SYNTHETIC PYRETHROIDS

SYNTHETIC PYRETHROIDS:-

Cypermethrin:-
                        It is sold under the trade names of Ripcord, Cymbush, Cyperkill,etc. and is available as emulsifiable concentrate. It is applied at the rate of 50 g.a.i. per ha in low concentrations on cotton, arhar, sugarcane, gram, lentil,coffee, etc. It is effective against the bollworm complex of cotton, pod borers of arhar, gram, lentil, etc.

Permethrin:-
                     It is sold under the trade name of permasect, Ambush, etc. as emulsifiable concentrate. It is applied at the rate of 50 g a.i. per ha in low concentration on cotton, arhar, vegetables and pulses. It is effective against the bollworm  the bollworm complex of cotton, tissue borers and pod borers.

Deltamethrin:-
                       It is sold under the trade name of Decis, as an emulsifiable concentrate. It is applied at the rate of 10 g a.i. per ha against the bollworm complex of cotton, pod borers and tissue borers of fruits, vegetable and pulses.

Fenvalerate:-
                       It is sold under the trade names of sumicidin, Fenval, etc. as an emulsifiable concentrate. It is applied at the rate of 50 g a.i. per ha in low concentration against the bolloworm complex of cotton, pod boreers and tissue borers of fruits,vegetable and pulses. 

HYDROCARBON OILS

HYDROCARBON OILS 

    The constituents of the oils are solely of hydrogen and carbon. Two groups, Viz. mineral (petroleum) oils and coal-tar oils are recognized. The mineral oils or peteroleum oil are derived from sedimentary rocks. Kerosene, lubricating oils,tar,asphalt and other mixture are derived from them. Among coal-tar oils,creosote oil and green oil or anthracene oil are useful for insecticidal purpose. Based on unsulfonatable residue (UR), which is expressed in terms of percentage to interpret the purity of the oil, two types of oil are recognized.

   Summer oils:-
                           These are highly refined and posses a UR rating of 90-96%. These are usually sprayed at 0.25-2.0% concentration and are less phytotoxic. As water emulsion sprays, these are applied for the control of scales, mealy bugs, whiteflies, etc.

 Dormant oils:-
                         These are heavy and less refined, and possess a UR rating of 50-90%. These are suitable for application on fruit trees and shrubs during dormant seasons when they are devoid of leaves. They are used at 2-5% concentration for the control of scales, mealy bugs, certain mites, aphids, etc.

INSECTICIDES OF PLANT ORIGIN

INSECTICIDES OF PLANT ORIGIN

Nicotinesulphate:
                              It is extracted from the leaves and stems of tobacco (Necotiana tabacum and N. rustica). It is used against sucking insects such as aphids, mealy bugs, psylids and jassids. This is mostly used on the crops where residue is undesirable. It is available in 40 per cent necotine sulphate concentrate and as dust (1-4).

Pyrethrum:-
                   It is contact poison and contains pyrethrin I, pyrethrin II cinerin I, cinerin II, jasmolin I, and jasmolin II which are the esters of chrysanthemic acid and pyrethric acids.  It is generally used as spray or dust for the control of household pests, such as mosquitoes, cockroaches, flies, bed bugs, silver fish and for the control of various vegetable crops and veterinary pests. LD 50 for white rat :  200mg/kg ;dermal for rat : 1800 mg/kg . It is formulated as dust, spray and aerosol.

Rotenone:-
                   It is an extract of roots of derris plants (Deguelia elliptica). It is a selective insecticide which acts as a content as well as stomach poison. It is used against external parasites of animals like line and fleas. It is available as dust, weettable powder, emulsifiable concentrate and aerosol. LD50 for white rat : oral 132-1500 mg/kg.

Neem(Azadirachta indica) :-
                                             The karnels of the neem tree possess azadirachtin, nimbidin-I and meliantriol which has repellent and insecticidal action against insects. The neem seed kernel powder mixed at 1-2 parts with 100 parts of wheat seeds affords protection against stored product pests. Shade dried leaves of this plant are highly effective against the woodly bear, Anthrenus flavipes Le donte and clothes moth, Tineola bisselliella (Hummel) or other insects when kept between the folds of warm clothes.
        Many commercial formulation of neem have been marketed in India. However, many of these formulation lack standardization and, therefore, lack consistency in their efficacy.  Therefore, the central Insecticides Board has recently approved the guideline and data requirements for registration of neem-based pesticides. Formulated neem products are required to contain at least 1500 ppm of azadirachtin in kernel – based products and 300ppm in neem-oil based products. Recently , some formulation with 10,000ppm of azadirachtin have also been approved.

Acorus calamus:
                            powdered rhizone mixed at 1 kg with 50kg of seed affords protections against stored pests for a year. Aphids and leaf eating caterpillars were controlled when suspension produced by soaking the powder at 7.5 to 15g in 5 litres of water with an equal quantity of soap was sprayed.

Sabadilla:
                 It is selective content poison used for the control of houseflies and domestic insect. It is found in the ground seeds of Sohoenocaulon officinale (Liliaceae).

Chinaberry:-
                     Chinaberry , Meliua aze larach L., also known as dharek, persion lilac or pride of India, is a close relative of neem tree . Several tetranortriterpenoids (limonoids) related to azadirachtin, have been found to be present in M. azedarach. These include melianone, melianone, melianol,meliantriol,toosendanin, meliacarpinin, etc. A wide range of toxic, behavioural and physiological effects of M. azedarach have been observed against E. varivestis, M.separata, N. lugens and p.xylostella.

Pongram:-
                  Pongram, pongamia pinnat(L.) pierre, commonly known as karanja, puna oil tree or Indian beech is indigenous to India. It possesses various types of bioactivity including antifeedant, oviposition deterrent and toxic effects. The active component has been identified as karanjin, a furoflavone. Karanja oil as a surface protectant effectively checked infestation by storage pests like callosobruchus maculatus (Fabricius), C. chinensis(Linnaeus), Rhyzopertha dominical (Fabticius) and sitotroge cerealella  (Olivier). Karanjin has been approved in 1977 in india under the Insecticides Act, 1968.

Custard apple:
                         Powdered seeds of custard apple, Annona squamosa L., applied to wheat and rice grains have reported to provide protection against storage insects. The plant extracts act as feeding deterrent against Amsacta moorei (Butler), N.lugens and s. litura. Annonine ,an alkaloid found in stems and leaves, has been found effiective against termites and root grubs . Other compounds which have been isolated from custard apple are annonacia and annonidines.
          Botanical pesticides are considered safe to nature enemies and being biodegradable do not leave toxic residues. Being multistatic in action, chances of development of resistance to these pesticides are minimum.

INORGANIC COMPOUND

A. INSECTICIDES:-

 (1) INORGANIC COMPOUNDS

(a) Arsenic Compounds

 Lcad arsenate-.
                        Basic lead arsenate and Acidlead arsenate . It is sold as a wettable powder containing 14 to 30 per cent arsenic in the from of pentoxide and about 60 per cent in the from of oxide. As a dust, it is diluted with take, hydrated lime, dust etc. , in the ratio of 1:10. Wettable powders are used at 1 to 3 kg in 500 litres of water. It is a stomach poison with little contact poison used against leaf eating caterpillars. It is not in large scale used now. LD50 for rat : oral 10-100mg/kg; dermal 2400 mg/kg.

Calcium arsenate
                           Tricalcium arsenate and Acid calcium arsenate. It is stomach poison and used against leaf eating insect. LD50 for mammals :oral 35:100

Whit arsenate- 
                     This is also known as arsenious oxide and contains 75 percent arsenic. This is used for poison baits for rats, grass-hopper, armyworms, ants and cockroaches. LD50  for rat :oral 20-300 mg/kg.

Paris green-
                  It is used as a bait for the control of slugs. LD50 for rat : oral  22mg/kg.

Sodium arsenite-
                       It is highly toxic to plants. Mainly used as bats for ants, locusts and for stock dip treatment for control of ticks and for weed control. LD50for mammals : oral 10-50 mg/kg.

(b) Fluorine Compounds

1. Sodium fluoride-
                             It is whit powder. It can be used for controlling cockroaches, earwigs, cutworms, grasshopper and chewing lice on animals and poultry. LD50 for rat : oral 200 mg/kg.

2.Sodium fluosilicate-
                                 Its soluble from is used in moth-proofing fabrics. LD50 for rabbit : oral 150-200 mg/kg.

(c) Other inorganic compounds 
      
   Suiphur.-
                Diluted with inert dusts or other insecticidal dusts is effective against mites, thrips, newly hatched coccids, etc.

Lime-sulphur.-
                    It is used against mites, scale insects and as fungicides.

Constituents-
                    Rock lime 900g, sulphur 675g, water 22.5 litres.

Method of preparation. –
                                       Required amount of lime is placed in an open metal container and to this is added water. Required quantity of sulpher is than added . The whole material is heated on an open fire for an hour. After boiling, the mixture is allowed to settle for several hours and the clear supernatant is than filtered off. This can be used by diluting with 30 parts of water.

Zinc phosphide.-
                        It is used as bait for the control of field rats.

Barium carbonate
                             It was also used as rat poison.

Thallium sulphate-
                            It is a slow acting rodenticide as well as an ant poison.

Classification pesticide | list of pesticides used in agriculture

Classification Pesticide use in Agriculture-The pesticides can be grouped in various ways,viz. according to the mode of their entry (stomach poisons, contact poisons and fumigants), classification pesticide use in Agriculture their mode of action ( physiological poisons, protoplasmic poisons, respiratory poisons and nerve poisons ) or according to their chemical composition. As an insecticide may enter and act in an insect body in more than one way, it may be desirable to group them according to their chemical nature.

     Chemically ,the types of pesticides are :
          (1) elements,  such as sulphur, phosphorus,thallium,mercury etc.
          (2) inorganic compounds such as lead arsenate, sodium fluosilicate, zinc phosphide, paris green, etc;
          (3) Organic compound (a) compounds of plant origin such as pyrethrum, nicotine, rotenone, etc ; (b)  animal and mineral oils such as fish oil, diesel oil, etc; (c) synthetic organic compounds such as DDT, malathion, carbaryl, etc,;
          (4) poisonous gases such as hydeogen cyanide,ethylene dichloride, carbon tetrachloride, methyl bromide, phosphine, etc, used as fumigants.

Classification Pesticide use in Agriculture

         Based on the target organisms, the ‘classificatio pesticide’ are grouped into insecticides, fungicides, weedicides nematicides, rodenticides, etc.
          For those interested in insect control, however, it is more meaningful to list these compounds according to their mode of entry in the insect body and lethal action on the pests. list of pesticides used in agriculture The above Classification pesticide mentioned compounds could, therefore, be rearranged under the following categories :

1.  STOMACH POISONS

           They are generally used against insects with chewing type of mouthparts and under certain conditions against those with sponging, siphoning,lapping or sucking mouthparts. Some of these poisons are also mixed with food for killing higher animal pests, such as rodents, jackals and birds.
   For the stomach poisons to be acceptable in common use, they should have certain prerequisites :
  •    The concentration which is applied to the plant for insect control should not be injuries to the foliage.
  •    The non-systemic compound should generally be insoluble in water, otherwise it might be absorbed   through leaves and roots and thus, poison the plant.
  •   It should be potent so as to kill the pest quickly and, thus, save the crop.
  •   It should be inexpensive and be easily available in large quantities.
  •   The compound should not be distasteful to the insect, so that they may not be repelled.
  •  Chemically , the compound should be stable, so that it does not lose its toxicity while in shipment, in storage or after it has been applied to the plants.
  • It should also not break down too easily when mixed with other chemicals .
  •  The insecticides should have the physical properties of adhering to the plant surface on application and yet after a certain period it should disintegrate or be washed away by rain etc., so that it does not persist on the plants for long periods and, thus, endanger the health of farm animals or of human beings.

2. SYSTEMIC POISONS

An insect with piercing mouthparts sucks cell-sap through its proboscis which it embeds into the plant or animal tissue. The only way a poison can reach its stomach its through the plant or animal system.  It is only in insecticide when applied to seeds, roots,stems or leaves of plants, is absorbed and translocated to various parts of the plant in amounts lethal to insects which feed on them. Some of them are quite specific to certain groups of insects. The systemic insecticides have a great value in an integrated approach to pests control, because through their application the pesticides, predators and other natural enemies of the pests escape damage. Most of these insecticides act primarily as stomach poisons, and they include oxydemeton methyl, dimethoate, phosphamidon,aldicarb,phorate,carbofuran and thers.

3. INERT DUSTS:-

Fine dusts of various compounds have been used for a long time to control insect pests of crops and stored grains. These dusts are mixed with the grain or dusted on a surface from where the insect pick up the fine particles which cause irritation and abrasions in the cuticle, particularly at the body articulation. It results in excessive loss of moisture from the body of an insect which ultimately dies of desiccation. These dusts are based on fine sand, powdered cowdung ash (which also acts as a hygroscopic compound), calcium carbonate, silica, aerogel, etc.

4. CONTACT POISONS:-

The other most effective and most prevalent method of insect control lies in the use of contact poisons, a large number of which are now available. The contact poisons are applied as sprays or dusts, either directly onto the body of insects or to the places frequented by them. These poisons kill the insect either by clogging spiracles and respiratory system or by entering through the cuticle into the blood and acting as nerve or general tissue poisons. It has been shown that the insect cuticie possesses very high absorptive properties, so that the lethal does applied externally is almost the same as the quantity required to kill by injecting it into the body. The contact insecticides, even though applied in the form of emulsion, suspensions or dusts are highly lipophilic and are readily absorbed by the lipids present in the epicuticle of insect exoskeleton. The residual film of a contact insecticide may kill an insect by its action on the sensory organs present in the tarsi of the legs.
A wide spectrunm of new synthetic organic compounds have revolutionzed the modern practices of pest control. The major groups include chlorinated hydrocarbons (DDT, HCH, aldrin, etc.),carbamates (carbaryl, aldicarb, carbofuran,etc.), and organophosphates (malathion, oxydemeton-methyl, monocrotophos,etc.).

5. FUMIGANTS :-
        
          Poisonous gases, derived from either solids or liquids, are used as fumigants to kill insect pests of stored grains and other products in warehouse, museums, godowns, etc. They are also used to kill insect pests found in animal sheds or human dwellings; soil-infesting grubs and nematodes, the scales infesting nursery stock , the borers founds in trees or wooden structures ; to control all kinds of greenhouse pests and even worms found inside the intestines of animals. Since practically all the fumigants are deadly poisons, great care is needed in their use. Some of the common fumigants, both old and new include nicotine, hydrogen cyanide, carbon bisulphide, sulphur dioxde, paradichlorobenzene, naphthalene, ethylene dichloride and carbon tetrachloride mixture, methyl bromide, phosphine, DBCP,D-D(dichloropropane-dichloropropene) mixture etc.

This article I am fully discuss “Classification pesticide” made there  action. If your any inquiry  then comment us. Thank you.

Pesticides and there Application

             

  INTRODUCTION :-


 Thousands of compounds have been synthesized and tested for their pesticidal properties. Quite few are application in market. Those which are finally accepted have to be subject to certain rigorous tests. A good pesticides should be cheap to produce and potent against insect pests. It should not endanger the health of man and domestic animals,and should ultimately break down into harmless compounds so that it does not persist in the human environment. It is not easy to find new compounds having all these desirable qualities;hence fewer chemicals are being added to the list of good pesticides then one would expect.

          

 in order to determine the potency of an pesticides, both the relative toxicity and the specific toxicity are to be worked out. The value of median lethal does(L D 50) of various poisons against a given insect species indicates the relative toxicity. LD50 is expressed in terms of dosage in mg/kg of body weight  necessary to kil 50 percent of a population of male white rats/rabbits/guinea pigs. The specific toxicity may vary a great deal from species to species. There are very few compounds which have all the qualities considered desirable and, therefore, we have to accept those which are comparatively cheap, more effective and less dangerous. 

 

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