Herbicide classification

1. HERBICIDE CLASSIFICATION AND ITS
CHARACTERISTICS -
Dinitrophenol
s,
Dinitroaniline
s,
Benzonitriles,
Triazines

2. HERBICIDE CLASSIFICATION
Dinitrophenols
Dinofenate, Dinoprop
Dinosam Dinoseb
Dinoterb DNOC Etinofen
And Medinoterb.
Dinitroanilines
Benfluralin, Butralin
Chlornidine, Dinitramine,
Dipropalin, Ethalfluralin,
Fluchloralin, Isopropalin,
Methalpropalin, Nitralin,
Oryzalin, Pendimethalin,
Prodiamine, Profluralin,
Prosulfalin, Trifluralin
Benzonitriles
Ioxynil, Bromoxynil,
Chloroxynil, Cyclopyranil,
Dichlobenil, Bromobonil,
Iodobonil, Pyraclonil.
Triazines
Triazine And Non-even
Triazine

3. DINITROPHENOLS
 Dinitrophenols (DNPs) occur as six different isomers: 2,3-DNP, 2,4-DNP, 2,5-DNP, 2,6-DNP, 3,4-DNP, and
3,5-DNP, with 2,4-DNP being the most commercially important isomer.
 DNPs are used mainly as fungicides, herbicides, and insecticides.
 The dinitro compounds are slightly water-soluble
 These compounds are extremely toxic to humans and other organisms.
 The dinitrophenols included DNOC, DINOSEB and some lesser known materials.
 The main member of the group, dinoseb† (6-sec-butyl-2,4-dinitrophenol), was banned as a herbicide in
the United States and the EU in 1986 and 1991, because of its toxicity on vertebrates and teratogenicity
on mammals

4. Characteristics of Dinitrophenol
 2,4-Dinitrophenol (2,4-DNP or simply DNP) is an organic compound with the formula HOC6H3(NO2)2.
 It is a yellow, crystalline solid that has a sweet, musty odour.
 It sublimes, is volatile with steam, and is soluble in most organic solvents as well as aqueous alkaline
solutions.
 When in a dry form, it is a high explosive and has an instantaneous explosion hazard.
 It is a precursor to other chemicals and is biochemically active, inhibiting adenosine triphosphate (ATP)
production in cells with mitochondria.
 Its use in high doses as a dieting aid has been identified with severe side-effects, including a number of
deaths.

5. Classification of Dinitrophenols
 Bromofenoxim
 Dinofenate
 Dinoprop
 Dinosam
 Dinoseb
 Dinoterb
 DNOC
 Etinofen
 Medinoterb

6. Dinofenate
 C17H14N4O11
 2,4-dinitrophenyl 2-[(1RS)-1-
methylpropyl]-4,6-dinitrophenyl
carbonate
Bromofenoxim
 C13H7Br2N3O6
 3,5-dibromo-4-hydroxybenzaldehyde (2,4-
dinitrophenyl)oxime

7. Dinoprop
 C10H12N2O5
 4,6-dinitro-o-cymen-3-ol
Dinosam
 C11H14N2O5
 (RS)-2-(1-methylbutyl)-4,6-dinitrophenol

8. Dinoseb
 C10H12N2O5
 2-[(1RS)-1-methylpropyl]-4,6-dinitrophenol
Dinoterb
 C10H12N2O5
 2-tert-butyl-4,6-dinitrophenol

9. DNOC
 C7H6N2O5
 2-methyl-4,6-dinitrophenol
Etinofen
 C9H10N2O6
 2-(ethoxymethyl)-4,6-dinitrophenol

10. Medinoterb
 C11H14N2O5
 6-tert-butyl-3-methyl-2,4-dinitrophenol
 DNOC (2-methyl-4, 6-dinitrophenol) was patented by
Bayer in Germany (1892) for use as an insecticide, but
was subsequently developed for use in Europe and
Great Britain as a selective herbicide (1932-1935).
 Dinoseb or DNBP (2- sec-butyl-4, 6-dinitrophenol)
was developed later for the U. S. markets by Dow
(1945).
 Bromoxynil (3, 5- dibromo-4-hydroxybenzonitrile) was
the last of the phenols to be introduced to the U.S.
markets. It still is of commercial importance because
of the development of bromoxynil-tolerant cotton

11. USES
 Commercially, DNP is used as an antiseptic and as a non-selective bioaccumulating pesticide.
 DNP is particularly useful as a herbicide alongside other closely related dinitrophenol herbicides like 2,4-
dinitro-o-cresol (DNOC), dinoseb and dinoterb.
 Since 1998 DNP has been withdrawn from agricultural use.
 Currently, there are no actively registered pesticides containing DNP in the US or Europe.

12. HERBICIDE MODE OF ACTION
 The target is the inhibition of oxidative phosphorylation, a
basic process in all living cells.
 Dinitrophenols decouple oxidation and phosphorylation
during mitochondrial electron transport.
 As a result, cellular respiration is accelerated as the cell
produces more and more NADH dinucleotides but is
unable to restore its damaged ATP production.
 Due to the general mechanism of action, zoocidal and
fungicidal agents are also found in the group.

13. Toxicity of herbicides
 The oral acute LD50 of DNOC in mice, guinea pigs, rabbits, hens, dogs, pigs and goats ranges from 25
to 100 mg/kg BW.
 In sheep, a dosage of 25 mg/kg/day causes toxicosis in 2–5 days.
 Clinical signs include fever, dyspnea, acidosis, oliguria, muscular weakness, tachycardia and
convulsions followed by coma and death with a rapid onset of rigor mortis.
 Abortions have been reported in sows.
 In cattle and ruminants, methemoglobinemia, intravascular hemolysis and hemoproteinemia have been
observed.
 Cataract can occur with chronic dinitrophenol intoxication. Exposure to these compounds may cause
yellow staining of skin, conjunctiva, or hair

14. EFFECTS ON HUMAN
 Fever is a very early sign of dinitrophenol toxicity.
 Severe poisoning may cause restlessness, seizures, and coma.
 Cerebral edema was reported in two cases of fatal poisoning.
 Fatal cases of poisonings have been reported as a result of dermal exposure to dinitrophenols.
 Hepatic and renal damage were reported within 12–72 h following acute exposure to dinitrophenols.
 Typical signs of dinitrophenol toxicity were reported to occur within a few hours following acute exposure to
3–5 mg kg−1 of dinitrophenol.
 Acute signs of toxicity include elevation of blood pressure, heart rate, and body temperature; headache; and
mental confusion.
 Typical gastrointestinal symptoms may include nausea, vomiting, and abdominal cramps.

15. DINITROANILINES
 The dinitroanilines are some of the most heavily used in agriculture, and are used almost exclusively as
soil-incorporated, preemergence selective herbicides in many field crops.
 Examples of substituted dinitroanilines are trifluralin, benefin, oryzalin, pendimethalin, and isopropalin.
Trifluralin has very low water solubility, which minimizes leaching and movement from the target.
 The nitroanilines inhibit both root and shoot growth when absorbed by roots, but they have an involved
mode of action, which includes inhibiting the development of several enzymes and the uncoupling of
oxidative phosphorylation.

16. Introduction
 The herbicides in the dinitroaniline family were originally discovered in evaluations of dyes and dye
chemical synthesis intermediates.
 Chemicals in this family are typically bright yellow in color due to the two nitro (-NO2) groups on the
phenyl ring, and are often refered to as the "yellow compounds".
 Trifluralin which was introduced first in 1964. Trifluralin is a major herbicide in soybean production, and it
had a big impact in that crop.
 Herbicides such as trifluralin, pendimethalin, oryzalin, etc. in this family generally are used to control
grassy weeds, as well as some dicot weeds like pigweeds and lambs quarters. Other dicots are not
controlled, such as ragweeds and smartweeds.
 TRIFLURALIN 48% EC. SUPER TIGER is a commonly used pre-emergence herbicide. It is one of the
widely used herbicides. Trifluralin is generally applied to the soil to provide control of a variety of annual
grass and broadleaf weed species
 Herbicides in this family also have some soil fungicidal activity.

17. Chemistry
This herbicide family is divided into two subfamilies:
 Methylaniline herbicides include trifluralin, pendimethalin, benefin,
dinitramine, fluchloralin, profluralin, etc.
 Sulfonylaniline members include oryzalin, nitralin, etc.

18. Physiology and metabolism of the dinitroanilines in plants
Mode of Dinitroaniline Action
 Dinitroaniline herbicides act by inhibiting cell division (mitosis).
 They inhibit microtubulin synthesis necessary in the formation of cell walls and in chromosome movement
to daughter cells during mitosis. The cell does not complete division and affected cells remain as single
cells with multiple nuclear chromosomes: multi-nucleated cells.
Mode of Dinitroaniline Lethality:
 Dinitroaniline herbicides kill susceptible plants by inhibiting cell division in root cells, which arrests normal
root growth. This inhibition leads to plant dehydration due to severely restricting the root system size and
function.
Uptake and Movement of Dinitroanilines in Plants
 Dinitroaniline herbicides are absorbed by plant root systems, and to a greater extent by young seedling
shoot organs such as the hypocotyl or coleoptile. Little or not translocation of these herbicides occurs in
plants.
 These herbicides are very lipophilic (oil loving) and tend to concentrate in high lipid areas of the shoot and
root symplast. It is in these areas they exert their toxic action.

19. Simulative structure of a microtubule. The ring shape depicts a
microtubule in cross-section, showing the 13 protofilaments
surrounding a hollow centre

20. BASIS OF SELECTIVITY BETWEEN PLANT SPECIES
Uptake Differences.
 The first is greater uptake of dinitroaniline herbicides by susceptible species. This greater uptake can result in greater
injury to roots developing at the site of uptake. Differential protection, and resistance, is afforded by differences in lipid
content of species. Because these herbicides are very lipophilic, they can be sequestered and rendered unavailable for
plant injury, by partioning into this lipid component.
Placement Selectivity.
 A second basis of selectivity between susceptible and resistant species is physically separating the herbicide layer in the
soil from the crop plant but not from the weeds.
 Trifluralin is applied to 7-10 cm (3-4 in) tall wheat and shallow incorporated into the soil with a drag harrow. The
herbicide is in contact with surface germinating weeds yet the established wheat plant has sufficient root system below
the herbicide to survive and grow.
 A second method is fall application of trifluralin. Weeds are controlled in the early spring by residual herbicide in the soil
yet there is not enough left to injure spring planted small grain crops.
Trifluralin Resistance.
 Resistance to trifluralin has been discovered in goosegrass (Eleucine sp.; southern USA) and green foxtail (Manitoba,
Canada). The basis of resistance was found to be due to hyperstabilization of microtubules, rendering them immune to
dinitroaniline inhibition. Resistant cells form microtubules in the presence or absence of dinitroaniline herbicides. Carrots
(Daucus carota) naturally has this hyperstabilized microtubule form and high levels of dinitroaniline resistance.

21. Fate of Dinitroanilines in the environment
Soil
 Dinitroaniline herbicides are strongly adsorbed to soil colloids. Use rates increase with increasing organic
matter content and on heavy, clay soils.
 Many of the herbicides in this family must be mixed, incorporated, into the soil to avoid volatilization
losses, therefore preplant incorporation (PPI) is the most common method of field application. Once
incorporated into the soil, the herbicides volatilize and fill the soil air spaces. It is most likely in the gas
phase that these chemicals are taken up by plants.
 Trifluralin is fairly long-lived in the soil and can persist for 4-6 months after application. In some cases,
trifluralin used in soybeans can persist in the soil until the following year and cause early season injury to
corn.
 Factors such as the rate used, time of herbicide application, soil type, herbicide degradation rate, soil
moisture, sensitivity of the genotype, etc. can lead to greater or lesser corn injury from this carryover.

22. Water
 Dinitroaniline herbicides are lipophilic and fairly insoluble in water. They pose little threat as ground- and
surface-water contaminants in the environment
Air
 Most dinitroaniline herbicides are volatile and will evaporate into the air if not incorporated into the soil
fairly soon (hours) after application. Herbicides such as pendimethalin and oryzalin are exceptions to
this.
 Dinitroaniline herbicies are subject to decomposition due to photodegradation.
Animal & Human Toxicology
 The synthesis of trifluralin can result in the synthesis of nitrosamines, a harmful and undesirable
byproduct. Nitrosamines are highly reactive chemical species. They are metabolized to acid (HNO2),
which acts in biological systems by deaminating molecules. They have been implicated as carcinogens by
by removing amino groups from DNA chromosome nucleotide bases (i.e. cytosine, adenine, tyrosine,
guanine). They also can act as toxic alkylating agents

23. Plant injury symptomology of dinitroanilines in plants
stunting and restricted root
development
Root systems can be inhibited,
roots may appear swollen
Root tips often appear short,
swollen and "club-shaped" due
to inhibition of root growth
Shoots may also be affected. Dicot shoots often
will have a swollen or cracked hypocotyl region,
near the soil surface
Injured corn can appear stunted and leaves
sometimes have a purplish color around the
margins.

24. RESISTANCE MECHANISMS TO DINITROANILINE HERBICIDES
 Generally, herbicide resistance mechanisms can be divided into target-site resistance (TSR) and non-target-site
resistance (NTSR).
 TSR refers to resistance caused by the changes in herbicide target protein including mutation, duplication and
overexpression, while NTSR includes all resistance mechanisms bypassing the TSR, primarily anything that
reduces the amount of herbicide reaching the target protein such as alterations in absorption, translocation or
metabolism (Powles and Yu, 2010).
 TSR is relatively easy and straightforward to study when the target protein is not part of a multi gene family
and in diploid plant species, whereas unraveling NTSR mechanisms is more technically challenging and
requires a more in depth understanding of the weed’s genetics and physiology.

25. BENZONITRILES
 Nitriles have a benzene ring, containing the CN or cyanide grouping. These two compounds, dichlobenil
and bromoxynil, are contact herbicides which control broadleaf weeds in grass-type crops. They are
registered for use on small grains, corn, grain sorghum, and for seedling turf for postemergence control
of broadleaf weeds.
 Benzonitrile is the chemical compound with the formula C6H5(CN), abbreviated PhCN.
 This is an aromatic organic compound, colorless liquid with a sweet almond odour.
 It is mainly used as a precursor to the resin benzoguanamine.
 In the laboratory it can be prepared by the dehydration of benzamide or by the Rosenmund–von Braun
reaction using cuprous cyanide or NaCN/DMSO and bromobenzene.
 Benzonitrile was reported by Hermann Fehling in 1844. He found the compound as a product from the
thermal dehydration of ammonium benzoate. He deduced its structure from the already known analogue
reaction of ammonium formate yielding formonitrile. He also coined the name benzonitrile which gave
the name to all the group of nitriles (nitrile is any organic compound that has a R−C≡N functional group)

26. 1. BROMOXYNIL:
 3,5-dibromo-4- hydroxybenzonitrile, C7H3Br2NO2
 It is a colorless solid which is sparingly soluble in water, fairly soluble in methanol, ethanol, and benzene, and
readily soluble in dimethylformamide, tetrahydrofuran, and acetone.
 Chemicals with low Kow values (e.g., less than 10) may be considered relatively hydrophilic; they tend to have
high water solubilities, small soil/sediment adsorption coefficients, and small bioconcentration factors for
aquatic life.
 Bromoxynil is produced by reaction of sodium hypobromide with 4-hydroxybenzonitrile.
 Bromoxynil is a selective contact herbicide used as post-emergence to control annual broadleaved weeds in
cereals, maize, sorghum, onions, garlic, mint, turf, noncropland, etc.
 It is a photosystem II inhibitor.
Formulation: Emulsifiable concentrate, suspension concentrate, wettable powder.
Trade Names: Brominal, Buctril, Bromox, Bromoxan, Emblem, Kaleis.
Half life: Bromoxynil decays with half-lives of 1, 0.5, and 13 d in soil, photolytically, and in water sediment,
respectively. It is stable towards hydrolysis.

27. 2. DICHLOBENIL
 2,6-dichlorobenzonitrile, C7H3Cl2N
 It forms colorless crystals which are sparingly soluble in water, fairly soluble in acetone, dioxane, benzene,
dichloromethane, xylene, and ethanol, and soluble in dichloromethane.
 Dichlobenil is produced by conversion of 2,6-dichlorotoluene into 2,6-dichlorobenzal chloride, which is
converted into 2,6-dichlorobenzaldehyde, 2,6-dichlorobenzaldoxime, and 2,6-dichlorobenzonitrile.
 Dichlobenil, a cellulose-biosynthesis inhibitor,
 It is a systemic herbicide used for selective weed control of many annual perennial weeds in woody
ornamentals, fruit orchards, vineyards, brush fruit, forest plantations, etc.
 Their mechanisms of action are broad, involving seedling growth inhibition, potato sprout inhibition, and gross
disruption of tissues by inhibiting oxidative phosphorylation and preventing the fixation of CO2. These effects,
however, do not explain their rapid action. Ioxynil belongs to the nitriles but is not registered in the U.S.
Formulation: Granules.
Trade Names: Sibenil, Osorno, Caseron. Dichlobenil
Half life: it decays with half-lives of 70, 6, and 150 d in soil, photolytically, and hydrolytically, respectively.

28. 3. IOXYNIL
 4-hydroxy-3,5-diiodophenyl cyanide, C7H3I2NO
 It is a colorless solid which is sparingly soluble in water, fairly soluble in acetone, ethanol, methanol, and
chloroform, and readily soluble in cyclohexanone, tetrahydrofuran, and dimethylformamide.
 Ioxynil is produced by iodination of 4-hydroxybenzonitrile with iodine monochloride.
 Ioxynil is a systemic, selective herbicide with contact activity, used post-emergence to control a wide range of
annual broad-leaved weeds in cereals, leeks, onions, garlic, on lawns, and on newly sown turf.
 It inhibits photosystem II.
Formulation: Emulsifiable concentrate.
Trade Names: Actril, Totril, Sanoxynil, Trionyl etc.
Half life: Ioxynil decays with half-lives of 6, 5, and 4.6 d in soil, photolytically, and in water-sediment, respectively. It
is stable towards hydrolysis.

29. 4. PYRACLONIL
 1-(3-chloro- 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-2-yl)-5- [methyl(prop-2-ynyl)amino]pyrazolo-4-
carbonitrile, C15H15ClN6
 It is a colorless solid which is sparingly soluble in water.
 Pyraclonil is a post-emergence herbicide used in rice to control grasses and broad-leaved weeds.
 It inhibits protoporphyrinogen oxidase.
Formulation: Granules, emulsifiable powder.
Trade Name: Sunshine.
Half life: Pyraclonil decays with a half-life of 320 d photolytically

30. TRIAZINES
 The triazines, which are six-member rings containing three nitrogens (the
prefix tri- means “three”) and azine (a nitrogen-containing ring) make up
the heterocyclic nitrogens.
 Triazines are strong inhibitors of photosynthetic electron transport. Their
selectivity depends on the ability of tolerant plants to degrade or
metabolize the parent compound (the susceptible plants do not).
 Triazines are applied to the soil primarily for their postemergence activity.
 Atrazine was estimated by EPA to have been the most heavily used
pesticide in the U.S. in 1999, used at the annual rate of about 80 million
pounds, primarily on corn (Donaldson et. Al., 2002).

31. Basic characteristics
 The water solubility of such agents has "Tone" type (Triketone) be of the largest, followed by "Zine"
category and "Tryne" class (prometryn) is of the lowest.
 Most triazine type herbicides have relatively stable property, thus having long-term persistence, low
toxicity to humans and animals and low toxicity to fishes as well.
 All of them has systemicity and can be quickly absorbed by the roots after the soil treatment, and
transported upward to the blade starting from xylem through the transpiration flow while the regents
which can be absorbed by the blade have almost no conducting property, among which simazine and
other "Tryne" category herbicidal agents are absorbed by the roots while only atrazine has strong
capability of only being subject to foliar uptake.
 The “Tryne” class herbicides such as prometryn are instead easier to be absorbed from the root, stem
and leaf with fast-acting property and strong herbicidal activity on weeds just unearthed.
 They are easily to be decomposed in the soil, so the residue duration is short with generally lasting 1 to
2 months.
 "Tone" category has the largest water solubility as well as the strongest herbicidal activity but a poor
selectivity.

32. MECHANISM OF ACTION
 The major mechanism is to inhibit the photosynthesis, affecting the synthesis of the assimilation product.
For example, the order of the several inhibitory effects of propazine, prometon, and prometryn on the
metabolic processes of bean is photosynthesis, lipid synthesis, RNA synthesis and protein synthesis.
 Chlorophyll may be the major pigment on which triazine herbicide exerting its toxic effect.
 The degree of toxicity is directly proportional to the light intensity and the herbicide doesn’t work in the
dark.
 The toxicity is the strongest upon a wavelength of 428 and 658 nanometers.
 Even triazine herbicide blocks the stream of electrons from water from to the chlorophyll, causing
oxidation of chlorophyll, leading to the gradually destruction of the layered structure of chloroplasts.
 In addition, the herbicide can inhibit the electron transport system during photosynthesis, causing the
accumulation of nitrate inside the blade, strengthening the damage to the sensitive plant.
 Chlorosis is the main symptom of this class of herbicides, first the blade tip will get chlorosis and
withered, the leaf edge will then turn yellow, and finally the whole plant dead.

34. Applications
 Triazine herbicide mainly targets on the week and bud with no lethal effect on seed as well as no effect on its
germination.
 Atrazine and cyanazine can also be used for stem, leafs and soil treatment in the weed trefoil stage of
postemergence, giving a better efficacy.
 The strongest drug resistance to the triazine herbicide has been observed in corn, millet, sugar cane and
apples, grapes. Some varieties of sorghum, carrots, celery, potatoes, cotton, sunflower, peas and soybeans also
have strong resistance to them.
 "Tryne" class has a general long persistence. The efficacy of using simazine for treatment of weeds belonging
to Digitaria and Panicum is better than atrazine.
 It is relatively safe to apply atrazine for weed control in sorghum field. At the same time, we can apply soil
mixture before sowing and apply pre- or post-emergence treatment after sowing.
 "Tryne" category herbicides have a strong activity on the treatment of the stems and leaves; therefore it can be
applied to stem-leaf and soil treatment during the early post-emergence.
 Sugarcane has a strong resistance without strict requirement on the varieties.

35.  Orchard administration of atrazine and prometryne etc. should be performed before the rainy season with
high efficacy in the rainy season.
 Because atrazine has a relative large water solubility and large mobility in soil as well, long-term high-dose
administration can be susceptible to be leached into deep layer of the soil by the layer, affecting the quality of
the underground water.
 Moreover, atrazine has negative effect on the stomach, kidney and liver as well as the genetic material DNA of
mammalian.
 Triazines also have wide use in the oil and gas and petroleum processing industries as a non-regenerating
sulfide removal agent
 Triazines are pre- and post-emergence herbicides used to control broad-leafed weeds and some annual
grasses.
 These herbicides inhibit the photosynthetic electron transport in certain plants.
 Human exposure to triazines has been linked with the development of ovarian cancer.
 Upon entering the body, they are metabolized via the glutathione detoxification pathway or by simple
dealkylation.

36. ATRAZINE
 Atrazine (C8H14ClN5)6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine
 Colorless powder which is sparingly soluble in water and n-hexane, fairly soluble in toluene, and n-octanol, and
readily soluble in ethyl acetate, acetone, dichloromethane, and ethanol
 Atrazine is the most studied triazine herbicide and It was also the single most heavily applied pesticide in the USA in
1997 and is currently the second most abundantly applied pesticide.
 Atrazine mercapturate was identified as the major human metabolite of occupational exposure to atrazine (Barr et al.,
2007).
 Triazines can also be measured as the intact pesticide in blood products.
 Atrazine is produced by reaction of cyanuric chloride with one equivalent of ethylamine, followed by treatment with
one equivalent of isopropylamine
 Atrazine is a selective, systemic herbicide with residual and foliar activity used pre- and post-emergence to control
annual broad-leaved weeds and annual grasses in maize, sorghum, sugar cane, etc, and in industrial weed control.
 It inhibits photosystem II.
Formulation: Suspension concentrate, wettable powder, water-dispersible granules, flowable.
Trade Names: Atrex, Bicep, Gesaprim, Primagram, Primextra, Mebazine, Vectal, Atratol, Primatol, Fenamin, Atrazinax.
Half-life: Atrazine decomposes with half-lives of 75, 2.6, 86, and 86 d in soil, photolytically, hydrolytically, and in water-
sediment, respectively.

37. AMETRYN:
 N2-ethyl-N4-isopropyl-6-methylthio-1,3,5-triazine-2,4-diamine, (C9H17N5S)
 It is a colorless powder which is slightly soluble in water, moderately soluble in n-hexane and toluene,
and readily soluble in acetone, methanol, and n-octanol
 Ametryn is produced by reaction of atrazine with methyl mercaptan in the presence of sodium
hydroxide.
 Ametryn is a selective, systemic herbicide used pre- and post-emergence for the control of most annual
grasses and broad-leaved weeds in pineapples, sugar cane, bananas, citrus fruit, maize, coffee, tea, etc,
and in noncropland.
Formulation: Water-dispersible granules, dry flowable, wettable powder, suspension concentrate.
Trade Names : Evik, Gesapax, Mebatryne, Amesip.
Half-life: Ametryn decays with a half-life of 37 d in soil.

38. CYANAZINE
 2-(4-chloro-6-ethylamino-1,3,5-triazin-2-ylamino)-2-methyl-propiononitrile, (C9H13ClN6)
 It is a colorless crystalline solid which is moderately soluble in water, fairly soluble in benzene and carbon
tetrachloride, and readily soluble in chloroform, acetone, and ethanol.
 Cyanazine is produced by successive reaction of cyanuric chloride with ethylamine and 2- methyl-2-
cyanopropylamine .
 Cyanazine is a selective, systemic herbicide with contact and residual activity used pre-emergence for general
weed control.
 It inhibits photosystem II.
Formulation: Granules, wettable powder, emulsion concentrate.
Trade Names: Bladex, Cy-Pro, Payze, Fortrol.
Half-life: Cyanazine decays with half-lives of 16 and 84 d in soil and water-sediment, respectively. It is stable
towards photolysis and hydrolysis.

39. SIMAZINE
 6-chloro-N2,N4-diethyl-1,3,5-triazine-2,4-diamine, (C7H12ClN5)
 It is a colourless powder which is slightly soluble in water and n-hexane, and moderately soluble in
ethanol, acetone, toluene, and n-octanol
 Simazine is produced by reaction of cyanuric chloride with two equivalents of ethylamine.
 Simazine is a selective, systemic, soil-acting herbicide used for the control of most germinating annual
grasses and broad-leaved weeds in many crops.
 It inhibits photosystem II.
Formulation: Granules, pellets, wettable powder, suspension concentrate, water-dispersible granules.
Trade Names: Caliber, Gesatop, Princep, Princep Caliber, Amizina, Sanasim, Drexel.
Half-life: Simazine decays with half-lives of 60, 1.9, 96, and 33 d in soil, photolytically, hydrolytically, and in
water-sediment.

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