PLANT GROWTH REGULATORS

Abstract: The plant growth regulators proposed by the invention comprise an inert carrier or diluent and, as the active substance, at least one substituted maphthalene, preferably in combination with another growth regulator, not being a substituted napthalene.

Description: "PANT GROWTH REGULATORS" DESCRIPTION. The present invention relates to plant growth regulators. It is an object of the present invention to provide novel and efficacious plant growth regulators. There is provided by the present invention a plant growth regulator comprising an inert diluent or carrier and as the active substance, at least one substituted naphthalene, other than, 1,4-and 1,6-dimethylnaphth- alenes. The invention includes a plant growth regulator comprising, as the active substance, at least one substituted naphthalene together with another growth regulator, not being a substituted naphthalene, and/or with a disease control material and optionally with an inert diluent or carrier. If more than one substituted naphthalene is- employed, the mixture may consist of isomers. The growth regulators of the present invention are particularly useful for preventing the premature sprouting of potatoes. The invention includes a method for preventing the premature sprouting of potatoes which comprises applying to the potatoes a plant growth regulator as defined above. It is generally preferred that the naphthalene be substituted in the l-position. Halogens and alkyl groups are suitable substituents and of the halogens bromine is preferred. However, generally alkyl groups are preferred to halogens but, if the alkyl group is methyl, it is preferred to have another alkyl group in the ring, preferably a methyl group, in the 3-position. Additionally, or alternatively, the naphthalene may be substituted in some other position. In the alternative preferably it is substituted in the 2-position with a methyl group or in the 2-and 3-positions with a methyl group. Examples of substituted naphthalenes for use in the present invention are l-ethylnaphthalene, 2 ethylnaphthal ene, l-bromo-2-methylnaphthalene, 1bromo-4-methylnaphthalene, l-chloro-4-methylnaphthalene, 1,4-dibromonaphthalene, 2,3-dimethylnaphthalene, l-bromo-2,3-dimethylnaphthalene, 1-ac etyl-4-methyl- naphthalene, 2,6-diisopropyl naphthalene, 2-isopropylnaphthalene and 2,3-dihydronaphthalene. However, it is preferred to use 1,3-dimethylnaphthalene, l-ethylnaphthalene, l-chloro-4-methylnaphthalene, l-bromo-4-methylnaphthalene, l-bromo-2-methyl- naphthalene, 2,3-dimethylnaphthalene or a mixture of isomers of dimethylnaphthanenes generally to prevent the premature sprouting of potates. Examples of disease control materials are guanidinium compounds, benzimidazole compounds chlorinated aromatic or aliphatic compounds or substituted thiocarbamates. Examples of growth regulators other than substituted naphthalenes are mitosis inhibitors e.g. substituted carbamates, or metabolic interference compounds having aC-C-N-N linkage e.g. N-dimethylamino succinamic acid or ethylene generators e,g. eth phon (that is 2-chloroethyl phosphoric acid). Dimethylnaphthalenes are particularly useful in that their rate of disappearance from the potatoes after application is such that the subsequent growth of the treated tubers shows little, if any, abnormality, Depending on the active substance or substances employed, a growth regulator according to the present invention may be made up by dispersing or dissolving the active substance or substances in a liquid or solid carrier; and depending upon the manner in which it is made up, it may be applied to the plants as a particulate solid or in the form of a mist or a thermal vapour or fog. Bor instance, 2,6-dimethylnaphthanene may be wet milled so as to produce a colloidal suspension e.g. of 5o w.Teight/volume of the active substance or mixture thereof, for subsequent dilution with water on application to the plants e.g. as a mist, or it may be dispersed as a powder throughout a granular carrier, e.g. diatamaceous earth, with a suitable sticker, e.g. carboxyl methyl cellulose, being used to adhere the particles of he active substance to the granules of the carrier. A suitable concentration of the 2,6-dimethylnaphthalene is 1 part to 9 parts by weight of the granular carrier. Again, a mixture of isomers of dimethylnaphthalene may be diluted with a suitable diluent e.g. a monomethylnaphthalene, for application to the plants as a thermal fog or vapour; a suitable dilution being one volume of the mixed isomers and five volumes of the diluent. Alternatively, the liquid mixture of isomers may be dispersed throughout a granular carrier along with a sealing agent, e.g. carboxy methyl cellulose, to give a granular composition containing, for example, l/o active substance. The mixture of isomers, however, may be used without a diluent and applied as a thermal fog. Dosage rates will depend 0u the precise manner in which the growth regulator is made up but, in the case of 2,6-dimethylnaphthalene, the dosage rate ispreferably such as to give a concentration of 100 to 240 milligrammes of the active substance per kilogramme of potatoes whereas, in the case of a liquid mixture of isomers of dimethylnaphthalenes, the dosage rate is such as preferably to give rise to a concentration of 20 millilitres to 200 millilitres per tonne of potatoes. Growth regulators according to the present invention are illustrated in the following Examples. Example 1. 2,6-dimethylnaphthalene (2NET) , a crystalline solid capable of being wet milled so as to produce a colloidal suspension with a particle size (10-20 microns) was combined with a fungicide 2,4-thiazolylbenzimidazole (TBZ) in the proportion of 4 parts of DEN to 1 part of TBZ. The combination was formulated as a colloidal suspension 50,%' wt/vol. active ingredient. This formulation was then diluted with water so as to give a dispersion suitable for application by low volume misting apparatus to potato tubers. The dosage rate was maintained at a constant total volume of one litre per tonne of tubers with a concentration of active materials which was varied so as to give a concentration of active substance ranging from 120240 mg. per kg. The tubers were then stored in a constant environment store and maintained under a storage regime of 10 C and relative humidity of 94. Example 2. 10 parts of dimethylnaphthalene isomers were combined with 1 part of a fungicide guanidinododecane acetate (GDA). The combination was formulated as a colloidal suspension 5% wt/vol. active ingredient. This formulation was then diluted with water as to give a dispersion suitable for application by low volume misting apparatus to potato tubers. The dosage rate was maintained at a constant total volume of one litre per tonne of tubers with a concentration of total active materials which was varied so as to give a concentration of active materials ranging from 120-240 mg. per kg. The tubers were then stored in a constant environment store and maintained under a storage regime of 10 0C and relative humidity of 94. ExamPle 3. 10 parts of dimethylnaphthalene isomers, 1 part of GDA and 1 part of copper ethylene diamine tetraacetate (CuEDTA) made up as in Example 2, GDA decays rapidly and the CuEDTA inhibits such decay. Example 4. 5 parts of dimethylnaphthalene isomers, 1 part of Byacin, made up as in Example 2. Byacin - a biocide - is nonyl phenoxy poly (ethyleneoxy) ethanol iodine. Example 5. 2 parts of dimethylnaphthalene isomers, 1 part of Tecnazene (TC), made up as in Example 2. Tecnazene is a fungicide and also a sprout growth regulator and is tetrachloronitrobenzene. Example 6. Combination of D.N.N.'s:- one litre of mixed isomers of dimethylnaphthalene was diluted with 5 litres of monomethylnaphthalene or of N-methylpyrrolidone for application to potatoes as a thermal vapour. This formulation is both stable and volatile and can be applied to bulk heaps of potatoes by means of thermal fogging apparatus. The dosage rate required varies from 50 ml per tonne of tubers to 100 ml per tonne of tubers and is best repeated at intervals of 70 to 100 days. To one litre of mixed isomers add one litre of Tubazole applied as a thermal fog. Tubazole is a mixture of Byacin and TBZ. Dosage rate to be 100 to 200 ml. per tonne. Example 7. 1 kilo of D.Is . was finely ground in an attrition mill to give a particle size no greater than 50 microns. This powder was then added to 9 kilos of a granular carrier composed of diatamaceous earth and of a size described as 22/44, that is the particles are small enough to go through a 22 mesh sieve but too large to go through a 44 nesh sieve, the sieve being standard B.S.I. series. The powder was fixed to the granule surface by means of a sticker and in this case carboy methyl cellulose was used. This granular product when dried was applied to freshly harvested potatoes at the rate of 2 kilos per tonne of potatoes. Example 8. A liquid mixture of dimethylnaphthalene isomers was added to an inert granular carrier composed of diamaceous earth so as to produce a granular product containing 1o' of active ingredient. After the addition of the isomers, the partial sealing of the material was accomplished by the addition of 2 wt/vol. of carboxy methyl cellulose. This formulation was applied to freshly harvested potatoes at the rate of 1.5 kilos per tonne of potatoes. Example 9. A liquid consisting of mixed isomers of dimethylnaphthalene was formulated with an emulsifying agent namely phosphate ester emulsifier diluted with water so as to give an aqueous preparation suitable for low volume application to potato tubers at the rate of 2 litres per tonne each litre-containing from 10 to 120 mg. per litre. All of the formulations produced in the above Examples were subject to similar tests so as to evaluate growth regulation properties. The variety of potatoes used in these trials was "Record" and the storage conditions were such as to give abundant sprout growth. The results of tests of the formulations of the above Examples are given in Table 1 below. In this Table, the effectiveness of the compositions is given for disease control, namely, against skin spot, dry spot, dry rot and black scurf and for sprout control The results are given in terms of a score on the scale: :- 0 to 10, in which in respect of sprouting "O" indicates no effect on sprouting growth and "10" indicates no sprouting growth and, in respect of disease control, "0" indicates no effect and '10" indicates no visible disease symptoms. EMI8.1 FORMULATION <SEP> RATE <SEP> APPLIED <SEP> (mg/kg) <SEP> SKIN <SEP> SPOT <SEP> DRY <SEP> ROT <SEP> BLACK <SEP> SCURF <SEP> SPROUT <SEP> CONTROL <tb> CONTROL <SEP> 0 <SEP> 0 <SEP> 0 <SEP> 0 <SEP> 0 <tb> Example <SEP> 1 <SEP> DMN <SEP> 90 <SEP> 9 <SEP> 7 <SEP> 9 <SEP> 10 <tb> <SEP> TBZ <SEP> 30 <tb> Example <SEP> 2 <SEP> Dimethylnapthalenes <SEP> 110 <SEP> 8 <SEP> 5 <SEP> 9 <SEP> 10 <tb> <SEP> GDA <SEP> 11 <tb> Example <SEP> 3 <SEP> Dimethylnapthalenes <SEP> 110 <SEP> 8 <SEP> 6 <SEP> 9 <SEP> 10 <tb> <SEP> GDA <SEP> 11 <SEP> CuEDTA <SEP> 11 <tb> Example <SEP> 4 <SEP> Dimethylnapthalenes <SEP> 100 <SEP> 9 <SEP> 6 <SEP> 7 <SEP> 10 <tb> <SEP> Byacin <SEP> 20 <tb> Example <SEP> 5 <SEP> Dimethylnapthalenes <SEP> 100 <SEP> 3 <SEP> 8 <SEP> 2 <SEP> 10 <tb> <SEP> TCNB <SEP> 50 <tb> Example <SEP> 6 <SEP> Dimethylnapthalenes <SEP> 25 <SEP> 9 <SEP> 9 <SEP> 10 <SEP> 8 <tb> <SEP> TBZ <SEP> & Byacin <SEP> 25 <tb> Example <SEP> 7 <SEP> Dimethylnapthalenes <SEP> 25 <SEP> 2 <SEP> 1 <SEP> 3 <SEP> 8 <tb> Example <SEP> 8 <SEP> Dimethylnapthalenes <SEP> 90 <SEP> 2 <SEP> 2 <SEP> 3 <SEP> 9 <tb> Example <SEP> 9 <SEP> Dimethylnapthalenes <SEP> 150 <SEP> 3 <SEP> 2 <SEP> 4 <SEP> 10 <tb> TABLE 1 DISEASE CONTROL The effect of growth regulators according to the present invention is further illustrated in the following Tables. Table 2 below shows the effect of the specified substances on the length of sprouts in potatoes after fifteen weeks in storage of the potatoes. A control was used which during this time provided a mean length of the longest sprout in millimetres of 175 in sixty of the potatoes. Table 3 gives the weight of the sprouts of the potatoes subjected to the tests of Table 2 Table 4 provides a comparison in relation to length of sprout and weight of sprout of alpha-ethyl naphthalene (methyl naphthalene) and beta-ethyl naphthalene (2-ethyl naphthalene). Table 5 shows the effect of the specified substances on potatoes which have been previously hand de-sprouted in respect of sprout length after a period of five weeks. Table 6 shows the effect of the specified. substances on sprout emergence after sixteen days following planting of the potatoes and Table 7 shows the effect of the specified substances on sprout emergence after thirty eight days following planting. TABLE 2 Final assessment (storae) - 15 weeks sprout length Length of longest sprouta Control 175 Dose mg/kg 20 100 500 2,3-dimethylnaphthalene 141 15 25 1-bromo-2,3 dimethylnapthalene 132 85 64b 1,4 Dimethylnaphthalene 59 10 1 1-chloro-4-methylnaphthalene 81 4 1 1-bromo-4-methylnaphthalene 63 10 2 1-bromo-2-methylnaphthalene 41 25 8 1-chloromethylnaphthalene 182 147 124 1-chlormethyl-2-methylnapthalene 170 184 185 1,4-dibromonaphthalene 120 11 26 1-acetyl-4-methylnaphthalene 156 85 83c 2-methylnaphthalene 162 121 4 1-methylnaphthalene 139 129 8 i-ethylnaphthalene 24 9 0 mixed monomethylnaphthalenes 172 174 6 LSD 5% (least significant 16 13 15 difference) a mean length of longest sprout (mm) 60 tubers blevel employed 161 ppm Clevel employed 173 ppm TABLE 3 Final assessment (stoage) after 15 weeks sprout weight Total Sprout Weighty Control 372 Dose mg/kg 20 100 500 2,3-dimethylnapthalene 290 29 56 1-bromo-2,3-dimethylnapthalene 295 205 197b 1,4-dimethylnaphthalene 159 28 2 1-chloro-4-methylnaphthalene 193 10 1 1-bromo-4-methylnaphthalene 172 29 6 1-bromo-2-methylnaphthalene 94 80 19 1-chloromethylnaphthalene 375 298 193 1-chlormethyl-2-methylnapthalene 317 332 366 1,4-dibromonaphthalene 280 26 75 1-acetyl-4-methylnaphthalene 305 224 189C 2-methylnaphthalene 311 245 18 I-methylnaphthalene 288 245 3 1-ethylnapthalene 52 10 0 mixed monomethylnapthalenes 346 300 11 atotal sprout weight from 60 tubers (g) blevel employed 161 ppm Clevel employed 173 ppm TABLE 4 &alpha;-napthalene versus P -naphthalene 14 weeks storage, 100 ppm. cv. Desiree. Length of longest sprout Total sprout weigth" control 339 822 a-ethylnaphthalene 10 26 ss-ethylnapthalene 63 127 atotal weight of sprouts from 30 tubers TABLE 5 Selected treatments hand desprouted 6.4.82. aired in trays 5 weeks under light. Planted 18.5.82. Length longest sprouta Control 19 20 100 500 ppm ppm ppm 1,4-dimethylnapthalene 23 8 3 1-ethylnaphthalene 23 22 2 vI-chloro-4-methylnaphthalene 25 13 5 1-bromo-4-methylnaphthalene 21 8 4 1-bromo-2-methylnaphthalene 17 - 4 1,4-dimethylnapthalene - 9 2,3-dimethylnaphthalene - 26 1-bromo-2,3-dimethylnapthalene - 15 a 60 tubers TABLE 6 % emergence after 16 days Control 81 20 100 500 ppm ppm ppm 1,4-dimethylnaphthalene 81 b 41 19 1-ethylnaphthalene 78 94 1-chloro-4-methylnaphthalene 85 62 9 1-bromo-4-methylnaphthalene 73 28 19 1-bromo-2-methylnaphthalene 60 1,4-dibromonaphthalene - 58 2,3-dimethylnaphthalene - 73 TABLE 7 % emergence after 38 days Control 100 20 100. 500 ppm ppm ppm 1,4-dimethylnapthalene 100 100 70 1-ethylnaphthalene 100 97 87 1-chloro-4-methylnaphthalene 97 100 97 1-bromo-4-methylaaphthalene 97 93 97 1-bromo-2-methylnaphthalene - 93 1,4-dibromonaphthalene - 93 2,3-dimethylnaphthalene - 100 r The above Tables 2 to 7 clearly demonstrate that all the presently preferred compounds have the effect of delay-. ing sprouting of potatoes and that certain of the substituted naphthalenes are especially effective for this purppse.

Claims: CLAIMS. 1. Plant growth regulator comprising an inert carrier or diluent and, as the active substance, at least one substituted napthalene, other than 1,4- and 1.6- a imethylnaphthalene S. 2. Plant growth regulator comprising, as the active substance, at least one substituted naphthalene together with another growth regulator, not being a substituted naphthalene, and/or with a disease control material and optionally with an inert diluent or carrier. 3. Plant growth regulator as claimed in claim 2 in which the active substance is 1,4- or 1,6- dimethylnaphthalene. 4. Plant growth regulator as claimed in claim 2 or 3, in which the growth regulator, not being a substituted naphthalene, is a mitosis inhibitor, a metabolic interference compound or an ethylene generator. 5. Plant growth regulator as claimed in claim 2, 3 or 4 in which the disease control agent is a guanidinium compound, a benzimidazole compound, a chlorinated aromatic or aliphatic compound or a substituted thiocarbamate. 6. Plant growth regulator as claimed in any of claims 1 to 5, in which the active substance is 1,3-dimethylnaphthalene, l-ethylnaphthalen, l-chloro-4-methylnaph- thalene, 1-bromo-4-methylnaphthalene, l-bromo-2methylnaphthalene, 2, 3-dimethylnaphthalene or a mixture of isomers of dimethylnaphthalene. 7. Method for preventing the premature sprouting of potatoes, which comprises applying to the potatoes a plant growth regulator as claimed in any of claims 1 to 6. 8. Method as claimed in claim 7, in which the plant growth regulator is in the form of a particulate solid, or in the form of a mist or thermal vapour or fog 9. Nethod as claimed in claim 7 or 8, in which the plant growth regulator is in the form of a particulate solid containing a granular carrier, the active substance being 2,6-dimethylnaphthalene and there being 1 part of the active substance to 9 parts by weight of the carrier. 10. Method as claimed in claim 9, in which the plant growth regulator is applied at a dosage rate such as to give a concentration of 10O to 240 milligrammes of active substance p-cr kilogram of potatoes. 11. Method as claimed in claim 7 or 8, in which the plant growth regulator is a mixture of one volume of isomers of dimethylnaphthalene with nine volumes of diluent. 12. Method as claimed in claim 11, in which the plant growth regulator is applied at a dosage rate such as to give rise to a concentration of 20 millilitres to 200 millilitres per tonne of potatoes.

Inventors: EVEREST-TODD, SELWYN
Applicants: COALITE GROUP PLC
Application year: 1983
Main classification: A01N27
IPC codes: A01N35, A01N47, A01N27, A01N43, A01N29