NATURAL PESTICIDES
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The document discusses natural pesticides, categorizing them into natural and artificial methods of pest control, detailing various types such as insecticides, herbicides, fungicides, and biological controls. It highlights the advantages and disadvantages of each type, focusing on substances like neem, pyrethrum, and sabadilla, which have insecticidal properties and modes of action. The document also emphasizes the importance of environmentally friendly pest control methods due to the health hazards associated with synthetic chemicals.
NATURAL PESTICIDES
- 3. A pesticide is a substance that disrupts or kills organisms that we consider to be pests such as weeds, damaging insects, or microbes that cause disease. Any substance or mixture of substances, intended for preventing, destroying, or mitigating any pest, or intended for use as a plant growth regulator, defoliant or desiccant. Pest- it is any animal, plant or microorganism that trouble, injuries or cause destruction of crop. Methods of pest control- They have two types- natural and artificial pest control. Natural pest control- they are prepared in nature due to prey- predator relationships. Beneficial insects are those insects which prey on harmful insects or their larvae. Artificial pest control- these are man mede methods to control pest. They have following types
- 4. In agricultural production the synthetic pesticides are used which has got sometimes carcinogenic, teratogenic and residual toxic effects. The excessive use of it also causes serious health hazards to live stocks, human life, wild life, fishes, birds and animals. mechanical- manual or mechanical method for collection or destruction of pest. Eg.handpicking, pruning, trapping, burning for destruction of eggs, larvae, pupae, insects Agriculture control- these methods are used to destroy life cycle of pest eg deep ploughing for eradication of weeds, alternate crop rotation, hybrid pest resistance crop species Chemical control- these are chemicals used to kill pest eg. insecticides, paraciticides Biological control- Living organisms are used to control pest. Eg microorganisms may be used to kill by causing fatal disease in insects
- 5. Classification of pesticides Pesticides are classified according to the pest they control Insecticides (Ants, moths, cockroaches) Herbicides (Weeds) Fungicides (Control fungal diseases) Rodenticides (Rats) Characteristics of ideal pesticide -should have high margin of safety for plants and animals -easy to handle and apply -should not be toxic for warm blooded animals -should not be inflammable or explosive should be available easily at affordable cost
- 6. Advantages: • 1. They are cheap (They are economical) • 2.They are less harmful to the human beings and more effective against pest • 3. They are more stable and can be kept for prolonged period (Degradation is less) • 4.They can be used to control the carriers of vector borne diseases like malarial, sleeping sickness and dengue fever. Dis- advantages: • The onset of action is slow • The quantity of pesticide required may be more due to crude components
- 7. Herbicides, also commonly known as weed killers, These are pesticides used to kill unwanted plants. Selective herbicides kill specific targets, while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic mimics of natural plant hormones. Some plants produce natural herbicides, action of natural herbicides, and other related chemical interactions, is called allelopathy. The most frequent application of herbicides occurs in row-crop farming, where they are applied before or during planting to maximize crop productivity by minimizing other vegetation(weed)
- 8. Fungicides- they are used to control fungal diseases of plants and food crops. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality, and profit Fungicides can either be contact, translaminar or systemic. Contact fungicides are not taken up into the plant tissue, and protect only the plant where the spray is deposited; translaminar fungicides redistribute the fungicide from the upper, sprayed leaf surface to the lower, unsprayed surface; systemic fungicides are taken up and redistributed through the xylem vessels. Few fungicides move to all parts of a plant. Some are locally systemic, and some move upwardly
- 9. Fumigation is a method of pest control that completely fills an area with gaseous pesticides—or fumigants—to suffocate or poison the pests within. It is used to control pests in buildings (structural fumigation), soil, grain, and produce, and is also used during processing of goods to be imported or exported to prevent transfer of exotic organisms.
- 10. Rodenticides, rat poison, are pest control chemicals intended to kill rodents. Rodenticides are controversial, due to secondary poisoning and their risks to children, pets and wildlife. Single feed baits are chemicals sufficiently dangerous that the first dose is sufficient to kill. rodents will eat a small bit of something and wait, and if they do not get sick, they continue. An effective rodenticides must be tasteless and odorless in lethal concentrations, and have a delayed effect.
- 11. Tobacco
- 13. Mode of action. In both insects and mammals, nicotine is an extremely fast- acting nerve toxin. It competes with acetylcholine, the major neurotransmitter, by bonding to acetylcholine receptors at nerve synapses and causing uncontrolled nerve firing. This disruption of normal nerve impulse activity results in rapid failure of those body systems that depend on nervous input for proper functioning. In insects, the action of nicotine is fairly selective, and only certain types of insects are affected.
- 15. Pyrethrum
- 16. Synonym Insect flowers, pyrethrum flowers Biological source :It consist of dried unexpanded flower-heads of Chrysanthemum cinerariaefolium belonging to the family Compositae, consists of NLT 0.7 % pyrethrins. Macroscopic study : Color : cream to straw coloured Odour : aromatic Taste : bitter to Numbness Size : 10 to 15 mm in diameter Shape : flower head is flat with convex receptacle. Peduncle is short and longitudinal striated. Ray florets s are 15-23 in number. Disc florets 200-300 ( hermaphrodite) 5 lobed, yellow colored corolla is present. Before drying flower heads are non toxic to insects
- 17. Mode of action. Pyrethrins exert their toxic effects by disrupting the sodium and potassium ion exchange process in insect nerve fibers and interrupting the normal transmission of nerve impulses. Pyrethrins insecticides are extremely fast acting and cause an immediate “knockdown” paralysis in insects. Despite their rapid toxic action, however, many insects are able to metabolize (break down) pyrethrins quickly. After a brief period of paralysis, these insects may recover rather than die. To prevent insects from metabolizing pyrethrins and recovering from poisoning, most products containing pyrethrins also contain the synergist, piperonyl butoxide (PBO). Without PBO the effectiveness of pyrethrins is greatly reduced. “pyrethrins” refers to the six related insecticidal compounds that occur naturally in the crude material, the pyrethrum flowers. They are extracted from crude pyrethrum dust as a resin that is used in the manufacture of various insecticidal products.
- 18. Chemical constituents Esters Pyrethrin- I,II, Jasmolin,- I ,II , cinerin- I,II, triterpine alcohol, pyrethrol, lactone, pyrethrocin. Other pyretol,pyrethrotoxic acid,chrysanthemine, chrysanthemumic acid Uses Domestic and agriculture insecticidal It act on nervous system of insects resulting in muscular excitation, convulsion, paralysis occurs. Toxic effect of pyrethrum on human are irritation to eyes, mucosa. maximum permissible atmospheric concentration is up to 5 mg per cubic meter. Insecticide, sometimes mixed with synthetic products such as D.D.T. scabicide for human beings , ectoparasiticide in veterinary medicine These compounds make a unique insecticide because they are relatively non-toxic to humans and warm blooded animals pyrethrins are quickly broken down into inactive forms, and pass from the body quickly
- 19. NEEMNEEM
- 20. The NEEM tree (Azadirachta indica belonging to the family Meliaceae) is a tropical evergreen tree native to India and is also found in other southeast countries. In India, neem is known as “the village pharmacy” because of its healing versatility, and it has been used in Ayurvedic medicine for more than 4,000 years due to its medicinal properties. In the first millennium BC the neem tree was called the "Sarva Roga Nivarini" (one that could cure all ailments and ills). Description : Leaves are imparipinnate, alternate, exstipulate, 3-6 cm long on long slender petioles; leaflets 7-17; alternate or opposite, very shortly stalked, 1-1.5 cm long. Apex: ovate-lanceolate, attenuate, bases are unequal, Smooth in touch and dark green in color, odour is typical, and taste is bitter in nature. Fruits are Ovoid, bluntly pointed, smooth drupe, appear in Green (Young and unripe); Yellow to brown (Mature and ripe) in color. Shows Very scanty pulp and hard bony endocarp. Solitary with a thick testa and embryo with foliaceous cotyledons in the axis of scanty endocarp.
- 23. The product known as “neem oil” is more like a vegetable or horticultural oil and acts to suffocate insects. Neem and neem oil are often confused. Mode of action. Neem is a complex mixture of biologically active materials, and it is difficult to pinpoint the exact modes of action of various extracts or preparations. In insects, neem is most active as a feeding deterrent, but in various forms it also serves as a repellent, growth regulator, oviposition (egg deposition) suppressant, sterilant, or toxin. As a repellent, neem prevents insects from initiating feeding. As a feeding deterrent, it causes insects to stop feeding. As a feeding, either immediately after the first “taste” (due to the presence of deterrent taste factors), or at some point soon after ingesting the food (due to secondary hormonal or physiological effects of the deterrent substance). As a growth regulator, neem is thought to disrupt normal development interfering with chitin synthesis. Susceptibility to the various effects of neem differs by species.
- 24. Uses Neem oil is extracted from the seeds of the neem tree and has insecticidal and medicinal properties due to which it has been used in pest control in cultivation. Neem seed cake (residue of neem seeds after oil extraction) when used for soil amendment or added to soil, not only enriches the soil with organic matter but also lowers nitrogen losses by inhibiting nitrification. It also works as a nematicide. Neem leaves are used as green leaf manure and also in preparation of litter compost. Neem leaves are also used in storage of grains. Twigs of neem when tender is used as green manure after decomposing and widely incorporated in rice cultivation fields. Neem (leaf and seed) extracts have been found to have insecticidal properties. has anti-bacterial, anti-fungal and anti-nematicidalproperties and positive effect in combating several diseases
- 25. DERRIS Biological source: It consists of dried root and rhizomes of Derris elliptica and Derris malaccensis belonging into the family Leguminosae Tubli is a rambling climber, with branches covered with brown hairs. Leaves are pinnate and 30 to 50 centimeters long. Leaflets are usually oblong, 9 to 13, when matured smooth above, and subglaucous and silky beneath, 10 to 15 centimeters long, and about half as broad. Racemes are lax, 15 to 30 centimeters in length, with reddish flowers in stalked clusters. Pods are 5 to 8 centimeters long and contain 1 to 3 seeds, flat and reniform, olive, brown or black. Synonym: Tubli
- 26. Mode of action Mode of action of rotenone is a respiratory enzyme inhibitor, acting between NAD+ (a coenzyme involved in oxidation and reduction in metabolic pathways) and coenzyme Q (a respiratory enzyme responsible for carrying electrons in some electron transport chains), resulting in failure of the respiratory functions. Acute toxicity: Local effects on the body include conjunctivitis, dermatitis, sore throat, and congestion. Ingestion produces effects ranging from mild irritation to vomiting. Inhalation of high doses can cause increased respiration followed by depression and convulsions. The compound can cause a mild rash in humans and is a strong eye irritant to rabbits . Chronic toxicity: Growth retardation and vomiting resulted from chronic exposures of rats and dogs. The compound is nontoxic to bees. However, it is toxic to bees when used in combination with pyrethrum.
- 28. SABADILLA synonym: stickweed Biological source: It consists of dried ripe seeds of Schoenocaulon officinale belonging to the family Liliaceae, it is a perennial plant growing up to 1 metre tall from an underground bulb. The plant is used locally as an insecticide. Brushy or grassy slopes, usually in pine or oak forest, mostly in rather dry and exposed places, sometimes on moist or wet slopes, chiefly at elevations of 500 - 2,000 metresThe seeds are 4 - 6 mm. long, wrinkled, black or dark brown outside, whitish within, hard, inodorous, and have an exceedingly acrid, burning taste. They contain veratrin and other alkaloids, and are poisonous. They formerly constituted an official drug of the British Pharmacopoeia.The seeds have emetic-cathartic properties, operating sometimes with great violence, and overdoses produce death. They were formerly used to some extent to expel tapeworms
- 30. The seeds are black, shining, flat, shrivelled and winged, odourless, with a bitter, acrid, persistent and disagreeable taste, the pale grey, amorphous powder being errhine and violently sternutatory. Chemical Constituents---Sabadilla contains several alkaloids, the most important being Cevadine, yielding cevine on hydrolysis; Veratrine, obtained from the syrupy liquor from which the cevadine has crystallized; and Cevadilline or Sabadillie, obtained after the extraction of the veratrine with ether. Two other alkaloids have been isolated: Sabadine, which is less sternutatory than veratrine, and Sabadinine, which is not sternutatory. Sabadilla yields about 0.3 per cent of veratrine. The seeds also contain veratric acid, cevadic acid, fat and resin. Uses: It is an insecticide used to kill house flies and bugs in the form of spray or dust.
- 33. • Uses: • Spinal cord stimulant. • In cases of neurasthenia (excessive fatigue of neurotic origin). • As a circulatory stimulant. • Nerve and sex tonic. • Bitter Stomachic (strengthening of stomach and promoting its action).
- 34. RYANIA Biological source: It consists of dried root and stems of Ryania speciosa belonging to the family Flacourtiaceae. Ryania is a botanical insecticide made from the ground stems of Ryania speciosa, a native plant of tropical America. The principal alkaloid in this stem extract is ryanodine, which makes up approximately 0.2% of the product. Ryania is highly toxic to the fruit moth, coddling moth, corn earworm, European corn borer, and citrus thrips, but it is ineffective against the cabbage maggot, cauliflower worm, and boll weevil. Ryania is a complex mixture of many compounds; thus, no single structure would represent it.
- 36. Citrus Oil Extracts: Limonene and Linalool Crude citrus oils and the refined compounds d-limonene (hereafter referred to simply as limonene) and linalool are extracted from orange and other citrus fruit peels. Limonene, a terpene, constitutes about 90% of crude citrus oil, and is purified from the oil by steam distillation. Linalool, a terpene alcohol, is found in small quantities in citrus peel and in over 200 other herbs, flowers, fruits, and woods.
- 37. Terpenes and terpene alcohols are among the major components of many plant volatiles or essential oils. Other components of essential oils are ketones, aldehydes, esters, and various alcohols. Essential oils are the volatile compounds responsible for most of the tastes and scents of plants. Many of the essential oils also have some physiological activity. Mode of action. The modes of action of limonene and linalool in insects are not fully understood. Limonene is thought to cause an increase in the spontaneous activity of sensory nerves. This heightened activity sends spurious information to motor nerves and results in twitching, lack of coordination, and convulsions. The central nervous system may also be affected, resulting in additional stimulation of motor nerves. Massive over stimulation of motor nerves leads to rapid knockdown paralysis.