Classification of acaricides based on it's chemical nature

1. Classification of
Acaricides Based on its
Chemical Nature
Aaliya Afroz
Ph. D. Scholar
Department of Entomology
Indira Gandhi Krishi Vishwavidyalaya

2. Botanical Acaricides
a. Carvacrol:
vCarvacrol is an active ingredient of essential oils from different plants,
mainly fromoregano and thyme species.
v It posesses biocidal activity against many arthropodes of the importance
for veterinary and human medicine.
vCarvacrol acts as repelent, larvicide, insecticide and acaricide.
v It acts against pest artropodes such as those that serve as mechanical or
biological vectors for many causal agents of viral, bacterial and parasitic
diseases for animals and humans.
vTherefore, it may be used not only in pest arthropodes control but in
vector borne diseases control, too.

3. Mode of Action-
vCarvacrol induce an immediate neurotoxicity and it is reported that
hydrophobicity of compounds influences the penetration through the cuticle
and piperonyl butoxide synergized the toxic effects.
vCarvacrol also inhibits acetylcholinesterase and acts as an antagonist of
GABA, thus, inhibiting the chloride uptake into the neuron through the
chloride channel.

4. b. Sanguinarine:
vSanguinarine is a toxic polycyclic ammonium ion.
v It is extracted from some plants, including the bloodroot plant
(Sanguinaria Canadensis).
Mode of Action-
Sanguinarine is a toxin that kills animal cells through its action on the
Na+/K+-ATPase transmembrane protein.

5. Bridged Diphenyl Acaricides
a. Dicofol:
v“Dicofol is used to kill crop-feeding mite pests such as the red spider
mite.
vIt is a contact poison which kills the pest after being ingested and picked
up from the surface of the crop.
vDicofol is chemically similar to DTT – C14H9Cl5 – which is lacking the
oxygen component of its miticide relative.
Mode of Action-
vA non systemic, acaricide or miticide with contact action.
vIt is an organochlorine that is a GABA-gated chloride channel
antagonist.

6. b. Benzyl Benzoate:
vBenzyl benzoate is a benzoate ester obtained by the formal condensation
of benzoic acid with benzyl alcohol.
vIt has been isolated fromthe plant species of the genus Polyalthia.
vIt has a role as a scabicide, an acaricide and a plant metabolite.
vIt is a benzyl ester and a benzoate ester.

7. Mode of Action-
vBenzyl benzoate exerts toxic effects on the nervous system of the parasite,
resulting in its death. It is also toxic to mite ova, though its exact mechanism of
action is unknown.
vIn vitro, benzyl benzoate has been found to kill the Sarcoptes mite within 5
minutes.

8. Carbamate Acaricides
a. Propoxur
vPropoxur(Baygon) is a carbamate non-systemic insecticide introduced in
1959 with a fast knockdown and long residual effect used against turf,
forestry, and household pests and fleas.
v It is also used in pest control for other domestic animals, Anopheles
mosquitoes, ants, gypsy moths, and other agricultural pests.
Mode of Action-
Similar to other
carbamate insecticides, propoxurinhibits acetylcholinesterase, an enzyme
involved in neurotransmission, producing neurotoxic effects in insects
and nontarget organisms.

9. b. Carbaryl
vCarbaryl is a chemical in the carbamate family used chiefly as an
insecticide.
vIt is a white crystalline solid commonly sold under the brand name Sevin.
Mode of Action-
vCarbaryl disrupts the normal functioning of the insect nervous system and
may cause toxicity by contact or ingestion.
vWhen the enzyme is inhibited, surplus acetylcholine builds up, resulting in
nervous system overstimulation.

10. Dinitrophenol Acaricides
a. Dinopenton
Mode of Action:
vContact with protective and curative action.
vRespiration inhibitor.
v Uncoupler of oxidative phosphorylation via disruption of proton gradient.

11. Formamidine Acaricides
a. Chlordimeform
vChlordimeform is a carboxamidine, a formamidine acaricide and a member of
monochlorobenzenes.
v It is moderately soluble in water and highly soluble in many organic solvents.
vIt is volatile.
vUnder normal conditions is would not be expected to leach to groundwater.
vIt is moderately persistent in soil systems but would not be expected to persist
in water systems.

12. Mode of Action:
vIt has a role as an antifeedant.
vIt is moderately toxic to mammals, a neurotoxin and has a high potential for
bio-concentration.
vIt is moderately toxic to birds and fish but less so to honeybees.
vAn acaricide used against many organophosphate and carbamate resistant
pests.
v It acts as an uncoupling agent and monoamine oxidase inhibitor.
vBroad spectrum acaricide that appears to interfere with the amine-mediated
control of nervous and endocrine systems.

13. b. Formetanate
Mode of Action:
vContact and stomach action.
vActs by inhibiting acetylcholinesterase.

14. Avermectines
Abamectin
Abamectin is used to control insect and mite pests of a range of
agronomic, fruit, vegetable and ornamentalcrops.

15. Mode of Action:
vThey stimulate the gamma-aminobutyric acid (GABA) system, a chemical
“transmitter” produced at nerve endings, which inhibits both nerve to nerve
and nerve to muscle communication.
v The affected insect/mite becomes paralyzed, stops feeding, and dies after a
few days.

16. Milbemycin acaricides
Milbemectin:
An insecticide and acaricide effective against all development stages of
mites and some other insects.
Mode of Action:
Contact and stomach action, acting on the targets nervous system

17. Mite Growth Regulators
a. Clofentezine
vIt is an acaricide that is used in plant protection products for the control
of spider mites on a wide range of crops.
v It acts primarily as an ovicide, but it has some activity against early motile
stages of mites.
Mode of Action:
Leading to inhibition of chitin biosynthesis.

18. b. Fluazuron
Insect growth regulator and broad spectrum antiparasitic substance used to
control ticks in livestock, especially cattle.
Mode of Action:
vChitin synthesis inhibitor.
v Treated immature ticks are unable to moult to the next stage, and no
larvae will hatch fromeggs laid by treated females.
vThe principle mode of action of fluazuron on the cattle-tick is by inhibition
of chitin incorporation into tick cuticle.
v The inhibition is presumably against enzymes involved in the final stages
of chitin synthesis (Kemp et al., 1990).

19. Organophosphorus Acaricides
a. Chlorfenvinphos
Chlorfenvinphos is the common name of an organophosphorus compound that
was widely used as an insecticide and an acaricide.
Mode of Action:
vThe toxicity of chlorfenvinphos is primarily caused by its inhibition
of cholinesterase activity.
v It reacts with the acetylcholine binding sites of enzymes that hydrolyze
acetylcholine, thereby preventing their catalysis of this reaction.

20. b. Dichlorvos
Mode of Action:
vDichlorvos, like other organophosphate insecticides, acts on
acetylcholinesterase, associated with the nervous systemsof insects.
vEvidence for other modes of action, applicable to higher animals,
have been presented.
vIt is claimed to damage DNA of arthropods.

21. Pyrethroid Acaricides
a. Lambda cyhalothrin
Lambda cyhalothrin is a synthetic pyrethroid insecticide and
acaricide used to control a wide range of pests in a variety of
applications.
Mode of Action:
vAs one of the pyrethroids, Lambda cyhalothrin affects the nervous
system of an organism by disrupting the gating mechanism of sodium
channels that are involved in the generation and conduction of nerve
impulses.
vTemperature influences insect paralysis and the toxicity of lambda-
cyhalothrin.

22. b. Flumethrin
vFlumethrin is a pyrethroid insecticide.
vIt is used externally in veterinary medicine against parasitic insects
and ticks on cattle, sheep, goats, horses, and dogs, and the treatment
of parasitic mites in honeybee colonies.
vThe pyrethroid flumethrin has been registered for animal use as an
acaricide since 1986.

23. Mode of Action:
vIts pharmacological activity is mediated through voltage gated sodium
channels in neural tissue which it causes to remain open for longer than
physiologically normal, thus extending the period of sodium influx.