IT8322270A1 - Process and product to selectively combat weeds in rice crops transplanted or sown in water - Google Patents

Description

DESCRIPTION

of the industrial invention entitled:

"Process and product to selectively combat weeds in rice crops transplanted or sown in water".

SUMMARY

A product that acts synergistically to selectively combat weeds in transplanted rice or sown in water? constituted, in addition to? inert additives, by a quantity? active of a mixture of the herbicide, 2 ~ chloro-4,6-diethyl-N - (2 "-propyloxyethyl) acetanilide" Pretilachlor "and

S-4-chlorobenzyl-N, N-diethyl-carbamate "Thiobencarb" or S-benzyl-N, N-diethylcarbaramate, to which in order to increase compatibility? with respect to rice, you can? add 2-phenyl - 4,6-dichloropyrimidine as antidote.

DESCRIPTION

The present invention relates to a synergistically active product which contains a combination of active substances which? excellently suited to selectively combat weed plants in rice crops transplanted even if sown in water, and also concerns a process for combating weed vegetables in rice crops transplanted or sown in water with this product,

'The cultivation of transplanted rice is carried out by transplanting rice plants raised from rice seeds into plant nurseries in a rice field already? flooded. Rice plants at the time of transplantation have 17-21 days. In such a rice crop, many infesting plants germinate immediately after transplanting, which can be fought on the one hand by weeding and on the other hand by the use of herbicides. Since? the spectrum of action of the herbicides used so far not? optimally suited to this problem, the fight against the weeds in transplanted rice must be carried out in two stages, namely early treatment and late treatment. It would be desirable to control weeds in transplanted rice by applying a herbicidal product once only. The herbicidal products endowed with an action against the most infesting plants? strong have for? a tendency to damage even young rice plants. Less strongly phytotoxic herbicides actually spare the rice plants, but they? they are not able to destroy all the infesting plants so that due to the infestation of the crop there is a decrease in the harvest.

In the case of rice sown in water, rice seeds that have been swollen or germinated previously for 24 hours in water, or are sown directly in the field flooded with water (for example in Italy or California) or in tropical countries, even inland very humid swampy. Even in the case of this cultivation method, herbicidal products are still missing whose spectrum of action, whose duration of action and whose activity? they completely adapt to special needs. In particular, even in the case of rice sown in water, there are problems of compatibility? since? the young rice plant during sprouting and shortly after sprouting? extremely sensitive to phytotoxic influences.

The present invention relates to a product which acts synergistically which? consisting of a combination of herbicidal active substances which consist of 2-chloro-4,6-diethyl ~ N- (2 "-propyloxyethyl) - 'acetamide (" Pretilachlor ") and S-4-chlorobenzyl-N, N- diethyl-thiocarbamate ('Thiobencarb ") respectively S-4-benzyl-NfN- <iethylthiocarbamate and to which in order to increase compatibility? with respect to rice, you can? to add 2-phenyl as an antidote? -4, 6-dichoropyrimidine?

Yup ? demonstrated that with the reduction of the doses of the active substances a synergistic effect of the herbicidal action against important weeds of rice could be achieved?

It was surprising the observation that in the case of dosages of the herbicide used in this way? low, a reinforcement of the actual synergic action has been achieved. Also by mixing or by adding 2-phenyl ~ 4,6-dichloropyrimidine as an antidote (antidote or safety product) yes? managed to significantly increase the compatibility? of rice against this herbicide mixture without the herbicidal action or the synergistic effect being diminished.

The product acting synergistically in accordance with the invention? therefore, in addition to inert additives, as the active substance of a mixture consisting of the herbicide: 2-chloro-2 ', 6'-diethyl ~ N- (2n - propyloxyethyl) acetanilide "Pretilachlor" of formula I

(I),

and from the herbicide s? 4-chlorobenzyl-N, N-diethyl? thiocarbamate "Thiobencarb '' or from S-4-benzyl-W, N ~ diethyl - thiocarbamate of formula II

(II),

wherein R represents chlorine or hydrogen and optionally from the antidote 2-f enyl-4,6-dichloropyrimidine of formula III

(III),

The active substance of formula I, namely 2-chloro -4,6-diethyl-N- (2 "-propyloxyethyl) -acetanilide is known, for example from DOS 2,328,340, from British patent N? 1,438,312 or from patent U.S. 4,168,565.

It? suitable as a selective herbicide in cereals, for? also in rice. It is an interesting herbicide considering its spectrum of action for what? until now it could not be used optimally.

The active substance of f? Rmula I pu? exist in the form of racemate or in the form R and S otti? c amente active.

One of the active substances of formula II, namely s-4-chlorobenzyl-N, N ~ diethylthiocarbamate? also known, for example from DE-OS patent 1,943,983, which describes its use to combat weed plants in rice crops. Do you recommend it?

quantity of 3-6 kg of active substance per hectare which must be applied from 3 to 7 days after transplanting on the surface of the crop water, see "The Pesticide Manual" pag. 106, th? British Crop Protection Council, 5th Ed. 1977? The other active substance of formula II, S-benzyl - N,? - diethyl-thiocarbamate is formed as a degradation product of S-4-chlorobenzyl-N, N-diethylthiocarbamate for example in the soil of rice fields. This substance until now is not you? revealed as a herbicide. Does it own property? phytotoxic and non-specific growth inhibitors which for example in Japan led to the growth of dwarf plants in rice crops, see J. Pesticide Sci. 5 (1980) p. 107-109.

Finally, the substance of formula III, that is 2 - phenyl-4,6-dichloropyrimidine, acts as an antidote to the chloroacetanilide of formula l and has allowed to increase in a specific way? the tolerance of rice and other crops such as cereals towards the phytotoxic action of this herbicide without the herbicidal action in general being diminished. Ba one side you can use quantities? of herbicide more? elevated in order to combat weeds, even resistant ones, on the other hand? possible by adding the antidote to prevent or for? decrease the damage due to an overdosing of the herbicide mixture caused by chance.

The antidote of formula III can? be mixed with the mixture of the herbicides of formulas I and II. It can? be applied alone before or after the herbicide mixture. The most? advantageous for? ? the one in which the rice seeds are treated for example during the pre-sprouting (swelling) with a quantity? activates the antidote, which process? known as seed swelling.

Through the combination of the active substances is achieved a phytotoxicity? against weed plants more? higher than that which could be expected from the simple addition of the single actions, the damage action against lysus crops is instead not increased synergistically so that at the time of application there is a safety margin against the crop more? large compared to that which would occur in the case of the use of individual active substances to obtain the same action against weed plants. On the other hand, to achieve the same herbicidal effect against weeds are sufficient quantities? of application of minor active substance and there? again leads to the decrease of phytotoxicity? on the crop.

The mixture can? be applied as such in the crop or you can? apply each of the components individually. The antidote is preferably employed simultaneously with the swelling step of the silos. In the end ? It is also possible to apply all the herbicide mixture or respectively all the herbicide-antidote mixture during the swelling of the seeds on the rice grains and so on? apply the mixture of active substances.

With the mixture in accordance with the invention, the following important rice weeds are mainly fought in a lasting way:

The quantitative ratio of components I and II in the product according to the invention can? vary within wide limits and as a rule? between 1: 1 and 1:25 Herbicidal products have proved to be particularly advantageous in which the quantitative ratio between / components I and II is included.

1: 4 to 1:10. The quantity of total application of the two active substances together amounts to 1 to 12 kg / hectare, preferably 1.5 to 6 kg / hectare? In this case, the antidote of formula III can? be added to the mixture (I II) in quantity? by 0.1 to 50%,

In such a range of concentrations of the application of the product according to the invention practically no harmful action is observed or only a scarce harmful action on rice crops is observed while weed grasses and weeds already? in the case of low concentrations they are practically completely destroyed.

The present invention also relates to the use of the product according to the invention and also to a process for selectively combating weeds and dicotyledonous weeds in rice and the product according to the invention can be applied both in the pre-emergence phase as well as in the post-emergency phase.

The product according to the invention with the new combination of active substances contains in addition to the mentioned active substances still suitable carrier substances and / or other additives. These can be solid or liquid and correspond to the substances usual in the formulation technique such as for example natural or regenerated mineral substances, solvents, dispersants, humectants, adhesives, thickeners, binders or fertilizing products? Suitable application forms are therefore for example emulsion concentrates, directly sprayable or dilutable solutions, diluted emulsions, spray powders, soluble powders, powdered products, granulates and also microencapsulations, for example in polymeric substances. Are the application process such as spraying, spraying, pulverizing, spreading or pouring as well as the type of product selected in accordance with the desired purposes and the indicated ratios? Formulations, i.e. products, preparations or compositions which contain the mixture of active substances according to the invention and optionally a solid or liquid additive, are prepared in a known way, for example by thoroughly mixing and / or grinding the active substance with diluents such as with solvents, solid carrier substances and possibly surfactant compounds?

As solvents, the following can be considered: aromatic hydrocarbons, preferably the C8 to C fractions, such as for example mixtures of xylols or substituted naphthalins, esters of phthalic acid such as dibutyl-phthalate or dioctyl-phthalate, aliphatic hydrocarbons such as cyclohexane or paraffins, alcohols and glycols and also their ethers and esters such as ethanol, ethylene glycol, ethylene glycolmonomethyl- or ethyl-ether, ketones such as cyclohexanone, highly polar solvents such as N-methyl-2-pyrrh? suitable, dimethyl sulfoxide or dimethylformamide and also possibly epoxidized vegetable oils such as oil epoxidized coconut or epoxidized soybean oil; or water.

Powders of natural minerals such as calcite, talc, kaolin, montmorillonite or attapulgite are generally used as solid carrier substances, for example for powdered products and dispersible powders. To improve the properties? physically, highly dispersed silicic acid or highly dispersed absorbent polymers can also be added. Porous types such as pumice stone, crushed brick, sepiolite or bentonite as non-absorbent support substances, e.g. calcite or sand, are considered as solid carrier for absorbent granules in the form of grains. Furthermore, numerous previously granulated materials of inorganic or organic nature can be used, such as in particular dolomite or shredded vegetable residues.

How do you deal with surfactant compounds? siderazione non-ionogenic, cation-active and / or anion-active surfactants with good properties emulsifiers, dispersants and humectants. Surfactants also mean mixtures of surfactants.

Suitable anionic surfactants can be both so-called water-soluble soaps as well as synthetic water-soluble surfactant compounds.

As soaps, salts of alkali metals, alkaline earth metals or ammonium salts possibly substituted by higher fatty acids (C10-C22) such as sodium or potassium salts of oleic acid or of stearic acid or mixtures of natural fatty acids which can be obtained for example from coconut oil or tallow oil. In addition, the methyltauride salts of fatty acids must also be mentioned.

Pi? often for? so-called synthetic surfactants are used, in particular fatty sulfonates, fatty sulphates, benzimidazolderivates, sulfonates or alkylaryl sulphonates

The sulfonates or fatty acids are usually in the form of alkali metal salts, alkaline earth metal salts or in the form of possibly substituted ammonium salts and have an alkyl radical having from 8 to 22 carbon atoms in which alkyl also includes the alkyl part of acyl radicals, for example the sodium or calcium salt of ligninsulfonic acid, of the dodecylsulfonic acid ester or of a mixture of fatty alcohol sulphates prepared from natural fatty acids. To these also belong the salts of the esters of sulfuric acid and of sulphonic acids of addition products of fatty alcohols-ethylene oxide. The sulfonated benzimidazole derivatives preferably contain two sulfonic acid groups and a radical of a fatty acid with 8-22 carbon atoms. Alkylaryl sulphonates are, for example, the sodium, calcium or triethanolamine salts of dofecylbenzenesulphonic acid, dibutylnaphthalinsulphonic acid, or of a condensation product between naphthalinsulphonic acid and formaldehyde.

Furthermore, corresponding phosphates such as for example salts of the phosphoric acid ester of a p-nonylphenol- (4-14) -ethylene oxide addition product are also considered.

As non-ionic surfactants, polyglycol ethers derived from aliphatic or cycloaliphatic alcohols, of saturated or unsaturated fatty acids and alkylphenols which may contain from 3 to 30 glycol ether groups and from 8 to 20 carbon atoms in the radical of the hydrocarbon (aliphatic) and from 6 to 18 carbon atoms in the alkyl radical of the alkylphenol.

Further suitable non-ionic surfactants are water-soluble polyethylene oxide additive products containing 20 to 250 ethylene glycol ether groups 10 to 100 propylene glycol ether groups on polypropylene glycol, ethylene diamine polypropylene glycol and alkyl polypropylene glycol with 1-10 carbon atoms alkyl. The compounds mentioned usually contain for each unit? of propylene glycol, from 1 to 5 units? of ethylene glycol.

Examples of non-ionic surfactants can be cited nonylphenolopciLethoxyethanols, polyglycol ethers of castor oil, polypropylene-polyethylene oxide addition products, tributylphenoxy polyethoxyethanol, polyethylene glycol and octylphenoxy polyethoxyethanol?

In addition, esters of polyoxyethylene sorbitan fatty acids such as polyosethylene sorbitan-trioleate are also considered.

In the case of cationic surfactants it is mainly quaternary ammonium salts which contain as N-substituents at least one alcohol radical with 8-22 carbon atoms and as further substituents possibly halogenated lower alkyl radicals, benzyl or lower hydroxyalkyl radicals. The salts are preferably in the form of halides, methylsulphates or ethylsulfates, for example stearyltri- chloride. methylammonium or benzyldi (2-chloroethyl) -ethylammonium bromide.

The surfactants usual in the formulation art are described among others in the following publications:

"Me Cutcheon's Detergents and Emulsifiers Annual"

MC Publishing Corp., Ridgewood, New Jersey, 1979.

Sisley and Wood, "Encyclopedia of Surface Active Agents, Chemical Publishing Co., Inc., New York, 1964.

The content in active substance in the usual products of the trade? comprised between 0.1 and 95% by weight, preferably between 1 and 80% by weight.

In particular preferred formulations are prepared in the following way (% = percent by weight).

While rather concentrated products are preferred as a commercial product, the final consumer usually uses diluted products. The shapes

of application can be diluted up to 0.001%

of active substance.

Other biocidal active substances or other biocidal products can be mixed with the products according to the invention described. What? the new products in addition to the compounds of general formula I and formula II mentioned may contain, for example, insecticides, fungicides, bactericides, fungostats, bacteriostats or nematocides to broaden the spectrum of action.

A synergistic effect in the case of herbicides

? always present when the herbicidal action of the combination of active substances I II? greater than the sum obtained from the action of the single active substances applied. _ __

The plant growth to be expected is for

a given combination of two herbicides, (COBY, S.R., "Calculating synergistic and antagonistic response of herbicide combinations ,,, Veeds 15. pages 20 - 22, 1967) can be calculated, as follows:

In this case the symbols mean:

X = Percentage inhibition of growth in the case of treatment with a herbicide I with a quantity? application rate of p kg per hectare compared to untreated controls;

Y = Percentage inhibition of growth in the case of treatment with a herbicide II with a quantity? of application of q kg per hectare compared to untreated controls;

E = Activities expected herbicide, (percentage growth inhibition compared to untreated controls) after treatment with the herbicide mixture I II in the case of a quantity? of?> lication of p q kg of active substance per hectare.

If the observed value really? greater than the predictable E value, there is synergism.

The synergistic effect of the combinations of substances II and II is demonstrated in the following examples.

In order to better highlight the synergistic action of the combination of active substances, the biological results have been obtained with quantity? of application that are in the lower limits of the activity? against the chosen model test plant Monochoria vaginalis in greenhouse conditions .. As a rule, ie in the application in practice, the quantities? of application are more? high, so that at the same time there is progressively greater damage to the infesting plants.

Example 1: Test in transplanted rice

Method of application: Tank mix

Rice plants of the variety? IR 36 are grown to the stage of 1.5 - 2 leaves in the earth. The plants are then transplanted in clumps (always 3 plants together) in containers (length 47 cm, width 29 cm and height 24 cm) in sandy clay. The surface of the earth is subsequently covered with water up to a height of 1.5-2 cm.

3 days or 8 days after transplanting, the herbicide mixture is applied in the form of a tank mixture directly into the water. 30 days after the transplant is the activity evaluated? of the herbicidal mixture in percent. Do you need control as a reference? completely untreated = 0% (= 100% growth) and total plant destruction = 100%? The results are collected below.

To demonstrate the synergistic effect, the growth inhibitions in percent measured and calculated according to Colby are shown in the table below.

Since? the growth inhibitions observed for Monochoria vaginalis are always greater than those

calculated according to Colby, is there synergy?

An overdose of the mixture and also of the

active substance of formula I or of the substance

active formula II may result

damage to the rice crop. Tests carried out in the greenhouse have shown that it is possible to neutralize these superdoses, that is the compatibility? of rice in

comparisons of these herbicidal active substances becomes

greater when adding the formula compound

IIIoxy 2-phenyl-4,6-dichloropyrimidine as an antidote

(or security product). It is equally favorable if this compound is incorporated directly

in the herbicidal mixture, if it is applied by

only more? or not simultaneously with the herbicide or if the rice seeds are previously treated with the antidote.

The synergistic herbicidal action against plants

weeds more? important of the two herbicides of formula I and II remains unchanged while si? observed a compatibility? strongly improved, of rice plants with respect to herbicides or respectively a mixture thereof.

The following examples illustrate this action: Example 2: Test with antidote and herbicide mixture in transplanted rice

Method of application: Tank mix

Rice plants of the variety? ? Yamabiko "are grown in the ground up to the stage of 1.5 - 2 leaves. The plants are then transplanted in clumps (always 3 plants together) in containers (length 47 cm, width 29 cm and height 24 cm) in sandy clay. The surface of the soil is subsequently covered with water having a height of 1.5 - 2 cm. On the day of transplant, 'r_the herbicides *' Pretilachlor "I and" Thiobencarb "II are applied together with the antidote III as a reservoir mixture directly into the water. 30 days after transplantation, the relative protective action of the antidote is evaluated in percent. As a reference we need plants treated only with the herbicide and also completely untreated controls. The results are shown below.

Example 3: Test with antidote and herbicide with rice

sown in water. Application of the antidote during the swelling of rice seeds * Seed of

rice of the variety? S 6 are soaked for 48 hours

with delti2-phenyl-4,6-dichloro-pyrimidine solutions used as antidote in concentrations of 100 and 1000

ppm. Subsequently the seeds are left to dry for 2 hours until they are no longer? sticky. Plastic containers (length 25cm, width 17

cm and height 12 cm) are filled up to 2 cm per

below the rim with sandy clay. The previously swollen seeds are sown on the earth surface of the container and are covered with only a small amount. of land. The earth is kept in a moist (non-marshy) state. Then the herbicidal mixture is sprayed in dilute solution on the surface of the earth. The water level is subsequently increased corresponding to the growth. 21 days later, the relative protective action of the antidote is evaluated in percent. The plants treated only with the herbicide (no protective action) and also the completely untreated controls (growth 100%) serve as references. The results are collected in the following tables.

Examples of formulation

Example 4:

Examples of formulations for mixtures of synergistic active substances of formulas I and II (# = percent by weight)

The mixture of active substances is well mixed with the additives and is well ground in a suitable mill. You get powders by spraying that

they can be diluted with water obtaining suspensions having any desired concentration.

From these concentrates by dilution with

water, emulsions having any desired concentration can be prepared,

Ready-to-apply powder products are obtained by mixing the mixture of active substances

with the carrier substance and grinding on a suitable one

mill.

The mixture of active substances is mixed with additives, ground and moistened

with water. This mixture is extruded / subsequently dried in a stream of air.

The finely ground active substance mixture is applied evenly in a mixer on the kaolin moistened with polyethylene glycol.

In this way, powder-free coating granules are obtained.

Claims (10)

1. Product that acts synergistically to selectively combat weed plants in transplanted rice or sown in water, characterized by the phtto of containing in addition to inert additives, as an active substance, a mixture consisting of the herbicide 2-chloro-2,6-diethyl -N- (2 "-propyloxyethyl) acetanilide of formula I (I) by the herbicide S-4-chlorobenzyl-N, N-diethyl-thiocarbamate or S-4-benzyl-N,? - diethyl-thiocarbamate of formula II (II) wherein R represents chlorine or hydrogen and optionally by the antidote 2-phenyl-4,6-dichloropyrimidine of formula III (III) 2. Product according to claim 1, characterized in that it contains in addition to inert additives, as active substance, a mixture of the herbicides of formula I and II. 3 * Product according to claim 1, characterized in that it contains, as an active substance, in addition to inert additives, a mixture consisting of the herbicides of formulas I and II and also of the antidote of formula III. 4 Product according to claims 1 - 3, characterized in that the quantitative ratio between herbicide (1) and herbicide (II)? between 1: 1 and 1:25. 5. Product according to claims 1? 4, characterized in that the quantitative ratio between herbicide (I) and herbicide (II)? between 1: 4 and 1:10? 6. Product according to claims 3-5, characterized by the fact that it contains, in addition to the mixture of herbicides, the antidote of formula III in quantity? between 0.1 and 50%, 7. Procedure to selectively combat weed plants in rice crops transplanted or sown in water, characterized by the fact that the crops in the pre-emergence or post-emergence phase are treated with a quantity? active ingredient of a product according to one of claims 1 to 6. 8. Process according to claim 7, characterized in that the rice, its cultivation surface or its seeds are treated with a quantity of active ingredient of a product according to one of claims 1 to 6. 9. Rice seeds that have been treated with a quantity? active ingredient of a product according to claims 1 - 6. 10. Process for the preparation of a synergistic product according to claim 1, characterized in that the herbicides of formulas I and II and optionally the antidote of formula III are mixed and thoroughly ground together.