FR2488490A1 - Control of growth of mono- and di-cotyledonous weeds - by post=emergence application of asulam with low doses of paraquat - Google Patents

Abstract

Control of the growth of mono- and di-cotyledonous weeds is achieved by post-emergence appln. of asulam (I) or its salts together with paraquat (II). The appln. rates are 1.5-3 kg (I) equiv. per sprayed ha and 50-150 g (II) equiv. per sprayed ha. The ratio of (I) equiv. to (II) equiv. is 10:1-30:1 by wt. At the appln. rates used excellent and persistent control of the growth of weeds is achieved, without the antagonistic effect observed with higher dose levels of (II). Reduced amts. of herbicide are required for satisfactory control of weed growth; frequency of appln. of the herbicide for weed control is reduced; and the spectrum of weeds controlled at a given appln. rate is increased.

Description

 The present invention relates to a novel method of controlling weed growth as well as herbicidal compositions for use in this method.

 Herbicide-active products have already been described in British Patents 1,040,541 and 1,052,881.

connu sous le nom de "Asulam" ainsi que ses sels acceptables en agriculture tels que les sels alcalins, alcalinoterreux et sels d'amine ou d'ammonium. Comme sels alcalins on connait notamment les sels de sodium et de potassium.These products are the product of formula (I)

known as "Asulam" and its agriculturally acceptable salts such as alkaline, alkaline earth, and amine or ammonium salts. As alkaline salts are known in particular sodium and potassium salts.

As amine salts, the salts of diethanolamine, triethanolamine, octylamine, morpholine and dioctylethylamine are known in particular. As alkaline earth salts are known in particular calcium and magnesium salts.

 Asulam is a very active product against monocotyledonous and dicotyledonous weeds. It is of real commercial importance because of its low toxicity to mammals, birds, fish and wildlife in general. Moreover, its persistence in the soil is low.

Asulam and Asulox (the commercial formulation of Asulam sodium salt) have been used to date to control the growth of a large number of annual grass weeds as well as some perennial broadleaf weeds.
Under. In tropical or subtropical climates, Asulam and its agriculturally acceptable salts can be used at doses of 3 to 4 kg / ha (dose counted in asulam equivalent per hectare). It can be applied post-emergence to control the growth of grasses and broadleaf broadleaf weeds in crops, either in general application (sugar cane and date palm in particular), or in directed application (banana). Asulam and its agriculturally acceptable salts move in the weeds to which they are applied, exerting systemic herbicidal activity and lasting control of weed growth. not
Asulam and its agriculturally acceptable salts inhibit cell division in weeds and prevent subsequent growth of the meristem.

After a period of, for example, 2 to 6 weeks, the weeds become chlorotic and wilt gradually. The visual manifestation of weed growth control is the onset of chlorosis. This manifestation may not become apparent until several weeks after the application of asulam and its agriculturally acceptable salts on weeds. However, at the application rates mentioned above, it is not possible to control persistently and satisfactorily several dicotyledonous annual weeds, in particular Achyranthes indica.

It is also known that paraquat (i.e. 4,4'-dimethyl-4,4'-bipyridylidyl) ion in the form of dichloride or other agriculturally acceptable salt may be used as a postemergence application to control the growth of a wide range of weeds in vineyards, orchards and other crops. This application can be carried out by directed spraying or general spraying of weed-infested areas, which are not areas where the crop is growing. In these applications, application rates of 400 to 600 g are available. Paraquat equivalent / hectare treated are generally suitable. It is to be understood that, unless otherwise indicated, the improper term "paraquat" as used hereinafter in this specification refers to agriculturally acceptable salts of dimethyl-1 ion, 4,4-bipyridyl-diethylium. . By the term "post-emergence application" is meant the application to exposed and aerial parts of weeds that have emerged on the soil surface. By the term "asulam and its agriculturally acceptable salts" is meant asulam or one or more of its agriculturally acceptable salts as indicated above. By the term "asulam equivalent" is meant the amount of methylamino-4-benzenesulfonylcarbamate or the product content of formula (I) of the Asulam salt in question. By the term "paraquat equivalent" is meant the content of 4,4'-dimethyl-4,4'-bipyridylidylium-4,4'-dimethyl-dipyridyl-4,4'-diisocyanate salt. "treated hectare" means the area of land in hectares on which asulam and its agriculturally acceptable salts are applied in association with paraquat
Application of paraquat to plants results in rapid necrosis and destruction of the plant tissue to which it is applied. The result is a control of plant growth but not necessarily a total destruction of the plant because the very rapid onset of necrosis limits the spread of paraquat through the plant. For example, under tropical or subtropical conditions, regeneration of plants that have been treated with paraquat reverses weed control in a relatively short time and requires repeated applications of paraquat to achieve effective control of growth. long-lived plants, especially vigorous weeds, perennial monocotyledonous weeds and broadleaf weeds.

 It has been desired to apply together asulam and its agriculturally acceptable salts (at a dose of 3 to 4 kg of asulam equivalent per hectare) with paraquat (at a dose of 250 to 600 g of paraquat equivalent per hectare). . The goal of this association was to combine the rapid control of weed growth with the post-emergence application of paraquat with the persistent weed control of the post-emergence application of asulam and its effects. salts. But this association has not made it possible to improve the control of weed growth as seen with paraquat alone (at the doses indicated above) or with asulam (or its salts) alone ( at the indicated doses).

This failure is believed to be due to the fact that the rapid necrosis of the plant tissue due to paraquat prevents the effective absorption and migration into the plant tissue of asulam and its agriculturally acceptable salts.

 It has now been found that this antagonistic effect from the combination of asulam and paraquat can be overcome at the indicated doses and that weed control (and other undesirable plants) can be improved. by applying asulam or its agriculturally acceptable salts and paraquat in combination at relatively low doses and / or lower than those normally used.

 The improvement obtained according to the invention in the control of weeds by the application of asulam or of agriculturally acceptable salts in association with paraquat must be considered in terms of power, that is to say of reduction of the quantity of herbicide required to achieve satisfactory control of weed growth and reduced frequency of herbicide application and weed control at a given herbicide rate.

 The excellent and persistent control of weed-free weed growth, produced by the combined application of asulam and its agriculturally acceptable salts and paraquat at the application rates described above, is performed by application from 1.5 to 3.0 kg of asulam equivalent / hectare treated in combination with 50 to 200 g of paraquat equivalent / hectare treated in a weight ratio of asulam equivalent and paraquat equivalent of 10: 1 to 3u: 1, especially 15: 1 to 25: 1 and more especially 2 (J 1.

More particularly, the present invention provides a method such as that just described, which can be applied especially to areas infested with monocotyledonous weeds and dicotyledonous weeds (unwanted vegetation), for example Commelina elegans, Borreria verticilliata,
Borreria latifolia, Sida acuta, Amaranthus dubius,
Pteridium aquilinum, Peperomia sp., Ipomea spp., Momordica charantia, Euphorbia hypericifolia, Xanthium spp.
Achyranthes indica, Caladium spp., Tridax spp., Digitaria ciliaris, Digitaria sanguinalis, Paspalum fasciculatum,
Setaria barbata, Panicum muticum, Panicum fasciculatum,
Panicum maximum, Panicum trichoides, Eleusine indica, and Sorghume halepense.Application of the herbicidal compositions according to the invention can be directed: it is directed spraying, to control the growth of weeds in the vineyards, orchards and trees. crops, sugar cane, coffee, date palm or banana trees and in general there ol application to the crop is not desirable.

The application of the herbicidal compositions according to the invention may also be a non-directed application (a non-directed spray), in an uncultivable and weed infested place, where a total hereditary effect is desirable. Banana plants are a preferred culture for carrying out the method according to the present invention with application or directed spraying, avoiding the application to the banana trees themselves.

Non-crop weed-infested sites, where weed control is desirable, include airports, industrial sites, railways, roadsides, river banks, irrigation canals and other waterways, scrublands, fallows and wild lands, especially where it is useful to control weed growth to reduce the risk of fire.

 According to a particular feature of the present invention, it relates to a method for the control of weeds which is particularly effective when the weeds to be controlled grow in shady areas by trees (example banana) this process comprises the application of asulam or an agriculturally acceptable salt thereof in combination with paraquat at doses of 1.75 and 2.25 kg asulam equivalent per hectare treated and 87.5 g and 112.5 g paraquat equivalent per hectare treated, the equivalent ratio of asulam and paraquat equivalent by weight is 20: 1. In another aspect, the present invention provides a method for weed control that is particularly effective when the control weeds do not grow in shady locations. This method includes the application of asulam or one of its agriculturally acceptable salts with paraquat at doses of 2.25 to 3.0 kg of asulam equivalent per hectare treated and from 112.5 to 150 g of paraquat equivalent per hectare treated, the ratio of asulam equivalent or- parquat equivalent per weight being 20: 1.

 In the process according to the invention & weed growth control, asulam and its agriculturally acceptable salts can be applied with paraquat separately or substantially simultaneously or, if preferred, formulations containing both asulam or its agriculturally acceptable salts and paraquat. Such formulations may, for example, be obtained by mixing concentrated formulations containing asulam and / or agriculturally acceptable salts thereof and concentrated formulations containing paraquat; this mixture may be carried out extemporaneously or by mixing concentrated formulations containing both asulam and / or its agriculturally acceptable salts and paraquat before spraying, and, if necessary, by diluting with appropriate diluents (eg example of water or organic solvents) to provide formulations suitable for application.

 By applying the herbicidal method according to the present invention, combinations of asulam or its agriculturally acceptable salts and paraquat are normally applied as spraying fluids, and such spraying fluids may, if desired, contain 0.1% to about 1% (w / v) of surfactant.Surfactants suitable for the present invention may be of ionic or nonionic type, for example sulforicinoleates, quaternary ammonium derivatives, polycondensates of ethylene oxide with nonyl or octyl phenols, carboxylic acid esters and anhydrosorbitols which have been rendered soluble by etherification of free hydroxy groups by condensation with ethylene oxide, metal salts alkali and alkaline earth esters of sulfuric acid and sulfonic acids such as dinonyl and dioctyl sodium sulfosuccinates and salts of alkali metals and alkaline earth metals of high molecular weight sulfonic acid derivatives of sodium and calcium lignosulfonates.

 In another aspect, the present invention also relates to compositions suitable for herbicidal use according to the method described above.

These compositions include asulam or an agriculturally acceptable salt with paraquat, the ratio of asulam equivalent and paraquat equivalent being in the range of 10: 1 to 30: 1 in the composition, particularly 15: 1. at 25: 1 and more preferably 20: 1, by weight.

 These compositions optionally comprise and furthermore one or more diluents or supports compatible with the herbicidal active ingredients. In a preferred manner, the herbicidal active ingredients are dissolved in these diluents or supports. These diluents or carriers are compatible with asulam and / or one of its agriculturally acceptable salts as well as with paraquat; they are of a type generally known in the art as being suitable for use in the herbicidal compositions.

 These compos-itions according to the invention are such that, optionally after dilution with water or an organic solvent, they can be dispersed at doses of 1.5 to 3 kg equivalent of asulam per hectare treated and 50 to 150 g of paraquat per hectare treated.

The term herbicidal compositions is used in a broad sense to include both ready-to-use compositions and concentrates to be diluted before use. Preferably, the compositions according to the invention contain from 0.05 to 100% by weight of asulam or of an agriculturally acceptable salt and paraquat. The compositions according to the invention may, if desired, contain from 0.01 to about 10% surfactant. Compositions suitable for immediate application as non-dilute herbicides may, for example, contain from about 0.01% to 1% (w / v) of surfactant associated with spray fluids. The compositions according to the present invention. The invention, in the form of concentrates to be diluted with water or an organic solvent prior to use as herbicides, may, for example, contain from about 0.05% to about 10% surfactant. percentages being expressed either by weight / volume in the case of liquid concentrates or by weight / weight in the case of solid concentrates.

 The herbicidal compositions may contain both diluents or carriers and surfactants (i.e., wetting, dispersing, suspending or emulsifying agents). Suitable surfactants which may be present in the herbicidal compositions of the present invention may be those described above. Examples of suitable solid diluents or carriers are water-soluble alkali metal derivatives, especially sodium or potassium derivatives. Examples of such compounds which may be mentioned are chlorides, carbonates, bicarbonates and sulphates; Sodium chloride and urea can also be used. Solid compositions (which may be in the form of water-soluble powders or granules) are preferably prepared by mixing the active ingredients with solid diluents. The granular formulations may be prepared by granulation of compositions which may themselves be obtained according to the description above.

 The liquid compositions according to the invention may take the form of aqueous solutions or suspensions in a solvent which may contain surfactants. Suitable liquid diluents for incorporation into liquid compositions include water and aliphatic and aromatic hydrocarbons.

The surfactants which may be present in the liquid compositions also serve as diluents or carriers. Liquid compositions in the form of concentrates may be diluted with water or an organic solvent, for example kerosene, to provide ready-to-use compositions.

 Spray solutions for use in the process of the present invention may also be prepared extemporaneously by mixing in a container asulam or an agriculturally acceptable salt or asulam and a salt thereof. suitable sodium, potassium or magnesium, for example sodium or potassium carbonate, bicarbonate or magnesium carbonate, paraquat and, if desired, surfactants with water.

 The herbicidal compositions according to the present invention may also contain, if desired, conventional adjuvants which include adhesives, coloring agents and corrosion inhibitors. These adjuvants may also be used as carriers or diluents.

 In another aspect, the present invention provides an article of manufacture comprising a herbicidal composition and preferably a herbicidal concentrate which is to be diluted prior to use, in a container for said herbicidal compositions, said container including instructions which are physically associated therewith and which expose the manner in which the herbicide composition mentioned above (and that this container contains) should be used to control the growth of weeds. The receptacles will normally be of the type conventionally used for the storage of herbicidal chemical substances: these may be room temperature solids eg metal boxes and tanks, which can be lacquered inside, they can be made of plastic materials, glass bottles or plastic materials, and, when the contents of the container is a solid, it can be boxes, pa example of cardboard, plastic and metal materials, or bags. The containers will normally have sufficient capacity to treat at least 40 ares of soil using weed growth control agent but they will not exceed the convenient size for handling in conventional manner. Instructions will be physically associated with the container, being printed for example directly above or on a label or plate attached thereto. Indications will normally indicate that the contents of the container, after dilution if necessary, should be applied to control weed growth in the manner and for the purposes described above.

 The following non-limiting examples illustrate the herbicidal compositions according to the invention and the methods for controlling weed growth according to the present invention.

Example 1
An aqueous concentrate containing - Asulam (as sodium salt) at a rate of
35% (w / v asulam equivalent) - paraquat (as dichloride) at the rate of
1.75% (w / v paraquat equivalent) - 100% water is prepared by dissolving asulam salt and paraquat in a portion of water and adding, with agitation, the rest some water.

Thus, the aqueous concentrate obtained can be diluted with water and applied at a rate of 6 liters of formulation (corresponding to 2.1 kg of asulam equivalent and 105 g of paraquat equivalent) in 400 liters of spraying fluid. hectare treated. The treated surface is a cultivable region, planted with banana plants. The weed growth control composition described above is applied as a post-emergence spray to weed foliage, taking care to avoid contact with the weed. product sprayed with the foliage of crops,
Example 2
An aqueous concentrate containing - asulam (as sodium salt)
40% (weight / volume equivalent asulam) - paraquat (as dichloride) at the rate of
2% (weight / volume paraquat equivalent) - water: enough to obtain a volume
100% total is prepared in a manner similar to that written above in Example 1.

 Thus the aqueous concentrate obtained can be diluted with water and applied in a proportion of 5 liters of formulation (corresponding to 2, u kg of asulam equivalent and 100 g of paraquat equivalent) in 400 liters of spray fluid per hectare. treaty. The treated area is a cultivable area planted with banana trees. The composition for controlling weed growth described above is applied by post-emergence spray-on weed foliage, taking care to avoid contact of the composition with the crop foliage.

Example 3
A water-soluble powder or a granular formulation containing - asulam (as sodium salt) at the rate of
85.5% by weight asulam equivalent or 94.1% by weight
asulam sodium salt - paraquat (as dichloride) at the rate of
4.27% by weight of paraquat equivalent or 5.9% by weight
The weight of paraquat chloride is prepared by mixing the components, by appropriate mixing equipment, followed if necessary by careful mixing and, if desirable, by putting the resulting powder in the form of granules by known methods, by for example, compaction, extrusion or granulation.

 The water-soluble powder and the granular formulations thus obtained can be dissolved in water and applied at the rate of 3.0 kg of formulation (corresponding to 2.57 kg of asulam equivalent and 128 kg of paraquat equivalent) in 400 liters of spray fluid per hectare treated to a banana growing area. The weed growth control composition described above is applied post-emergence to weed foliage, taking care to avoid contact with the crop foliage.

Example 4
A water-soluble powder or a granular formulation containing - asulam (as sodium salt) at the rate of
50% by weight equivalent of asulam - paraquat (as dichloride) at the rate of
2.5% by weight paraquat equivalent - sodium chloride to make up to 100% is prepared by the method described above in Example 3.

 The water-soluble powder and the granular formulations thus obtained can be dissolved in water and applied at a dose of 6 kg of formulation (corresponding to 3 kg of asulam equivalent and 150 g of paraquat equivalent) in 400 liters of spray fluid per hectare treated at a sugarcane growing area. The weed growth control composition described above is applied post-emergence to weed foliage, taking care to avoid contact with the crop foliage.

Example 5
An organic suspension (formulation) containing - asulam (as sodium salt)
SU% by weight / volume of equivalent asulam - paraquat (as dichloride) at the rate of
2.5% w / v paraquat equivalent of ethylan 55 (ethylene oxide condensate and
nonylphenol containing 5.5 moles of ethylene oxide
per mole of nonylphenol) is z% by weight /
volume - Atlox 4856 B (Triglyceride surfactant mix
of polyoxyethylene and alkyl aryl sulphonates)
at a rate of 5% w / v - deodorized kerosene to make up to 10% by volume; is prepared by suspending the asulam salt and paraquat in a solution of Ethylan 55 and Atlox 4856 B in a portion of deodorized kerosene and then adding, with stirring, the remainder of the deodorized kerosene.

 The oil suspension formulation thus obtained can be diluted with water and applied at the rate of 4 liters of formulation (corresponding to 2 kg of asulam equivalent and 100 g of paraquat equivalent) in 4 liters of spray fluid. per hectare treated at a planted banana growing area. The composition for controlling weed growth described above is applied post-emergence to weed foliage, taking care to avoid contact with the crop foliage.

 The organic suspension formulation can also be diluted in deodorized kerosene and applied at a rate of 4 liters of formulation (corresponding to 2 kg of asulam equivalent and 10u g of paraquat equivalent) in 30 liters of spray fluid per hectare treated. to a growing area planted with banana trees.

The weed growth control composition described above is applied post-emergence to weed foliage, taking care to avoid treating crop foliage.

 The following experiment illustrates the process according to the present invention.

Experience
Plots of 0, u186 hectare are treated in a randomized block system in a banana plantation (Robusta variety) whose weeds include Commelina elegans, AIDS acuta, Eleusine indica,
Borreria verticilliata, Zorreria latiflora, Etaria barbata and Achyrantnes indica at growth stages of 15 to 30 cm. Treatments were carried out using a knapsack sprayer sprayed against weeds, taking care to avoid application to banana foliage. The treatments 1, 2 and 3 were prepared by diluting amounts of the aqueous concentrate prepared according to the indications of Example 1 corresponding to the volume of concentrate indicated per hectare treated with water. The application took place at a rate corresponding to 448 liters of spray fluid per hectare treated. Treatment 4 was prepared by diluting an amount of an aqueous paraquat concentrate of 20% (w / v as dichloride) corresponding to the volume of concentrate indicated per hectare treated with water and applied at a corresponding dose. to 448 liters of spray fluid per hectare treated.

Treatment 1. 5.6 liters of aqueous concentrate prepared as in Example 1 (1.96 kg asulam equivalent and 98 g paraquat equivalent) per hectare treated
Treatment 2. 7.0 liters of aqueous concentrate prepared as in Example 1 (2.45 kg asulam equivalent and 122.5 g paraquat equivalent per hectare treated.

Treatment 3. 8.4 liters of aqueous concentrate prepared as in Example 1 (3.0 kg of asulam equivalent and 150 g of paraquat equivalent) per hectare treated.

Treatment 4. 2.8 liters of aqueous concentrate containing 20% w / v of paraquat in the form of dichloride (560 g of paraquat equivalent) per hectare treated.

 Each treatment was repeated 3 times.

 The evaluation of weed control and treatment effect on banana was performed one week after treatment and every two weeks thereafter according to the scale of assessments shown in Table 1.

TABLE I: Evaluation scale of the European Council
weed research
(Rawle 1978)

Symptoms <SEP> Control <SEP> of
<tb> Scale <SEP> Evalutation
<tb> of <SEP> phytotoxicity <SEP> bad <SEP> herbs
<tb> evaluation <SEP> general
<tb> on <SEP> the <SEP> culture <SEP>%
<tb> 1 <SEP> Nothing <SEP> 100 <SEP> Excellent
<tb> 2 <SEP> Symptoms <SEP> Very <SEP> 98 <SEP> Very <SEP> Good
<tb> light
<tb> 3 <SEP> Symptoms <SEP> mild <SEP> 95 <SEP> Good
<tb> 4 <SEP> Strong <SEP> Symptoms <SEP> 90 <SEP> Satisfactory
<tb> 5 <SEP><SEP> Appearance of <SEP> 82 <SEP> Uncertain
<tb> damage
<tb> 6 <SEP> Damage <SEP> evident <SEP> 70 <SEP> No <SEP> Satisfactory
<tb> 7 <SEP> Damage <SEP> severe <SEP> 55 <SEP> Bad
<tb> 8 <SEP> Tr8s <SEP> severe <SEP> damage <SEP> 30 <SEP> Very <SEP> bad
<tb> 9 <SEP> Destruction <SEP> 0 <SEP> Absolutely
<tb> complete <SEP> useless
<Tb>
The following results were obtained
Results
Safe treatments for bananas
The results presented in Table II show that there was no phytotoxicity for banana plants.

Table II: Effect of treatments on bananas

<tb> TREATMENT <SEP> WEEKS <SEP> AFTER <SEP> TREATMENT
<tb><SEP> 1 <SEP> 3 <SEP> 5 <SEP> 7 <SEP> 9 <SEP> 11 <SEP> 13 <SEP> 15 <SEP> 17
<tb> Treatment <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1
<tb> Treatment <SEP> 2 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1
<tb> Treatment <SEP> 3 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1
<tb> Treatment <SEP> 4 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1 <SEP> 1
<Tb>
Global weed control
The overall weed control during the test period is given in Table III.

Table III: Effect of treatments on control
global weed

<tb><SEP> WEEKS <SEP> AFTER <SEP> TREATMENT
<tb> TREATMENT
<tb><SEP> 1 <SEP> 3 <SEP> 5 <SEP> 7 <SEP> 9 <SEP> 11 <SEP> 13 <SEP> 15 <SEP> 17
<tb> Treatment <SEP> 1 <SEP> 7.0 <SEP> 6.0 <SEP> 5.7 <SEP> 4.3 <SEP> 3.7 <SEP> 4.0 <SEP> 4.0 <SEP> 4.7 <SEP> 5.0
<tb> Treatment <SEP> 2 <SEP> 6.0 <SEP> 5.0 <SEP> 5.7 <SEP> 5.0 <SEP> 3.7 <SEP> 3.7 <SEP> 3.0 <SEP> 4.7 <SEP> 4.7
<tb> Treatment <SEP> 3 <SEP> 6.7 <SEP> 4.7 <SEP> 3.7 <SEP> 3.7 <SEP> 2.7 <SEP> 3.0 <SEP> 2.7 <SEP> 2.7 <SEP> 3.7
<tb> Treatment4 <SEP> 3.6 <SEP> 4.0 <SEP> 4.7 <SEP> 4.7 <SEP> 5.7 <SEP> 6.0 <SEP> 6.0 <SEP> 6 , 3 <SEP> 6.7
<Tb>
The results given in Table III show that the herbicidal effects of treatments 1, 2 and 3 show up visually relatively slowly during the first 5 to 9 weeks afterwards. the treatment, which is, according to the preceding indications, characteristic of the herbicidal properties of asulam and its agriculturally acceptable salts. Subsequently, a high level of weed control, including the growth of Achyranthes indica, was achieved up to 17 weeks after treatment, particularly with treatment 3. By contrast, although treatment 4 provided a rapid weed control characteristic of paraquat, weed control no longer functions approximately 5 weeks after treatment.

Experience 2
Plots of 100 m2 were treated in a randomized block system in two plantations (sites 1 and 2) of approximately 6 months old banana (Valery variety) in Jamaica. In site 1, the soil was very clayey and derived from yellow limestone, and in site 2, the soil was essentially alluvial. Both sites were in plain with annual rainfall of about 1778 min. Treatment coincided with the onset of the rainy season. An assessment of emerged weed species observed in both sites prior to treatment revealed that dicotyledonous species were more common than monocoty ledones. Weeds are
Site 1: Cynodon dactylon, Digitaria ciliaris, Panicum
maximum, Cyperus rotundus, Digitaria decumbens,
Amaranthus dubius, Bidens pilosa, Mimosa pudica,
Physalis angulata, AIDS acuta Desmodium adscen
dens and wild mustard (Brassica Kaber
or Sinapis arvensis).

Site 2: Cynodon dactylon, Digitaria ciliaris, Panicum
maximum, Cyperus rotundus,, Cyperus ferax,
Amaranthus dubius, Bidens pilosa, Aida acuta,
Brassica Kaber, Mimosa pudica and Desmodium
adscendens.

 Treatments 2 and 3 are prepared by diluting with water quantities of the aqueous concentrate prepared according to the indications of Example 1 corresponding to the indicated volume of concentrate per hectare treated. The application takes place at a dose corresponding to 450 liters of spray fluid per hectare treated. Treatment 4 was prepared by diluting a quantity of aqueous concentrate containing 20% w / v of paraquat (as dichloride) corresponding to the indicated volume of concentrate per hectare treated. The application takes place at a corresponding dose. to 337.5 liters of spray fluid per hectare treated Treatments 5 and 6 were prepared by diluting with water quantities of asulam concentrate (as sodium salt) at 40% w / v corresponding at the indicated volume of concentrate per hectare treated. The application at a rate corresponded to 450 liters of spray fluid per hectare treated. The application was carried out with an atomizer carried on the back, taking care to avoid an application on the banana plants.

Treatment 1. 6 liters of the aqueous concentrate prepared according to
the indications of Example 1 (2.1 kg
equivalent of asulam and 105 g equivalent
paraquat) per hectare treated.

Treatment 2. 8 liters of aqueous concentrate prepared sui
before the indications of Example 1 (2.8 kg
equivalent of asulam and 140 g equivalent
paraquat) per hectare treated.

Treatment 3. 10 liters of prepared aqueous concentrate
following the indications of example 1
(3.5 kg asulam equivalent and 175 g
equivalents paraquat) per hectare treated.

Treatment 4. 1.41 liters of aqueous concentrate containing
20% w / v paraquat under
dichloride (280 g of para equivalents)
quat) per hectare treated.

Treatment 5. 8.46 liters of aqueous concentrate containing
40% w / v of asulam in the form of
sodium salt (3.4 kg asulam equivalent)
per hectare treated.

Treatment 6. 11.28 liters of aqueous asulam concentrate
at 40% w / v as salt
sodium (4.5 kg asulam equivalent) per
hectare treated.

 Each treatment was repeated 3 times and the untreated plots were retained as controls.

 Weed control assessment and treatment effects on banana plants were conducted at weekly intervals after treatment. The time between treatment and the achievement of effective weed control identified by the name ("time (days) to control weeds") and the time between treatment and recrudescence were recorded. weeds at a level requiring more extensive weed control, referred to as "duration (days) of effective weed control"). The following results were retained.

Results
Safety of banana treatments.

 No phytotoxic effects were observed on banana plants in any of the plots treated at the sites. The plants were uniform in size and color and showed no signs of chlorosis or necrosis.

 Weed control.

Weed control obtained at sites 1 and 2 with the treatments is given in Table IV TABLE IV - CONTROL OF MAUVALISES HERBES

Time <SEP> (days) <SEP> for <SEP> Time <SEP> (days)
<tb> Bad
<tb> complete <SEP> a <SEP> of the <SEP> control
<tb> Treatment <SEP> herbs <SEP> no
<tb> control <SEP> of <SEP> effective <SEP> of
<tb> controlled
<tb> bad <SEP> herbs <SEP> bad <SEP> herbs
<tb> 1 <SEP> 4 <SEP> - <SEP> 10 <SEP> 130 <SEP> None <SEP> (none
<tb> bad <SEP> grass <SEP> did not
<tb> survived <SEP> at <SEP> processing)
<tb> 2 <SEP> 2 <SEP> - <SEP> 7 <SEP> 130 <SEP> None <SEP> (none
<tb> bad <SEP> grass <SEP> did not
<tb> survived <SEP> at <SEP> processing)
<tb> 3 <SEP> 2 <SEP> - <SEP> 5 <SEP> 150 <SEP> None <SEP> (none
<tb> bad <SEP> grass <SEP> did not
<tb> survived <SEP> at <SEP> processing)
<tb> 4 <SEP> 2 <SEP> - <SEP> 5 <SEP> 80 <SEP> Desmodium <SEP> adscendens <SEP> - <SEP> Side <SEP> acuta
<tb> 5 <SEP> 14 <SEP> - <SEP> 19 <SEP> 150 <SEP> None
<tb> 6 <SEP> 14 <SEP> - <SEP> 17 <SEP> 150 <SEP> None
<Tb>
The results given in Table IV show that the treatments according to the present invention (Treatments 1 and 2) provided a rapid weed control characteristic of paraquat at doses (105 to 140 g per hectare treated) lower than those generally used. for paraquat, combined with maintaining a high level of weed control for 130 days after treatment at doses of asulam (2.1 and 2.8 kg per hectare treated) lower than those generally used for Aslam alone by contrasting treatment 3 showed no improvement in the results obtained using asulam alone (Treatments 5 and 6) and treatment 4, although providing rapid weed control characteristic of paraquat, effective weed control only up to 80 days after treatment.

Claims (10)

1) Process for controlling the growth of bad  herbs characterized in that it consists of applying  on the cultivation zone of asulam or its salts accep  tables in agriculture associated with paraquat. 2) Method according to claim 1) characterized in that  1.5 to 3 kg equivalent of asulam per  treated hectare and 50 to 200 g of paraquat equivalent  per hectare treated, asulam and paraquat being  in an equivalent weight ratio asulam / equiva  slow paraquat from 10/1 to 30/1. 3) Process according to claim 2) characterized in that  that the equivalent weight ratio asulam / equivalent  paraquat is between 15/1 and 25/1, preferably  between 15/1 and 20/1. 4) Method according to one of claims 2 or 3) carac  in that asulam or its salts are applied  in shaded areas from 1.75 to 2.25  kg / ha equivalent of asulam and paraquat at the rate of  87.5 to 112.5 g / ha paraquat equivalent. 5) Method according to one of claims 2 or 3) carac  in that asulam or salts thereof are applied  in unshaded areas at 2.25 to  3 kg / ha asulam equivalent and paraquat at right  from 112.5 to 150 g of paraquat equivalent. 6) Method according to one of claims 1 to 5) carac  it is applied in a culture of  banana trees. 7) Herbicidal compositions, solid or liquid,  usable for the implementation of a method according to  one of claims 1 to 6) characterized in that  that they include asulam or one of its salts  acceptable in agriculture as well as paraquat  from 0.05 to 100% by weight, the weight ratio  equivalent asulam / paraquat equivalent being included  between 10/1 and 30/1, preferably between 15/1 and 25/1.  8) Compositions according to claim 7) characterized  in that they comprise 0.01 to 10% of surfactant  active.  9) Manufactured object characterized in that it is consti  killed from a container containing a composition  one of claims 7 or 8), said container  with instructions that are physically  associated and which expose the way in which  said composition must be applied to control  weed growth by a process  according to one of claims 1 to 6) 10) Object according to claim 9) characterized in that  its capacity is sufficient to hold a quantity  herbicide composition for the treatment of  less than 40 ares of land.