POISONOUS PLANTS AND NATURAL PESTICIDE Shahana Sharmin Pharmacognosy-II PHR 205 1

Botanicals are naturally occurring insecticides and compounds derived from plants. They are processed into various forms which include, Preparation of crude plant material Plant extract or resins & Pure chemicals isolated from plants. Generally they are used in form of dust, sprays, paste, suspension or preparations. Sometimes they are dispensed in the form of aerosol or liquefied gas propellants. For the application of pesticides the equipment used are small hand sprayers, paint brushes for use in home to large power sprayers for treating livestock's and field crops. For vast area dispersal airplanes and helicopters are also used. INTRODUCTION

Advantages 1. Rapid degradation: Less persistence in environment and reduced risk to non target organism. May be applied shortly before harvest without leaving excessive residue. 2. Rapid action: Act very quickly to stop feeding by pest insects. They may not cause death for hrs. or days, but they often cause immediate paralysis or cessation of feeding. 3. Low mammalian toxicity: Most botanicals have low to moderate mammalian toxicity. 4. Selectivity: In the field, their rapid degradation and action as stomach poisons make them more selective in some instances for plant- feeding pest insects and less harmful to beneficial insects. 5. Low toxicity to plants: Most botanical are not phytotoxic (toxic to plants). Insecticidal soaps and nicotine sulphate, may be phytotoxic to some ornamentals. 6. Botanical pesticides are absolutely environment friendly. 7. Safe to other botanicals including to the person who applies them.

8. Systematic and do not attack host organism. 9. Do not cause pesticides resistance as they comprise of a group of complex chemical compound. 10. Easily bio degradable and do not posses any toxic effect. 11. Inexpensive and produce from natural renewable sources. 12. Do not exhibit any dosage problems as their drug tolerance limit is very high 13. May also be tried by mixing with one or more botanicals or the synthetic organic compound ( synergistic effect) and such combination may be more effective.

Disadvantages 1. Rapid degradation: This characteristic, although desirable in some respects, creates a need for more precise timing or more frequent applications. 2. Toxicity: All toxins used in pest control pose some hazard to the user and to the environment. 3 Cost and availability: Botanicals tend to be more expensive than synthetics and some are not as widely available. 4. Lack of test data: Data on effectiveness of long term ( chronic ) toxicity are unavailable for some botanicals and tolerances for some have not been established.

CLASSIFICATION The plant derived compounds with pesticidal potential are:  Pesticides  Insecticides  Fungicides  Herbicides  Nematicides and Molluscicides  Rodenticides  Ascaricides - controls the ticks & mites.  Algicides - controls the Algae & other equatic veretation  Antiseptics - controls micro - organisms.  Arbericides - Defoliate & destroy trees & shrubs.  Miticides  Plant Incorporated protectants (PIPs) The miscellaneous pesticides are antimicrobial, Attractants, Bactericide, Disinfectant etc.

PESTICIDES Pesticide is a general term for substances that kills pests. Pest can be weeds, insects, rodents, diseases, etc. Pesticides can also be classified according to the type of action that result in destruction of pest. Three broad categories are, (1) Stomach poison kill by being taken into stomach (2) Systemic poison absorbed in the blood & leads to death of the pest due to toxic action (3) Contact insecticides kill by direct or indirect contact with the insect or sometimes it penetrate inside the body & causes oxidation & suffocate the insect.

Essential of good pesticides ( a) It should have a high margin of safety for plants & animal causing very little or no damage to the foliage or live stocks respectively. (b) It should be safer. (c) It should be easier to handle & easy for application. (d) It should not show toxicity in case of warm blooded animals. (e) It should not have flammable or explosive character. (f) It should have safety & palatability of the food products exposed to insecticides & should not show the residual effects of pesticides.

Plants used for pest control experimentally and traditionally in different parts of world: Name of the drug and B. S. Family Allium sativum (Garlic) Liliaceae Anacardium occidentalis Anacardiaceae Annona cuneata Annonaceae Azadirachta indica (Neem) Meliaceae Capsicum frutescens (chilli) Solanaceae Cassia spp. Leguminosae Eucalyptus spp. Myrtaceae Euphorbia tirucalli (milk bush) Euphorbiaceae Melia azedarach (Persian lilac) Meliaceae Nicotiana spp. (tobacco) Solanaceae Ocimum spp. (Basil) Labiatae Pyrethrum Compositae Rhuspyroides Anacardiaceae Solanum nigrum (blackpepper) Solanaceae Tagetes spp. (Marigold) Asteraceae

Basil species (ocimum sanctum family labiatae, holy basil)  It is reported by irvine(1955) for its potential as a pesticide.  Leaves and seeds are rich in essential oils which are repellent,toxic, or growth inhibitory to many insects.  In held and laboratory experiments with seed exracts against bugs in turnip.  The eugenol content in the essential oil has got strong repellent efect on mosquitos.

Cocaine, a Naturalinsecticide (erythroxyton coca, erythroxylaceae)  Cocaine found in the leaves of coca plants has been found to have insecticidal effects.  Elicit a blocking of a key neurotransmitter and hormone that regulates movement, behaviour and metabolism in insects.

Tobacco Nicotine  Prepare from west materials of tobacco industry, volatile liquid alkaloid consists of pyridine and pyrrolidine rings.  Pure Nicotine highly toxic to warm blooded animals.  The insecticide usually is marketed as a 40% liquid concentrate of nicotine sulfate.  Effective against aphids, whiteflies, leaf hoppers and thrips.

 Nicotine is more effective when applied during warm weather.  It degrades quickly so used on food plants nearing harvest.  Tobacco dust along with black pipper and liquid dish washing detergent mixed in water used as natural pesticide.

Derris Root Rotenone  Rotenone (compound from the Roots and Rhizomes of Derris elliptica Roxb, D.malaccensis pran, Lonchocarpus utilis, Lonchocarpus nicou and L. urucu, Leguminosae ).  It is a isoflavanoid derivative which strongly inhibits mitochondrial respiration.  It acts as both a contact and stomach poison to insects.  This general garden insecticide is harmless highly toxic to fish and many insects, moderately toxic to mammals and leaves no harmful residue on vegetable crops.  It is slow acting and, in the presence of sun and air, its effectiveness is lost within a week after application.  Wear a mask during application because rotenone can irritate the respirator tract.

 Rotenone dusts and sprays have been used for years to control aphids,certain beetles and caterpillars on plants as well as fleas and lice on animals.  It is a potentially lethal toxin for aphids, cockroaches,houseflies, corn bores,Mexican bean beetles and mosquitoes.

RODENTICIDE  Strychnine The occurrence of strychnine in Strychons species (Loganiaceae)has already been discussed. This alkaloid has been used traditionaly for the extermination of moles, but its toxicity to other animals and its painful poisonous action do not make it a poison of choice.

Red squill Red squill and white squill are both varieties of Urginea mortima (Liliaceae). It may be distinguished in either the whole or powdered state by the reddish brown outer scales and white to deep purple inner ones. In addition of other cardio active glaycosides the bulb of red squill also contain the glucosides scilliroside and scillirubroside. Strain selected for high scilliroside content have been developed from plants. Unlike other mammals, rodents do not regurgitate the squill bulb,and death follows convulsions and respiratory failure.

Marijuana – Cannabis sativa Cannabis sativa – multi-use plant: - fibers  ropes, fishnets, clothing - seeds  food, oil (non-food uses) - glands  psychoactive drug Cannabaceae - Includes only Cannabis and Humulus (hops) - Related to Moraceae, Celtidaceae, Ulmaceae - herbaceous, laticifers, dioecious

Cannabis Biology Major Drug Component – delta-trans-tetrahydrocannabinol (THC) - binds to specific receptors in brain THC- produced in glands on leaves and flowers -- female plants produce more glands -- gland production stimulated by heat, sunlight, drought -- sinsemilla (sin = without semilla = seeds) – particularly strong Hashish – product - relatively pure resin GlandsTHC

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