Pesticides

1. Presentation on Pesticides Submitted to- Dr. Richa k. Tyagi Asstt Professor Deptt of Env. Sc. BBAU Submitted by- Shailja Singh M.sc 1sem Deptt of Env. Sc. BBAU

2. PESTICIDES A pesticide is a substance or mixture of substance intended for preventing, destroying, repelling or lessening the damage caused by the pest. A pesticide can be a insect, plant pathogen, weed, bacteria, bird etc. That compete with the human for food, destroy property, spread disease. A pesticide can be a chemical, biological agent, antimicrobial, disinfectant etc. Many chemical pesticides are poisonous to human and animals.

3. Classification of pesticides 1. Herbicide-These are the chemicals used to kill weeds (i.e., unwanted plants) e.g. Borax, Nitrofen. 2. Insecticide-These are used to kill insect. E.g. DDT, BHC. 3. Rodenticide-These are used to kill rodents. e.g. Warfarin, Zinc phosphide. 4. Nematicide-These are used to kill namatodes e.g. DBCP, Phorate 5. Molluscicide-These ar used to kill molluscs e.g Sodium pentachloridephenate.

4. 6.Fungicides-These are used to kill fungus e.g. Bordeaux mixture 7.Algaecides-These are used to kill algae e.g. Copper sulphate, Endothal 8.Bactericide-These are used to kill bacteria e.g. Dichlorophen,Oxolinic acid 9.Piscicides-These are used to kill fishes e.g. Trifloro methyl nitrophenol(TFM)

5. Chemical or Synthetic Pesticides Organochlorenes-These are non-biodegradable and persist in soil for long time e.g., DDT, BHC, Endosulfan, Aldrin. Organophosphate-These are esters of alcohols with phosphoric acid or with some other acids. These are very toxic acetyl-cholinesterase inhibitors as a result of which the breakdown of acetyl choline stops.The accumulation of acetyl choline resulting in convulsion paralysis and death e.g.,Malathion. Carbamates-They are derived from carbamic acid. Mode of action of carbamates is almost similar to organo- phosphates e.g.,Carbaryl, Dimetilan.

6. Working of Pesticides Pesticides work in the following ways-  By blocking the cellular processes of the target organisms in a purely mechanical way e.g., Spray oils, petroleum oils.  By destroying or altering the pest’s metabolism e.g., Rotenone and cyanide which disrupt respiratory function in pests.  By disrupting enzyme processes or denature proteins e.g. Inorganic Copper compounds  By simulating or interfering with hormones e.g., Phenoxy herbicides.  By disrupting photosynthesis and preventing the weed plant from producing or storing energy e.g., Triazine.

7. Benefits of pesticides • They are used in public health programmes to control vector born diseases • They are used to protect the stored food grains. • They protect the standing crop in the field. They do not increase the crop yield like fertilizer but by protecting the crop from pests. • They can be used to control household pests.

8. Hazards of pesticides 1. The pesticide industries cause pollution of soil, water and air.The pesticidal residue washed along with rain water, is added to the nearby water resources making it unfit for drinking. 2. They enter the food chain chain and cause problem of bioaccumulation or biomagnification. 3. They are not target specific hence also kills non-pest insects. It adversely affect the mechanism of entomophily. 4.Continuous and indiscriminate use of pesticides may develop resistance in insect pest like superpest and superbugs.

9. 5. They are non-biodegradable and affect the balance of ecosystem. 6.They are highly toxic in nature and if not handled carefully, they can cause serious health problems like cancer, deformities and disease. 7. Accidents in pesticides manufacturing units cause great loss of human life e.g., Bolsover(England,1968), Seveso(Italy,1976), Bhopal Gas Tragedy(India,1984)

10. The Bhopal Gas Tragedy: Pesticides in our midst  The worst industrial disaster in the history of the world is related to pesticide production. This Occurred at Union Carbide Factory in Bhopal, India Dec. 3, 1984.  In this incident, Methyl Isocyanide (MIC) – an ingredient in the production of the insecticide Carbaryl , escaped into the atmosphere killing more than 3,000 people within a few hour.  The insecticide, Carbaryl, itself is a highly toxic chemical and carcinogen (cancer causing agent) to humans.  The tragedy occurred due to lack of adequate safeguards in the storing the chemical and lack of adequate warning to the public. (Top) Survivors of the tragedy lineup outside the factory awaiting treatment. Pesticides such as Lindane (middle) and Sevin (bottom) are still being stored in unsafe manner in the now abandoned the factory.

11. Alternative to pesticides • Integrated Pest Management (IPM)- is an effective and environmentally sensitive approach to pest management that relies on a combination of common-sense practices. • IPM programs use current, comprehensive information on the life cycles of pests and their interaction with the environment. • These include use of pest resistant or tolerant, predators, and pathogens, use of parasites, summer ploughing, late planting, quarantine measures etc.

12. Biological control methods- It include the use of living beneficial organisms, called natural enemies to control pests. • Biological control is an important part of any integrated pest management programme. All insect and mites have some natural enemies. • Managing these enemies can effectively control many pest. There are three component of biological control- Importation, Conservation, Augmentation

13. Bio-Pesticides • These are most effective, important and commercially viable because these are inexpensive, cause no pollution and pose no threat to human health. • It include naturally available agents in nature e.g.- Viruses-Nuclear polyhedrosis virus Bacteria-Bacillus thuringiensis Fungi-Metarhizium, Beauveria • It also includes the use of natural extracts obtained from plants and microbes e.g. Azadiractin from neem, Nicotine from tobacco.

14. Thank you

16. Definitions According to EPA substances or mixtures of substances intended for preventing, destroying, repelling or mitigating any pest A substance that kills a pest (insect, weed, bacteria, nematode etc.) 1. Herbicide = plant killer 2. Insecticide = insect killer 3. Rodenticide = rodent killer  And other cides e.g to kill bacteria and fungi

17.  Pesticides produce their effect by inhibiting or destroying the metabolic processes of animals  All pesticides have their own  Mechanism of action  Potency  Speed of effect (onset of action)  Dose required to produce effect

18. Types of pests Pests Animals Pests Plant Pests Insects Rodents Microbes Weeds Fungi Sucking Biting

19. Animal pests  Rodents: are responsible for damaging and destroying medicinal and agricultural crops  They spoil and contaminate the crude drugs in storage. The spoilage makes crude drugs unsuitable for use in pharmaceutical industry

20.  The spoilage and contamination is done by  By excretory products  Hairs  Rodents responsible for damage may be  Rabbits  Rats  Mice

21. Insects  More than 1M species of insects are present in this world  Out of these , 10K species are responsible for crop eating  Out of 10K, only 700 species can cause epidemic loss to medicinal plants and crops  Insects are divided into 2 groups  Biting insects  Sucking insects

22.  Biting insects: grass hopper, corn ear worm  They bite seeds, stem, fruit and leaves etc.  Sucking insects: suck instead of biting and examples include mosquito and butterflies

23. Plant pests  Microorganisms  Bacteria, Fungi and Viruses  Weeds  Microorganisms  Bacteria: Xanthomonas causing leave spots  Fungi: spores when come in contact cause rhinitis and if inhaled cause asthma and hay fever

24. Virus: Tobacco Mosaic virus

25. Weeds  Undesirable plants in desirable or cultivated plants  Such plants consume minerals, water and fertilizer given to cultivated plants hence inhibit their growth  Weeds may also be toxic for example spores of Agrostemma githago contain cyanophore glycoside and which upon hydrolysis release HCN

26. Pesticides  Grouped into 4 groups  Rodenticides- against rodents (rabbit, rat, mice)  Insecticides- against insects  Herbicides-against weed and herbs  Fungicides-against fungus

27. Mechanism of action  Pesticides kill the pests in many ways. Each pesticide has its own mechanism of action, onset of action, potency and dose required.  Usually they perform their function by one of the following ways  When ingested kill the pest also called stomach poison  When come in contact kill the pest also called contact poisons  When inhaled also called fumigants

28. Choice of chemicals  The choice of chemical used to kill the pest depends  Types of pest  Rodents, herbs or insects  Habitat of the pest  Indoor or outdoor  If rodents are present indoor, chemical used should be such that it should not cause damage to human

29. Methods of controlling pests  Some of the methods are given as follows:  Mechanical methods  Biological methods  Environmental methods  Agricultural methods  Chemical methods

30. Mechanical methods  Hand picking  Method of choice when pests are slowly crawling and are not able to fly e.g caterpillars  Trapping  Is used for flying pests which cant be picked by hand or burned.  Burning  Is used for flying pests which cant be picked by hand and can cause damage. Pests are burned and waste is removed frequently.

31. Biological methods  This method is applicable for removal of animal pests. It depend on the following considerations:  Animals and insects which feed upon smaller forms  Hawk, owl, eagle and cats etc.  Insects having small life span parasitize bigger  Some flies lay eggs on larvae of the crop which cause damage. They attack slowly moving larvae. After few days when eggs are hatched , small larvae appear and consume the body tissues of the crop larvae. Hence death of pest occurs

32. Environmental methods  The surrounding of the pest is changed in such a way it becomes unfavorable for its growth  It can be achieved by removing food stuff needed for the growth of the pest or draining swamps e.g mosquito control

33. Agricultural methods  Involves cultivation of such crops which are resistant to pests  It may be achieved using biotechnology and genetic engineering  Another method for removal is crop rotation

34. Chemical methods  In this method, certain chemicals are used for controlling pests. E.g.  Rodenticides  Insecticides  Herbicides  fungicides

35. Why are pesticides used in agriculture and the environment? 1. Agriculture: a. Use of “crop protecting” agents improves yield and quality of agricultural products b. Prevents the spread of diseases to crops and livestock (Pierce’s Disease) c. The use of pesticides is regulated by the E.P.A. (Environmental Protection Agency, State law and Country regulation

36. Containers or equipment used for chemical control  Spray solutions  Spray suspensions  Baits  Stomach Poisons  Fumigants  Contact poisons

37. Concerns With Pesticide Use 1. Environmental concerns a. They kill beneficial insects and plants (non selective). b. Pollution – runoff of herbicides and insecticides into irrigation water and then into rivers - damages wildlife habitat, kills fish. c. Cause cancer – organophosphates d. Disrupt the natural ecosystem and natural biodiversity e. Creates chemical resistance – insects and weeds.

38. 2. Society & Environment: a. Aesthetics - used regularly in city parks and other recreational areas to control insect damage and weeds b. Protect humans from insect-borne diseases, mosquitoes transmit many diseases, Malaria. c. Protect our food supply. In developing countries up to 1/3 of all harvested grain is destroyed by rodents and insects.

39. Integrated Pest Management (IPM) Pest management that utilizes several strategies to control insects and other pests rather than strictly relying on chemical control. It has 4 components…

40. Integrated Pest Management (IPM) Components 1. Pest identification – important for proper pest control  Confuse beneficial insects with harmful (not all bugs are bad!)  Pest that’s on the plant may not be the one causing damage.  Damage may not even be caused by an insect or herbicide- nutritional deficiency due to weather

41. Integrated Pest Management (IPM) Components 2. Surveying for pests – systematically check for pests and pest damage  Pheromone traps  Sweeping the field  Random leaf, fruit and stem samples

42. Integrated Pest Management (IPM) Components 3. Encourage Beneficial Insect/Animal Populations  Use milder chemicals or selective sprays that don’t kill beneficial animals.  Examples – “Barn Owl Nesting Boxes” – rodent control  Predatory wasp populations – fly control in poultry and dairy operations  Natural insect enemies – lady bugs

43. Integrated Pest Management (IPM) Components 4. Control Action Guidelines – Application of pesticides only after a certain number of pests have been found and there is a threat of economic loss.

44. Future Challenges?  IPM – “requires people to work smarter” dealing with biology & ecology and utilizing…   Mycotoxins – aflatoxins, naturally occurring toxins in peanuts, mushrooms Environmentally Friendly pesticides  Organic Farming – now will be regulated by the federal government, fringe element no more.  Biotechnology – fear of the unknown, no risk is acceptable according to anti-biotech groups.

45. Future of Chemicals & Pesticides Alternatives will be Key Issue…not a new concept!  Beneficial insects  Mechanical control  Chemical controls  Hedgerows – create a place for native species- self perpetuating  Cover crops that produce nitrogen…lower fertilizer use  Cover crops that encourage beneficial insects...  Proper irrigation for various crops…reduce runoff

46. Pesticide Routes of Entry  Dermal (skin) most common  Oral  Respiratory  Ocular

47. Rodenticides • Rodents: vectors of disease – Zinc phosphide - PH3 (cell toxicity, necrosis, GI, liver, kidneys) – Fluoroacetic acid and derivatives (Fluoroacetyl-CoA --> fluorocitrate: Krebs cycle collapse) ? α-naphthyl thiourea (ANTU) must be metabolically activated --> resistance – Anticoagulants (coumadin, warfarin) - antagonist of vit. K in synthesis of clotting factors; requires multiple doses; resistance

48. Important properties of rodenticides  Should be so toxic/potent to kill the rodents  Should be acceptable to rodents so that lethal dose can be taken by rodents

49. Warfarin  Chemically it is 3-acetyl benzyl 4-hydroxy coumarine  Very important anticoagulant drug used in mammalian  Death occurs due to hemorrhage  Toxicity appears with dose of 1 mg/kg  Used for 4-5 days  Also used to prevent cereals from rats

50. Scilliroside-stomach poison • Obtained from Red squill (Liliaceae) • Also present in white squill • Part used is fleshy scale of bulb • Contains cardio-active glycoside-Scilliroside