will now be described in connection with certain preferred embodiments in the following examples , it will be understood that it is not intended to limit the invention to these particular embodiments . on the contrary , it is intended to cover all alternatives , modifications and equivalents as may be included within the scope of the invention as defined by the appended claims . thus , the following examples , which include preferred embodiments , will serve to illustrate the practice of this invention , it being understood that the particulars shown are by way of example and for purposes of illustrative discussion of preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of procedures , as well as of the principles and conceptual aspects of the invention . a solution of 86 g of crotonic acid ( 1 mole ) and ethanol - amine ( 1 mole ) in pyridine ( 200 ml ) is refluxed for 2 - 3 hours and subsequently cooled . the resulting produce is filtered and recrystallized to yield the title compound having m . p . 178 °- 180 ° c . ( compound 1 . 1 , table 1 ). following analogous procedure , the compounds 1 . 2 - 1 . 7 , 1 . 10 , 1 . 11 , and 1 . 13 - 1 . 15 set forth in table 1 are obtained . a mixture of 2 hexenoic acid ( 7 . 0 g , 0 . 06 mol ) and concentrated aqueous ammonium hydroxide ( 70 ml ) is heated for 24 hours in an autoclave at 150 ° c . the cooled mixture is treated with carbon black and filtered . after evaporation of the solvent the crude product is recrystallized from ethanol to give the title compound m . p . 203 ° c . ( compound 1 . 21 , table 2 ). following an analogous procedure , the compounds 1 . 8 , 1 . 9 , 1 . 12 and 1 . 18 - 1 . 20 of table 1 are obtained . to a cooled solution of 3 - aminobutyric acid ( 13 g ) in 2m naoh ( 130 ml ) is added benzoyl chloride ( 19 . 7 g ) over the course of two hours . the mixture is allowed to warm to room temperature . washing with diethyl ether , acidifying of the aqueous phase with 20 % hci , extraction with diethyl ether , drying over mgso 4 , evaporation of the solvent and recrystallization in ether / hexane gives the title compound m . p . 150 °- 152 ° c . ( compound 1 . 16 , table 1 ). to 3 . 0 r dl - n - benzoyl - 3 - aminobutyric acid in 30 ml dichloro methane , was added 3 . 0 g pc15 in small portions , keeping the mixture temperature at 5 ° c . the mixture was allowed to warm to 22 °- 20 ° c . and stirred during 5 hr . petrol ether 60 - 80 ( 150 ml ) was added , the chloride was filtered and dried , yielding 2 . 3 g product . to the chloride in 20 ml dichloroethane was added 4 . 1 g . n - octanol in 10 ml dichloroethane , during 10 minutes at 20 ° c . the mixture was heated to 65 ° c . during 6 hr . after distillation , 20 ml dichloroethane was added and washed with 3 × 10 ml sodium bicarbonate ( 2 %) dried over mg50 4 . evaporation of the solvent gave 2 . 0 g of the titled compound having a molecular weight of 319 . following an analogous procedure , compound 1 . 17 of table 1 is obtained . table 1______________________________________compounds prepared of the formula : ## str8 ## cpd r . sub . 1 r . sub . 4 r . sub . 5 r . sub . 6 m . p . (° c . ) ______________________________________1 . 1 h ch . sub . 3 h hydroxyethyl 178 - 1801 . 2 h ch . sub . 3 h isopropyl 167 - 1691 . 3 h ch . sub . 3 h benzyl 178 - 1801 . 4 h ch . sub . 3 h cyclohexyl 161 - 1631 . 5 h ch . sub . 3 h n - hexyl 151 - 1531 . 6 h ch . sub . 3 h p - chlorobenzyl 152 - 1541 . 7 h ch . sub . 3 h benzyl 180 - 1821 . 8 h ethyl h h 128 - 1301 . 9 h ch . sub . 3 ch . sub . 3 h 2161 . 10 ch . sub . 3 h h benzyl 1481 . 11 h ch . sub . 3 h phenyl - ethyl 1641 . 20 h phenyl h h 220 - 2211 . 13 h ch . sub . 3 h n - octyl 1501 . 14 h ch . sub . 3 h n - decyl 1481 . 15 h ethyl h benzyl 157 - 1601 . 16 h ch . sub . 3 h benzoyl 150 - 1521 . 17 h ch . sub . 3 h benzyloxycarbonyl 128 - 1301 . 18 h ethyl h h 178 - 1801 . 19 h ch . sub . 3 h h 209 - 210 * 1 . 20 h ch . sub . 3 h ch . sub . 3 86 - 87 ** 1 . 21 h propyl h h 203______________________________________ *( r ) enantiomer ** monohydrate z - protected β - aminobutyric acid ( 0 . 02 ml ), ( 4 - chlorophenyl )- 1 - ethylamine and 1 . 1 equivalents of dcc ( dicyclohexyl carbonimide ) are stirred in ethyl acetate at room temperature for 16 hours . the precipitate is filtered , the filtrate evaporated and chromatographed on silica gel ( hexane / ethyl acetate 1 : 1 ) to give the title compound as a mixture of diastereomers m . p . 168 °- 178 ° c . 5 . 15 g β - aminobutyric acid ( 50 mol ) are dissolved in 650 ml methanol . after addition of 5 . 5 ml concentrated hci the solution is evaporated . the residue is triturated in diethyl ether , decanted and dried . a colorless oil is isolated . microanalysis : c , 34 . 4 ; h , 7 . 2 ; n , 10 . 0 ; cl , 25 . 4 2 . 06 g β - aminobutyric acid ( 20 mol ) are dissolved in 100 ml of a mixture of water : methanol ( 1 : 1 ). one equivalent naoh in 10 ml water is added . the solution is evaporated and the resulting amorphous solid is dried . microanalysis : c , 37 . 4 ; h , 6 . 7 ; n , 10 . 9 . 1 . 4 g β - aminobutyric acid ( 10 mol ) are dissolved in 100 ml of methanol . diethylamine ( 0 . 9 g , 12 . 3 mol ) is added and the residue is evaporated . the oily residue is washed with ether , decanted and dried to afford an amorphous material , h - nmr ( cd 3 od , 200 mhz ) 1 . 29 ( m , 9h , 3 ch 3 ; 2 . 25 - 2 . 45 ( m , 2h , ch 2 ); 3 . 14 ( p , 4h , ch 2 ch 3 ); 3 . 34 - 3 . 58 ( m , 1h , ch ) tomato plants were grown in sterile soil in the greenhouse . when they reached the 4 - leaf stage they were treated with compound of the formula ( i ) solution by a soil drench . four days later the plants were uprooted , washed with water and their root system immersed for two minutes in conidial suspension ( 10 7 conidia / ml ) of the fungus fusarium oxysporum f . sp . lycopersici . plants were then transplanted ( without washing ) in pots filled with sterile soil . twelve days later all challenged -- control plants wilted of the disease whereas none of the challenged treated plants wilted . growth of the latter plants was similar to that of control , unchallenged - uninoculated plants . results are shown in table 2 . following the method of example 8 , a similar experiment was run using lower concentration of baba . the results are shown in table 3 . table 2______________________________________protection of tomato plants ( cv . rehovot - 13 ) againstfusarium wilt caused by fusarium oxysporum f . sp . lycopersici by aminobutyric acids ( soil drench ) percent of plantscompound healthy wilted______________________________________none 0 100aaba 34 66baba 100 0gaba 7 93______________________________________ plants were soil - drenched with 2000 ppm of the compound and inoculated 4 days later ; rating was taken 12 days after inoculation . table 3______________________________________protection of tomato plants ( cv . rehovot - 13 ) againstfusarium wilt caused by fusarium oxysporum f . sp . lycopersici by lower concentrations of baba ( soildrench ) concentration o ( ppm ) percent wilted plants______________________________________0 100250 53500 431000 0______________________________________ following the above described methods , the effect of aminobutyric acids on downy mildew in sunflower was studied . the results appear in table 4 , which shows the marked activity of baba in percent protection . following the above described methods , the effect of aminobutyric acids on plasmopara viticola in grape plants were studied . the results which appear in table 5 , show the good protection given by baba . following the above described methods , the effect of aminobutyric acids on downey mildew in cucumber and melon plants were studied . the results , which appear in table 6 , show the good protection given by baba . following the above described methods , the effect of r - baba and s - baba against peronospora parasitica and alternaria brassicicola in broccoli , kohlrabi , and cauliflower were studied ; and the results , which appear in tables 7 - 9 , respectively , show the good protection given by r - baba . table 4______________________________________the effect of aminobutyric acids on systemic downymildew of sunflowers ( cv . d . i . - 3 ) caused by plasmoparahalstedii . method ofcompound application conc . percent protection______________________________________ 18 / 21 mg / laaba spray 2000 10baba spray 2000 100gaba spray 2000 0 mg / plantaaba soil drench 5 0baba soil drench 5 100gaba soil drench 5 0aaba root uptake 2 0baba root uptake 2 100gaba root uptake 2 0______________________________________ in all experiments inoculation with the fungus was done either 1 day before treatment ( curative ) or 2 days after treatment . table 5______________________________________the effect of aminobutyric acids on downy mildew causedby plasmopara viticola in grape plants ( cv . sauvignonblanc or cabernet sauvignon ) conc . application % protection withppm mode aaba baba gaba______________________________________10 mg per plant soil drench 0 60 0100 spraying 0 30 0200 intact 0 60 0500 plants 15 90 51000 in pots 20 95 510 0 90 0 50 floating 5 95 0100 leaf discs 10 100 5______________________________________ disease rating was taken 9 days after inoculation . baba has also curative effect as follows : when applied to inoculated leaf discs at 0 , 1 , 2 and 3 days after inoculation percent protection was 100 , 86 , 50 and 30 percent , respectively . table 6______________________________________the effect of aminobutyric acids on downy mildew causedby pseudoperonospora cubensis in cucumber and melonplants ( foliar spray ) or leaf discs ( floating ) plant & amp ; conc . cultivar ppm aaba baba gaba______________________________________ percent protection by whole plantscucumber 250 0 0 0 ( dlila ) 500 0 38 0 1000 0 65 0 2000 5 87 0melon 250 0 30 0 ( galia ) 500 0 38 0 1000 0 86 0 2000 0 92 0 leaf discscucumber 6 0 94 0 ( dlila ) 12 0 97 0 25 0 100 20 50 0 100 60melon 6 0 19 0 ( ananas ) 12 0 25 0 25 0 70 0 50 37 85 30______________________________________ table 7______________________________________ ( broccoli ) protection of ( cv . shugon ) against peronosporaparasitica and alternaria brassicicola with amino butyricacids applied as a foliar spray . percent protectioncompound conc . ppm p . parasitica a . brassicicola______________________________________ 125 33 0 250 50 20r - baba 500 95 60 1000 100 85 2000 100 90 500 0s - baba 1000 0 not tested 2000 0______________________________________ table 8______________________________________ ( kohlrabi ) protection of ( cv . white wien ) against peronosporaparasitica and alternaria brassicicola with aminobutyric acids applied as a foliar spray . percent protectioncompound conc . ppm p . parasitica a . brassicicola______________________________________r - baba 125 33 0 250 50 20 500 95 60 1000 100 85 2000 100 90 500 0s - baba 1000 0 not tested 2000 0______________________________________ table 9______________________________________protection of cauliflower ( cv . nurit ) against peronosporaparasitica and alternaria brassicicola with amino butyric acidsapplied as a foliar spray . percent protectioncompound conc . ppm p . parasitica a . brassicicola______________________________________ 125 33 0 250 50 20r - baba 500 95 60 1000 100 85 2000 100 90s - baba 500 0 1000 0 not tested 2000 0______________________________________ following the above described methods , the effect of a 25 % formulated dl baba in potatoes was studied . the results are shown in table 10 . following the above described methods , the markedly good effect of dl - baba against late blight in potatoes ( bintje ) in growth chambers was studied . the results are shown in table 11 . following the method of example 16 but running field trials in both alpha and bintje cultivars , the results are shown in table 12 . resistance to peronospora tabacina induced in tobacco plants was studied as outlined by y . cohen ( physiological and molecular plant pathology ( 1994 ) 44 : 273 - 88 ) where the active ingredients were applied as a stem injection or foliar spray . results are shown in table 13 . following the method of examples 19 - 20 , the effect of a soil drench with dl - baba ( 3 mg per plant ) on blue mold development in tobacco cv . ky 16 showed an 80 percent control of the disease some 20 days after challenge inoculations . table 10______________________________________effect of 25 % wp formulated dl - baba in potatoes percent protection againstppm dl - baba phytophthora infections______________________________________control -- 31 062 7125 67250 67500 811 , 000 912 , 000 97______________________________________ table 11______________________________________effect of aminobutyric acids against late blightin potato crops in growth chambercompound days after inoculation percent blighted leaf area______________________________________control 2 0 4 80 6 95 8 98 10 98gaba 2 0 4 60 6 85 8 90 10 98dl - aaba 2 0 4 45 6 70 8 80 10 98dl - baba 2 0 4 0 6 10 8 10 10 10______________________________________ table 12______________________________________percentage control of late blight epidemics induced byphytophthora infestans ( isolate mr1 ) in potato cropstreated with baba ( 25 wp ) in three independent fieldexperiments . doseexperiment kg a . i . interval between sprays , daysand cultivar per ha 7 10 14______________________________________autumn 0 -- -- 0alpha 0 . 2 -- -- 24 . 6 0 . 4 -- -- 52 . 6 0 . 8 -- -- 55 . 1winter 0 0 0 0bintje 0 . 2 55 . 0 42 . 1 38 . 4 0 . 4 57 . 4 52 . 5 47 . 1 0 . 8 62 . 6 62 . 6 58 . 0spring 0 0 -- -- alpha 0 . 57 38 . 0 -- -- 1 . 15 77 . 7 -- -- 2 . 30 75 . 0 -- -- spring 0 0 -- -- bintje 0 . 57 35 . 2 -- -- 1 . 15 64 . 5 -- -- 2 . 30 76 . 0 -- -- ______________________________________ table 13______________________________________resistance to peronospora tabacina in tobacco plants byaminobutyric acids stem injection . sup . c folia spray disease severitycompound (% protection ) ( mean ± sd ) ______________________________________water 0 2 . 0 ± 0adl - aaba 10 1 . 3 ± 0 . 2bdl - baba 78 0 . 7 ± 0 . 2cr - baba 99 0 . 07 ± 0 . 09dgaba - 2 2 . 0 ± 0asaa 80 1 . 5 ± 0binab 61 0 . 5 ± 0c______________________________________ a sodium salicylate b 2 , 6 dichloroiso - nicotinic acid . sup . c the letters refer to statistics . sunflower plants were protected against downy mildew caused by plasmopora halstedii by treating the seeds with baba . thus , the seeds were soaked for 24 hours in solution containing 10 mg baba per ml , and then sown in pots in the greenhouse . two weeks later the developed plants were inoculated with plasmopora halstedii . the progress of the disease was assessed after seven more days with the following results : while the control had 100 percent of the plants remained infected ; the treated plants had only a 2 percent rate of infection . maize ( line 3376 ) seeds were allowed to sprout in water for 5 days . they were then dipped in a baba solution for one day . the sprouted seeds were washed and placed in contact with fusarium moniliforme for one day and then planted in pots . after two weeks the progress of the disease was as follows : ______________________________________baba ( ppm ) 0 125 250 500 2 , 000______________________________________percent plants 70 80 40 0 0infected . ______________________________________ the activity of n - benzoyl - 3 - aminobutyric acid n - octyl ester against late blight ( phytophthora infestans ) on potato in growth chamber was studied . six week old plants in pots were sprayed with the compounds and inoculated two days later . disease records taken 7 days post - inoculation are listed in table 14 . table 14______________________________________activity of n - benzoyl - 3 - aminobutyric acid n - octyl esteragainst late blight ( phytophthora infestans ) on potatoin growth chambers . concentration % ppm protection______________________________________500 771000 892000 96______________________________________ the effect of baba against grey mold in tomatoes and cucumbers was studied . young tomatoes ( cultivar baby ) plants ( 4 - leaf stage ) and young cucumbers ( cultivar diila ) plants ( 1 - leaf stage ) were sprayed with baba and inoculated two days later with spores suspension of botrytis cinera . the plants were kept under a moist perspex cover in a growth chamber for four days and then monitored for infection . the results are listed in table 15 . table 15______________________________________the effect of baba against grey mould , incited by botrytiscinerea , in tomato and cucumbers . baba conc percent plants infected ( ppm ) tomato cucumber______________________________________0 100 10062 20 50125 0 30200 0 0500 0 01000 0 02000 0 0______________________________________
a method for protecting a crop against fungal diseases by inducing local and systemic resistance of the crop comprising applying to the crop or its locus a composition containing an effective amount of a β - aminobutyric acid or β - amino valeric acid and derivatives thereof .