Botanicals:
Toxicants or chemicals derived from plants parts like leaves, stems,
roots, seeds etc which are used in insect pest and disease control
Ex. Neem products, Nicotine, Ryania, Rotenone and Pyrethrum
A botanical pesticide is a type of bio pesticide formulation made up of
crude plant extracts or purified compound of plant species for
managing pest and diseases.
• Extracted from plants
• Broad spectrum pesticides
• Low environmental persistence
• Low residual value
• Degrade very fast under the sunlight
Advantages:
• Do not leave harmful residues
• Cheaper than chemical
• Safe to user, environment and non target sp.
• Safe for insect enemies – predator, parasitoids
• Prevent resistance and resurgence
Disadvantages:
• Not true pesticides
• Readily degraded by UV rays or sunlight
• Slow speed of action
• High specificity
• Effective period is less – low self life
2. Botanicals:
Toxicants or chemicals derived from plants parts like leaves,
stems, roots, seeds etc which are used in insect pest and disease
control
Ex. Neem products, Nicotine, Ryania, Rotenone and Pyrethrum
A botanical pesticide is a type of bio pesticide formulation made
up of crude plant extracts or purified compound of plant species
for managing pest and diseases.
• Extracted from plants
• Broad spectrum pesticides
• Low environmental persistence
• Low residual value
• Degrade very fast under the sunlight
3. Advantages:
• Do not leave harmful residues
• Cheaper than chemical
• Safe to user, environment and non target sp.
• Safe for insect enemies – predator, parasitoids
• Prevent resistance and resurgence
Disadvantages:
• Not true pesticides
• Readily degraded by UV rays or sunlight
• Slow speed of action
• High specificity
• Effective period is less – low self life
4. 1. Azadirachtin (Neem): Azadirechta indica
• Almost every part of the tree is bitter and finds its application in
indigenous medicine.
• The refined and purified neem seed oil has many therapeutic
properties.
• Considerable quantities of oil are used in cosmetic preparations.
• The neem cake after oil recovery is used for slow release of
nitrogenous fertilizers.
• Extracts from the neem tree have been reported to control over 200
types of insects, mites, and nematodes.
6. 1.2. Properties:
• Neem oil contains limonoids, a class of compounds that act as
antifeedants or growth regulators in insects.
• They do not kill instantly but wipe out a whole generation of
insects by preventing the young ones from maturing and the
adults from reproducing.
• The most effective of the limonoids is a compound called
azadirachtin.
• The neem spray solution should not be exposed to sunlight and
must be prepared with water having a temperature between 50
and 90°F.
• The solution is effective for only 8 hours after mixing.
• Neem is most effective under humid conditions or when the
insect and plants are damp.
• It has a low toxicity to mammals.
7. 1.3. Mechanism:
• It is similar to the insect hormone ecdysone, which is needed for
moulting during insect development.
• It works at a concentration of 1-10 ppm by blocking ecdysone’s
action, thereby preventing the larvae from shedding their external
skeletons and maturing.
• It also prevents feeding in about 200 insects at a concentration of
10-100 ppm.
• A number of neem formulations are being produced by small-scale
formulators and marketed as insecticides.
• Neemguard, Margocode, Nimbicidine, Neemplus, Sukrina,
Achook etc.
8. 2. Nicotine: Tabacco (T. sativum)
It is the principal alkaloid in tobacco which is very poisonous.
An alkaloid may be defined in general as a naturally occuring
heterocyclic, optically active nitrogenous base of relatively high
molecular weight and having marked physiological activity.
9. 2.1. Properties:
• Nicotine (C10 H14 N2).
• Its chemical name is I-methyl-2,3 (pyridyl) pyrrolidine.
• Nicotine is found in the leaves of Nicotinana tabacam and N.
rustica in the range of 2 to 14 per cent.
• Among the twelve alkaloids present in tobacco nicotine is the
most important one contributing about 97 per cent
• And the other two of insecticidal value are
(i) Nornicotine (C9 H12 N2) 2-(3-pyridyl pyrrolidine)
(ii) Anabusine (Neonicotine, 3-(2-piperdyl) pyridine.
11. 2.3. 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.
• Nicotine is a fast acting contact killer for soft bodied insects, but
does not kill most chewing insects.
• It is less effective when applied during cool weather.
• Do not spray within 7 days of harvest.
• Commonly sold as 40% Nicotine sulphate concentrate.
12. 3. Pyrethrum : Chrysanthemum cinraerifoilum
• The insecticidal principle in pyrethrum is found in the flower heads
of certain plants of chrysanthemum genus, family compositeae.
• Pyrethrin is a fast acting contact poison derived from the pyrethrum
daisy.
• It is very toxic to cold blooded animals.
• Some people and most cats have allergic reactions to it.
• Pyrethrin is effective on most insects, but does not control mites.
• It rapidly breaks down in sunlight, air and water.
• the term “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.
15. 3.2. 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.
16. 4. Sabadilla (veratrine alkaloids):
Schoenocaulon
officinale
Source :
• Sabadilla is derived from the ripe seeds of Schoenocaulon officinale, a
tropical lily plant which grows in Central and South America.
• Sabadilla is also sometimes known as cevadilla or caustic barley.
• When sabadilla seeds are aged, heated, or treated with alkali, several
insecticidal alkaloids are formed or activated.
• It is a broad spectrum contact poison, but has some activity as a
stomach poison.
• It is most effective against true bugs such as harlequin bugs and
squash bugs.
• Sabadilla degrades rapidly in air and sunlight, and has little residual
toxicity.
• It is very toxic to honey bees.
19. 4.2. Mode of action:
• In insects, Sabadilla’s toxic alkaloids affect nerve cell membrane
action, causing loss of nerve cell membrane action, causing loss of
nerve function, paralysis and death.
• Sabadilla kills insects of some species immediately, while others
may survive in a state of paralysis for several days before dying.
• Sabadilla is effectively synergized by PBO or MGK 264
20. 5. Rotenone: Lonchocarpus sp. And Derris
sp.
• Source: Rotenone is insecticidal compound that occurs in the roots
of Lonchocarpus species (Cube Root) in South America, Derris species
in Asia, and several other related tropical legumes.
• Rotenone is extracted from cube roots in acetone or ether.
• Extraction produces a 2-40% rotenone resin which contains several
related but less insecticidal compounds known as rotenoids.
• The resin is used to make liquid concentrates or to impregnate inert
dusts or other carriers.
• cube roots may be dried, powdered and mixed directly with an inert
carrier to form an insecticidal dust.
23. 5.2. Properties:
• It has a short residual.
• Rotenone is a broad spectrum poison mainly used to control leaf-
eating caterpillars and beetles.
• Direct contact may cause skin and mucous membrane irritation.
• It is more toxic when inhaled.
5.3. Mode of action:
• Rotenone is a powerful inhibitor of cellular respiration( the
process that converts nutrient compounds into energy at the
cellular level).
• In insects rotenone exerts its toxic effects primarily on nerve and
muscle cells, causing rapid cessation of feeding.
• Death occurs several hours to a few days after exposure.
• Rotenone is extremely toxic to fish, and is often used as a fish
poison (piscicide) in water management programs.
• It is effectively synergized by PBO or MGK 264.