3. pesticides
A pesticide is any substance used to kill, repel, or control
certain forms of plant or animal life that are considered to be
pests.
A pests can be a insect, plant pathogen, weed, bacteria, bird
etc. that compete with the human for food, destroy property,
spread disease.
A pesticides can be a chemical, biological agent,
antimicrobial, disinfectant etc.
Many chemical pesticides are poisonous to human and
animals.
8. insecticides
Chemicals which are used to kill, repel or otherwise prevent the insects.
Properties of an ideal insecticide
1. It should be freely available in the market under different
formulations
2. It should be toxic and kill the pest required to be controlled.
3. It should not be phytotoxic to the crops on which it is used.
4. It should not be toxic to non target species like animals,
natural enemies etc.
5. It should be less harmful to human beings and other
animals.
Classificationof insecticides
Insecticides are classified on the basis of –
1. Chemical Composition.
2. Mode of entry of insectisides into the body of
insects.
3. Mode of action.
4. Toxicity.
5. Stage specificity.
9.
10. Syntheticinsecticides
Organochlorides : The best known organochloride, DDT, was
created by Swiss scientist Paul Müller.
Organophosphates: These also target the insect's nervous
system. Organophosphates interfere with
the enzymes acetylcholinesterase and
other cholinesterases, disrupting nerve
impulses and killing or disabling the
insect.
Carbamates : Carbamate insecticides have similar mechanisms
to organophosphates, but have a much shorter
duration of action and are somewhat less toxic
11. Pyrethroids : Pyrethroid pesticides mimic the insecticidal activity of the
natural compound pyrethrin, the biopesticide found
in Pyrethrum. Compounds in this group are often applied
against household pests
Neonicotinoids : Neonicotinoids are synthetic analogues of the natural
insecticide nicotine. These chemicals
are acetylcholine receptor agonists.
Butenolides : Butenolide pesticides are a novel group of chemicals, similar to
neonicotinoids in their mode of action, that have so far only
one representative-flupyradifurone
Ryanoids/diamides : Diamides are synthetic ryanoid analogues with the same
mode of action as ryanodine, a naturally occurring insecticide
extracted from Ryania speciosa (Salicaceae). They bind
to calcium channels in cardiac and skeletal muscle, blocking
nerve transmission.
