New Chemistries For Insect Management


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Novel insecticides, New chemistry, Novel mode of action, New group of insecticides, New insect control chemicals, Novel chemicals for insect management

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New Chemistries For Insect Management

  1. 1. IndianAgriculturalResearchInstitute,NewDelhi
  2. 2. IndianAgriculturalResearchInstitute,NewDelhi Introduction
  3. 3. Introduction Insects damages crops IndianAgriculturalResearchInstitute,NewDelhi Drawbacks of existing insecticides
  4. 4. Classification Of Old Insecticides Organochlorines (DDT, aldrin, HCH, endrin) Organophosphates (dichlorvos, parathion, chlorpyrifos, acephate) Carbamates (carbaryl, aldicarb, isolan, carbofuran) Sythetic pyrethroids (allethrin, cypermethrin, cyfluthrin, fluvalinate) IndianAgriculturalResearchInstitute,NewDelhi
  5. 5. Problems Of Old Insecticides IndianAgriculturalResearchInstitute,NewDelhi Residue Resistance Resurgence
  6. 6. IndianAgriculturalResearchInstitute,NewDelhi New Chemistry
  7. 7. Seminar (AC 691) IndianAgriculturalResearchInstitute,NewDelhi
  8. 8. Outline Selectivity New Insecticide Classes •Neonictinoids •Phenyl pyrazoles •Oxadiazines •Halogenated pyrroles •Thiourea derivatives •Quinazolines •Pyridazinones •Thiazolidines •Carbazates •Diamides •IGRs (Benzoyl ureas, Thiadiazines) •Diacylhydrazines •New insecticides from microorganisms (Avermectins, Spinosyns, B. thuringiensis, M. anisopliae) •Pyridine azomethines •Tetronic acid derivatives •Sulfoximes (Sulfoxaflor) IndianAgriculturalResearchInstitute,NewDelhi
  9. 9. Neo-nicotinoids Synthetic analogues of nicotine  Drawbacks of nicotine - Expensiveness - Lack of commercially applicable synthesis - Extreme toxicity to mammals - Limited insecticidal spectrum  Introduction of new nicotine like compounds  4 groups IndianAgriculturalResearchInstitute,NewDelhi  Chloronicotinyl compounds  Thionicotinyl compounds  Furanicotinyl compounds  Pyridincarboxamides 1
  10. 10. Chloronicotinyl Compounds Imidacloprid IUPAC: (E)-1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin- 2-ylideneamine  systemic insecticide having good xylem mobility and used as seed treatment, soil and foliar application  Formulations: 17.8% SL (Confidor®), 70% WS (Gaucho®)  Effective against sucking pests (aphids, leaf hoppers, plant hoppers, whiteflies, thrips) IndianAgriculturalResearchInstitute,NewDelhi  Acetamiprid  Imidacloprid  Nitenpyram
  11. 11. Clothianidin IUPAC: (E)-1-(2-chloro-1,3-thiazol-5-ylmethyl)-3-methyl-2- nitroguanidine  Broad spectrum insecticide  Formulations: 48% FC (Poncho®)  Effective against hemipteran, thysanopteran and coleopteran sucking insect pests IndianAgriculturalResearchInstitute,NewDelhi Thionicotinyl Compounds  Clothianidin  Imidaclothiz  Thiacloprid  Thiamethoxam
  12. 12. Furanicotinyl compounds Dinotefuran IUPAC: (EZ)-(RS)-1-methyl-2-nitro-3-(tetrahydro-3- furylmethyl)guanidine  Highly systemic insecticide  Formulations: 20% SG (Token®)  Effective against sucking pests (hoppers, jassids, aphids) IndianAgriculturalResearchInstitute,NewDelhi  Dinotefuran
  13. 13. Pyridincarboxamides Flonicamid IUPAC: N-cyanomethyl-4-(trifluoromethyl)nicotinamide  Systemic and trans-laminar activity; long time protection; feeding deterrent  Formulations: 50% WG (Ulala®)  Effective against major species of aphids; also controls mealy bugs, whiteflies, plant hoppers IndianAgriculturalResearchInstitute,NewDelhi  Flonicamid
  14. 14. Mode Of Action  They are nicotinic acetylcholine receptor agonists  They bind strongly to nicotinic acetylcholine receptors (nAChRs) in the central nervous system of insects, causing nervous stimulation at low concentrations, but receptor blockage, paralysis and death at higher concentrations  Neonicotinoids bind more strongly to insect nAChRs than to those of vertebrates, so they are selectively more toxic to insects (Tomizawa & Casida, 2005) IndianAgriculturalResearchInstitute,NewDelhi
  15. 15. Phenyl pyrazoles Fipronil IUPAC: (±)-5-amino-1-(2,6-dichloro-α,α,α-trifluoro-p-tolyl)-4- trifluoromethylsulfinylpyrazole-3-carbonitrile  Systemic insecticide with contact and stomach action  Formulations: 5% SC (Regent®)  It controls stem borers, gall midge, DBM, thrips, root borers IndianAgriculturalResearchInstitute,NewDelhi  Acetoprole  Ethiprole  Fipronil  Flufiprole  Pyraclofos  Pyrafluprole  Pyriprole  Pyrolan  Vaniliprole 2
  16. 16. Mode Of Action  Acts as an inhibitor at the γ-aminobutyric acid (GABA) receptor as a non-competitive blocker of the GABA-gated chloride channel (similar to lindane and cyclodienes)  Chemical and biological activation producing equally toxic and sometime more persistent metabolites with same mode of action IndianAgriculturalResearchInstitute,NewDelhi Cl- Cl- Cl- Na+ Cl- Fipr K+ Antagonist at GABA-gated Chloride Channel
  17. 17. Oxadiazines Indoxacarb IUPAC: Methyl 7-chloro-2,5-dihydro-2-[[(methoxycarbonyl)[4- (trifluoromethoxy)phenyl]amino]carbonyl]indeno[1,2-e] [1,3,4]oxadiazine-4a(3H)-carboxylate  Formulations: 15.8% EC (Avaunt®)  Effective against lepidopteran pests (American boll worm, DBM, Helicoverpa armigera, Plutella xylostella) IndianAgriculturalResearchInstitute,NewDelhi  Indoxacarb 3
  18. 18. Mode Of Action  This pro-insecticide is bioactivated in the insect by enzymatic (insect esterase) N-decarbomethoxylation changing it to a more active, highly insecticidal metabolite  It produces its potent effects at a unique binding site in voltage- gated sodium ion channels of the nervous system of susceptible insects  The active metabolite of indoxacarb induces irreversible hyperpolarization of insect nerve cell membranes. It blocks the sodium current amplitude in the neuron differently than the pyrethroids IndianAgriculturalResearchInstitute,NewDelhi
  19. 19. Halogenated pyrroles Chlorfenapyr IUPAC: 4-Bromo-2-(4-chlorophenyl)-1-ethoxymethyl-5-trifluoromethyl- 1H-pyrrole-3-carbonitrile  Formulations: 10% SC (Intrepid®)  Effective against DBM in cabbage and cauliflower, mites in chilli IndianAgriculturalResearchInstitute,NewDelhi  Chlorfenapyr 4
  20. 20. Mode Of Action  Chlorfenapyr works by disrupting the production of ATP, specifically, Oxidative removal of the N-ethoxymethyl group of chlorfenapyr by MFO forms the compound CL 303268 which uncouples oxidative phosphorylation at the mitochondria, resulting in disruption of production of ATP, cellular death, and ultimately organism mortality IndianAgriculturalResearchInstitute,NewDelhi Oxidative phosphorylation Uncouplers
  21. 21. Thiourea derivatives Diafenthiuron IUPAC: 1-tert-butyl-3-(2,6-diisopropyl-4-phenoxyphenyl)thiourea  Formulations: 50% WP (Polo®)  Effective against sucking insects (whiteflies, aphids, jassids), mites, capsule borers IndianAgriculturalResearchInstitute,NewDelhi  Diafenthiuron 5
  22. 22. Quinazolines Fenazaquin IUPAC: 4-tert-butylphenethyl quinazolin-4-yl ether  Formulations: 10% EC (Magister®)  Mode of action: Broad spectrum acaricide; It inhibits mitochondrial electron transport chain by binding with complex I at co-enzyme Q  Effective against mites in tea and chilli IndianAgriculturalResearchInstitute,NewDelhi  Fenazaquin 6
  23. 23. Pyridazinones Fenpyroximate IUPAC: tert-butyl (E)-α-(1,3-dimethyl-5-phenoxypyrazol-4- ylmethyleneamino-oxy)-p-toluate  Formulations: 5% EC (Mitigate®)  Effective against red spider mites and two spotted mites IndianAgriculturalResearchInstitute,NewDelhi  Fenpyroximate  Pyridaben  Pyridalyl 7
  24. 24.  It is photochemically converted in sunlight to its carbodiimide derivative, which is a more powerful toxicant than diafenthiuron (Steinmann et al., 1990)  The carbodiimide acts as an adenosine triphosphatase (ATPase) inhibitor following metabolic activation to the corresponding carbodiimide (Petroske and Casida, 1995)  The carbodiimide metabolite inhibits mitochondrial respiration by selective and covalent binding to the proteolipid ATPase (Ruder et al., 1992; Kayser and Eilinger, 2001) Mode Of Action IndianAgriculturalResearchInstitute,NewDelhi
  25. 25. Thiazolidines Hexythiazox IUPAC: (4RS,5RS)-5-(4-chlorophenyl)-N-cyclohexyl-4-methyl-2-oxo- 1,3-thiazolidine-3-carboxamide  Formulations: 5.45% EC (Maiden®)  Mode of action: Unknown or non-specific mode of action (mite growth inhibitors)  Effective against red spider and yellow mites in tea and chilli IndianAgriculturalResearchInstitute,NewDelhi 8  Hexythiazox
  26. 26. Carbazates Bifenazate IUPAC: Isopropyl 2-(4-methoxybiphenyl-3-yl)hydrazinoformate  Selective acaricide  Formulations: 24% SC (Floramite®)  Mode of action: Neuroactive; exact mode of action is unclear  Effective against spider mite IndianAgriculturalResearchInstitute,NewDelhi 9  Bifenazate
  27. 27. Diamides Flubendiamide IUPAC: 3-iodo-N’-(2-mesyl-1,1-dimethylethyl)-N-{4-[1,2,2,2- tetrafluoro-1-trifluoromethyl)ethyl] -o-tolyl} phthalamide  Pthalic diamide  Formulations: 20% WG (Takumi®), 39.35% SC (Fame®)  Effective against insect pests of rice (stem borer. Leaf folder) and cotton (Helicoverpa armigera, spotted boll worm) IndianAgriculturalResearchInstitute,NewDelhi  Flubendiamide  Chlorantraniliprole  Cyantraniliprole  Cyclaniliprole  Tetraniliprole 10
  28. 28. Diamides … Cyantraniliprole IUPAC: 3-bromo-1-(3-chloro-2-pyridyl)-4′-cyano-2′-methyl-6′- (methylcarbamoyl)pyrazole-5-carboxanilide  Anthranilic diamide  Formulations: 20% SC (Cyazypyr®)  Effective against key chewing and sucking insects (Homopterans and lepidopterans) IndianAgriculturalResearchInstitute,NewDelhi
  29. 29.  Ryanodine receptors are intracellular Ca2+ channels specialized for the rapid and massive release of Ca2+ from intracellular stores, which is an essential step in the muscle contraction process  Pthalic diamides interacts with a site distinct from the ryanodine binding site and disrupts the Ca2+ regulations of the ryanodine receptor completely by an allosteric mechanism Mode Of Action IndianAgriculturalResearchInstitute,NewDelhi
  30. 30.  Anthranilic diamides cause death of insects by disruption of Ca2+ within muscle tissue.  The anthranilic diamide insecticides bind to ryanodine receptors locking them partially open. Ca2+ leaks out of muscle tissues which results in the inability to regulate muscle function which causes paralysis and death (Cordova et al., 2006) Mode Of Action …
  31. 31. Flufenoxuron IUPAC: 1-[4-(2-chloro-α,α,α-trifluoro-p-tolyloxy)-2-fluorophenyl]- 3-(2,6-difluorobenzoyl)urea  Insect growth regulator  Formulations: 10% DC (Cascade®)  Effective against immature stages of many phytophagous mites and insects pests of pome fruit, vines, citrus, tea, ornamentals IndianAgriculturalResearchInstitute,NewDelhi Benzoyl Urea  Bistrifluron  Chlorbenzuron  Chlorfluazuron  Dichlorbenzuron  Diflubenzuron  Flucycloxuron  Flufenoxuron  Hexaflumuron  Lufenuron  Novaluron  Noviflumuron  Penfluron  Teflubenzuron 11
  32. 32. Mode Of Action  It acts as a chitin synthesis inhibitor by blocking terminal polymerization step catalysed by chitin synthase enzyme IndianAgriculturalResearchInstitute,NewDelhi  These compounds alters cuticle composition—especially that of chitin—thereby affecting the elasticity and firmness of the endo-cuticle (Grosscurt & Anderson, 1980)  The reduced level of chitin in the cuticle seems to result from inhibition of biochemical processes leading to chitin formation (Hajjar & Casida, 1979)  They might affect the insect hormonal site, thereby resulting in physiological disturbances such as inhibition of DNA synthesis, alter carbohydrase and phenoloxidase activities, or suppress microsomal oxidase activity (Ishaaya & Ascher, 1977; Van Eck, 1979; Soltani et al., 1984)  They inhibit 20E-dependent GlcNAc incorporation into chitin (Oberlander & Silhacek, 1998)
  33. 33. Thiadiazines Buprofezin IUPAC: (Z)-2-tert-butylimino-3-isopropyl-5-phenyl-1,3,5- thiadiazinan-4-one  Insect growth regulator  Formulations: 44% SC (Applaud®)  Effective against homopteran insects (hoppers, jassids, whiteflies) IndianAgriculturalResearchInstitute,NewDelhi  Buprofezin 12
  34. 34. Mode Of Action  It acts as a chitin synthesis inhibitor having both contact and vapour phase activity IndianAgriculturalResearchInstitute,NewDelhi  It acts on the nymph stages of leaf hoppers, scales, plant hoppers,and whiteflies (Ishaaya et al., 1988)  It inhibits incorporation of 3H- glucosamin into chitin (Uchida et al., 1985)  As a result of chitin deficiency, the pro-cuticle of the nymphs loses its elasticity and the insect is unable to complete the moulting process (De Cock and Degheele, 1998)
  35. 35. Diacylhydrazines Chromafenozide IUPAC: N′-tert-butyl-5-methyl-N′-(3,5-xyloyl)chromane-6- carbohydrazide  Insect growth regulator  Formulations: 5% SC (Virtu®)  Effective against lepidopteran insects on top fruits IndianAgriculturalResearchInstitute,NewDelhi  Chromafenozide  Halofenozide  Methoxyfenozide  Tebufenozide 13
  36. 36. Mode Of Action  These compounds bind to the ecdysteroid receptors, accelerating the molting process and thereby disrupting the insect hormonal balance (Wing, 1988; Palli et al., 1996) IndianAgriculturalResearchInstitute,NewDelhi
  37. 37. New Insecticides From Microorganisms Avermectins Source: Streptomyces avermitilis  A series of 16-membered macrocyclic lactone derivatives with potent anthelmintic and insecticidal properties IndianAgriculturalResearchInstitute,NewDelhi 14
  38. 38.  Abamectin (Avermectin B1) Agri-Mek® 15% EC Used against sucking pests, phytophagous mites, dipterans, psyllidae, leaf miners  Ivermectin (22,23-dihydroavermectin) Ivomec® 1% S Used to control parasites of cattle  Emamectin benzoate Proclaim® 5% WSG Used against lepidopteran insects Mode of action They block the transmittance of electrical activity in nerves and muscle cells by stimulating the release and binding of GABA at nerve endings. This causes an influx of chloride ions into the cells, leading to hyperpolarisation and subsequent paralysis of the neuromuscular systems IndianAgriculturalResearchInstitute,NewDelhi New Insecticides From Microorganisms …
  39. 39. Spinosyns  Spinosad 1st a.i.  Source: Saccharopolyspora spinosa  Mixture of 2 most active metabolites, Spinosyn A and Spinosyn D  Formulations: 45% SC (Tracer ®) Mode of action They primarily target binding sites on nicotinic acetylcholine receptors (nAChRs) of the insect nervous system that are distinct from those at which other insecticides have their activity. Spinosoid binding leads to disruption of acetylcholine neurotransmission. Spinosad also has secondary effects as a GABA neurotransmitter agonist IndianAgriculturalResearchInstitute,NewDelhi New Insecticides From Microorganisms …
  40. 40. Entomopathogenic Bacteria Bacillus thuringiensis  Bacillus thuringiensis (Bt), a gram-positive, motile, rod shaped bacterium produces a parasporal crystal composed of one or more proteins  The strains of Bt characterized so far affect members of 3 insect orders: Lepidoptera (butterflies & moths), Diptera (mosquitoes & biting flies) and Coleoptera (beetles)  3 Bt products registered in India  B.t. kurstaki is the most commonly used Bt formulation IndianAgriculturalResearchInstitute,NewDelhi  B.t. israelensis (diptera)—frequently used for mosquitoes  B.t. kurstaki (lepidoptera)—frequently used for gypsy moth, spruce budworm, and many vegetable pests  B.t. galleriae (lepidoptera)—frequently used for leaf beetle, Colorado potato beetle
  41. 41. Bacillus thuringiensis strains produce crystalline proteins (called δ-endotoxins) Caterpillar consumes the Bt spore (diagram 1) & crystalline toxin-treated leaf The Bt crystalline toxin (diamond shapes in diagram 2) binds to gut wall receptors, and the caterpillar stops feeding Within hours, the gut wall breaks down, allowing spores (oval tube shapes) and normal gut bacteria (circular shapes) to enter body cavity, where the toxin dissolves The caterpillar dies in 24 to 48 hours from septicemia, as spores and gut bacteria proliferate in its blood (diagram 3) Mode Of Action IndianAgriculturalResearchInstitute,NewDelhi
  42. 42. Entomopathogenic Fungi Metarhizium anisopliae  They cause green muscardine disease in various insect pests Mode of action  Fungi have virulent spores adsorbed to the carrier/neutral material that remain either dormant or active on the carrier particles and start multiplying when congenial environmental conditions are met with  The soil borne insect like termites come in contact with the fungus and the mycelia of fungus starts growing on the body of termites and starts feeding on the body fluid of insects and results in disease and death of the insect pest IndianAgriculturalResearchInstitute,NewDelhi Conidia Different cultures of M. anisopliae Cockroach killed by M. anisopliae
  43. 43. Pyridine azomethines Pymetrozine IUPAC: (E)-4,5-dihydro-6-methyl-4-(3-pyridylmethyleneamino)- 1,2,4-triazin-3(2H)-one  Formulations: 50% WDG (Fulfill®)  Mode of action: It has no direct toxicity against insects but it blocks stylet penetration of sucking insects which may cause immediate cessation of feeding after exposure to this insecticide  Effective against sucking pests (whiteflies, hoppers and aphids) IndianAgriculturalResearchInstitute,NewDelhi 15  Pymetrozine
  44. 44. Tetronic Acid Derivatives Spiromesifen IUPAC: 3-mesityl-2-oxo-1-oxaspiro[4.4]non-3-en-4-yl 3,3- dimethylbutyrate  Formulations: 24% SC (Oberon®)  Mode of action: Prevent Lipid biosynthesis by inhibiting acetyl CoA carboxylase  Effective against mites and moth scale insects IndianAgriculturalResearchInstitute,NewDelhi  Spiromesifen 16
  45. 45. Sulfoximines Sulfoxaflor IUPAC: [methyl(oxo){1-[6-(trifluoromethyl)-3-pyridyl]ethyl}- λ6-sulfanylidene]cyanamide  Systemic insect neuro-toxin  Formulations: 24% SC (Transform®)  Effective against major species of sap feeding insects IndianAgriculturalResearchInstitute,NewDelhi  Sulfoxaflor 17
  46. 46. Mode Of Action  It causes a blockage in the nicotinergic neuronal pathway leading to the accumulation of acetylcholine, an important neurotransmitter, resulting in the insect's paralysis and eventually death  Sulfoxaflor is stable to monooxygenases that are known to readily metabolize other insecticides such as organochlorines and the neonicotinoids (Zhu et al., 2011) IndianAgriculturalResearchInstitute,NewDelhi
  47. 47. Methoxyacrylates Naphthoquinones Nereistoxin analogues Sulfite esters Botanicals Miscellaneous compounds Other Insecticidal Groups IndianAgriculturalResearchInstitute,NewDelhi
  48. 48. Future Challenges  To develop more and more new molecules having  More discoveries in macromolecular pesticides  More innovations required for new neo-nicotinoids IndianAgriculturalResearchInstitute,NewDelhi  Low dose compounds  High efficacy and quick knockdown effect  Low mammalian toxicity  Relatively safer formulations  Less leaching potential  New chemistry  Less harmful to beneficial species
  49. 49. Future Challenges …  More biotechnological innovations to be directed in transgenic plants etc.  More innovative technology to be developed in application of pesticides  Minimization of residue load in ecosystem  More emphasis shall be given in bio-control agents  Research emphasis shall be given in innovations of more plant derived bio-pesticides IndianAgriculturalResearchInstitute,NewDelhi
  50. 50. Conclusion  Scientific community has been involved in approaches towards the developments of newer molecules which could be easily biodegradable, target-specific with very low mammalian toxicity  A distinct division in scientific opinion was made to decide whether to go for bio-based products or for using synthetic chemicals for protecting the crops  A new horizon of analytical chemistry was evolved as pesticide residue analysis to judge the residue level of these harmful chemicals in food grains IndianAgriculturalResearchInstitute,NewDelhi
  51. 51. Conclusion …  Researches were carried out to develop safer molecules which could undergo photo-degradation, microbial degradation as well as chemical degradation leaving very less amount of residues in the environment  The prime motto for this development is to give protection to the crops along with safety to the natural enemies of different pests as a whole safety to environment IndianAgriculturalResearchInstitute,NewDelhi
  52. 52. IndianAgriculturalResearchInstitute,NewDelhi “If you're not part of the solution, You're part of the precipitate …”