Note: Descriptions are shown in the official language in which they were submitted.
It is known that many herbicides in important
crops of cultivated plants have no, or too little, selective
action, i.e. in addition to the weeds to be destroyed they also
injure the cultivated plants to a greater or lesser degree. This
applied to most classes of herbicide, e.g. triazines, urea
derivatives, carbamates, thiolcarbamates, haloacetanilides etc.
This property has particularly disadvantageous conse-
quences in large scale crops, such as cereals and maize, and
despite successful efforts to find herbicides of good selectivity,
this problem has still not been completely satisfactorily solved.
On the other hand, substances have been proposed for
pretreating seeds, e.g. for providing cereal and maize seeds with
protective layers before sowing in order to make them resistant
to specific herbicides. Both the protective agent and the herbi-
cide are very largely species-specific with respect to the culti-
vated plant. Thus in German Offenlegungsschrift 1.952.910 issued
June 25, 1970 to Gulf and in French patent 2.021.611 issued
July 24, 1970 to Gulf, the use of 1,8-naphthalic acid derivatives,
oxamic acid derivatives ~derivatives of the oxylic monoamide
HOOC-CONH2) and malonic diamide has been proposed for treating
cereal and maize seeds in order to protect these against attack
by herbicidal N,N-dialkylated thiocarbamic acid-S-alkyl esters.
Earlier, proposals had already been made for treating cereal seeds
with the most diverse substances, such as hydroxyaminoacetanilide,
dichloroxanthenones, hydantoins, isopropyldithiocarbamate salts,
N-methyl-dichlorobenzene-sulphonamide etc.~ in order to protect
the seeds against *he action of herbicidal carbamates, such as
IPC, CIPC ~German patent 1.576.076 issued 1968 to Gulf, United
States patent 3.131.509 issued May 5, 1968 to Gulf).
Of more recent date are publications relating to the
~'
. .
; ~; - 2-
, . . .
.
~ 1 ~i8~38~
treatment of the seeds and shoots of corn and sorghum with N,N-
disubstituked oxamic acid esters, diallyl proprionamide, diallyl
acetamide, naphthalates etc. in order to protect these against
attack by N-methoxymethyl-~2',6'-diethylchloroacetanilide) cf.
British patent 1.277.557 issued June 14, 1972 to Gulf.
This particular seed treatment before sowing entails
substantial economic disadvantages, in particular the expenditure
in terms of labour and money involved in the special steps carried
out in special mixing devices for the large amounts of seeds which
are sown in large-scale crops.
Attempts have therefore already been made to find
what are known as safening agents or antidotes which can be applied
not to the seeds, but either together with, or before or after, the
herbicidal applica*ion to the crop area to be sown, or which has
already been sown (preemergent treatment), or after the seeds have
germinated ~post-emergent treatment), and which have the same pro-
tective effect, i.e. they cause the non-selective herbicide to act
selectively in that the weeds are damaged as much as possible with-
out any more injury to the cultivated plants. Belgian patent
771.928 issued February 29, 1972 to Stauffer and German Offenle-
gungsschrift ~Stauff0r) describe such an agent for protecking cereals
against the herbicidal action of thiolcarbamates and ~riazines.
Besides these herbicides, this agent contains antidote halogenated
alkanesulphonates of the type
X- ~CH2) -0-S02-R
herein X represents a halogen atom, R represents alkyl, haloalkyl,
halogen, acetoxy(halo)-alkyl, aryl, and n is a whole number from 1
to 5.
~ere too a pronounced species-specificity of the
herbicides and the antidote on cereals is evident.
Finally, there has recently appear0d a publication
~German Offenlegungsschrift 2.218.097 issued October 14, 1972 to
Stauffer) in whic}l, besides a straight forward pretreatment of
the seeds with halogenated alkoylamides, there are also described
herbicidal agents which contain such haloalkoylamides as antidotes.
The majority of the antidotes described and tested
therein are used specifically with respect to the active com-
ponents in the application o~ herbicidal thiolcarbamates and
mixtures thereof with other herbicidal active substances. The
emphasis is clearly on antagonising undesirable injury to the
crop plants by thiolcarbamates. It is true that this publica-
tion does also mention among the herbicides to be protected
ckloroacetanilides as mixture components and individual active
substances. However, the individual tests with such active
substances refer only to two her~icides of this type, namely
~ N-methoxymethyl-2,6-diethyl-chloro-acetanilide ~"~ASSO") without
~,
antidote and with an uneconomic surplus of an antidote in sorghum
vulgare, and N-isopropyl-chloroacetanilide ~"RA~ROD") without
antidote and with a surplus of antidote in corn. Despite the
surplus of antidote, the result in both cases was far from con-
vincing, the decrease in injury of the crop plant with the anti-
dote moderate, and the ultimate injury determined still consider-
able (20%). It is known that, in contradistrinction to other
and recent, more active chloroacetanilides, no antidote at all
is required when applying these two herbicides to maize.
It is probably for this reason that, despite
a vast number o tests, this publication contains no further
examples witk ckloroacetanilides as herbicides. Evidently, the
applicant of German Offenlegungsschrift 2.212.268 issued
~ dcl O ~h ~ rK,
-- ~ 1 3 ~86
September 28, 1972 to Sumetomo has not realised the exceptional-
ly important fact that other more active chloroacetanilides of
different constitut:ion can be conspicu-
.
e
ously improved in their selective ~ct$vlty against weeds incereals and maize by small amounts oE some of the antidotes
proposed by her, and for this reago~ has proposed these
antidotes with proved success onl~ together with thiolcarha-
mates as herbicides.
Whereas certain herbicides oE the triazine and
phenylurea series are already knwon ~or the selective control
of weeds in cereals and maize and ~e con~lercially available,
it has not been possible to avail ~f more recent haloacetani-
lides to the desired extent on ac~ount o~ their generally
unsatisfactory selectivity in cereQl and ~aize plantations,
since they cause severe injury to these crop plants, which
means diminishedyield, and still no effective antidote
against such haloacet~nilides has become known.
Specific disclosure of _he invention
The surprisin~ discovery has now been made that~ contrary
to the presumptions to be inferred Erom the literature,
it is possible to impart firstrat~ protection to n~ize
plan~s from injury by ~he above mèntiohed herbicidal
chloracetanilide by treating the ~oll with a N,N-di-
substituted dichloracetamide.
This invention is concerned ~itb a ~ethod Eor
the selective control of weeds in ~or~ (maize) which
comprises treating the crop areas $o~ th~ cultivation
of maize with the chloracetanilidè hè~bl~ide.
N-(2'-methoxyethyl)-2,6-di~ethyl-~hloracetanilide
of formula
-- 6 --
:
8S
CH
3 / C2~40C~l3
\ COC~IzC
CH3
~ blch is known from
Canadi.an Patent (a-pplication Ser. No, 162 4~0) or British
Patent No. 1 422 473 together with a saEening agent (antidote),
selected from the group o~ N,N-dig~bstlt~ted dichloracetamides
corresponding to the formula II
2 -~ N - CO - CHC12 (II)
.1
'
wherein Rl and R2 are individually allyl or lower alkyl
radicals or together with the nitrogen atom form the 1,3-
oxazolidine ring, which optionall.~ may be substituted by
methyl radicals, said antidote being presen~ in a concentration
of from about 0,01 to 1 part by welght per part by weight
of said chLoracetanilide.
~ uch antidotes oE forlnul.a II a~ dlscl.osed in part in
the German OfEenlegungsschrift No, 2 21B ~97.(Stauffer Feb. 29, 1972)
It is conceivable that an a~tld~te ~hich is used
in higher rates of application in ~e~e~i~ itself exerts a
herbicidal action, but insmall amounts a~tagonises the
herbicidal action of the chloroacetanlildes on maize.
- 7 -
' ~q
;~
Pre~erred antidotes of the ~rm~l~ II are
~H2~CH-CI-I
N-C0-C~ICl N,~-~iallyl-dichloroacetamide,
~H2aCH-CH2 nD ~ 1~5036
~1l =C~I-C~
2 2~ N-eth~l-N-~lLyl-d3cllloro~ce~atllide
() ~CI i(: 1.,
~2H5 n2d ~ 1,4~54
~H2=CH-c~l2.~ N-iæ~pr~pyl-N-a].lyl-dichlora oet-
/ N-C0-CHC12 amide
t 3)2 nD ~ i,4~1
2 C~l2
t~ N-CO-CHC12 N-d~ch~ o~cetyl-2,2-dimethyl.-
9 3~bx~z~lidine
m.p~ 121
C~
3 3
The invention therefore provlde~ a ~ethod ~or the
selective control of weeds in maize cultu~es, which consists
in treating the seeds or the crop ~e~ lhtended for ~he
cultivation of maize in which the ~eed~ ~e to be SOWIl, or
which have been sown, or in which thè s~ds have already
germi~ ted, simultaneously or succéssl~el~, in optional
!
~ ~ ~8~8~
sequer)ce and in an appropriate interval ~f time, on the
one hand witll a lerbicide, tne chloroacetanilide of the
formula I, and on the other with ~n antldote of the
N,N-disubstituted dichloracetamide ~E the above formula II
which protects the germinated crop pl~nt~ and/or the seeds
thereof.
The invention is also conce~ned with an agent for
selective control of weeds in maize, which contains as
herbicidally active component the chloro~cetanilide of the
formula I as well as an atidote o~ the formula II.
These agents can be applied ~n any suitable form.
Thus they can be manuactured in known manner by intimately
mixing and grinding the herbicidaly active substances and
the antidote with suitable carriers and/or additives optio-
nally accompanied by the addition of dispersants or sol-
vents.
The conventional process ~orms a~e either solid,
such as dusts, tracking agents, g~anùles, or liquid solu-
tions, or they take the Eorm of actlve substance concentrates
which can be dispersed in water, g~h ~9 wettable powder,
emulsions, or pastes.
The agent according to the lnv~ntl~n i9 incorporated
into the soil either beEore or afte~ th~ ~aize has been sown.
But naturally it is also possible t~ ~pply ~irst the herbi-
'~
: ' .
cide and then the antidote to the ~oil, Finally, it wouldalso be possible to pre~reat the ~eeds themselves first
with the antidote and then to so~ them in the soil, which
has either been treated with the herblcide or in which the
herbicide will later be incorporated. ~ is essential that
the addition o~ the antidote doe~ not lmpair the herbicidal
action oE the chloracetanilide ol1 th~ weeds.
The amount of antidote used varies between about
0.01 and abou~ 1 pflrt by weight pe~ p~t by welght oE
the haloacet~nilide. According ta cir~stances, i.e.
depending on the chloroacetanilide and àntidote used and
the corp plant, the most suitable ~atio for attaining the
most ideal actlvity is ascertainèd.
Experiments have proved, for example, that by
treating sown maize fields with 2 kg/ha of a chloracetanilide
alone there occured total injury after 3 1/2 weeks, but
treatment with a mixture of the same amount of this chloro-
acetanilide and 0.5 kg/ha of an ~ntidote caused no injury
at all to the maize, while weeds s~ch as Sorghum hybridum,
Echinochloa and Setaria were jus~ ~s ~ompletely destroyed
as without the antidote.
'`
.~
~ 1 6~6
dependin~ on the chloroacetanilide and antidote used and the crop plant,
the most suitable ratio for attaining the most ideal activity is ascertained.
Experiments have proved, for example, that by treating sown
maize fields with 2 kg/ha of a chloroacetanilide alone there occurred total
injury after 3 1/2 weeks; but treatment with a mixture of the same amount
of this chloroacetanilide and 0.5 kg/ha o:E an antidote caused no injury at
all to the maize~ while weeds such as Sorghum hybridum, Echinoclea and
Setaria were just as completely destroyed as without the antidote.
Preferred antidotes of the formula II are
CH2=CH- CH
\ N~N-diallyl-dichloroacetamide,
N-CO-CHC12
/ n20 = 1,5036
CH2=CH-CH2 D
CH2=CH-CH2
\ N-ethyl-N-allyl-dichloracetamide
N-CO-CHC12
C2H5 nD = 1,4954
CH2=CH-CH2
\ N-isopropyl-N-allyl-dichloracetamide
N-C0-CHC12
3)2cH nD = 1,4921
CH2- CH2
-` / \ N-dichloroacetyl-2~2-dimethyl-1,3-
0 / N-C0-CHC12 oxazolidine m.p. = 119-121
' / \
CH3 CH3
The invention ~herefore provides a method for the selective control
:
- 11 -
1 3 B~3B
of weeds in maize cultures, which consists in treating the seeds or the
crop areas intended for the cultivation of maize in which the seeds are to
~e sown, or which have been sown, or in which the seeds have already
germinated, simultaneously or successively, in optional saquence and in
an appropriate interval of time, on the one hand with a herbicide, the
chloroacetanilide of the formula I, and on the other with an antidote of the
N,N-disubstituted dichloracetami.de of the above formula II which protects
the germinated crop plants and/or the seeds thereof.
The invention is also concerned with an agent for selective control
of weeds in maize, which contains as herbicidally active component the
chloroacetanilide of the formula I as well as an atidote of the formula II.
- 12 -
~f
The followil-~" ~ests were carried out to determine
the selecti.ve herbicidal actinn of chloroacetanilides of
the for~-nula I alone and togetheL with anti~otes of the
, formula II:
Pre-emer~_nt ap~lication
N-(2'-me~iloxyethyl)-2,6-dime~hy]-chloroace~an,i].ide (A) o
the formula
c~3
~, ~/ C~l ~CH ~O-CH~
\~ N 2 2 J m.p. ~ 42~45
\===,~\ CO - CH 2C l
CH3
was used as herbicidal active substance.
This compound was manufactured by reacting 2,6-dimethyl-
aniline with methoxyacetaldehyde dissolved in benzene in
the presence of trimethylamine by boiling to give 1-(2'-
methoxy~ethylidene-amino)-2,6-dimethylbenzene (b.p. 58-
61C/O.l Torr), converting this product by hydrogenation
in ethanol with palladium-charcoal to N-(2'-methoxyethyl)-
2,6-xylidine (b.p. 64C-65~C/0.2 Torr), and reacting this
latter as a suspension together with potassium bicarbonate
in benzene with chloroacetyl chloride.
N,N-diyllyl-dichloroacetamide (B) and N3-dichloroacetyl-
2,2-dimethyl-1~3-oxyzolidine (C) were used as antido~,e, bo~h
substances described in German OE~enlegungsschrift2.21$~0~7
- 16 -
g
(Lxamples 1 and 42), as well as N-ethy'l.-N-al.lyl-dichloro-
acetamide (D) and N-isopropyl--N-al].yl~dlchloroacetamide
(E). Aqueous stock broths(suspenslorls) were prepared from
wettable powders based on substances A, B, C, D, and E,
and these suspenslons were applled 'both ~ingly and as
mixtures, in the i.ndicated concentra~lons and mixture
ratios, immediately after the test plants had been sown
in seed dishes in a greenhouse, to the surface of t'he soil
in the dishes, The seed dishes were then kept for 24 dags
at 22 to 23C and 50% to 70% relative humidity while
appropriately watering the dishes and the emergent plants.
The results were evaluated ater 13 and 24 days accordi.ng to
a scale of rating from 1-9:
9 = plants not injured (as untreated control)
1 = plants completely withered
2 to 8 = intermediate stages of injury
As test plants there were used:
crop plant: maize ("Orlea") [Zea]
weeds: Sorghum hybridum
Echinochloa crus galli
Setaria it.alica
Digitaria sanguinalis
Bromus tectorum
The results are tabulated 'below,
The amounts in kg/ha are in the ollowing relation to other
units of measurement:
1 k~/ha = 0.1 ~/m2 _ 2 mg ~er l;tle of soil,
the depth of the seed dishes i5 5 cm, so ~hat 1 m~ - 50
litres of soil.
Table I
,
Herbicide A Antidote s Antidote B
amount in after 13 days after 24 days
Plant kg/ha amo~mt in kg/ha amount in kg/ha
3 2 1 0,75 0,5 072! ,~ 2 1 ;0,75 0,5 0,25
. _ _ _ _ __ _ _ _ _
9 9 9 9 9 9 9 9
~aize 0,25 9 9 9 9
0,5 ~ 9 8 9
0,75 7 9 6 9
1,0 6 9 9 5 9 9
2,0 ~ 7 8 ~ ~ 8
_ _~ _ _ __ _ _ _
~ 9 8 9 9 9 9 9 9
Sorghum 0,25 2 2 1 2
0,5 1 2 1 1
0,75 1 1 1 1
1,0 1 1 1 1 1
2,0 1 1 1 ~ 1 1
_ _ _. _ _ _ _ _ _
0 9 6 8 9
crus galli 0,25 2 1 1 1
0,5 1 1 1
0,75 1 1 1 1
1,0 1 1 1 1 1
2,0 1 1 1 1 1 1 1
_ _ _ . _ _ _ _ _ __
Stealarica 0 55 1 5 1 1 1 1 7 9 1 1
1 075 1 1 1 1 1 1 1 1
2,0 1 1 1 1 1 1 1
_ _ _ _ _ _
0 9 9 9 99 9 9 9
Digitaria 0,25 1 1 1
sanguinalis 0,5 1 1 1 1
0,75 1 1 1 1
1,0 1 1 11 1 1
2,0 1 1 1 11 1 1 1 ..
- `
~ 1 6~
Table II
_ __ _ __
Herbicide A Antidote C Antidote C
amount iD after 13 days after 24 days
Plant kg/ha amount kg/ha amount ln ~g~ha
0 2 l 0,75 ~0,5 0,2' 0 ~ l 0,75 0,5 0,75
_ __ ~ _ _ . _ _ _
0 9 9 9 9 9 9 9 9
Maize 0,25 9 9 9 9
(Orl~) 0,5 8 9 8 9
0,75 7 8 6 9
l,0 6 8 8 5 9 9
2,0 ~ 8 7 1~3 ~ 7
__ _ ~ _ l _ _
hybgrhiUdmum 0 25 2 9 9 2 2 1 9 9 2 2
~,75 l 2 1 2
1,0 1 2 2 l 1 l
2,0 1 2 1 l l
_ _ _ _ I i _ _ _ __
O 9 9 9 9 9
crus galli 0 25 2 l 1 1 l
0,75 1 1 1 l
~ . 1,0 1 1 1 1 1 1
2 0 1 1 l l l l l 1
_ ~ _ ~ _ I _ _ _ _
0 9 9 8 9 9 7 8 9
italica o,255 1 1 l 1 1 l
0,75 1 1 l l
1,0 1 1 1 1 1 1
_ 2,0 1 1 1 1 l l 1 .
0 9 9 9 9 9 9 9 9
Digitaria o 255 1 1 1 1 1
0,75 l l l l
1,0 1 1 1 1 1 1
2,0 1 ~ ~ l l 1 ~ l
/ 7 -
---' ~- ~. .
I
$ 8 ~
Table II~
Pl.ant ~lerbicide A ¦ An~ldote D Antidote E
.~mount in 1 after 24 days after 24 c1ays
kg/ha amoun~ in kg/ha amount in kg/ha
O 21 l1 0,5 O 2 ~. 10.5
. ~ __. _~ I . ~.. ~ ~ ___ _ ~
O 9 9 g 9 9 9 ~ 9
l~aize 0,5 8 9 5 9 ~ 9 9 9
~Orla) l,O 3 9 9 9 3 9 9 9
2,0 2 9 9 2 9 ~
~ ~ _ ~ __ ____ ___ _ __ .____ ___
O 9 9 9 ~ 9 9 9 9
Sorghum 0,5 2 2 2 2 2 2 2 l
hybridum 1 0 2 21 2 2 21 21 21 2
. . __ _ _ ___~ _ ~___.
O 9 9 9 9 9 9 9 9
Echinochloa 0,5 l 1. l l l l l
crus galli l,O l l l l l l l
2,0 l l l ~. l l
_~ . _ __ _ ~
O 9 9 9 5 9 9 9 9
Setaria 0,5 2 l l l 2 l l
italica l,O l l l 1 l l 1.
2,0 l l l l l l ~
_ _ _ _. _.__ . _ __ . __ __
: . O 9 9 9 9 9 9 9 9
Digitaria 0,5 l l l l l l l
. 1,0 1 1 1 1 ' 1 1 1
sanguinalis 2,0 l l l l l 1.
_~ _ __ . _ ___ _ __ ~.
O 9 9 9 9 9 9 9 9
0,5 2 2 2 2 2 2 2 1 2
Bromus
tectorum l,O l 2 l . l l l 2 1 l
.~ . 2,0 l l l ~ 1 l l
___._~_ _ _ _ _ ___~
~ .
-,:
; . , , , , . .. ., . ., ....... .~ . ~.. . . ........ . . .. . . .. . . ... . ~
~ .
.
~ ~ 168~6
The results show clearly that the crop plant maize, which is
virtually completely destroyed after 13 days using a rate o application
of 2 kg/ha of herbicide A alone, suffers no more injury at all even after
24 days using the same amount of herbicide together with only 1/4 the amount
~0.5 kg/ha) of the antidote B, C, D or E, whereas all weeds are just as
severely injured as without the antidote. It can even be seen that better
results are often obtained with the application of smaller amounts of
antidote than with larger ones. No surplus of antidote is therefore
necessary and the ratio of antidote to herbicide can be 1:4.
It is advisable in practice, especially in regions with low
rainfall, not only to apply the agent according to the invention to the
surface of the soil, but to work it into the soil before the crop plants are
sown~ thus preventillg only the perhaps more soluble herbicide from pene-
trating into the soil when rainfall is slight and the antidote which remains
on the surface from not being sufficiently active.
In the above tests, a surface treatment of the soil alone
was sufficient to prove clearly an optimum effectiveness of the antidote
lCI
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