Grass seed head suppression process

Composition and method for preventing the formation of cobs in grass

This invention relates to a synergistic composition useful for reducing the formation of cobs in grass, which gives a surprisingly advantageous result at low levels of use, and to a method for preventing the formation of cobs by means of this composition.

Several compounds have been reported to be effective in inhibiting grass growth. Some of them are in fact commercially available for this purpose. However, a recurring difficulty with these compounds is that they are often so effective that the range of application between the amount of application that produces the desired effect and the amount at which the grass suffers from unpleasant discoloration or even destruction is often small. This means that there is a significant potential for destruction as a result of excessive or misuse.

Despite these difficulties, the use of compounds to impair grass growth has expanded on road sides and similar uses in large areas, as well as in pasture renewal.

This impairment may be a real reduction in the amount of vegetation growth and / or a reduction in the formation of grass spikes. This invention is particularly directed to a method of preventing the formation of cobs in grass by applying to it a synergistic mixture of two compounds which is particularly useful in small dosage amounts.

The composition of the invention contains A. 50-83% by weight of acetanilide of formula

<img file="FI75722B_D0001.tif" />

. 1 2 wherein R · * · and R independently represent a C 1 -C 4 alkyl group or a C 1 -C 4 alkoxy group, R³ on Cj_LA -C 3 alkyl group and X is chlorine or bromine; and

B. 50-17% by weight of a triazole of formula

<img file="FI75722B_D0002.tif" />

R wherein R is hydrogen or methyl and X is chlorine or bromine, and all percentages are based on the combined weight of components A and B.

The invention further relates to a method of preventing the formation of cobs by applying to the herbs an effective amount of the composition of components A and B as defined above during a period beginning when the green growth of the herbs is at least 50% and ending about 6 weeks thereafter, but not later than started.

In a preferred method of preventing the formation of cobs, a composition is used in which R and R in the formulas of components A and B are both ethyl and R³ is a methyl group. The preferred substituent is chlorine in both components A and B of the mixture.

Green growth is the transition from dormancy (winter phase) to active growth. Green growth is

7572 % when this step has occurred in about half.

With respect to component B of the mixture, each of the groups R is preferably methyl.

The weight ratios of components A and B are preferably between 5: 1 and 1: 1, and most preferably this ratio is about 2: 1.

The effective application rate may vary depending on the current and future growing conditions of the grass and pasture.

However, it has been found that the synergistic effect decreases with increasing application rate. Thus, when more than about 1.4 kg / ha of component A is used, the synergistic effect is not significant and if the amount of component A is less than about 0.84 kg / ha, its effect alone or with component B is not sufficient. Thus, in the preferred method, up to about 1.12 kg / ha of component A is used together with 0.224-0.672 kg / ha of component B. In general, an application rate of less than about 2.24 kg / ha of the combined weight of components A and B is preferred in the case of cool season grasses. However, for warm season grasses, higher application rates may be appropriate, perhaps as high as 3.36 or even 4.48 kg / ha.

The mixture can be applied to the grass for a period of 4-45 days before the formation of cobs can be expected without treatment. This usually occurs about 30 days after 100% green growth, and application 5-20 days before the formation of the cotyledons is particularly preferred.

The preparation of ingredient A is disclosed, for example, in U.S. Patent 3,829,306 and the preparation of ingredient B in U.S. Patent 4,205,075. Both ingredients are known to have a plant growth regulating effect independently. However, the finding that together they may have an unexpectedly beneficial cob growth-reducing effect on grasses was very surprising, especially considering that component B alone actually appears to improve cob formation.

The unexpected nature of this synergistic effect can be clearly seen by looking at the following examples, which are given for illustrative purposes only and are not intended to limit the scope of the invention.

Example 1

The Laiho tested in this example was a large area of ​​Merion Kentucky grass. Compounds and

Et

<img file="FI75722B_D0003.tif" />

CO.CHnCl Z ²

N \

ingredient A ch₂.nh.co.ch₃

N - N - CH.CH

<img file="FI75722B_D0004.tif" />

The C1 component B mixture was applied in the indicated dosage amounts to different parts of the range. Separate ingredients were also applied separately for comparison.

Different parts of the area were treated with different amounts and there was an untreated reference area for each part.

The compounds were applied as an aqueous suspension using a portable CC&gt; 2 sprayer equipped with two 11010 nozzles in a domed boom. When the mixture was applied, the ingredients were dosed sequentially on top of each other.

The application was performed on April 25 and the study was conducted 77 days later as follows.

A square frame measuring 30 cm x 30 cm was placed in each similarly treated area. The frame was also placed in six separate control areas, with the dosing amounts shown at each end of each of the three groups (repeats). The grass in each frame was carefully cut to a length of 7.62 cm and the cut grass was set aside. The number of cones and the weight of cut grass in each frame were determined and averaged from three similarly treated plots and six control plots. The results are shown in Table 1.

table 1

Ver- Ingredient A Ingredient B Link tail (acetanilide) (triazole) (A + B)

Application rate 0 kg / ha 1.12 kg / ha Cob heads 94 49

Plant growth weight (g / 0.0929 m²) 44,9 25,4

Application rate 0 kg / ha 1.68 kg / ha Cobs 76 4

Plant growth weight (g / 0.0929 m²) 48,4 18,7

Application rate 0 kg / ha 2.8 kg / ha Cob heads 68 0

0.56 kg / ha 1.12 + 0.56 kg / ha 138 21

32,6 19,0

0.84 kg / ha 1.68 + 0.84 kg / ha

4

15,9 12,8

1.68 kg / ha 2.8 + 1.68 kg / ha

1

From the above, it can be clearly seen that component B actually increases the number of cobs at all dose levels, while component A effectively reduces their number. However, at low dose levels, the addition of a small amount of component B to component A causes a 57% reduction in the number of cobs. This is completely unexpected compared to the separate effect of ingredient B at this level of application. It should be noted that this effect can only be observed at doses at which component A is not fully effective and that component B thus acts as an unexpectedly effective addition for component A.

Example 2

In this example, the procedures set forth in Example 1 are repeated unless otherwise noted. Kentucky grass was treated on April 25, and the density of cobs was determined 52 days after treatment.

The density of the cobs for each square was determined visually on a scale of 1-9. The lowest reading means that no cobs were observed and a value of 9 corresponds to complete cob development. Also in this case, the reading was determined as the average of the three treated areas and the six untreated control areas. The results are shown in Table 2.

Table 2

<td rowspan="2">Comparison</td><td colspan="2">Ingredient A</td><td colspan="2">Ingredient B</td><td colspan="2">A and B</td>

<td>kg / ha</td><td>density</td><td>kg / ha</td><td>density</td><td>kg / ha</td><td>tihey</td>

<td> 9,0</td><td> 1,12</td><td> 5,0</td><td> 0,56</td><td> 9,0</td><td> 1, 12 + 0,56</td><td> 2,7</td>

<td> 9,0</td><td> 1,68</td><td> 2,0</td><td> 0,84</td><td> 9,0</td><td> 1,68+0,75</td><td> 2,0</td>

<td> 9,0</td><td> 2,8</td><td> 1,3</td><td> 1,68</td><td> 8,7</td><td> 2,8+1,68</td><td> 1,0</td>

In addition, a visual assessment of vegetation was performed. Again, a scale of 1-9 was used, with 1 denoting an initial mowing height of 7.62 cm and 9 denoting a value approximately 20.32 cm above the original mowing height. Thus, the integer increments represent an increase of 2.54 centimeters.

There were no disturbances in the growth areas during the evaluations. All plants were vertical and no necrosis was observed. Each value entered is the average of three replicates of the treated area and the average of six replicates. Details are shown in Table 3.

Il

Table 3

<td>Comparison</td><td colspan="2">Ingredient A</td><td colspan="2">Ingredient B</td><td></td><td>A + B</td>

<td>grass</td><td></td><td>grass</td><td></td><td>grass</td><td></td><td>grass</td>

<td>growth</td><td>kg / ha</td><td>growth</td><td>kg / ha</td><td>growth</td><td>kg / h</td><td>, a growth</td>

<td> 9,0</td><td> 1,12</td><td> 7,0</td><td> 0,56</td><td> 8,0 1</td><td> ,12 +</td><td> 0,56 4,0</td>

<td> 9,0</td><td> 1,68</td><td> 5,7</td><td> 0,84</td><td> 6,0 1</td><td> ,68 +</td><td> 0,84 2,3</td>

<td> 9,0</td><td> 2,8</td><td> 5,3</td><td> 1,68</td><td> 6,7</td><td> 2,8 +</td><td> 2,68 3,3</td>

Again, it can be seen that the benefits of the mixture only become apparent at doses at which component A is not fully effective. In this example, however, the synergistic effect is also clearly evident in the increase in vegetation.

The compositions used in the process of this invention include concentrates which require dilution prior to use and which contain ingredients A and B and an additive in liquid or solid form. The compositions are prepared by mixing the ingredients with additives, including diluents, extenders, carriers, and treating agents, to form the compositions as finely divided solids, granules, pellets, solutions, dispersions, or emulsions. They may thus be used with additives such as a finely divided solid, a liquid of organic origin, water, a wetting agent, a dispersing agent, an emulsifying agent or a suitable combination thereof.

The compositions used in the process of this invention may also be in the form of liquids and wettable powders. These preferably contain, as a treating agent, one or more surfactants in an amount sufficient to cause the administered composition to be readily dispersed in water or oil. The addition of a surfactant to the compositions greatly improves their effectiveness. The term surfactant is understood to include wetting agents, dispersing agents, suspending agents and emulsifying agents. Anionic, cationic and non-ionic substances can be used as well.

Preferred wetting agents include alkylbenzenes and alkylnaphthalene sulfonates, sulfonated fatty alcohols, amines and acid amides, long chain acid esters of sodium thionate, esters of sodium sulfosuccinate, sulfated or sulfonated fatty acid esters, sulfated or sulfonated fatty acid esters, rock oil sulfonates, sulfonic oil sulfonates polyoxyethylene derivatives of alkylphenols (especially isooctylphenol and nonylphenol) and polyoxyethylene derivatives of higher mono-fatty acid esters of hexitol anhydrides (e.g. sorbitan). Preferred dispersants include methylcellulose, polyvinyl alcohol, sodium lignin sulfonates, polymeric alkyl, naphthalene sulfonates, sodium naphthalene sulfonate and polymethylene bisnaphthalene sulfonate.

Wettable powders are water-dispersible compositions containing one or more active ingredients, an inert solid extender, and one or more wetting and dispersing agents. Inert solid extenders are usually of mineral origin such as natural clays, diatomaceous earth and synthetic minerals derived from silicon and the like. Examples of these extenders include kaolinites, attapulgite clay and synthetic magnesium silicate. The wettable powder compositions of this invention usually contain from about 0.5 to 60 parts (preferably from 5 to 20 parts) of active ingredient, from about 0.25 to 25 parts (preferably from 1 to 15 parts) of wetting agent, from about 0.25 to 25 parts (preferably 1 to , 0-15 parts) of a dispersant and about 5-95 parts (preferably 5-50 parts) of an inert solid extender, all parts being by weight based on the total weight of the composition. If desired, about 0.2 to 2.00 parts of the solid inert extender may be replaced by a corrosion inhibitor or an antifoam agent, or both.

Other preparations include concentrates containing from 0.1 to 60% by weight of active ingredient with a suitable excipient; these dusts can be diluted for application to concentrations in the range of about 0.1 to 10% by weight.

Aqueous suspensions or emulsions can be prepared by mixing an aqueous mixture of the water-insoluble active ingredient and an emulsifying agent until a uniform mixture is obtained and then homogenizing to obtain a stable emulsion of very fine particles. The resulting concentrated aqueous suspension is characterized by its very small particle size so that when diluted and sprayed, the coverage is very even. Suitable concentrates for these preparations contain from about 0.1 to 60%, preferably from 5 to 50% by weight of active ingredient, the upper limit being determined by the solubility of the active ingredient in the solvent.

In another form of aqueous suspension, the water-immiscible component is encapsulated to form a microencapsulated phase dispersed in the aqueous phase. In one embodiment, small capsules are formed by combining an aqueous phase containing a lignin sulfonate emulsifier and a water-immiscible chemical and polymethylene polyphenyl 20 isocyanate, dispersing the water-immiscible phase in the aqueous phase, followed by the addition of a polyfunctional amine. The isocyanate and amine compounds react with each other to form a solid urea shell wall around the water-immiscible chemical particles, forming their microcapsules. In general, the concentration of microencapsulated material is in the range of about 480-700 g / l of the total composition, preferably in the range of 480-600 g / l. The microencapsulation method disclosed herein is described in more detail in U.S. Patent No. 4,280,833.

Concentrates are usually solutions of the active ingredient in water-immiscible or partially water-immiscible solvents with a surfactant. Suitable solvents for the active ingredients of this invention include dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, hydrocarbons, water-immiscible ethers, esters or ketones. However, other strong, liquid concentrates can be prepared by dissolving the active ingredient in a solvent and then diluting, for example with fuel oil, to an injection concentration.

The concentrate compositions disclosed herein generally contain from about 0.1 to 95 parts (preferably from 5 to 60 parts) of active ingredient, from about 0.25 to 50 parts (preferably from 1 to 25 parts) of surfactant, and optionally from about 4 to 95 parts of solvent, all parts are parts by weight based on the total weight of the oil to be emulsified.

Granules are physically stable, finely divided compositions formed from active ingredients attached or distributed to a matrix of an inert, finely divided extender. To aid in the extraction of the active ingredient from the granules, a surfactant such as that described above may be included in the composition. Natural clays, pyrophyllites, illite, gypsum, and vermiculite are examples of useful classes of finely divided mineral extenders. Preferred extenders are porous, absorbent, preformed particles such as preformed and screened fine particle attapulgite or thermally expanded fine vermiculite and fine clays such as kaolin clays, hydrogenated attapulgite or bentonite clays. These extenders are sprayed on or mixed with the active ingredient to form herbicidal granules.

The granular compositions useful in this invention may contain from about 0.1 to 30 parts, preferably from about 0.5 to 10 parts by weight of active ingredient per 100 parts by weight of clay and from 0 to 5 parts by weight of surfactant per 100 parts by weight of finely divided clay.

Other ingredients may also be added to Ingredients A and B, for example, fertilizers, other herbicides, other pesticides, preservatives and the like used as additives or in combination with the above substances. Chemicals that can be used in conjunction with the active ingredient of this invention include, for example, triazines, ureas, carbamates, acetamides, acetanilides, uracils, acetic acid or phenolic derivatives, thiol carbamates, triazoles, benzoic acids, nitriles, biphenyl ethers, and the like.

Fertilizers that can be used with the active ingredients include, for example, ammonium nitrate, urea, Potassium, superphosphate. Other useful additives include materials in which plant organisms are rooted and growing, such as compost, livestock manure, humus, sand, and the like.