This ppt is about natural pesticides. and how they are better than synthetics. this lecture is helpful for students of pharmacognosy and agriculture. synthetic pesticides are need to be replaced with natural substances and natural methods to control like biological control etc. pests are creating a huge economic loss so its the need of the time to focus on natural pest control methods. if you like the lecture comment and share

1. Pesticides
Hafiz Waheed Ullah

2. PEST
Pest is any animal , plant or micro – organism that causes
trouble , injuries (Economic damage) or destruction to
plants or crops.
Pest control is a majoia problem in cultivation of plants
throughout the world.

3. Types of pests
Types of pests
1.Animals Pests
a)Rodents
b)Insects
i)Biting ii)Sucking
2.Plant Pests
3.Weeds Fungi
4.Microbes

4. Animal pests
Rodents:
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

5. The spoilage and contamination is done by
• By excretory products
• Hairs
Rodents responsible for damage may be
• Rabbits
• Rats
• Mice

6. 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

7. Insects
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

8. Microorganisms:
Bacteria, Fungi and Viruses
Bacteria: Xanthomonas causing leave spots
Fungi: Among the most common and widespread diseases
of plants caused by fungi are the various downy mildews
(e.g., of grape, onion, tobacco), the powdery mildews (e.g.,
of grape, cherry, apple, peach, rose, lilac), the smuts (e.g.,
of corn, wheat, onion), the rusts (e.g., of wheat, oats, beans

9. Weeds:
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

10. Pesticieds
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
• The Environmental Protection Agency >United States

11. 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

12. 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

13. 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

14. Methods of Control of Pests
• There are two methods available for the control of pest.
1. Natural control
2. Artificial control

15. NATURAL CONTROL
NATURAL CONTROL:
Topographical influence of the seasons changes, changing
temperatures, rainfall, soil, atmospheric humidity and other
natural factors also shows their effect on insects and their
hosts.

16. ARTIFICIAL CONTROL
Artificial control of pest have been developed by man.
Some of the methods are given as follows:
 Mechanical methods
 Biological methods
 Environmental methods
 Agricultural methods
 Chemical methods

17. 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.

18. Biological control:
Biological control:
Biological control by using plant or animal materials for
controlling many harmful pests
Some animals or insects feed upon smaller forms which
destroy the plants. Some insects have a short life cycle
which parasitize larger Insects.
For examples, rabbits are helpful in destroying certain type
of weeds. Cats, owls, kites and hawks are enemies of mice
and rats. Insects are eaten by birds.

19. • Bacillus thuringiensis, a soil-dwelling bacterium, is the
most widely applied species of bacteria used for biological
control, with at least four sub-species used against
Lepidopteran (moth, butterfly), Coleopteran (beetle) and
Dipteran (true fly) insect pests.

20. Agriculture control:
It is the oldest method.
It includes deep ploughing for eradication of weeds and
early stages of insects.
Alternative crop rotation of changing environmental
conditions are some methods which lead to obstruction of
the life cycle of pests.
It Involves cultivation of such crops which are resistant to
pests
It may be achieved using biotechnology and genetic
engineering

21. Chemical control:
Chemical agents are used for killing pests or for protecting
crops, animals or other properties against the attack of the
pest.
Like DDT(Dichlorodiphenyltrichloroethane),
BHC (β-Hexachlorocyclohexane)
Aldrin
Endrin

22. 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.

23. 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
1. Pest identification – important for proper pest control
2. Surveying for pests – systematically check for pests and
pest damage
3. Encourage Beneficial Insect/Animal Populations
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.

24. Rodenticides
Rodents: vectors of disease
– Zinc phosphide - PH3 (cell toxicity, necrosis, GI, liver,
kidneys)
– Fluoroacetic acid and derivatives (Fluoroacetyl-CoA -->
fluorocitrate: Krebs cycle collapse)
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

25. Warfarin
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

26. Insecticides
Stomach poisons:
These are toxic substances which when enter in GIT lead to
death. Death occurs due to respiratory failure
Available in the form of dry powders, solution spray and
suspension spray
Effective for biting insects –
Methods • Substance is sprinkled over the plants. The
resinous material gets attached to various plant parts.
When biting insects eat the plant, toxic material is also
taken in. After ingestion, respiratory failure leads to death

27. • Commonly used stomach poisons
• For growing plants – Lead arsenate
• For tomatoes, potatoes and cotton – Calcium arsenate
• Some phosphorous compounds are also used – e.g
octamethyl pyrophosphoimide, phosphorous is absorbed
from root and make the plant resistant to pest attack
• Sodium fluoride
• Sodium fluoroacetate

28. Contact poisons
Contact poisons :
These poisons penetrate through the skin or cuticle and
cause death of the pest
These are commonly used for sucking insects

29. Natural Pesticides:
Pyrethrum Flower
Tobacco leaves
Neem leaves and oil
Nuxvomica seed

30. Pyrethrum
Synonyms:
Natural pyrethrum, insect flowers
Biological source:
Pyrethrum consists of more or less fully expanded flower
heads of Chrysanthenium cinerarifolium
Family: Compositae
Other varieties:
Chrysanthemum coccineum
Chrysanthemum marschalli

31. Chemical constituents:
Chemical constituents:
• Active constituents are Pyrethrins, which are organic
esters, chemicals made up of carboxylic acid and keto
alcohols.
• The main constituents are Pyrethrin I and II. It also
contains Cinerin I and II, Jasmoline I and II

32. I.P. Standards
i) Pyrethrum should contain not more than 5% of naturally
adhering stems.
ii) Ash: Not more than 8%
iii) Acid insoluble ash - Not more than 1%

33. Uses:
1.Used as insecticide
2.Contact poison, • It paralyses in short time, used in the
form of wettable powder, emulsion concentrate, kerosene
solution (20% of Pyrethrins)
Many a time, • Pyrethrum extract is mixed with other
insecticides ( like DDT • (Dichloro-diphenyl-trichloro-
ethane), Sulfoxides etc) which increase the action of
pyrethrum.

34. Tobacco:
Tobacco:
Synonyms : Tamaku (Hindi)
Biological source:
Tobacco consists of the dried leaves of Nicotiana tobacum
Family: Solanaceae

35. Chemical constituents:
Chemical constituents:
• It contains pyridine alkaloids. The main constituent is
Nicotine, Nicotyrine, Nicotimine, Anabasine, Anatabine
• It also contains carbohydrates – Sucrose, starch, pectin,
cellulose, lignins and pentoses

36. Uses:
• Sedative,
• Antispasmodic,
• Veterinary anthelmintic,
• Useful in smoking and agriculture insecticide
• Manufacture of nicotinic acid and nicotinamides
It cause death by convulsions • Effective against soft pests