Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
K 1846 CAN
'HERBICIDAL COMPOSITION AND METHOD OF COMBATING ~NDESIRED
PLANT GROWTH"
This invention relates to herbicidal compositions and method
of combating undesired plant growth.
U.K. Patent Application No. 2064537 discloses that the
compound 3-(3-methyl-4-isopropylphenyl)-l,l-dimethylurea is
effective in the control of weeds. It has now been found tha-t
this compound can also act as a synergist when mixed with certain
other herbicidal compounds, and thus -that mixtures of certain
herbicides with 3-(3-methyl-4-isopropylphenyl)-l,l-dimethylurea
exhibit an unexpected synergistic effect.
The invention therefore provides a herbicidal composition
which comprises 3-(3-methyl-4-isopropylphenyl)~ dimethylurea
(hereinafter referred to as compound A), together with at leas-t
one compound selected from:
(i) a compound which has the generaL formula
C~
xl ~x2
or is a salt or an ester thereof, in which each of X and X
independently represents an iodine, bromine or chlorine atom;
'~
~i~
~ 3~
(ii) 2,6-dinitro-N,N-dipropyl-4-trifluoromethylarliline;
and
(iii) a compound which has -the general formula:
R
02N ~ / \ ~ OH (II)
~ NO
or is a salt or an ester thereof, in which R is a C(1-4) alkyl
group.
The composi-tions according to the invention may con-tain two
or more compounds within one of the groups (i) and (iii),
and/or two or more compounds from different groups (i), (ii) and
(iii). Preferably however the compositions con-tain
components selected from one only of groups (i), (ii) and (iii).
The invention further provides a method of combating un-
desired plant growth at a locus, which comprises applying to the
locus compound A and at least one compound selected from (i) to
(iii) above.
In the formula I, each of Xl and X preferably independently
represents an iodine or bromine atom, and preferably Xl and X are
the same.
A compound (i) may be the free phenol of formul I, or it may
be a salt or an ester thereof. Suitable salts include alkali
metal salts, especially the sodium or potassium sa~t, and a~nine
salts. Suitable amine salts include for example those of amines
having up to three organic groups attached to the nitrogen, the
organic groups being, for example, aIkyl groups having up to 10
carbon atoms and being optionally substituted by, for example,
hydro~y groups or halogen atoms. Suitable esters are for example
alkyl esters, having for example up to 20, especially 6 to 12,
carbon atoms in -the aIkyl moiety. Preferably, a compound (i) is
the free phenol or its octanoate ester.
An alkyl group Rl in the formula II is preferably a butyl
group. Most preferably R is a secondary or tertiary butyl group.
~ ypical compounds of group (iii) include 2-tert-butyl-4,6-
dinitrophenol, 2-sec-butyl-4,6-dinitrophenol and salts and esters
thereof.
A compound of group (iii) may be the free alcohol of formula
II or it may be a salt or an ester thereof. Suitable salts
include alkali metal salts, especially the sodium or potassium
salt, alkaline earth metal salts, for example the magnesium salt,
the ammonium salt and amine salts.
Suitable esters are derived from substituted or unsubstituted
carboxylic acids, especially alkanoic acids.
Preferably a compound of group (iii) is the free alcohol or
the ace-tate thereof.
The weight ratio of compound A to the compound selected from
(i) to (iii) may vary widely depending on the intended application.
Preferably said ratio is in the range of from 1:50 to 50:1,
preferably 1:20 to 20:1, especially 5:1 to 1:5. Suitably the
dosage of each co~pound applied is in the range of from 0.05 to
5 kg/ha.
Especially preferred dosages of certain binary mixtures are
for example, from 0.3 to 3 kg/ha of compound A together with 0.05
to 2.5 kg/ha of a compound of group (i); 0.25 to 3 kg/ha of
compound A together with 0.25 -to 3 kg/ha of compound (ii); and
0.25 to 3 kg/ha of compound A together with 0.25 to 3 kg/ha of a
compound of group (iii).
The composition and method of the invention may be used for
the control of weeds in a wide variety of crops, depending of
course on the nature of the compound (i) to (iii). Typical crops
include, for example, cotton, soyabean, plantation crops such as
sugar cane or vines, and, especially, cereals such as wheat,
barley, maize and sorghum. Mixtures containing a compound of
group (iii) may also be especially useful in leguminous crops such
as peas and beans. A wide range of broad leaved and grassy weeds
are controlled. Application may be pre-emergence or, preferably,
post-emergence. For certain applications, especially ~hen resistant
weeds are present, it may be desirable also -to apply a further
herbicide. For example, if severe infestations of wild oat are
present in cereal crops, it may be advan-tageous to apply along
with compound A and one or more compounds (i) to ~iii), one of the
5~
N,N-disubstituted alanine derivatives which are specialised
narrow spectrum herbicides and described in U.I~. Patent No.
1,16~,160, for example the e-thyl ester of N-benzoyl-N-(3,4-dichloro-
phenyl)-2-aminopropionic acid, or the racemic mixture or laevo-
rotatory isomer of the methyl or isopropyl ester of N-benzoyl-N-
(3-chloro-4-fluorophenyl)-2-aminopropionic acid or a broad-spectrum
herbicide such as a triazine, for example cyanazine, atra~ine or
simazine. Fur-ther suitable compounds which may be present as a
third component include metolachlor, chlortoluron, isoproturon and
dichlofopmethyl.
A composition according to the invention preferably also
comprises one or more carriers. A carrier is any material with
which the active ingredients are formulated to facilitate appli-
cation to the locus to be treated, or to facilitate storage,
transport or handling. A carrier may be a solid or a liquid,
including a material which is normally gaseous but which has been
compressed to form a liquid, and any of the carriers normally used
in formulating herbicidal compositions may be used.
Suitable solid carriers include natural and synthetic clays
and silicates, for example natural silicas such as diatomaceous
earths; magnesium silicates, for example talcs; magnesium alumin-
ium silicates 3 for example attapulgites and vermiculites; alumin-
ium silicates, for example kaolinites, montmorillonites and
micas; calcium carbonate; calcium sulphate; synthetic hydrated
silicon oxides and synthetic calcium or aluminium silicates;
elements, for example carbon and sulphur; natural and synthetic
resins, for example coumarone resins, polyvinyl chloride, and
styrene polymers and copolymers; solid polychlorophenols; bitumen;
waxes, for example beeswax, paraffin wax, and chlorinated mineral
waxes; and solid fertlisers, for example superphosphates.
Suitable liquid carriers include water; alcohols, for example
isopropanol and glycols; for example acetone, methyl ethyl ketone,
methyl isobutyl ketone and cyclohexanone; ethers; aromatic or
araliphatic hydrocarbons~ for example ben~ene, -toluene and xylene;
petroleum fractions, for example kerosine and light mineral oils;
.L~ rg~-~
chlorina-ted hydrocarbons, for example carbon tetrachloride,
perchloroethylene and trichloroethane. Mixtures of different
liquids are of-ten suitable.
Agricultural compositions are often formula-ted and transported
in a concentrated form which is subse~uently diluted by the user
before application. The presence of small amounts of a carrier
which is a surface-active agent facilitates this process of
dilution.
A surface-ac-tive agent may be an emulsifying agent, a dis-
persing agent or a wetting agent; it may be nonionic or ionic.
Examples of suitable surface-active agents include the sodium or
calcium salts of polyacrylic acids and lignin sulphonic acids;
the condensation products of fatty acids or aliphatic amines or
amides containing at least 12 carbon atoms in the molecule with
ethylene oxide and/or propylene oxide; fatty acid esters of
glycerol, sorbitan, sucrose or pentaerythritol; condensa-tes of
-these with ethylene oxide and/or propylene oxide; condensation
products of fatty alcohol or alkyl phenols, for example p-
octylphenol or p-oetylcresol, with ethylene oxide and/or propylene
oxide; sulphates or sulphonates of these condensation produc-ts;
alkali or alkaline earth metal salts, preferably sodium salts, of
sulphuric or sulphonic acid esters containing at least 10 carbon
atoms in the molecule, for example sodium lauryl sulphate, sodium
secondary alkyl sulphates, sodium salts of sulphonated castor
oil, and sodium alkylaryl sulphonates such as sodium dodecyl-
benæene sulphonate; and polymers of ethylene oxide and copolymers
of ethylene oxide and propylene oxide.
The compositions of the invention may for example be formu-
lated as wettable powders, dusts, granules, solutions, emulsifi-
able concentrates, emulsions, suspension concentrates and aero-
sols. Wettable po~ders usually contain 25, 50 and 75% w of
active ingredient and usually contain, in addition to solid inert
carrier, 3-10% w of a dispersing agent and, where necessary, 0-
10% w of stabiliser(s) and/or o-ther additives such as penetrants
or stickers. Dusts are usually formulated as a dus-t concentrate
.L~
having a similar compositions to -that of a we-ttable powder but
without a dispersant, and are diluted in the field with further
solid carrier to give a composition usually containing 2-10% w of
active ingredient. Granules are usually prepared to have a size
between 10 and 100 BS mesh (1.676 - 0.152 mm), and may be manu-
factured by agglomera-tion or impregnation techniques. Generally,
granules will contain ~-25% w active ingredient and 0-10% w of
additives such as stabilisers, slow release modifiers and binding
agents. Emulsifiable concentra-tes usually contain, in addition
to a solvent and, when necessary, co-solvent, 10-50% w/v active
ingredient, 2-20% w/v emulsifiers and 0-20% w/v of other addi-
tives such as stabilisers, penetrants and corrosion inhibitors.
Suspension concentrates are usually compounded so as to obtain a
stable, non-sedimenting flowable product and usually contain 10-
75% w active ingredient, 0.5-15% w of dispersing agents, 0.1-
10% w of suspending agents such as protective colloids and thixo-
tropi~ agents, 0-10% w of other additives such as defoamers,
corrosion inhibitors, stabilisers, penetrants and stickers, and
water or an organic liquid in which the active ingredient is
substantially insoluble, certain organic solids or inorganic
salts may be present dissolved in the formulation to assist in
preventing sedimentation or as anti-freeze agents for water.
~ queous dispersions and emulsions, for example compositions
obtained by diluting a wettable powder or a concentrate according
to the invention with water, also lie within the scope of the
present invention. The said emulsions may be of the water-in-oil
or of the oil-in-water type, and may have a thick 'mayonnaise'-
like consistency.
The compositions of the invention may also contain other
ingredients, for example~ compounds possessing insecticidal or
fungicidal properties.
The following Examples illustrate the invention.
General Procedure
The tests conducted were foliar spray tests, in which seed-
ling plants were sprayed with a formulation containing the test
compound. Various test plant species were used, including black-
grass9 speedwell, black nightshade and wild oats.
The soil used in the tests was a prepared horticultural loam.
Speedwell and wild oat seedlings had O or 1 true leaves, and
blackgrass and black nightshade seedlings had 2 or 3 true leaves.
The formulations used in -the tests were prepared by diluting
wi-th water, solutions of -the test compound or mix-ture in acetone
containing 0.4% by weight of an alkylphenol/ethylene oxide conden-
sate available under the trade name TRITON X-155. The acetone
solutions were diluted with an equal volume of water and the
resulting formulations applied at 4 different dosage levels
designed to produce a range of responses. Three replicate pots
were used for each treatment. Untreated seedlings plants were
used as controls.
As specifie~ number of days after treatment, phytotoxicity
compared with the untreated control, was assessed visually on a O
to 9 scale, O indicating no effect and 9 indicating death.
The results were subjected to a standard probit analysis by
computer to calculate the dosage of each compound or mixture, in
Kg/ha, required to kill 50% of the test species. This dosage is
referred to as the GID50 dosage. If a mixture of herbicides A
and B act together in an additive way, one would expect the GID50
values for A and B in the mixture to be given by the equations
(i) and (ii) below:
GID of B in mix-ture = a
5 c~ ~ a (i)
b
GID50 f A in mixture = (GID50 f B in mixture)xG~ (ii)
where a = GID50 of A used alone
b = GID50 f B used alone
= weigh-t ratio of compound A to compound B in
mixture.
If the measured GID50 values are in fact less than the
calculated values, the mixture is synergistic.
The results of the tes-ts are given in the following Tables.
The GID50 values are actual~ measured values in kg/ha, and calculated
values are given in brackets after -the measured values.
Example 1
This Example was carried out using the following compounds:
A: 3-(3-methyl-4~isopropylphenyl)-1,l~dimethylurea.
B: 3,5-dibromo-4-hydroxybenzonitrile, the commercial
herbicide "Bromoxynil".
It can be seen from the table of results (Table I) that this
mixture was synergistic against all plant species tested - i.e.,
the measured dosages of the mixture required to kill 50% of the
test plants were less than the calculated dosages.
3~'~
_ABLE I
_esults
.
Blackgrass Speedwell
(assessment after 2 days) (assessment after 2 days)
Mixture GID50 Mixture GID50
ratio A B ratio A B
A:B A:B
. . . _
1:0 .46(.46) o(o) 1:0 .27(.27) o(o)
1:1 .16(.21) .16(.21)16:1 .091(.15) .oo6(.oog)
1:2 .070(.14) .14(.28) 8:1 .051(.10) .006(.013)
1:4 .056(.082) .23(.33) 4:1 .051(.064) .013(.016)
1:8 .039(.045) .31(.3~) 2:1 .022(.036) .011(.018)
0:1 0(0) .40(.40) 0:1 o(o) .021(.021)
.
Black Ni~htshade Wild Oats
(assessment after 2 days) (assessment after 7 days)
Mixture GID50 Mixture GID50
ratio A B ratio A B
A:B A:B
1:0 .28(.28) 0(0) 1:0 .092(.092) 0(0)
4:1 .11(.18) .025(.044) 1:2 .034(.071) .068(.14)
2:1 .052(.13) .026(.065) 1:4 .045(.057) .18(.23)
1:1 .o55(.084) .055(.084) 1:8 .035(.042) .28(.33)
1:2 .o40(.o49) .080(.099) 1:16 .022(.027) .36(.43)
0:1 0(0) .12(.12) 0:1 0(0) .61(,61)
le 2
This Example was carried out using the following compounds:
A: 3-(3-methyl-4-isopropylphenyl)-1,1 dimethylurea
B: 3,5-dibromo-4-hydro,Yybenzonitrile octanoate ester.
It can be seen from the table of results (Table II) that
this mixture was synergistic in its action against black night-
shade and wild oa-ts, and approximately additi~e in its effect
against speedwell and blackgrass.
S'~
TABBE II
Example 2 - Resul-ts
Blackgrass Speedwell
(assessment after 2 days) (assessment after 2 days)
Mixture GID50 Mixture GID50
ratio A B ratio A B
A:B A:B
1:0 .44(.44)0(0) 1:0 .49(.44) 3(0)
1:1 .13(.12).13(.12)32:1 .26(.34) .008(.010)
1:2 .054(.072) .11(.14) 16:1 .30(.27) .01~(.017)
1:4 .o46(.o39) .18(.16) 8:i .22(.1g) .028(.024)
1:8 .023(.021) .18(.17) 4:1 .11(.12) .027(.031)
0:1 0(0) .17(.17) 0:1 0(0) .044(.043)
-
Black Nightshade Wild Oats
(assessment a~ter 2 days) (assessment a~ter 12 days)
Mixture GID50 ~ixture GID~o
ratio A B ratio A B
A:B A:B
_ . . .
1:0 .34(.34)0(0) 1:0 .14(.14) 0(0)
l~:l .14(.25) .035(.063) 1:2 .057(.13) .11(.26)
2:1 .20(.20) .10(.10) 1:4 .10(.12) .41(.47)
1:1 .072(.14) .072(.14) 1:8 .058(.10) .46(.81)
1:2 .038(.089) .076(.18) 1:16 .034(.079) .54(1.27)
0:1 0(0) .24(.24) 0:1 0(0) 2.93(2.93)
Example 3
In this Example, the following compouncls were used:
A: 3-(3-methyl-4-isopropylphenyl)-1,1-dimethylurea.
B: 2,6 Dinitro-N,N-dipropyl-4-trifluoromethlaniline the
commercial herbicide trifluralin. The resul-ts, assessed
after 13 days, are given in Table III, and show that the
mixtures tested showed significant synergism.
3~
TABLE III
Speedwell
GID 0
Mix-ture 5
Ratio
A:B A B
1:0 0.37(0.37) ()
8:1 0.27(0.32) 0.033(0.039)
l~ l 0.16(0.28) 0.039(0.069)
2:1 0.13(0.22) 0.066(0.011)
1:1 0.10(0.16) 0.10(0.16)
0:1 0(0) 0.27(0.27)
Blackgrass
GID
Mixture 5
Ratio
A:B A B
1:0 0.~13(0.013) 0(0)
1:2 0.006(0.011) 0.011(0.021)
1:4 0.003(0.009) 0.014(0.035)
1:8 0.003(0.007) 0.023(0.053)
1:16 0.003(0.00l~) 0.048(0.072)
0:1 0(0) 0.11(0.11)
Wild Oats
GID
5o
Mixture
Ratio
A:B A B
_
1:0 o.96(o.96) o(o)
2:1 0.25(0.56) 0.13(0.28)
1:1 0.15(0.39) 0.15(0.39)
1:2 0.085(0.25) 0.17(0.49)
1:4 0.081(C.14) 0.32(0.56)
0/1 0(0) o.66(o.66)
_
14
ple 4
In this Example, -the following compounds were used:
A: 3-(3-methyl-4-isopropylphenyl)-l,l-dimethylurea.
B: 2-tert-butyl-4,6-dinitrophenol the commercial herbicide
Dinoterb.
The results, assessed af'ter 6 days, are gi~en in Table IV, and
show that the mixtures tested showed significant synergism.
~ rp~
TA3LE IV
_
.
Speedwell
GID,~o
Mixture
Ratio
A:B A B
1:0 3-55(3-55) ()
16:1 0.99(1.10) o.o62(o.069)
8:1 0.52(0.65) o.o65(0.082)
4:1 0.27(0.36) o.o66(Q.o90)
2:1 0.13(0.19) 0.067(0.095)
0:1 0(0) 0.10(0,10)
_ _ .
Black ~ightshade
GID O
Mixture 5
Ra-tio
A:B A
1:0 0.0~7(0.047) ()
~:l 0.012(0.027) 0.003(0.007)
2:1 0.008(0.019) 0.004(0.010)
1:1 0.00~(0.012) 0.004(0.012)
1:2 0.003(0.007) 0.005(0.014)
0:1 0(0) 0.016(0.016)
Wild Oats
GID50
Mixture
Ratio
A:B A B
1:0 3.36(3.36) 0(0)
2:1 1.24(2.18) 0.62(1.09)
1:1 1.~8(1.61) 1.48(1.61)
1:2 0.86(1.06) 1.73(2.12)
0.58(0.63) 2.31(2.51)
0:1 0(0) 3.09(3.09)
_
