Herbicidal treatments for control of Papaver somniferum L.

Sections

ABSTRACT
Introduction
Materials and methods
Results
Discussion
Acknowledgements

Details

Author: Menashe HOROWITZ
Pages: 33 to 43
Creation Date: 1980/01/01

Herbicidal treatments for control of Papaver somniferum L. *

Menashe HOROWITZ
Division of Weed Research, Agricultural Research Organization, Newe Ya'ar Experiment Station, P.O. Haifa, Israel

ABSTRACT

Fifty-five commercially available herbicides were evaluated for possible use to destroy illicit opium poppy crops (Papaver somniferum). In the first stage, herbicides were sprayed on poppy plants grown in containers. The following compounds killed poppy plants: (a) herbicides with typical foliar activity - amitrole, bromoxynil, 2,4-D, glyphosate, ioxynil and paraquat; and (b)herbicides with root and foliar activity-the triazines ametryn, atrazine, metribuzin, prometryn, simazine and terbutryn; the substituted ureas benzthiazuron, chloroxuron, diuron, fluometuron, linuron, methabenzthiazuron, neburon and phenobenzuron; and the miscellaneous compounds karbutilate, methazole, oxadiazon and pyrazon. Severe but sublethal injury was caused by cycloate, EPTC, molinate, pobulate, cacodylate + MSMA, ethofumesate, perfluidone and phenmedipham. Abnormal development of vegetative or reproductive parts of the plant was induced by benefin, butralin, dinitramine, pendimethalin, trifluralin, diphenamid, napropamide, dalapon and propham.

Efficient herbicides with negligible persistence in soil at the doses applied were evaluated on poppy plants in the field at various stages of growth. Small plants were severely injured by 2,4-D, killed rapidly by bromoxynil, ioxynil, paraquat (in mixture + diquat), and more slowly by glyphosate and metribuzin. The resistance to herbicides increased with the age of the poppy plant. Severe damage with partial kill of developed plants was obtained with bromoxynil, ioxynil, glyphosate, and paraquat + diquat; the last treatment produced the fastest effect.

Introduction

One of the means of limiting the narcotic drug problem is to eradicate the production of narcotic plants at their source. The present work was undertaken as part of a binational effort to provide the appropriate authorities with a choice of chemicals for effective destruction of illicit stands of narcotic plants such as cannabis (Cannabis sativa L.) and poppy (Papaver somniferum L.). Results of experimental herbicidal treatments of cannabis have already been published ("Herbicidal treatments for control of Cannabis sativa L.", M. Horowitz, Bulletin on Narcotics, vol. XXIX:1, 75-84, 1977), and the present paper deals with chemical control of poppy plants.

*Contribution from the Agricultural Research Organization, Israel; 1979 series, No. 244-B.

Poppy plants are grown legally in many parts of the world, for their seeds, which are used for oil extraction or baking, and for the alkaloids which are extracted mainly from capsules or gum. Several herbicides selective to poppy are available and are often used to kill the weeds infesting poppy fields. The purpose of this investigation was just the opposite-to screen for herbicides which will destroy poppy plants as rapidly and as completely as possible.

The appropriate chemicals were chosen from among herbicides reasonably safe from the toxicological point of view and approved for normal agricultural use. The ideal herbicide should be applied on illicit poppy plants which have been detected; thus it must be active in post-emergence treatment. Since the drug is extracted mainly from the capsules, the herbicide should either completely kill the plant or at least prevent flowering and/or the normal development of the capsule. Techniques of delivering the herbicide were not investigated since the technology of spraying herbicides, from the ground and from aircraft, is readily available and in common use in agricultural practice.

The herbicide used for the destruction of illicit narcotic plants should have a minimum impact on the environment, i.e., negligible drift and limited persistence in soil. Drift toward surrounding crops is a frequent problem in the use of agricultural sprays, especially when they are applied by aircraft. Techniques for drift reduction are practised; for example, utilization of low-volatile formulations of 2,4-D. More particular is the prerequisite of using herbicides with a relatively short soil persistence, so that treated fields can be replanted with alternative crops.

In the first stage of this work, herbicides from different chemical groups and having various types of foliar activity were sprayed on poppy plants grown in containers and the plants' responses were observed until flowering. In the second stage, efficient herbicides with limited residual effect were evaluated in field experiments.

Materials and methods

Most trials were carried out on poppy plants of the variety P.I. 223798 (Afghan origin, white flowers); another variety used for some trials was P.I. 221946 (also Afghan origin, violet flowers). The seeds of both varieties were obtained from the Plant Introduction Service of the U.S. Department of Agriculture.

Screening of container-grown poppy

Poppy plants grown in small containers were very sensitive to soil diseases and to both lack and excess of soil moisture; after preliminary trials, the following growth procedure was used. Seeds were sown in 150-ml plastic cups with drainage holes at their bottom, filled with autoclaved local soil. The cups were maintained in a cool room (15°-20°C) until complete emergence, and then placed outdoors in a screenhouse. Because of the sensitivity of poppy plants to high temperatures and drought, the period of experimentation was limited to winter and spring. Herbicide evaluation was carried out during three seasons, from 1973/74 to 1975/76. During this period, in the screenhouse, the monthly minimum temperatures varied from 6.5° to 13.1 °C, and the monthly maximum temperatures from 14.0° to 27.7°C.

Altogether 55 herbicides were tested in 13 series; each compound appeared in at least one series, and those of particular interest were included in several series. Each herbicide was applied at two doses, single and double, in 200 1 water/ha, with an automatic sprayer; an untreated control was included in each series. Each treatment was tested in five replications. Plants were selected for uniformity and had between two and six true leaves at the time of treatment. After spraying, treated plants were kept in the screenhouse for observations, in general until flowering. They were top-watered, according to need, except for three days following the spray treatment.

Although conditions varied slightly between series, herbicides included in different series produced similar results, and therefore the various treatments were comparable.

Field experiments

Three field experiments were carried out on typical clay soil, at the Newe Ya'ar Experiment Station.

Experiments 1 and 2: Seeds of the variety P.I. 223798 were sown on 17 November 1974. The plants of Experiment 1 were sprayed on 23 January 1975, when at the rosette stage with l0 to 14 leaves. The first rain (5 mm) fell three days after spraying. The plants of Experiment 2 (25-50 cm tall) were sprayed on 25 February 1975. Rain started to fall about 10 hours after spraying; the rainfall totalled 11 mm during the three days following the treatment.

Experiment 3: Seeds of the variety P.I.221946 were sown on 15 January 1976; the plants were sprayed on 20 April 1976, when they were 60-80 cm tall and just before flowering. No rain fell during the two weeks following the treatment.

Rows were sown 50 cm apart and were 100 m long. Each plot consisted of three rows and was 5 m (Experiments 1 and 2) or 8 m (Experiment 3) long, and each treatment was replicated four times. Spraying was carried out with a portable knapsack-sprayer working at a spray volume of 200 l/ha. In accordance with the safety regulations of the Israel Ministry of Health, the field experiments had to be destroyed when flowering started in the control plots.

Results

Screening of herbicides on container-grown poppy

A total of 55 herbicides were tested; of these, 24 compounds caused complete kill and 17 compounds caused severe injury and/or growth abnormalities of the poppy plants.

Herbicides which killed poppy plants

Two types of herbicides were included in this group: six compounds with typical foliar activity, and 18 compounds which act through the roots and/or through leaves. The lowest tested dose which killed the plants, the rapidity at which the plants died, and the persistence of the applied herbicide in soil, are represented in table 1.

Foliar-active herbicides

Herbicides of this type are applied in agricultural practice post-emergence to weeds, and most of them have a negligible persistence in soil.

Amitrole produced a slow discoloration and whitening of the leaves; poppies sprayed with 2500 g/ha wilted and died only after several weeks. Addition of thiocyanate to the amitrole formulation ("amitrole TL") did not improve or accelerate the herbicidal effect.

Symptoms of glyphosate also appeared slowly and gradually. After one week, the foliage lost its turgor and became discoloured. At doses ≥ 820 g/ha, the plants wilted and died within two to three weeks. At lower doses, growth and flowering were impaired but most of the plants remained alive.

2,4-D induced severe nastic effects after a few days, but plants died only after two to three weeks.

Paraquat was very toxic to poppies; scorching of leaves was followed by desiccation and death within a few days. Even at 50 g/ha, the lowest dose tested, the plants were severely injured and failed to flower; at 100 g/ha, all plants died. Diquat was much less effective and even at 200 g/ha only partial kill was achieved. In many tests we used the locally commercialized formulation based on a mixture of 13 per cent paraquat + 7 per cent diquat (as compared with 20 per cent formulations of diquat or paraquat); the mixture was strongly phytotoxic at 200 g/ha.

Bromoxynil and ioxynil also induced rapid desiccation of poppy foliage, and caused kill of the plants within a week.

Phenmedipham caused severe scorching. In one experiment, 825 g/ha killed all plants within two weeks and in another experiment this dose produced strong but sublethal injury.

Root-and foliar-active herbicides

Herbicides of this type are known for their persistence in the soil and their effective weed-kill when sprayed on the soil, in pre-emergence application, and in many cases also when applied at early post-emergence. In our experiments all herbicides were sprayed topically; part of the applied compound may have acted directly through the leaves, and part of it reached the soil, where it was probably activated by the water which was applied by sprinklers a few days later. No attempt was made to differentiate between foliar- and root-uptake. The rapidity at which herbicidal symptoms appear and develop can be considered to be an indication of the foliar activity of the herbicide.

Table 1

Herbicidal treatments which killed poppy plants inscreenhouse trials

Herbicide

Dose (g a.i./ha)*

Rapidity of action**

Persistence in soil***

Foliar-active compounds
     
Amitrole
2500
VS
X
Bromoxynil
660
F
0
2,4-D
375
S
X
Glyphosate
820
S
0
Ioxynil
500
F
0
Paraquat
100
VF
0
Root and foliage activity
     
Ametryn
250
F
X
Atrazine
250
F
XX
Metribuzin
140
F
X
Prometryn
250
F
X
Simazine
250
VS
XX
Terbutryn
250
F
X
Benzthiazuron
3200
VS
XX
Chloroxuron
2000
VS
XX
Diuron
400
VS
XX
Fluometuron
800
S
XX
Linuron
750
F
XX
Methabenzthiazuron
1400
F
XX
Neburon
900
VS
XX
Phenobenzuron
1250
S
XX
Karbutilate
2000
F
XXX
Methazole
1875
F
XX
Oxadiazon
500
F
XX
Pyrazon
1600
VS
XX

* Lowest dose tested in the trials, which killed all poppy plants (a.i. = active ingredient).

**F= fast, plants died within 2 weeks after spraying; VF=very fast, plants died within several days; S = slow, plants died 2.5 weeks after spraying; VS = very slow, complete kill only 5 weeks or more after spraying.

***Persistence of herbicidal activity in soil, at the doses required for killing poppy plants: 0 = negligible, X = short, XX = marked, XXX = long residual effect.

Among symmetrical triazines, applied at 250 g/ha, rapidity and intensity of action ranked as follows: ametryn ≥ terbutryn > prometryn > atrazine > simazine. Simazine was slow acting and its effect was mainly due to root uptake. Metribuzin, an asymmetrical triazine, exhibited rapid and strong phytotoxicity at 140 g/ha.

The tested substituted ureas required higher doses than the triazines to kill poppy plants. Linuron and methabenzthiazuron were most phytotoxic. Fluometuron and phenobenzuron killed poppy plants having four to six leaves within two to three weeks, and benzthiazuron, chloroxuron, diuron and neburon killed these plants within six to eight weeks.

In table 1, the herbicides were listed according to the chemical group they belong to: six triazines, eight substituted ureas, and four miscellaneous compounds.

Several other herbicides belonging to various chemical groups killed poppy plans: karbutilate, methazole, and oxadiazon within two to three weeks and pyrazon at a slower rate.

Table 2

Herbicidal treatments which caused severe injury and/or growth abnormalities on poppy plants in screenhouse trials. Dose in g/ha of active ingredient*

Severe injury

Deformations

Cycloate
7400
Benefin
760
EPTC
7600
Butralin
2000
Molinate
7100
Dinitramine
960
Pebulate
7600
Pendimethalin
660
Cacodylate + MSMA
1000
Trifluralin
960
Ethofumesate
2000
Diphenamid
4800
Perfluidone
1250
Napropamide
2500
Phenmedipham
825
Dalapon
4250
   
Propham
5000

*Lowest dose tested in the trials.

Herbicides which caused serious sublethal damage

Herbicides which caused severe injury or abnormal growth features to poppy plants are listed in table 2.

Four thiocarbamate herbicides, cycloate, EPTC, molinate and pebulate, at ca. 7 kg/ha, killed more than 50 per cent of the treated plants within two weeks; two other thiocarbamates included in the tests, butylate and vernolate, were less phytotoxic.

Among arsonates, the mixture of cacodylate + MSMA-a commercial preparation with strong weed-kill properties-caused severe wilting of poppy plants. MSMA alone was less phytotoxic and DSMA, a related compound, was harmless even at 8 kg/ha.

Effects ranging from severe wilting to complete kill were caused by ethofumesate, perfluidone and phenmedipham.

Scorching, often followed by wilting or by abnormal growth of the leaves, stems and/or flower buds, was induced by several dinitroaniline and amide herbicides: benefin, butralin, dinitramine, pendimethalin, trifluralin, diphenemid and napropamide. These herbicides are essentially soil acting, affecting germination and roots, and the severity of the effects induced by their application on the plants was unexpected. Two grass killers-propham and dalapon-acting mainly through shoot uptake, also caused strong growth effects: the former produced leaf deformations, and the latter, abnormal development of flower buds.

The herbicides alachlor, asulam, barban, difenzoquat, nitralin, nitrofen and pronamide caused little or no injury to poppy plants.

Experiments (not detailed in this paper) indicated that the addition of surfactants to the herbicidal spray could slightly enhance and accelerate the effect of those compounds which are active on the foliage, but would not change the typical pattern of the herbicidal action.

Field experiments. Herbicides which were particularly active in screening tests, with negligible soil persistence at the rates used, were included in field experiments.The three experiments reported were made at various stages of growth-rosette stage in Experiment 1, 20-50-cm-tall plants in Experiment 2, and prior to flowering in Experiment 3.

The most efficient herbicides in the field are listed in table 3. Several compounds which had shown strong phytotoxicity in container trials, such as amitrole and phenmedipham, had an insufficient effect in the field.

Table 3

Effect of herbicidal treatments on poppy plants* in field experiments

Severe Infuriating**in

Exp.1

Exp.2 observed after spraying

Exp.3

Herbicide

Dose a.i. g/ha

1 weeks

4 weeks

1 weeks

4 weeks

3 days

9 days

2,4-D
660 4.4 8.0 5.2 6.8
-
-
Bromoxynil
660 8.0 10 3.6 7.2
-
-
  1320 9.0 10 4.6 7.6
-
-
  1650
-
-
-
-
4.8 8.0
Ioxynil
1000 9.2 10 4.6 6.6
-
-
  1250
-
-
-
-
4.0 8.0
Diquat+ paraquat
200
-
-
5.0 10
-
-
  400 9.6 10 5.8 10 5.4 8.2
  800
-
-
-
-
7.2 9.0
Glyphosate
410 3.6 10 1.8 6.6
-
-
  820 4.4 10 2.6 8.6 1.0 8.4
  1640
-
-
-
-
1.0 8.8
Metribuzin
175 0.4 10 1.8 5.6
-
-
  350 0.8 10 1.8 6.2 1.0 6.2

* Plants were at rosette stage in Exp. l,20-50 cm tall in Exp. 2, and just before flowering in Exp. 3.

** Visual rating from 0 = normal, as in control, to 10 = complete kill. Each note is the average of 4 replications.

2,4-Dcaused abnormal curvature of new leaves two to three days after spraying. Partial wilting and cessation of growth were apparent on both small and developed poppy plants, but most plants remained alive even one month after the treatment.

Bromoxynil, ioxynil, the mixture of diquat +paraquat, glyphosate and metribuzin killed all poppy plants sprayed at the rosette stage (Experiment 1), and were also very effective-although less lethal-on developed plants.

Bromoxynil and ioxynil produced brown, necrotic spots on the leaves a few days after spraying. Young poppy plants died within two weeks after application. Among developed plants about half died, but surviving plants recovered. In Experiment 3, on tall plants, the leaves wilted and had a dark brown coloration, flower stalks appeared abnormal, and many flowers wilted before unfolding. In.general, ioxynil affected poppy plants similarly to bromoxynil, but was slightly less active.

Diquat and paraquat were tested in all three experiments at various doses. The effect was always very rapid and the foliage wilted in a few days. At a dose of 100 g/ha, plants were injured but recovered; developed plants sprayed with 200 g/ha died. Tall plants of Experiment 3 were greatly affected by 400 g/ha; at the last observation, nine days after spraying, the leaves were wilting and light brown in colour, the stems were yellowish, and no flower had developed-as compared with full flowering in the control plots.

The effects of glyphosate appeared slowly: leaves yellowed and lost their turgor, the whole plant wilted and eventually died. Small plants were killed by 410 g/ha within three weeks. In Experiment 2, 410g/ha induced partial wilting and growth retardation; at 820 g/ha most plants died within three weeks. In Experiment 3, on the leaves of tall plants, glyphosate caused patches of scorching which gradually enlarged. The plants lost their turgor, the stem bent downwards, and the leaves wilted and were dark green in colour. At the last observation, only a few flowers had unfolded. There was no marked difference between the two doses tested at that stage: 820 and 1640 g/ha.

Metribuzin also acted slowly. At first, scorching appeared on the tips and margins of leaves. Small plants were completely killed by 175 g/ha within two to three weeks. On older plants, 350 g/ha caused cessation of growth and partial wilting only, and flowering was normal.

Discussion

Among the 55 herbicides tested in screening trials, 24 compounds with various modes of action and environmental behaviour, killed poppy plants. Six of the efficient herbicides are typically foliar-active with negligible persistence in soil: amitrole, 2,4-D, glyphosate, bromoxynil, ioxynil and paraquat. Their main sites of uptake and of action are within the leaves, but they differ in other properties. Amitrole, glyphosate and 2,4-D are translocated within the plant and their effect is relatively slow. The primary symptoms following treatment with amitrole (whitening of new leaves) or with glyphosate (yellowing and loss of turgor of leaves) appear only after several days; subsequently, the growth of the plant slows down and after two to three weeks the plant dies. The typical symptoms of treatment with 2,4-D-twisted petioles and stems-may appear already after one day, but the lethal effects take one to two weeks to develop.

On the other hand, bromoxynil, ioxynil and paraquat acted essentially by contact and their action was very rapid-leaf scorching occurred within a day or two and the plant wilted and died a few days later. Paraquat was the fastest-acting herbicide in our trials. The appearance of necrotic patches around the points where droplets of paraquat landed is accelerated by high temperatures and light intensity. In agricultural practice, however, it is often recommended to spray paraquat in early morning or late evening-which produces a slower action but allows better penetration and distribution of the chemical into the plant.

A related herbicide, diquat, was less potent on poppy plants than paraquat. In some of the experiments we used a mixture of diquat + paraquat, which is the locally commercialized formulation recommended for general weed control.

The six above-mentioned foliar-active herbicides were tested subsequently in field experiments. On young poppy plants (Experiment 1) amitrole had a slow and partial effect, 2,4-D produced severe damage although kill was not complete, while bromoxynil, ioxynil, paraquat (+ diquat) and glyphosate killed all plants. The increased resistance of plants to herbicides with age and development is a well known phenomenon, and explains the decrease in efficiency of herbicidal treatments in Experiment 2 (on poppy plants 20-50 cm tall) and Experiment 3 (on plants 60-80 cm tall, just before flowering). Increasing the dose of the herbicide increased only partially the efficiency of the treatment on grown plants. In practice, weeds taller than 20 cm are considered to be very difficult to kill, and therefore all efforts are made to apply the herbicide either before or soon after their emergence. However, the destruction of illicit fields of poppy often has to be carried out at later stages of growth. Glyphosate, due to its systemic behaviour, is one of the few herbicides capable of destroying developed weeds, provided the plants are still growing actively. The efficiency of contact herbicides depends very much on the thoroughness of the application and meteorological conditions prevailing at spraying time.

Other herbicides which killed poppy plants in screening trials were triazines, substituted ureas, and those of other chemical groups which act primarily through root uptake. The observed foliar effects were due to upward translocation of the absorbed compound and also, in many cases, to direct foliar absorption. In agricultural practice, these herbicides are sprayed before weed emergence and on seedlings. The possibilities of using these compounds against developed poppy plants are limited because their foliar activity decreases rapidly with the growth of the plant. An increase in the dose in order to kill developed plants could result in serious residue problems since most of these herbicides have an appreciable degree of persistence in soil.

Several of the triazines included in the screening trials killed poppy plants at lower application rates than that required for substituted ureas or other herbicides. Ametryn, atrazine, prometryn and terbutryn were efficient at 250 g/ha, and metribuzin already at 140 g/ha. Metribuzin was also included in the field experiments since it has a short soil persistence at these low doses: metribuzin at 175 g/ha killed young poppy plants within two to three weeks, but double of that dose produced only sublethal damage to older plants.

In order to appreciate the true impact of soil residues of herbicides, it must be remembered that a high concentration of herbicide in the soil is a problem for sensitive species but not for species, weeds or crops, which tolerate the compound. For instance, atrazine is selective to sorghum or corn, and metribuzin is selective to potatoes and tomatoes-and the presence of residues of these herbicides in the soil soon after their application on poppy plants would not prevent replanting the treated field with resistant crops. Obviously, the presence of residues in the treated field limits the farmer's choice of subsequent crop and requires a great deal of understanding to cope with the situation.

Several herbicides did not kill poppy plants but caused severe damage to the plant, which may reduce the yield harvested and/or impair its quality. Among the compounds listed in table 2, the mixture of the arsenates cacodylate + MSMA, and phenmedipham, have negligible soil residues.

Opium is produced from many varieties and ecotypes of P. somniferum. In one of our experiments (not detailed in this paper), several herbicides (including paraquat and metribuzin) were sprayed on eight varieties of poppy of different origin, and had similar effects.

Another approach to combat the production of opium from poppy, short of killing the plant, is to cause abnormal development of the vegetative or reproductive parts, which would reduce the commercial value of the yield.

W. Gentner found that several herbicides, such as chlorpropham, dichlobenil, barban or trifluralin, applied on young poppy plants, would "blast" or debud the treated plant (personal communication). In our screening tests (see table 2), five dinitroanilines, two amides, dalapon and propham, induced marked deformation of leaves, stems and buds. These herbicides had caused similar abnormalities on cannabis plants. It is noteworthy that the dinitroaniline and amide herbicides act on germination and through root absorption and are not used for post-emergence application; dalapon and propham are foliar-acting grass-killers selective to dicots. It is possible that the formulation is responsible for their foliar activity. The influence of these treatments on the opium production in the capsules was not investigated in this work, and their practical effects should be evaluated in the field.

Acknowledgements

This research was conducted under contract with the U.S. Department of Agriculture, which provided also the seeds for experimental poppy growing. I wish to thank Dr. W. A. Gentner, USDA, ARS, Beltsville, Maryland, USA, who was the sponsor of the research programme, for his advice and help.

The experimental work was conducted at the Newe Ya'ar Experiment Station, on poppy plants grown according to special authorization of the Israel Ministry of Health. I wish to express my appreciation to Ing. Agr. G. Horzlinger and the technical staff of the Division of Weed Research, for their assistance in carrying out the experiments.

APPENDIX

List of herbicides mentioned in the paper

In parentheses, the type of formulation used in experiments (L = liquid, P=powder) and its content in active matter.

Alachlor
2-chloro-2', 6'-diethyl- N-(methoxymethyl) acetanilide (P.50%)
Ametryn
2-(ethylamino)-4-(isopropylamino-6-(methylthio)- S-triazine (P.50%)
Amitrole
3-amino- S-triazole (P.50%)
Amitrole TL
3-amino- S-triazole (L.25%) + thiocyanate
Asulam
methyl sulfanilylcarbamate (L.40%)
Atrazine
2-chloro-4.(ethylamino)-6-(isopropylamino)- S-triazine (P.50%)
Barban
4-chloro-2-butynyl- m-chlorocarbanilate (L.25%)
Benefin
N-butyl- N-ethyl-α,α,α, trifluoro-2.6-dinitro- p-toluidine (L.19%)
Bentazon
3-isopropyl-I H-2,1,3-henzothiadiazin-(4)3 H-one-2,2-dioxide (L.50%)
Benzthiazuron
1-methyl-3-(2-benzothiazolyl)-urea (P.80%)
Bromoxynil
3,5-dibromo-4-hydroxybenzonitrile, octanoic acidester (L.33%)
Butralin
4-(1,1-dimethylethyl)- N-methylpropyl)-2,6-dinitrobenzenamine(L.50%)
Butylate
S-ethyl diisobutylthiocarbamate(L.76%)
Cacodylate
hydroxydimethylarsine oxide (L.12% cacodyfic acid and Na cacodylate + 26% MSMA)
Chloroxuron
3-[ p-( p-chlorophenoxy) phenyl]-1,1-dimethylurea (P.50%)
Cycloate
S-ethyl N-ethylthiocyclohexanecarbamate (L.74%)
2,4-D
(2,4-dichlorophenoxy) acetic acid (L.33%)
Dalapon
2,2-dichloropropionic, sodium salt (P.85%)
Difenzoquat
1,2-dimethyl-3,5-diphenyl-1 H-pyrazolium methylsulfate (L.40%)
Dinitramine
N4, N4-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine (L. 24%)
Diphenamid
N,N-dimethyl-2,2-diphenylacetamide (P.80%)
Diquat
6,7-dihydrodipyrido [1,2-α2',l'-c]pyrazinediium dibromide (L. 20% or mixture 7% diquat + 13% paraquat)
Diuron
3-(3,4-dichlorophenyl)l,l-dimethylurea (P.80%)
DSMA
disodium methanearsonate (P.81%)
EPTC
S-ethyl dipropylthiocarbamate (L.76%)
Ethofumesate
2-ethoxy-2,3-dihydro 3,3-dimethy1-5-benzofuranyl methanesulphonate (L.20%)
Fluometuron
1,1-dimethyl-3-(α,α,α'trifluoro-m-tolyl) urea (P.80%)
Glyphosate
N-(phosphonomethyl) glycine (L.41%)
Ioxynil
4-hydroxy-3,5-diiodobenzonitrile (L.25%)
Karbutilate
tert-butylcarbamic acid ester with 3-( m-hydroxyphenyl)-1,1-dimethylurea (P.80%)
Linuron
3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (P.50%)
Methabenz-
 
thiazuron
1,3-dimethyl-3-(2 benzothiazolyl)-urea (P.70%)
Methazole
2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione (P.75%)
Metribuzin
4-amino-6- tert-butyl-3-(methylthio)- as-triazine-5(4 H)one (P.70%)
Molinate
S-ethyl hexahydro-1 H-azepine-l-carbothioate (L.71%)
MSMA
monosodium methanearsonate (L.35% or mixture 26% MSMA + 12% cacodylic acid and cacodylate)
Napropamide
2-(α-naphtoxy)-N,N-diethylpropionamide (P.50%)
Neburon
1-butyl-3-(3,4-dichlorophenyl)-l-methylurea (P.60%)
Nitralin
4-(methylsulfonyl)-2,6-dinitro- N,N-dipropylaniline (L.44%)
Nitrofen
2,4-dichlorophenyl-p-nitrophenyl ether (P.50%)
Oxadiazon
2- tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4-oxadiazolin-5-one(L.25%)
Paraquat
1,1' dimethyl-4,4'-bipyridinium dimethyl sulfate(L.20% or mixture 13% paraquat + 7% diquat)
Pebulate
S-propyl butylethylthiocarbamate (L.76%)
Pendimethalin
N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzamine (L.33%)
Perfluidone
1,1,1-trifluoro- N-[2-methyl-4-(phenylsulfonyl)phenyl] methanesulfonamide(P.50%)
Phenmedipham
methyl m-hydroxycarbanilate m-methylcarbanilate (L.16.5%)
Phenobenzuron
N-benzoyl- N-(dichloro-3,4-phenyl)- N4 N4-dimethylurea (P.50%)
Prometryn
2,4-bis (isopropylamino)-6-(methylthio)-s-triazine (P.50%)
Pronamide
3,5.dichloro( N-l,l-dimethyl-2-propynyl)benzamide (P.50%)
Propham (IPC)
isopropyl carbanilate (P.50%)
Pyrazon
5-amino-4-chloro-2-phenyl-3(2 H)-pyridazone (P.80%)
Simazine
2-chloro-4,6-bis(ethylamino)- s-triazine (P.50%)
Terbutryn
2-( tert-butylamino)-4-(ethylamino)-6-(methylthio)- a-triazine (P. 50%)
Trifluralin
α,α,α-trifluoro-2,6-dinitro- N,N,-dipropyl- p-toluidine (L.48%)
Vernolate
S-propyl dipropylthiocarbamate (L.76%)