FIELD OF THE INVENTION
This invention relates to synergistic herbicidal compositions comprising a herbicidal
pyrazole derivative and at least one co-herbicide selected from a range of coherbicides.
It further relates to the use of the aforesaid herbicidal compositions for
controlling undesired vegetation in crops, especially for management of weed flora in
wheat crop.
BACKGROUND OF THE INVENTION
Weeds damage agricultural crops and reduces productivity by competing with the crop
and forage plants for mineral nutrients, nitrogen, water, and sunlight. Several methods
of using herbicides to control or eliminate weedy species are known in the art. Chemical
herbicides are typically categorized according to the time of application (e.g., preemergence
or post-emergence herbicides). Pre-emergence herbicides are applied prior
to germination of weeds for control of germinating weed seeds without harming the
desired plant species. Post-emergence herbicides are applied after planting and over
the top of establishing or established plants for control of unwanted plant species.
Generally, current methods of attempting to control weeds include applications of preemergent
herbicides followed by post emergent herbicides i.e. sequential applications of
herbicides to address the issue of weeds in agricultural crop cultivation. Most of the crop
lands under cultivation are weeded by hand, hence, much human effort is expended in
raising crops. Most of the times, the dosage used varies as the herbicide selection is not
based on the technical knowhow which results in poor weed control affecting the
productivity of the crop.
Other conventional methods of producing agricultural crops include the use of different
combinations of herbicides such as tank mix herbicides to address the issue of emerged
weeds without having proper application knowledge of the weed spectrum individual
herbicides. In such usage the chances of varied dosage of individual herbicides end up
3
with poor weed control, Therefore, successful weed management is essential for
economical crop production.
To overcome these type of problems, a need arises for the use of pre-mix (ready-mix)
herbicidal compositions in which more than one type of herbicide is present in
appropriate contents and delivery form i.e. the formulation. It is, nonetheless, difficult to
determine appropriate combinations of herbicides in view of the considerable number of
different types of herbicides available and the plurality of individual herbicides within
each such type.
The herbicides or combination of herbicides can be applied in different ways for
example sequential application, tank-mix application and pre-mix application. In
sequential application, farmers use different herbicides, wherein the herbicide selection
is not based on the technical knowhow and herbicides having the same mode of action
are being used, which leads to resistance development. In tank-mix application, farmers
use different combinations of herbicides, most of the times without having training to
properly mix products. Homemade tank mixes may therefore not be as stable as a premix.
The tank-mix usually results in non-judicious use of individual herbicides and end
up with poor weed control. Moreover, the tank mixture is less convenient and potentially
hazardous to people who are not trained to properly mix products.
The pre-mix application is a combination of two or more herbicides as active ingredients
but the rates of the active ingredients are unchangeable, the components rates and
formulation are optimized during development, hence no mixing or stability issue exists.
The pre-mix application also helps in reducing the development of herbicides
resistance.
The sequential application or / and tank-mix application of herbicides with inappropriate
doses, when employed to address weeds of wheat, result in development of herbicide
resistance.
4
It is therefore desired to provide an improved composition and convenient method which
safely and effectively control weed species in the agricultural crops and therefore, there
is a constant need for the development and application of synergistic formulations which
are not only effective in weed control, but also help in increasing the yield of crop.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a synergistic herbicidal
composition comprising an herbicidal pyrazole derivative and at least one co-herbicide
selected from a range of co-herbicides said compositions having a broader spectrum of
weed control than each individual herbicide constituent, whilst retaining the selectivity of
herbicidal action of each of the constituent.
A further object of the present invention is to provide synergistic herbicidal compositions
which, when applied pre-emergent or post-emergent, display an enhanced and broader
spectrum of herbicidal activity with regard to the crops being treated.
A further object of the present invention is to provide a method of controlling the
germination and growth of undesired vegetation in a selective manner with regard to
crops, e.g. weed flora in wheat crop, being treated, which comprises applying to the
crop, pre- or post-emergent, preferably a pre-mix composition according to the present
invention.
A further object of the present invention is to provide an herbicidal composition that
efficaciously contributes in Herbicide Resistance Management (HRM).
Another object and advantage of the present invention is to provide a stable synergistic
herbicidal composition that shows technical advancement over the existing herbicides
or combination of herbicides.
5
Yet another object and advantage of the present invention is to provide a cost-effective
and convenient method for the preparation of said composition, which is effective
against a wide variety of undesired vegetation in crops, especially for management of
weed flora in wheat crops.
Another object of the invention is to provide a stable synergistic herbicidal composition
which meets the environmental and economic requirements imposed on modern-day
herbicides which are continually increasing, with regard, for example, to the spectrum of
action, toxicity, selectivity, application rate, formation of residues, and favorable
preparation ability.
DETAILED DESCRIPTION OF THE INVENTION
It is known that combined application of certain different herbicides with specific action
might result in an enhanced activity of an herbicide component in comparison with a
simple additive action. Such an enhanced activity is also termed a synergism or
synergistic activity. As a consequence, it is possible to reduce the application rates of
herbicidally active compounds required for controlling the weeds.
Accordingly, the present invention relates to A stable synergistic agrochemical
composition for management of weed flora in wheat comprising an herbicidal pyrazole
derivative as a first component (A) and at least one co-herbicide selected from a range
of co-herbicides as a second component (B), and agriculturally acceptable formulation
additives (C), wherein the weight percentage of (A) is 1 to 14%, weight percentage of
(B) is 9 to 81% and weight percentage of (C) is 5 to 90%.
Preferred pyrazole derivative i.e. component (A) according to the present invention, not
being limited to, is pyroxasulfone, i.e. 3-[5-(difluoromethoxy)-1-methyl-3-
(trifluoromethyl)pyrazol-4-ylmethylsulfonyl]-4,5-dihydro-5,5-dimethyl-1,2-oxazole.
6
Preferred co-herbicides i.e. component (B) according to the present invention are
selected from the group consisting of dinitroaniline herbicides, in particular from the
group consisting of benfluralin, butralin, dinitramine, ethalfluralin, fluchloralin,
isopropalin, methalpropalin, nitralin, oryzalin, pendimethalin, prodiamine, profluralin and
trifluralin, especially prodiamine, oryzalin, pendimethalin and trifluralin and pyridine
herbicides, in particular from the group consisting of dithiopyr and thiazopyr.
Preferred dinitroaniline herbicides is pendimethalin.
The invention also relates to an herbicide formulation, which comprises a herbicidally
active composition as defined herein and at least one carrier material, including liquid
and/or solid carrier materials.
Surprisingly, the compositions according to the invention have better herbicidal activity
against the target weeds would have been expected by the herbicidal activity of the
individual compounds. In other words, the joint action of herbicidal pyrazole A and the at
least one herbicide B results in an enhanced activity against weeds in the sense of a
synergy effect (synergism). Moreover, the compositions of the present invention provide
good pre-emergence herbicidal activity, i.e. the compositions are particularly useful for
combating/controlling harmful plants (weeds) before and during their emergence.
Moreover, it has been found that the use of a dinitroaniline herbicide, in combination
with certain herbicidal pyrazole derivatives, extends the spectrum of herbicidal activity
without loss of crop selectivity. Therefore the said combinations represent an important
technological advance. The term "combination" as used in this specification refers to the
"combination" of a herbicidal pyrazole derivative and a dinitroaniline herbicide.
The compositions of the present invention are suitable for controlling a large number of
harmful plants, including monocotyledonous weeds, in particular annual weeds such as
gramineous weeds (grasses) including Echinochloa species such as barnyardgrass
(Echinochloa crusgallivar. crus-galli), Digitaria species such as crabgrass (Digitaria
7
sanguinalis), Setaria species such as green foxtail (Setaria viridis) and giant foxtail
(Setaria faberii), Sorghum species such as johnsongrass (Sorghum
halepense Pers.), Avena species such as wild oats (Avena fatua),Cenchrus species
such as Cenchrus echinatus,
Bromus species, Lolium species, Phalaris species, Eriochloa species, Panicum species,
Brachiaria species, annual bluegrass (Poa annua), blackgrass (Alopecurus
myosuroides), Aegilops cylindrica, Agropyron repens, Apera spica-venti, Eleusine
indica, Cynodon dactylon and the like.
The compositions of the present invention are also suitable for controlling a large
number of dicotyledonous weeds, in particular broad leaf weeds
including Polygonum species such as wild buckwheat (Polygonum
convolvolus), Amaranthus species such as pigweed (Amaranthus
retroflexus), Chenopodium species such as common lambsquarters (Chenopodium
album L.), Sida species such as prickly sida (Sida spinosa L.), Ambrosia species such
as common ragweed (Ambrosia
artemisiifolia), Acanthospermum species, Anthemis species, Atriplex species,Cirsium sp
ecies, Convolvulus species, Conyza species, Cassia species, Commelina species, Datu
ra species, Euphorbia species, Geraniumspecies, Galinsoga species, Morningglory
(Ipomoea species), Lamium species, Malva species, Matricaria species, Sysimbrium sp
ecies,Solanum species, Xanthium species, Veronica species, Viola species, common
chickweed (Stellaria media), velvetleaf (Abutilon theophrasti), Hemp sesbania
(Sesbania exaltata Cory), Anoda cristata, Bidens pilosa, Brassica kaber, Capsella
bursa-pastoris, Centaurea cyanus, Galeopsis tetrahit, Galium aparine, Helianthus
annuus, Desmodium tortuosum, Kochia scoparia, Mercurialis annua, Myosotis arvensis,
Papaver rhoeas, Raphanus raphanistrum, Salsola kali, Sinapis arvensis, Sonchus
arvensis, Thlaspi arvense, Tagetes minuta, Richardia brasiliensis, and the like.
The compositions of the present invention are also suitable for controlling a large
number of annual and perennial sedge weeds including cyperus species such as purple
nutsedge (Cyperus rotundus L.), yellow nutsedge (Cyperus esculentus L.), hime-kugu
8
(Cyperus brevifoliusH.), sedge weed (Cyperus microiria Steud), rice flatsedge (Cyperus
iria L.), and the like.
The compositions of the present invention are in particular suitable for
combating/controlling undesired vegetation in wheat, corn, sugarcane, soybean, pulse
crops, etc.
The compositions of the present invention can be applied in conventional manner by
using techniques a skilled person is familiar with. Suitable techniques include spraying,
atomizing, dusting, spreading or watering. The type of application depends on the
intended purpose in a well-known manner; in any case, the techniques should ensure
the finest possible distribution of the active ingredients according to the invention.
The compositions can be applied as pre-emergence, i.e. before, during emergence of
the undesirable plants (Weeds). Since the composition show good crop tolerance, even
when the crop has already emerged, they can be applied after seeding of the crop
plants and in particular during or after the emergence of the crop plants.
The present invention also relates to formulations of the compositions according to the
present invention. The formulations contain, besides the composition, one or more kinds
of agriculturally acceptable formulation additives (C) such as surfactant, carrier, binder,
disintegrant, pH adjuster, thickener, preservative, anti-freezing agent, defoamers and/or
coloring agent or a combination thereof.
Suitable surfactants (a dispersant, a wetting agent, a spreader, an adjuvant for
penetration enhancement, rain fastness, soil leaching control etc.) are nonionic or
anionic or a combination of these surfactants. It is preferred to use more than two kinds
of surfactants which have different chemical structure. Suitable surfactants are, for
example, sugar esters (such as sorbitan monolaurate, polyoxyethylene sorbitan
monolaurrate), polyoxyethylene alkyl ethers (such as polyoxyethylene lauryl ether or
polyoxyethylene coconut fatty alcohol ether), polyoxyethylene aryl ethers (such as
9
polyoxyethylene nonylphenyl ether or polyoxyethylene trystyrylphenyl ether),
polyoxyethylene vegetable oil ethers (such as polyoxyethylene castor oil),
polyoxyethylene fatty acid esters (such as polyoxyethylene monolaurate),
polyoxyethylene polyoxypropylene block co-polymers, polyoxyethylene
polyoxypropylene alkyl ether (such as polyoxyethylene polyoxypropylene lauryl ether),
polyoxyethylene alkyl amines (such as polyoxyethylene stearyl fatty amine), alkyl
sulfates (such as sodium lauryl sulfate), polyoxyethylene alkyl ether sulfates (such as
sodium polyoxyethylene lauryl ether sulfate), polyoxyethylene aryl ether sulfates (such
as sodium polyoxyethylene nonylphenyl ether sulfate or ammonium polyoxyethylene
tristyrylphenyl ether sulfate), alkane sulfonates (such as sodium dodecyl sulfonate),
‘alpha’-olefin sulfonate, aryl sulfonates (such as sodium dodecylbenzene sulfonate,
sodium alkylnaphthalene sulfonate, sodium ‘beta’-naphthalene sulfonate formaldehyde
condensate or sodium alkyl diphenyl ether sulfonate), alkylsulfosuccinates (such as
sodium dioctylsulfosuccinate), lignosulfonates, polyoxyethylene alkyl ether phosphate,
polyoxyethylene aryl ether phosphates (such as polyoxyethylene phenyl ether
phosphate) and polyoxyethylene polyoxypropylene block co-polymer phosphate or a
combination thereof.
Suitable liquid carriers are, for example, water, alcohols (such as ethanol, propanol,
isopropanol ethylene glycol, diethylene glycol, propylene glycol, polyethylene glycol,
glycerin), polyol ether (such as ethylene glycol monopropyl ether, diethylene glycol
monomethyl ether), ketones (such as methyl isobutyl ketone, cyclohexanone), ethers
(such as dipropyl ether, dioxane, ethylene glycol monoethyl ether, tetrahydrofuran,
dipropylene glycol dimethyl ether), aliphatic hydrocarbons (such as normal paraffin,
naphthene, isoparaffin, kerosene, mineral oil), aromatic hydrocarbons (such as xylene,
solvent naphtha, alkyl naphthalene), esters (such as ethyl acetate, diisopropyl phthalate,
dimethyl adipate), lactones (such as gamma-butyrolactone), amides (such as
dimethylformamide, N-methylpyrrolidone, N,N-dimethyldecanamide), nitriles (such as
acetonitrile), sulfur compounds (such as dimethyl sulfoxide) and vegetable oils (such as
soybean oil, rapeseed oil, cotton seed oil). These liquid carriers may be used alone or in
a combination of two or more kinds.
10
Suitable solid carriers are, for example, natural minerals (such as talc, kaolinite,
pyrophyllite, montmorillonite, attapulgite, bentonite, calcite, diatomaceous earth),
synthetic minerals (such as precipitated silica, fumed silica and calcium carbonate),
inorganic salts (such as calcium carbonate, ammonium sulfate, sodium sulfate,
potassium chloride) and organic materials (such as urea, lactose, starch, cellulose,
plant powders). These solid carriers may be used alone or in a combination of two or
more kinds.
Suitable binders are, for example, polyvinyl alcohol, dextrin, denatured dextrin, soluble
starch, carboxymethyl cellulose and bentonite or a combination thereof.
Suitable disintegrants are, for example, sodium tripolyphosphate, sodium
hexametaphosphate, carboxymethyl cellulose, sodium polycarbonate and bentonite or a
combination thereof.
Suitable pH adjusters are, for example, sodium or potassium carbonate, sodium or
potassium hydrogen carbonate, sodium or potassium dihydrogenphosphate, disodium
or dipotassium hydrogenphosphate, citric acid, malic acid and triethanolamine or a
combination thereof.
Suitable thickeners are, for example, xanthan gum, welan gum, guar gum, polyvinyl
alcohol, carboxymethyl cellulose and its salt, silica and bentonite or a combination
thereof.
Suitable preservatives are, for example, 4-hydroxybenzoic acid esters, 2-methyl-4-
isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one and 1,2-benzisothiazolin-3-
one or a combination thereof.
Suitable anti-freezing agents are, for example, glycerin, ethylene glycol, propylene
glycol, diethylene glycol, dipropylene glycol and urea or a combination thereof.
11
Suitable defoamers are, for example, silicone compounds and organic fluorine
compounds or a combination thereof.
Suitable coloring agents are, for example, organic dyestuffs (such as azo dye,
phthalocyanine dye or alizarin dye) and inorganic pigments (such as iron oxide) or a
combination thereof.
The formulation may be in the form of a single package formulation for pre-mix
application containing both the herbicide A and the at least one herbicide B together
with agriculturally acceptable formulation additives for crop protection compositions. The
formulation may be in the form of a two package formulation, wherein one package
contains a formulation herbicide A while the other package contains a formulation of the
at least one herbicide B and wherein both formulations contain agriculturally acceptable
formulation additives for crop protection compositions. In the case of two package
formulations the formulation containing herbicide A and the formulation containing the
herbicide B are mixed prior to application. Preferably the mixing is performed as a tank
mix, i.e. the formulations are mixed immediately prior or upon dilution with water.
In the formulation of the present invention the active ingredients, i.e. herbicide A,
herbicide B and optional further actives are formed to several types of formulations such
as not being limited to, emulsifiable concentrate (EC), wettable powder (WP), water
dispersible granules (WG), suspension concentrate (SC) etc.
In one embodiment of the present invention, the composition of the wettable powder
formulation is provided. The composition of wettable powder comprises pyrazole
derivative and dinitroaniline herbicide as active ingredients, surfactant and carrier. Other
formulation additives such as pH adjuster and colorant may be additionally used.
A method for preparing the wettable powder formulation of the present invention is also
provided. The wettable powder formulation can be prepared by mixing the active
12
ingredients, surfactant and carrier. Usually active ingredients, surfactant, carrier and
other formulation additives are mixed uniformly in a mixer and milled by a mill such as
an air jet mill to median diameter 5 to 50 micrometer.
In another embodiment of the present invention, the composition of the water
dispersible granule formulation is provided. The composition of water dispersible
granule comprises pyrazole derivative and dinitroaniline herbicide as active ingredients,
surfactant, binder, disintegrant and carrier. Other formulation additives such as pH
adjuster and colorant may be additionally used.
A method for preparing the water dispersible granule formulation of the present
invention is also provided. The water dispersible granule formulation can be prepared
by mixing the active ingredients, surfactant, binder, disintegrant and carrier. Usually the
active ingredients, surfactant, binder, disintegrant, carrier and other formulation
additives are mixed uniformly in a mixer and milled by a mill such as an air jet mill to
median diameter 5 to 50 micrometer. The milled mixture is kneaded by adding 2 to
10 % of water, extruded and dried. Other granulation method such as spray dry may be
used. In this case, the milled mixture is well mixed with enough amount of water to get
slurry.
In yet another embodiment of the present invention, the composition of the suspension
concentrate formulation is provided. The composition of suspension concentrate
comprises pyrazole derivative and dinitroaniline herbicide as active ingredients,
surfactant, thickener, preservative, anti-freezing agent and water. Other formulation
additives such as defoamer, pH adjuster and colorant may be additionally used.
A method for preparing the suspension concentrate formulation of the present invention
is also provided. The suspension concentrate formulation can be prepared by wet
milling of the active ingredients mixed with surfactant, water and other formulation
additives. Usually the active ingredients, surfactant and anti-freezing agent are mixed by
dissolving or dispersing in water. The mixture is preliminary milled by a homogenizer
13
such as a colloid mill and then milled by a bead mill till median diameter reaches to 1 to
10 micrometer. Defoamer may be used during milling. After the milling, aqueous
solution of thickener containing preservative is added.
Example: Water dispersible granule (WG)
Composition of Pyroxasulfone 10.2% Pendimethalin 60.0 % WG
Pyroxasulfone technical 10.2 w/w% (as a.i.)
Pendimethalin technical 60.0 (as a.i.)
Sodium lignosulfonate 4.0
Sodium naphthalenesulfonate 2.0
Sodium dioctylsulfosuccinate 2.0
Polyvinyl alcohol 1.0
Kaolin clay 20.8 (Balance)
Total 100.0 w/w%
The compositions or formulation according to the present invention are effective in the
pre-emergence control of numerous monocotyledonous and dicotyledonous weeds.
The composition or formulation according to the present invention has a reduced or
zero phytotoxicity with respect to important agricultural crops. This results in the present
invention effective and possible in the selective control of weeds.
For practical use in agriculture, the composition or formulation of the present invention
can be applied in such quantities as to guarantee applicative dosages of the synergistic
mixture.
The term “herbicide” is used herein to mean an active ingredient that kills, controls or
otherwise adversely modifies the growth of plants. An herbicidal effective or vegetation
controlling amount is an amount of active ingredient which causes an adversely
14
modifying effect and includes deviations from natural development, killing, regulation,
desiccation, retardation and the like. The terms plants, weeds and vegetation include
germinant seeds, emerging seedlings, plants emerging from vegetative propagules and
established vegetation.
It has been found that the combination of Pyroxasulfone and Pendimethalin provides
synergies in controlling weeds of wheat and also contributes in Herbicide Resistance
Management (HRM) for sustainability of the life of this chemistry.
Following test results illustrate the present invention and not intended to limit the
present invention.
Evaluation of pyroxasulfone 10.2 % WG + pendimethalin 60 % WG against weeds of
wheat
Field Study:
Two field experiments were conducted at Tepla-village of Patiala district in Punjab and
at Padhana village of Karnal district in Haryana during Rabi 2015 to evaluate the
efficacy of Pyroxasulfone and Pendimethalin and its combination, along with Clodinafop,
Metsulfuron methyl and Metribuzin, were used for comparison in wheat. The
experiments were carried out with variety HD 2967 in plots having 10m x 5m size in
randomized block design with 7 treatments and replicated thrice. Pre-emergence
herbicide application was done on 1 day after sowing and post emergence treatment
was done around 35 days after sowing. The target weeds of wheat viz., Phalaris minor,
Avena ludviciana, Chenopodium album, Rumex sp. and Melilotus indica were counted
to determine the efficacy of the products. Bio-efficacy, in terms of species wise weed
count, total weed count and total dry weed weight were taken up.
Validations for Inventions Concepts:
The above mentioned field studies were undertaken with the following objectives.
15
 To determine the effective dose of herbicides combination on the weed flora of
wheat.
 To establish the synergistic action in terms of increased efficacy and broad weed
spectrum control over the single application of both herbicide.
 Compatibility of the formulations in terms of physical appearance of mixture
solution, safety to crop plants, spray operator etc.
A. Effective Dose:-
Two trials were conducted to observe the efficacy of different herbicides on major
weeds of wheat. Major weeds were Phalaris minor, Avena ludviciana, Chenopodium
album, Rumex sp. and Melilotus indica. Bio-efficacy, in terms of species wise weed
count, total weed count and total dry weed weight are presented in Table1.1 and Table
2.1. It is revealed from tables that the best treatment was ready mix of Pyroxasulfone
10.2% + Pendimethalin 60.0 % WG @877 g a.i./ha had good efficacy on both grasses
and broad leaf weeds followed by solo application of Pyroxasulfone 85 % WG @127.5
g a.i./ha, Pendimethalin 30% EC @750 g a.i/ha and Clodinafop 15 % WP@60 g a.i./ha.
Least total weed count of (7.0/m2 and 8.7/ m2) respectively at both locations was
observed with Pyroxasulfone 10.2% + Pendimethalin 60 % WG @877 g a.i/ha followed
by Pyroxasulfone 85 % WG @ 127.5 g a.i./ha (23.0/m2 and 25.8/ m2) as compared to all
other treatments including control having a total weed count of (114/m2 and 97.3/m2)
respectively at both locations.
B. Establishment of synergistic action:
Extensive literatures survey and more number of trials revealed that the herbicide
of different groups when used as pre-mix at certain reduced rate may have synergistic
effect instead additive or deleterious effect. Based on the literature available,
combinations of herbicides have been developed and globally used on to combat on
16
many weeds. Such combinations also provides enhanced spectrum of activity and avoid
resistance development for longer period.
Present study also provides evidence on the synergistic effect of combination in terms
of increase of weed spectrum as well as increase of efficacy. Solo application of
Pyroxasulfone 85 % WG @ 127.5 g a.i./ha was well effective against grasses weeds as
Phalaris minor and Avena ludviciana but moderate on broad leaves weed (BLW) and
solo application of Pendimethalin 30 % EC @ 750 g a.i./ha was working well against a
number of BLW and moderate on grasses weed. While combination of Pyroxasulfone
10.2 % WG + Pendimethalin 60 % WG @ 877 g a.i./ha was found most effective to
control both grasses and broad leaf weeds with least weed count and higher yield, thus
establishing synergism in term of broader weed spectrum coverage as well as higher
efficacy.
C. Compatibility of combination: -
Physical observation on the treated plants involving either solo products or the
combination does not affect the safety of the crop plants and provided the normal yield.
It has been observed that no detrimental effect on the skin and eyes irritation to the
spray operators either by combination or solo products (Table -1.3 & 2.3)
D. Yield data:
Yield data was also recorded and presented in Table-1.2 and Table-2.2. Highest
yield of (39.3 q/ha and 36.3 q/ha) was recorded in the combination of Pyroxasulfone
10.2 % + Pendimethalin 60 % WG @ 877 g a.i./ha followed by Pyroxasulfone 85 %WG
@127.5 g a.i./ha (37.8 q/ha and 34.2 q/ha) and Pendimethalin 30 % EC @ 750 g a.i./ha
(35.2 q/ha and 32.7 q/ha) at both trial locations, respectively. In the control, lowest yield
was recorded (30.6 q/ha and 29.7 q/ha) at both the location respectively. It is evident
from the table that the combination developed for the control of weeds of wheat gave
good control on weeds and thereby increased the yield.
17
Location - 1
Location detail :Tepla, Patiala, Punjab
Date of sowing : 5/11/2015
Date of application (PE) : 06/11/2015 (1DAS)
Date of application (POE) : 10/12/2015 (35 DAS)
18
Treatment detail: -
Sr.
No. Treatment
Dose/ha
Type Technical Time of Application
g a.i.
Formulation
(g or ml)
1. Pyroxasulfone 85 % WDG PE 127.5 150 1 day after sowing
2. Pendimethalin 30 % EC PE 750 2500 1 day after sowing
3. Pyroxasulfone 10.2 % +
Pendimethalin 60 % WG
PE 877 1250 1 day after sowing
4. Metribuzin 70 % WP PE 175 250 1 day after sowing
5. Clodinafop 15 % WP POE 60 400 35 day after sowing
6. Metsulfuron methyl 20 % WP POE 4 20 35 day after sowing
7.
Control
- - - NA
PE - Pre-emergence; POE - Post-emergence
19
Table-1.1: - Bio-efficacy of different treatments on the weed flora of wheat.
Sr.
no.
Treatment Type Dose/ha Species wise Mean weed count/0.25 m2 (Avg. of 3
replications) 45 DAS
Total weed
count / m2
Total weed
Dry weight
(g/ m2) ga
.i./ha
g or
ml
Phalaris
minor
Avena
ludviciana
Chenopodium
album
Melilotus
indica
T1 Pyroxasulfone 85 %
WDG
PE 127.5 150 14.3
(3.8)
0.7 (1.1) 4.7 (2.3) 3.3 (2.0) 23.0 (4.8) 2.9 (1.8)
T2 Pendimethalin 30 %
EC
PE 750 2500 56.7
(7.6)
2.3 (1.7) 1.7 (1.5) 2.7 (1.8) 63.3 (8.0) 7.9 (2.9)
T3 Pyroxasulfone 10.2 %
+ Pendimethalin 60 %
WG
PE 877 1250 5.3 (2.4) 0.3 (0.9) 0.3 (0.9) 1.0 (1.2) 7.0 (2.7) 0.9 (1.2)
T4
Metribuzin 70 % WP
PE 175 250 66.7
(8.2)
3.0 (1.9) 7.0 (2.7) 4.0 (2.1) 80.7 (9.0) 10.1 (3.3)
T5
Clodinafop 15 % WP
POE 60 400 46.0
(6.8)
0.7 (1.1) 16.0 (4.1) 5.7 (2.5) 68.3 (8.3) 8.5 (3.0)
T6 Metsulfuron methyl 20
% WP
POE 4 20 89.7
(9.5)
4.7 (2.3) 3.7 (2.0) 1.7 (1.5) 99.7 (10.0) 12.5 (3.6)
T7
Control
- - - 88.0
(9.4)
5.0 (2.3) 15.7 (4.0) 5.3 (2.4) 114 (10.7) 14.3 (3.8)
CD 5% - - - 0.422 0.411 0.345 0.251 0.447 0.146
PE - Pre-emergence; POE – Post-emergence Figures given in parenthesis are square root value
20
Table -1.2: - Impact of different treatments on yield of wheat:-
S. no. Treatment Time of
application
Dose/ha Yield data
g a.i./ha g or ml q/ha
T1 Pyroxasulfone 85 % WDG PE 127.5 150 37.8 (6.2)
T2 Pendimethalin 30 % EC PE 750 2500 35.2 (6.0)
T3 Pyroxasulfone 10.2 % + Pendimethalin 60
% WG
PE 877 1250 39.3 (6.3)
T4 Metribuzin 70 % WP PE 175 250 33.6 (5.8)
T5 Clodinafop 15 % WP POE 60 400 35.0 (6.0)
T6 Metsulfuron methyl 20 % WP POE 4 20 32.7 (5.8)
T7 Control - - - 30.6 (5.6)
CD 5% 0.105
PE - Pre-emergence; POE – Post-emergence Figures given in parenthesis are square root value
21
Table – 1.3 Impact of different treatments on crop heath of Wheat.
PE - Pre-emergence; POE – Post-emergence
Sr.
No.
Treatment Type Dose/ha Phytotoxicity (0-10 scale) in terms of yellowing,
necrosis, wilting, epinasty, hyponasty etc.
g a.i. g or ml 1 DAS 3 DAS 5 DAS 7 DAS 10 DAS
T1 Pyroxasulfone 85 % WDG PE 127.5 150 0 0 0 0 0
T2 Pendimethalin 30 % EC PE 750 2500 0 0 0 0 0
T3 Pyroxasulfone 10.2 % +
Pendimethalin 60 % WG
PE 877 1250 0 0 0 0 0
T4 Metribuzin 70 % WP PE 175 250 0 0 0 0 0
T5 Clodinafop 15 % WP POE 60 400 0 0 0 0 0
T6 Metsulfuron methyl 20 % WP POE 4 20 0 0 0 0 0
T7 Control - - - 0 0 0 0 0
22
Location - 2
Address : Village, Karnal, Haryana
Date of sowing : 08/11/2015
Date of application (PE) : 09/11/2015 (1DAS)
Date of application (POE) : 13/12/2015 (35DAS)
Treatment detail: -
Sr.
No.
Treatment
Dose/ha
Type Technical Time of Application
g a.i.
Formulation
(g or ml/ha)
1. Pyroxasulfone 85 % WDG PE 127.5 150 1 day after sowing
2. Pendimethalin 30 % EC PE 750 2500 1 day after sowing
3. Pyroxasulfone 10.2 % +
Pendimethalin 60 % WG
PE 877 1250 1 day after sowing
4. Metribuzin 70 % WP PE 175 250 1 day after sowing
5. Clodinafop 15 % WP POE 60 400 35 days after sowing
6. Metsulfuron methyl 20 % WP POE 4 20 35 days after sowing
7.
Control
- - - NA
PE = Pre-emergence; POE = Post-emergence
23
Table-2.1: - Bio-efficacy of different treatments on the weed flora of wheat.
Sr.
no.
Treatment Type Dose/ha Species wise Mean weed count/0.25 m2 (Avg. of 3
replication) 45 DAS
Total weed
count / m2
Total weed
Dry weight
g a.i. g or (g/ m2)
ml
Phalaris
minor
Avena
ludviciana
Chenopodium
Album
Rumex
dentatus
T1 Pyroxasulfone 85 %
WDG
PE 127.5 150 15.5
(4.0)
0.7 (1.1) 5.3 (2.4) 4.3 (2.2) 25.8 (5.1) 3.2 (1.9)
T2
Pendimethalin 30 % EC
PE 750 2500 44.3
(6.7)
2.7 (1.8) 3.7 (2.0) 3.7 (2.0) 54.3 (7.4) 6.8 (2.7)
T3 Pyroxasulfone 10.2 % +
Pendimethalin 60 % WG
PE 877 1250 5.7
(2.5)
0.3 (0.9) 0.3 (0.9) 2.3 (1.7) 8.7 (3.0) 1.1 (1.3)
T4
Metribuzin 70 % WP
PE 175 250 56.3
(7.5)
3.7 (2.0) 5.7 (2.5) 6.7 (2.7) 72.3 (8.5) 9.0 (3.1)
T5
Clodinafop 15 % WP
POE 60 400 35.3
(6.0)
1.3 (1.3) 7.3 (2.8) 7.7 (2.9) 51.7 (7.2) 6.5 (2.6)
T6 Metsulfuron methyl 20 %
WP
POE 4 20 75.7
(8.7)
4.7 (2.3) 2.7 (1.8) 5.7 (2.5) 88.7 (9.4) 11.1 (3.4)
T7
Control
- - - 76.7
(8.8)
4.3 (2.2) 8.0 (2.9) 8.3 (3.0) 97.3 (9.9) 12.2 (3.6)
CD 5% - - - 0.281 0.355 0.295 0.222 0.330 0.093
PE - Pre-emergence; POE – Post-emergence Figures given in parenthesis are square root value
24
Table -2.2: - Impact of different treatments on yield of wheat
Sr.
no.
Treatment Time of
application
Dose/ha Yield data
g a.i. g or ml q/ha
T1 Pyroxasulfone 85 % WDG PE 127.5 150 34.2 (5.9)
T2 Pendimethalin 30 % EC PE 750 2500 32.7 (5.8)
T3 Pyroxasulfone 10.2 % + Pendimethalin 60 % WG PE 877 1250 36.3 (6.1)
T4 Metribuzin 70 % WP PE 175 250 31.6 (5.7)
T5 Clodinafop 15 % WP POE 60 400 32.8 (5.8)
T6 Metsulfuron methyl 20 % WP POE 4 20 30.9 (5.6)
T7 Control - - - 29.7 (5.5)
CD 5% 0.021
PE - Pre-emergence; POE – Post-emergence Figures given in parenthesis are square root value
25
Table – 2.3 Evaluation of impact of Pyroxasulfone 10.2 % + Pendimethalin 60 % WG on crop heath of Wheat.
PE - Pre-emergence; POE – Post-emergence
Sr.
No.
Treatment Type Dose/ha Phytotoxicity (0-10 scale) in terms of yellowing,
necrosis, wilting, epinasty, hyponasty etc.
g a.i. g or ml 1 DAS 3 DAS 5 DAS 7 DAS 10 DAS
T1 Pyroxasulfone 85 % WDG PE 127.5 150 0 0 0 0 0
T2 Pendimethalin 30 % EC PE 750 2500 0 0 0 0 0
T3 Pyroxasulfone 10.2 % +
Pendimethalin 60 % WG
PE 877 1250 0 0 0 0 0
T4 Metribuzin 70 % WP PE 175 250 0 0 0 0 0
T5 Clodinafop 15 % WP POE 60 400 0 0 0 0 0
T6 Metsulfuron methyl 20 % WP POE 4 20 0 0 0 0 0
T7 Control - - - 0 0 0 0 0

WE CLAIM:
1. A stable synergistic agrochemical composition for management of weed
flora in wheat comprising an herbicidal pyrazole derivative as a first component
(A) and at least one co-herbicide selected from a range 5 of co-herbicides as a
second component (B), and agriculturally acceptable formulation additives (C),
wherein the weight percentage of (A) is 1 to 14%, weight percentage of (B) is 9 to
81% and weight percentage of (C) is 5 to 90%.
10 2. The composition as claimed in claim 1, wherein the preferred component
(A) is pyroxasulfone, i.e. 3-[5-(difluoromethoxy)-1-methyl-3-
(trifluoromethyl)pyrazol-4-ylmethylsulfonyl]-4,5-dihydro-5,5-dimethyl-1,2-oxazole.
3. The composition as claimed in claim 1, wherein the component (B)
15 selected from the group consisting of dinitroaniline herbicides, in particular from
the group consisting of benfluralin, butralin, dinitramine, ethalfluralin, fluchloralin,
isopropalin, methalpropalin, nitralin, oryzalin, pendimethalin, prodiamine,
profluralin and trifluralin, especially prodiamine, oryzalin, pendimethalin and
trifluralin and pyridine herbicides, in particular from the group consisting of
20 dithiopyr and thiazopyr.
4. The composition as claimed in claim 1 to 3, wherein the preferred
component (B) is pendimethalin.
25 5. The composition as claimed in claim 1, wherein (C) is selected from at least
one organic or inorganic carrier material including agriculturally acceptable
formulation additives such as surfactant, solid carrier, liquid carrier, binder,
disintegrate, pH adjuster, thickener, preservative, anti-freezing agent, defoamers
and coloring agent, or a combination thereof.
30
6. The composition as claimed in claim 5, wherein suitable surfactants include
sugar esters (such as sorbitan monolaurate, polyoxyethylene sorbitan
monolaurrate), polyoxyethylene alkyl ethers (such as polyoxyethylene lauryl ether
or polyoxyethylene coconut fatty alcohol ether), polyoxyethylene aryl ethers (such
35 as polyoxyethylene nonylphenyl ether or polyoxyethylene trystyrylphenyl ether),
polyoxyethylene vegetable oil ethers (such as polyoxyethylene castor oil),
polyoxyethylene fatty acid esters (such as polyoxyethylene monolaurate),
polyoxyethylene polyoxypropylene block co-polymers, polyoxyethylene
polyoxypropylene alkyl ether (such as polyoxyethylene polyoxypropylene lauryl
40 ether), polyoxyethylene alkyl amines (such as polyoxyethylene stearyl fatty amine),
27
alkyl sulfates (such as sodium lauryl sulfate), polyoxyethylene alkyl ether sulfates
(such as sodium polyoxyethylene lauryl ether sulfate), polyoxyethylene aryl ether
sulfates (such as sodium polyoxyethylene nonylphenyl ether sulfate or ammonium
polyoxyethylene tristyrylphenyl ether sulfate), alkane sulfonates (such as sodium
dodecyl sulfonate), ‘alpha’-olefin sulfonate, aryl sulfonates 5 (such as sodium
dodecylbenzene sulfonate, sodium alkylnaphthalene sulfonate, sodium ‘beta’-
naphthalene sulfonate formaldehyde condensate or sodium alkyl diphenyl ether
sulfonate), alkylsulfosuccinates (such as sodium dioctylsulfosuccinate),
lignosulfonates, polyoxyethylene alkyl ether phosphate, polyoxyethylene aryl ether
10 phosphates (such as polyoxyethylene phenyl ether phosphate) and
polyoxyethylene polyoxypropylene block co-polymer phosphate or a combination
thereof.
7. The composition as claimed in claim 5, wherein suitable liquid carriers
15 include water, alcohols (such as ethanol, propanol, isopropanol ethylene glycol,
diethylene glycol, propylene glycol, polyethylene glycol, glycerin), polyol ether
(such as ethylene glycol monopropyl ether, diethylene glycol monomethyl ether),
ketones (such as methyl isobutyl ketone, cyclohexanone), ethers (such as
dipropyl ether, dioxane, ethylene glycol monoethyl ether, tetrahydrofuran,
20 dipropylene glycol dimethyl ether), aliphatic hydrocarbons (such as normal
paraffin, naphthene, isoparaffin, kerosene, mineral oil), aromatic hydrocarbons
(such as xylene, solvent naphtha, alkyl naphthalene), esters (such as ethyl
acetate, diisopropyl phthalate, dimethyl adipate), lactones (such as gammabutyrolactone),
amides (such as dimethylformamide, N-methylpyrrolidone, N,N25
dimethyldecanamide), nitriles (such as acetonitrile), sulfur compounds (such as
dimethyl sulfoxide) and vegetable oils (such as soybean oil, rapeseed oil, cotton
seed oil) or a combination thereof.
8. The composition as claimed in claim 5, wherein suitable solid carriers
30 include natural minerals (such as talc, kaolinite, pyrophyllite, montmorillonite,
attapulgite, bentonite, calcite, diatomaceous earth), synthetic minerals (such as
precipitated silica, fumed silica and calcium carbonate), inorganic salts (such as
calcium carbonate, ammonium sulfate, sodium sulfate, potassium chloride) and
organic materials (such as urea, lactose, starch, cellulose, plant powders) or a
35 combination thereof.
9. The composition as claimed in claim 5, wherein suitable binders include
polyvinyl alcohol, dextrin, denatured dextrin, soluble starch, carboxymethyl
cellulose and bentonite or a combination thereof.
40
28
10. The composition as claimed in claim 5, wherein suitable disintegrants
include sodium tripolyphosphate, sodium hexametaphosphate, carboxymethyl
cellulose, sodium polycarbonate and bentonite or a combination thereof.
11. The composition as claimed in claim 5, wherein 5 suitable pH adjusters
include sodium or potassium carbonate, sodium or potassium hydrogen carbonate,
sodium or potassium dihydrogenphosphate, disodium or dipotassium
hydrogenphosphate, citric acid, malic acid and triethanolamine.
10 12. The composition as claimed in claim 5, wherein suitable thickeners include
xanthan gum, welan gum, guar gum, polyvinyl alcohol, carboxymethyl cellulose
and its salt, silica and bentonite or a combination thereof.
13. The composition as claimed in claim 5, wherein suitable preservatives
15 include 4-hydroxybenzoic acid esters, 2-methyl-4-isothiazolin-3-one, 5-chloro-2-
methyl-4-isothiazolin-3-one and 1,2-benzisothiazolin-3-one or a combination
thereof.
14. The composition as claimed in claim 5, wherein suitable anti-freezing
20 agents include glycerin, ethylene glycol, propylene glycol, diethylene glycol,
dipropylene glycol and urea or a combination thereof.
15. The composition as claimed in claim 5, wherein suitable defoamers include
silicone compounds and organic fluorine compounds or a combination thereof.
25
16. The composition as claimed in claim 5, wherein suitable coloring agents
include organic dyestuffs (such as azo dye, phthalocyanine dye or alizarin dye)
and inorganic pigments (such as iron oxide) or a combination thereof.
30 17. A method for the preparation of a stable synergistic herbicidal composition
as claimed in claim 1 comprising an herbicidal pyrazole derivative as a first
component (A) and at least one co-herbicide selected from a range of coherbicides
as a second component (B), and agriculturally acceptable formulation
additives (C).