Note: Descriptions are shown in the official language in which they were submitted.
~ t ~
HOECHST ARTIENGESELLSC~AFT HOE 89/F 368 Dr. WE/fe
Description
Herbicidal agents
It is known that the active substance glufosinate-
ammonium (1)
O - +
C~3 - P - CH2 - C~2 - CH - CO~ ~H4 (1),
OH NH2
i.e. the ammonium salt of 4-[hydroxy(methyl)phosphinoyl]-
DL-homoalanine, can be used as a leaf-acting herbicide,
namely, for example, for the non-selective control of
weeds in fruit growing and viticulture, in tropical
plantation crops, in vegetable growing before drilling or
before transplanting, before the direct drilling of maize
or soya beans, and on wasteland such as verges, indus-
trial terrain and railway installations (cf. Z.
PflKrankh. PflSchutz, Special Edition IX, 431 ~ 440,
1981). The active substance mentioned contains an asym-
metric carbon atom. The formula (1) embraces all stereo-
isomers and their mixtures, in particular tlacuna)racemate and the biologically acti~e L-enantiomer. The
racemate is conventionally applied at dosage rates of
between 200 and 1000 grams per hectare (in the form of
the formulated product containing 200 g of a.i./l). At
these dosage rates, glufosinate-ammonium is only effec-
tive if it is taken up via the green parts of the plant.
Since it is microbially degraded in the soil in a few
days, it has no permanent action whatsoever in the soil.
This also applies in a ~imilar way to the related active
~ubstance bialaphos (sodium salt of 2-L ~mino-4-[hydroxy-
(methyl)phosphinoyl)butanoylalanylalanine) of the
formula (2)
2 ~
- 2 -
CH3 CH3 _ ~
CY3PC~2CH2C~CO-NHCHC~-NHCHCOO Na ~2)
O~ NH3
Furthermore, it is known that ~he active substance
imazapyr~ 2 (4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-
yl)-nicotinic acid which belongs to the chemical group of
the Lmidazolinones, can be used in the form of the iso-
propylamine salt of the formula (3)
(CH3)2C~ ~ ~ (CH3)2c~-Nx3
CH3 COO~
as a total herbicide for various indications (10th
Internat. Congr. Plant Protection, 339 et seq., 1983~.
This active substance can be taken up by the plant via
green parts of the plant such as leaf or stalk and also
via subterranean parts such as roots or rhizomes. It is
known for its long action, on the one hand, and, on the
other hand, for the fact that its degradation rate in the
soil-is slow, so that, in consequence, it remains active
in the soil over a long time. It is customarily employed
on wasteland at dosage rates of between 25~ and
1000 g/ha. On areas under culti~ation, imazapyr can only
be used as an exception since even low do~age rates, for
example 125 g/ha, damage most crop plants.
Active sub~tances of the s~me chemical group, such a~,
for example,
Imazamethabenz, i.e. methyl 6-(4-isopropyl-4-methyl-5-
oxo-2-imidazolin-2-yl-m,p-toluenecarboxylate,
Imazaquin, i.e. 2-(4,5-dehydro-4-methyl-4-(1-methyll
ethyl)-5-oxo-1-H-imidazol-2-yl) 3-quinolinecarboxylic
acid, or ;
~ - 3 - 2~3~
Imazethapyr, i.e. (+)-5-ethyl-2-(4-i~opropyl-4-methyl-5-
oxo-2-imidazolin-2-yl)-nicotinic acid,
have a similar type of action, but can also be used in
some crops for the selective control of weeds.
Because of the particularly high water-~olubility of the
active substance imazapyr (62 - 65%, information provided
by manufacturers), there is danger of leaching of the
active substancP after heavy rainfalls and, mainly, on
light soils whose sorption capacity is low, in particular
when substantial amounts are applied.
It is furthermore known that the action of glufosinate-
ammonium and that of its L-enantiomer can be markedly
Lmproved by a substantial number of surface-active
substances, preferably by wetting agents such as alkyl
polyglycol ether sulfates, which are preferably used in
the form of their alkali or ammonium salts, but also as
the magnesium salt, for example sodium C~/Clb fatty
alcohol diglycol ether sulfate, such as ~Genapol LRO (cf.
EP-A-0,048,436 or US-A-4,400,196, and EP-A 0,336,151, and
also EWRS Symp. ~Factors Affecting Herbicidal ActiYity
and Selectivity", 227 - 232 (1988)). In the examples
which follow, this substance is termed Wetting Agent A.
EP-A 0,252,237 discloses that synergism is possible when
glufosinate-ammonium and Lmazapyr are combined, the
~5 application rates used, however, being kept within the
range of the abovementioned quantities.
Surpri~ingly, it has now been found in further experi-
ment~ that the application rate of imazapyr or its
analogs or certain glufosinate/Lmazapyr combination~ or
analog herbicide combination~, which i8 required for a
sufficient action, can ~urprisingly (sic) be markedly
reduced when used against various weed3 by adding a
wetting ayent of the type mentioned.
.
. . .
. ., .. ~ . . . .; : .
2 ~
- 4 _
The invention relates to herbicidal agents which have an
ef~ective content of
- a) one or moxe herbicide~ of the formulae (I) and (II)
or salts thereof
R2
~'_</; ~ ~ N ~
R2 CH(C~3)7 C~(CH3)7
(I) (II)
where
Rl is phenyl, pyridyl or quinolinyl, each of which
is optionally mono- polysubstituted (sic) by
(Cl-C4)alXyl, (Cl-C4)alkoxy, (Cl-C4)haloalkyl,
(Cl-C4)haloalkoxy, a radical of the formulae
-CooR3, -Coo-CHR3-CooR3, -CHR3-COO(C1-C4-alkyl) or
-CHR3-CooCHR3-CooR3l where in each case indepen-
dently of one another R3 radicals are H or
(Cl-C4)alkyl,
or by a r~dical of the formula -CH2-S(O)n-(C1-C4)-
aIkyl where n is 0, 1 or 2, and
R2 is H, or a radical of the formula -CONH(Cl-C4-
alkyl); -OCO( Cl-C4-alkyl ) or -co ( Cl-C4-alkyl ) ~
or a combination of one or more compounds of the
formula (I) or (II) with one or more compounds of
~he formula (III) or salts thereof,
O O
H3C-P-CH2CH2CH-C-Z1 (III) :
0~ NH2
where
~1 i5 a radical of the formula -OM~ :
- N H C H ( C H3) C O N ~ C H ( C H3) C O O M o r ~ :
-NHCH(CH3)CONHCH E CHzCH(CH3)~]COO~ i~ which M in
each case is hydrogen or an inorganic or organic
cation,
'~" :
:, , ' . . .:
2~v~
in a ratio by weight of 1:3 to 1:30 of the compounds
of the formula ~I) or (II) to compounds of the
formula (III)I
b) anionic wetting agents from the group of the C10-Cla-
fatty alcohol polyglycol ~ther sulfates in the form
of the alkali metal salts, ammonium salts or alka-
line earth metal salts or of the ammonium salts
which are substituted by alkyl or hydroxyalkyl
groups, and
c) if appropriate, customary inert additives.
Herbicidal agents which are of particular int~rest are
those which have an effective content of
a) one or more herbicides selected from the group
comprising Lmazapyr, imazaquin, imazamethabenz and
imazethapyr and the salts thereof, or
a combination of one or more of the herbicide~
selected from the group comprising imazapyr, Lmaza-
quin, imazamethabenz and imazethapyr, and the salts
thereof, with one or more of the herbicides selected
~0 from the group comprising glufosinate and bialaphos,
and the salts thereof, in a ratio by weight of 1:3
to 1:30, preferably 1~3 to 1:15,
b) anionic wetting agents selected from the group of
the anionic wetting agents mentioned, and
c) inert additives.
Preferred herbicidal agents according to the invention
are those in which component a) is Lmazapyr-isopropyl-
ammonium or a combination of glufosinate~ammonium with
imazapyr-isopropylammonium in a ratio by weight of 10:1
to 3:1.
Preferred anionic wetting agents are sodium s~lts of
C10-Cl8-fatty alcohol polyglycol ether sulfates.
The compounds of the ~ormulae (I) to (III) are known (~ee
EP-A-0,252,237 and the references cited therein; cf. also
. ~ . ....... . . . ........ . . .... . . ... . .. . . . .
- 6 - 2~
"The Pesticide Manual", British Crop Protection Council,
8th edition, 1987). They also embrace all stereoisomers
including ~he pure enantiomers which are possible, and
mixtures thereof.
In the event that R2 is H, the two formulae (I) and (II)
are in an equilibrium of tautomers. Depending on the
radicals R2 and ~he remaining substituents, there can
therefore exist one or the other form (I or II) or a
mixture of the two forms, see DE-A 3,121,636 and DE-A
2,833,274.
The compounds of the formulae (I) to (III) which are
employed according to the invention also embrace the
salts which can be employed in agriculture. Examples of
suitable salts are the customary alkali metal salts,
alkaline earth metal salts, ~ubstituted or unsubstituted
ammonium, phosphonium or sulfonium salts. Particular
emphasis amongst the alkali metal salts and alkaline
earth metal salts must be given to the Na, K, Mg or Ca
salts.
Furthermore, the compounds of the formulae (III) also
embrace acid-addition salts with inorganic acids such as
HCl, HBr, H2SO4 or H3PO4, or with organic acids such as
(Cl-C4)carboxylic acids, chlorinated acetic acids, tar-
taric acid or citric acid.
The herbicidal agents accordi~g to the invention can be
in the form of mixed formulations of the components
(active substance + wetting agent) which are then applied
in a customary mann~r in the form of a dilution with
water, or they can be prepared as so-called tank mixes by
mixing the unformulated, or separately formulated, acti~e
substances with the wetting agent, and diluting the
combination with water. If necessary, further wetting
agent can be added to the spray liquor before applica-
tion. -
7 2 ~ ~ 9 1 ~ L~
The herbicidal agents can be ~ormulated in various ways,
as predetermined by the biological and/or chemico-
physical parameters. The following are suitable formula-
tion possibilities: wettable powder~ (WP), emulsifiable
concentrates (EC), aqueous solutions (S~), emulsions,
sprayable solutions, dispersions on an oil or water base,
suspoemulsions, dusting powders (DP), seed-treatment
agents, granules for soil application or for broadcasting
(FG), water-dispersible granule~; (WG)I ULV formulations,
microcapsules or waxes.
These individual types of formulations are known in
principle and are described, for example, in: Winnacker-
Kuchler, "Chemische Technologie [Chemical Technology]",
volume 7, C. Hauser Verlag, Munich, 4th edition, 1986;
van Valkenburg, "Pesticides Formulations", Marcel Dekker
N.Y., 2nd Ed. 1972-73; ~. Martens, ~'Spray Drying Hand-
book", 3rd Ed. 1979, G. Goodwin Ltd. London.
Preferred formulations are those in the form of emul-
sions, aqueous solutions, sprayable solutions, emulsifi-
able concentrates and water-dispersible granules.
The customary additives which the agents according to the
invention can contain are those which are necessary or
advantageous for preparing the specific types of formula
tions.
Customary additi~es for preparing a~ueous solution~ and
emul~ions such as, for example, water, organic solvents
and further anionic and non-ionic surfactants, are
preferred.
Example~ of pre~erred solvents are alcohols such as
methanol, ethanol, propanol, isopropanol, n~ , t- and
2-bu$anol. Preferred ~urfactants are polyalkylene glycol
monoalkyl ethers and polyalkylene glycol dialkyl ethers
such as propylene glycol monomethyl~ ether and propylene
glycol monoethyl ether, perfluoroalkyl-containing
, ~. : ` , ,, , . ' '' :
': , - : '' ' ,.;,.' ' ' '; ~ ,, ` ' ~
~ 8 - 2~
surfactants such as perfluoro-(C6-Clz)-alkylphosphinic
acids and -phosphonic acids and their alkali metal ~alts,
ammonium salts and alkyl-substituted ammonium salts tfor
example ~Fluowet PP, Hoechst AG).
In general, the agents according to the invention contain
10 to 95~ by weight of component a) and b) and 5 to 90
by weight of customary additives. Aqueous solutions
contain preferably 10 to 40~ by weight, in particular 15
to 30% by weight, of active substances of component a),
10 to 40% by weight, in particular 25 to 35% by weight,
of component b), 30 to 60~i by weight of water and 5 to
30% by weight of customary additives, in particular S-20%
by weight of non-ionic surfactants or solvents.
The agents according to the invention act against a broad
spectrum of weeds. They are suitable, for example, for
controlling annual and perennial weeds such as, for
example, inter alia, Agropyron, Paspalum, Cynodon,
Imperata, Pennisetum, Convolvulus, Cirsium and Rumex.
.~ .
The agents according to the invention can be employed for
selectively controlling harmful plants in plantation
crops such as oil palm, coconut palm, rubber tree~
citrus, pineapple, cotton, coffee, cocoa, etc., and in
fruit growing and viticulture. The combinations according
to the invention can likewise be employed in arable
farming using the so-called "no till" or "zero till"
method. ~owever, they can also be used non-selectively on
paths, squares, indu~trial terrain etc. so as to keep
these areas free from undesired plant growth.
.: .
Herbicidal agents according to the invention which do not
contain a compound of the formula (III) can be employed,
in particular, in wasteland for controlling a broad
spectrum of annual and perennial weeds, and in planta-
tions of rubber treeq and oil palmæ; in this context, the
application rate of the active ~ubstance of ~he formula
- (I) and/or (II) can be markedly reduced in comparison
- g -
with agents without component b) according to the inven-
tion. The danger of leaching of the active substance and
hence the risk of contaminations of the ground water i9
likewise reduced.
Herbicidal agents according t:o the invention which
contain a compound of the formula (III) can be employed
very advantageously in fruit growing and viticulture,
including citrus cultures, in addition to the indications
mentioned. One advantage is the fact that an addition of
the wetting agent b) results in an acceleration of the
uptake of the active substances of the formula (I) or
(II) and that relatively low dosage rates of the active
substances (I) or (II) and (III) suffice for achieving a
good action. Moreover, rain-fastness of the active
substances of the formula (III) is also considerably
improved. A particular advantage which is important here
is that the effective dosage rates, which are used in the
combinations, of compounds of the formula (I) and/or (II)
are so low that their action via the soil is considerably
reduced. This not only makes their application in sensi-
tive crops possible in the first place, but contamina-
tions of the ground water are virtually avoided.
The combination according to the invention of acti~e
substances and wetting agents makes possible a consider-
able reduction of the necessary application rate of the
active sub6tances.
The invention therefore also relates to a method of
controlling undesired plant growth, which comprise
applying, to the plants or the area under cultivation,
a) one or more herbicides of the mentioned formulae ~I)
and/or (II), or salts ~hereof, or a combination o~
one or more c~mpounds of the formula tI) and/or
- (II), or salts thereof, with one or more compound~
of the mentioned formula (III) or salts thereof, the
ratio ~y weight of (I) or (II) to tIII) in the
combination b~ing 1:3 to 1:30, preferably 1:3 to
~ - lo 2~
3:15, together with
b) an anionic wetting agent selected ~rom the group of
the C10-C18-fatty alcohol polyglycol ether sulfates in
the form of the alkali metal salts, ammonium (~ic),
alkaline earth metal salts or alkyl- or hydroxy-
alkyl-substituted clmmonium salts.
The application can be effectecL in such a way that the
components are mixed and applied together, or the com-
ponents are applied in Lmmediate succession in a suit- :
able, separate or partly-ç,eparate, formulation.
In general, the applica~ion rate is 10 to 400 g/ha, ~
preferably 25 to 200 g/ha, in the case of the compounds -
of the formula (I) and/or (II), and salts thereof, and 50
to 800 g/ha, preferably 200 to 600 g/ha, in the case of
compounds of the formula (III) and salts thereof.
The amount of component b) is generally around 500 to
2500 g/ha, preferably 700 to 1500 g/ha. : ~
:.~ ' . '
Formulatio~ E~amples
In the examples which follow, wetting agent A is the :~-
sodium salt of C,2/Cl4-fatty alcohol) (sic) dieth~lene :
glycol ether sulfate (~Genapol LRO, ~oechst AG)
~ample 1
To a solution of :
11.50 g of imazapyr-isopropylammonium in
48.25 g of water
there are added
30 g of wetting agent A (70% strength in H2O)
and
10 g of propylene glycol mo~omethyl ether. The
mixture i~i stirred at 40C until a clear olution ha,s
formed.
: .
11- 2~
0.25 g of Fluowet PP (80% strength in water) is
then added, and stirring is continued for a short time.
Example 2
To a solution of
22.30 g of imazapyr-isopropylammonium in
37.45 g of water
there are added
30 g of wetting agent A (70% strength in water)
and
lO g of isopropanol. The mixture is stirred
until a clear solution has formed.
0.25 g of Fluowet PP (80~ strength in water) is
then added, and stirring is continued for a short ~Lme.
E~mple 3
To a solution of
18.00 g of glufosinate-am~onium and
2.25 g of Lmazapyr-isopropylammonium in
39.50 g of water
there are added
30.00 g of wetting agent A (70% strength in water)
and
10.00 g of propylene monoglycol monomethyl ether.
The mixture is stirred at 40C until a ~lear solution has
formed.
0.25 g of Fluowet PP (80~ strength) is then
added, and stirring is continued for a short time. r
~ample 4
To a solution of
18.00 g of glufosinate-ammonium and
4.50 g of Lmazapyr-isopropylammonium in
37.25 g of water
there are added
30.00 g of wetting agent A (70~ strength in water)
.. , ~ ' . , `~ ~ .
~ - 12 - 2~
and
10.00 g of propylene glycol monomethyl ether and
0.25 g of Fluowet PP (80% strength)
and the mixture is stirred until a clear solution has
5 formed.
Example 5
To a solution of
9.30 g of L-glufosinate-ammonium and
2.30 g of imazapyr-isopropylammonium in
48.15 g of water
there are added
30.00 g of wetting agent A (70% strength in water)
and
10.00 g of propylene glycol monomethyl ether.
Stirring of the mixture at 40C is continued until a
clear solution has formed.
0.25 g of Fluowet PP (80% strength) are then
added, and stirring is continued for a short time.
.
Use Examples
E~ample 6
For a model experiment, peas were sown in pots tdiameter
10 cm) which had been filled with a loam/sand mixture;
the pots were subsequently placed in the open until the
emerged plants had fo~med 3 to 4 leaves. They were then
treated with imazapyr on its own (in the form of the
commercially available preparation ~Arsenal with 250 g of
a.e./l; a.e. = acid equivalent) or as a mix~ure wi~h the
wetting agent A (WA A = ~Genapol LRO li~uid with 290 g~l
~detergent~' = D, i.e. effective wetting agent)~ Water was
used in amounts of 300 l/ha. 3 to 4 hours after the
treatment, some of the pots were exposed to an artifical
rain of about 10 mm. The dosage rate of wetting agent was ~v
870 g of SAS/ha. The effect of the treatment can be seen
from Table 1 below:
:.
~ - 13 - 2~
Table 1
. ~ae n t and Action in %2) . .
application No rain _ No rain
ratel ) 2 wat ~ wat 2 wat 4 wat
:,
~~ a-~- Va~iar.~ P Va~~a~
~',2; 0 i5 0 5~
~.; 20 50 20 5a
125 3C ;3 35 70
.~ 37 72 ~0 83
-,a-ap~r WA A Va-ia~- C Variant ~ ,.
3~.2; 87G 30 65 25 60
62,5+ 870 50 83 35 70
'2;+ ~70 55 9S 40 85
250~ 870 65 93 58 90
~A A 870 0 0 __ 0
Application rate of imazapyr in g of a.e./ha
Application rate of wetting agent A in g of D/ha
2) Action in ~ (100 = complete destruction, O = no
damage),
wat = weeks after treatment
It is evident from the figures
1. that ths action of imazapyr is not very powerful yet
after 2 weeks, but, in contrast, considerably more
powerful after 4 weeks (variant A);
2. that the action of Lmazapyr increases after an
overhead irrigation treatment (~ariant B), which can
be explained easily by the fact that the active
substance which has been washed off the leaf now
acts on the plant via the ~oil;
3. that the initial and the final action of imazapyr
increases oonsiderably when wetting agent A is added
.. . . ~
. .. : ~ : ,
, .
- 14 - 2 ~ L~
(variant C);
4. but that, in contrast to variant B, the action of a
treatment with imazapyr + wetting agent is lower
with overhead irrigation (variant D) than in variant
S C without overhead irrigation, but considerably more
powerul than in variant B or, especially, in
variant A.
This permits the conclusion that uptake of the active
substance Lmazapyr via the leaf 7 5 considerably acceler-
ated by an addition of wetting agent A.
Example 7
In a field trial for controlling the perennial weed
twitch ~Agropyron repens), plots of size 10 m2 were
treated with various dosage rates and combinations
according to the invention of glufosinat~-ammonium,
imazapyr and wetting agent A, and the e~fect on the
visible green matter was scored by comparison with an
untreated control (see Table 2).
Colby's formula was used for assessing the combination
action:
E = X + y _ XY ~
100 :'. .
where E is the effect (in %) expected from the combina
tion of the active substance X with the active substance
Y (cf. Weeds 15, 20 - 22, 1967). In the combination
treatment, this effect to be expected is gi~en in brac-
kets in front of the effect which was actually achieved.
In Table 2, WAA = ~Genapol LRO with 290 g/l detergent, D
(dosage in g of D/ha), GLUA = glufosinate-ammonium
(dosage in g of a.i./ha) and IMZP = imazapyr ~dosage in
a.e./ha). The column under X indicates the number of the
tests which were used as a reference for the calculation
- using Colby's formula.
~, .. ~ .
- 15 - 2~ 1
Tahle 2 Action in
_ _ . _ Weeks aft r treatment
~roducts and dosage X 4 _ _ . _
G_~A :~? WA A _ _ ___________
1. 2C5 60 0
2. 2C~ ~ 1000 75 lO
'. ~00 8S 25
4 ~ + 1000 92 30 i~
5. 600 a5 30 0
6. 600 + 1000 9S 50 C
7. 2; 10 10 0
&. 2; 1 1000 40 30 ~0
9. 50 25 45 35
10. 50 + 1000 45 55 . ~
~1. 200 ~ 25 1~7 (64) 70 (') 20 ( ) 0
12. 200 + 25 t 1000 2~8 (85) 91 (37) 75 (10) 65
~3. ~C0 + 25 3+7 (86,5) go (32.5) ~0 ( ) 1
'~ 0 + 25 1 1000 4+8 (95,2) 95 (51) 87 (lO) 7
1~. 600 ~ 25 5+7 (95.5) 95 (37) 50 ( 0) 1
16. 600 + 25 + 1000 6+8 (97) 96 (6~) 90 (10) 8
17. 200 + 50 1+9 (70) 72 (45) 50 (35) 4
18. 200 1 50 + 1000 2+10 (86.2) 93 (59.5) 85 (40) 7
19. 400 + 50 3+9 (a8,7) 96 (SB,7) 65 (35) 40
20. 400 1 50 + lO00 4+10 (95.6) g6 (68,5) 9~ (40) 8
21. 600 + 50 5l9 (96.2) 98 (61.5) 72 (35) 45
22. 600 + 50 + 1000 6~1C _(97.2~_99 ~ (40) o~
. , . .. ..... . . .,, ,. ~,.. . . . .
- 16 -
The conclusions from this experiment are:
1. Glufosinate-ammonium dosage rates of 200 to 600 g/ha
result in a relatively rapid visible action; in some
cases, the scores 2 weeks after the treatment were
S e~en higher than the val~es for 4 weeks after the
treatment, shown in Table 2. The action was slightly
improved by adding the wetting agent; this was
evident even 8 weeks after the treatment when the
new growth from the perennial organs in the soil,
the rhizomes, was assessed; however, 4 weeks later
the stand has regenerated completely and no action
whatsoever can be detected.
2. As expected, imazapyr treatments with 25 or 50 g/ha
had only a very slight action which, howe~er, was
Lmproved by adding the wetting agent.
3. 4 weeks after the treatment, the combinations of
glufosinate-ammonium + Lmazapyr had a similar
effectiveness as glufosinate-ammonium on its own,
or only slightly better. A markedly better action
which was above the action to be expected was
revealed 8 weeks after the treatment, but was lost
again 12 weeks after the application.
4. In contrast, if the Wetting Agent A was added to the
mixturementioned, the scores (lacuna) 8 and 12 weeks
were markedly higher, in some cases substantially
higher, than the values which would have been
expected using Colby's formula on the basis of the
action of the individual active substances. Assuming
that the action via the soil, of the relatively low
imazapyr dosage rates, is independent on the wetting
agent, it can be concluded that imaæapyr uptake via
the leaf and the translocation to the subterranean
parts was considerably improved by adding the
wetting agent, which was surprising.
: .
~,J ~ /9 ~
- 17 -
Example 8
In a 3-year old apple plantation, various treatments were
effected in the rows of the trees in spring, at the end
of April; the weeds which occurred were mainly various
perennial grasses and, inter alia, thistles (Cirsium
arvense), and ground ivy (Glechoma hederacea). (lacuna)
effect on the weeds and the compatibility with the crop
plants were recorded at intervals. The apple trees did
not come in contact with the spray liquor (see Table 3).
Table 3
... . ~ .
Products and dosages in g Action (%) Damage
of 2* ' 3* ~* 3*
a; fha, a.e./ha and g of
Gufosinate- Imazapyr WA A
ammonium
500 125 80 85 marked
500 125 1000 95 98 damage
500 50 50 55 no ;
500 50 1000 90 85 damage
_ . .. _
* = months after treatment
~5 As expected, the actio~ (sic) of combinations with a -~
higher proportion of imazapyr were more effective over a
longer period o~ tLme, the variant with an addi~ion of
wetting agent performing even better than those without
wetting agent. However, in both treatment variants,
marked damage on the shoot tips of the tree occurred
after 1.5 to 2 months, which led to a standstill of
growth; the symptoms corresponded to normal i~azapyr
symptoms, the active substance obviously having bee~
taken up via the root (sic).
.. ".. ~. ... .. , . .... , . . ,. . ~ , ~ , .
. . ~ , . , ~ - .................................... -
", , , .,. i . ~ ~ ' : ' ''
~ - 18 - 2~
If the application rate of imazapyr was reduced, the
development of the weeds dLminished to such an extent
that it was (sic) insufficient 2 - 3 months after the
treatment. However, damage occurred no longer in this
case. The same herbicide combination with an addition of
wetting agent resulted in a cons:iderably Lmproved action
against weeds, which could be assessed as satisfactory
even 3 months later. In this treatment, damage to the
trees was not observed either.
Example 9
In a field trial in (sic) barley as a monocotyledon test
plant, plots were treated with glufosinate-ammonium in
combination wikh very small amounts of imazapyr, with and
without the addition of Wetting Agent A. At the point of
tLme when the treatment was effected, the plants were in
the tillering phase. The amount of water applied was
about 300 l/ha. 3 hours after application, some of the
plots were exposed to an artificial overhead irrigation
of about 10 mm. The result in the form of score figures
two weeks after the treatment is shown in T~ble 4.
.
Table 4
Products and dosages in g of a.i./ha, without with ~ .
g of a.e./ha and ~ of D/ha overhead overhead
irrigation irrigation
. .................................. . .. _ . ... _
Glufosinate- Imazapyrwetting
ammonium agent A
500 0 0 90 20
30500 1000 95 45
0 20 0 0
0 201000 0 ~
500 20 0 92 50
500 201000 95 B5
_
............... .. . . . .. . ... . .
- 19 - 2~
The result shows that glufosinate on its own or glufo-
sinate plus wetting agent showed good effectivene3s/ and
that the action in both variants declined very rapidly
when an overhead irrigation was carried out 3 hours after
the treatment, the decline being not quite as pronounced
when a wetting agent was added. By no means however was
the action sufficient for conditions encountered in
practice. Low amounts of 20 g/ha was without ef~ect,
without and with the addition of wetting agents.
Glufosinate-ammonium plus imazapyr were very effective,
in contrast, the action in the plot with overhead irriga-
tion was entirely insufficient. Only in the treatment
according to the invention, the combination glufosinate-
ammonium plus imazapyr plus wetting agent A, was the
action so good even in the plot with overhead irrigation
that it could be called satisfactory under co~ditions
encountered in practice.
Similar results can also be achieved when, in place of
- glufosinate-ammonium, its L-enantiomer or, alternatively,
the active substance bialaphos is used. Likewise, the
active substance imazapyr in such combinations can be
replaced by another active substance from the same group,
for example imazamethabenz, imazaquin or imazethapyr.
. ~
