CS211151B1 - Selective herbicidal agent - Google Patents

Abstract

The invention relates to a selective herbicidal composition containing a mixture of biscarbamates of the general formula I, where X is hydrogen, alkyl or alkoxyl each with one to four carbon atoms, halogen, especially chlorine, trifluoromethyl, and R is alkyl with one to four carbon atoms, and further benzoates of 3-propionylaminophenol of the general formula II, where Y is hydrogen, halogen, nitro, alkyl with one to four carbon atoms in the chain. Mixtures of biscarbamates I and benzoates II can be in a weight ratio of 5:1 to 1:5. In all cases of the mixtures mentioned, a synergistic effect was confirmed. The mixtures are not phytotoxic, especially to beet, while they extend the spectrum of herbicidal action to other weeds on which biscarbamates I are not very effective.

Description

The invention relates to a selective herbicidal composition comprising a mixture of biscarbamates and benzoates of 3-propionylaminophenol.

Currently, a group of herbicides, the so-called biscarbamates of the formula I below, are used to treat beet and other crops. These substances are applied to emerging weeds in the initial stage of their development. The disadvantage of these substances is that in case of overdose or also due to the influence of deteriorated weather conditions, the crop plant, especially beet, is also damaged. This adverse effect, which results in a lower crop yield, is not completely eliminated during the growing season.

It has now been found that the addition of 3-propionylaminophenol benzoates of the formula II below completely eliminates the phytotoxic effect on beets and other cultivated plants, while the effect on weeds remains preserved and is extended over a longer vegetation period.

The subject of the invention is a selective herbicidal composition for controlling weeds in beet stands and in other crops, which is characterized in that it contains a mixture of biscarbamates of the general formula I,

NH-COO-R where X is hydrogen, alkyl or alkoxyl each with one to four carbon atoms in the chain, halogen, especially chlorine, trifluoromethyl group, and R is alkyl with a linear or branched chain, containing one to four carbon atoms, and further benzoates of 3-propionylaminophenol of the general formula II ?' ^C0_ W (II)

NH-CO-C ₂ H ₅ where Y is hydrogen, alkyl with one to four carbons in the chain, halogen or nitro group, whereby the mutual weight ratio of the biscarbamate of general formula I to the benzoates of general formula II in the mixture is 5:1 to 1:5

The active ingredients according to the invention can be prepared into an applicable form using organic solvents, miscible or immiscible with water, such as alcohols, ketones, esters, aromatic or aliphatic hydrocarbons and their halogenated derivatives, dimethylformamide, dimethyl sulfoxide, etc. As solid carriers of the above active mixtures, natural and artificial clays can be used, such as, for example, kaolin, chalk, dolomite, active alumina or silica. In all cases of mixtures, it is also necessary to use other auxiliary substances, stabilizing the aqueous dispersions of the active ingredients. These are surfactants of the ionic or nonionic type, dispersants, such as lignin or cellulose derivatives, or substances stabilizing the pH of aqueous solutions and dispersions. The active ingredients according to the invention can be used either in concentrated form or in the form of very dilute aqueous solutions and dispersions.

Example,

The following biscarbamates were used to verify the combined effect of the mixture of active substances (see formula I):

A ethyl 3-(phenylcarbamoyloxy)phenylcarbamate (X = R = -C^)

B methyl 1-Cl^-methylphenylcarbamoyloxyJphenylcarbamate (X = 3-CH^O-, R = -CH^)

C isopropyl 3-(3’-methoxyphenylcarbamoyloxy)phenylcarbamate (X = 3-CH3O-, R = -CH3CH^Íj)

D isobutyl 3-(4-chlorophenylcarbamoyloxyphenylcarbamate (X = 4-C1-, R = -CHgCHCCH-j) ₂ 1

Ethyl 3-(3'-trifluoromethylphenylcarbamoyloxy)phenylcarbamate (X = 3-CF,-, R = -C-Hj

2 5

211151 2 and substituted benzoates of 3-propionylaminophenol (see formula II):

a unsubstituted benzoate (Y = H) b 3-chlorobenzoate (Y = 3-C1) c 4-methylbenzoate (Y = 4-CH3) d 3-nitrobenzoate (Y = 3-NO2) a 4-tert.butylbenzoate (Y = 4-(CH^J^G)

White mustard (Sinepia alba L.) and sugar beet (Beta vulgaris-sacc. varr. Dobrovická A) were sown in six vegetation pots. After the development of two pairs of true leaves, the surface of the plants was sprayed with an aqueous dispersion of the tested substances and their mixtures, prepared from a 10% solution of the tested compounds in isophorone in the presence of 20% emulsifiers. After the herbicidal effects were determined (10 to 14 days after application), the degree of damaged plants was determined by the gravimetric method. The percentage of herbicidal effect was calculated from the obtained data and the average weight of the treated and control plants. The effective dose (in kg.ha ^- ') that caused 50% plant death (ED^q) was calculated from the values found for the individual components of the mixture. The combined effect of the mixtures of substances was evaluated using formula (1).

# components M # components N of the mixture ⁼ EDjq of components Μ x 100 ⁺ ΕΪΙ^θ of components Ò x 100 (, j

If the relative efficiency Εϋ^θ calculated : ΕΒ^θ determined is greater than one, the joint effect of the mixture can be considered synergistic. For biscarbamate A and benzoate a, the EDjq values were determined on mustard, which are given in the following table. Beet plants were not damaged by the effect of the mixture of starting substances.

Table 1

Evaluation of a mixture of biscarbamate A and benzoates a”

Contents of the folders in # ED ₅₀ values (kg.ha") Relative efficiency x 100 A and established calculated 100 0 1.30 75 25 0.90 1.94 171 50 50 1.84 2.20 120 25 75 2.90 3.75 ,29 0 100 7.20 - -

The table shows that all mixtures have a significant synergistic effect, with the mixture containing 75% of component A and 25% of component A being more herbicidally active than both starting substances.

Example 2 to 5

Further mixtures of biscarbamates and benzoates were tested in a completely similar manner to that described in Example 1. The test results are given in Table II.

Table II

Evaluation of the combined effect of mixtures of biscarbamates and benzoates

Ingredient content in % biscarbamate benzoate ED values _5Q /kg.ha ^- ') Relative efficiency x 100 established calculated B b .00 0 1 .20 75 25 0.95 1.51 159 50 50 1.65 2.03 123 25 75 2.70 3.08 114 0 100 6.50 - - B c 100 0 1.20 - - 75 .25 1.35 1.52 113 50 50 1 .86 2.07 111 25 75 2.85 3.25 114 0 .00 7.50 - - c e .00 0 1.80 - - 75 25 1.60 2.20 137 50 50 2.30 2.84 123 25 75 3.40 4.02 118 0 100 6.80 - - E d .00 0 1 .60 - - 75 25 1 .95 2.01 103 50 50 2.40 2.71 113 25 75 4.80 5.43 113 0 100 9.00 - -

The results show that mixtures of biscarbates and benzoates have a synergistic effect in all cases.

Small-plot experiments were carried out in a sugar beet stand (Dobrovická A). The site had medium-heavy soil and the preceding crop was winter wheat. The aqueous dispersion of active ingredients was applied to the beet at the stage of the second pair of true leaves and the other weeds were at the stage of two or three pairs of true leaves. Spraying was carried out with a backpack hand sprayer at an operating pressure of 0.2 MPa. The following weed species were mainly represented at the site: white sedge (Chenopodium album L.), red radish (Raphanus raphanistrum L.), marsh sedge (Staohys palustris L.), bird's-foot trefoil (Stellaria media VILL.), shepherd's-foot trefoil (Capsella bursa-pastoris L.), annual pheasant (Mercuriaris annua L.), bent amaranth (Amaranthus retroflexus L.), field speedwell (Veronice arvensis L.), tricolor violet (Viola tricolor L.), bird's-foot trefoil (Polygonum aviculare L.), common ragwort (Lamium amplexicaule L.), white knotweed (Melandrium album), field sedge (Anagallis arvensis L.), hairy vetch (Vioia hirsuta L.), black nightshade (Solanum nigrum L.), common dodder (Datura stramonicum L.) and others.

A mixture of biscarbamate A and benzoates b in a weight ratio of 2:1 in the form of a 15% isophorone solution containing 20% emulsifiers at a dose corresponding to 6 to 8 liters of concentrate per hectare was used for spraying. The concentrate was diluted with water to a total volume of 300 l. The comparison substance was the herbicide Betanal (16.5% solution of methyl 3(3’-methylphenylcarbamoyloxy)phenylcarbamate in isophorone) at a dose of 6 to 8 l of concentrate per hectare.

The herbicidal effect was evaluated 2 weeks and then 4 weeks after spraying according to the EWBC rating scale. Compared to Betanal, the herbicide mixture has the same effects on the following weeds: merle, fire radish, shepherd's purse, cowslip, and cowslip. A stronger effect was seen in violet, pheasant, eggplant, but also in vetch. A weaker effect was seen in bird's-foot trefoil. In all cases, beet phytotoxicity was not evident. Betanal already at a dose of 6 1-ha ^- ' causes yellowing of the edges of beet leaves, which disappears within 3 to 4 weeks after herbicide application.

The advantages of the herbicidal mixture according to the invention lie in the fact that the spectrum of herbicidal action is extended to other weeds, while the applied mixture does not have a phytotoxic effect on the cultivated plant, especially on beet. The active substances in the mixture and their decomposition products do not leave residues in the soil.

Claims (1)

SUBJECT OF THE INVENTION A selective herbicidal agent for controlling weeds in beet and other crops, characterized in that it contains, as an active ingredient, a mixture of biscarbamates of the formula I, O-CO-IMH NH-COO-R wherein X is hydrogen of alkyl or alkoxy of one to four carbon atoms, halogen, especially chloro, trifluoromethyl, and R is linear or branched alkyl of one to four carbon atoms, and 3-propionylaminophenol benzoates of formula II, O-CO-Q Wherein Y is hydrogen, halogen, especially chlorine or bromine, nitro, alkyl of one to four carbons in the chain, the ratio of biscarbamates to benzoates being 1: 5 to 5: 1;