botanicals - GVN E

Several pesticides are derived directly from plant or plant products. These are called botanical
insecticides or botanicals. Many botanicals are preferred by organic farmers as they are natural
products. Extraction of botanicals from the plants is expensive. Hence the use of botanicals in
commercial agriculture is impractical. Following are some of the botanicals used by man:
 Pyrethrum is an insecticide extracted from the flower petals of Chrysanthemum sp.
grown in Kenya and Ecuador.
 It is commonly contained in household aerosol sprays. It is used use on fruit trees,
.ornamentals, vegetables and flowers.
 Nicotine is an alkaloid obtained from the extracts of tobacco leaves.
 Nicotine sulphate is very toxic to insects and also to man. It is the most dangerous botanical
 It is mainly used in the gardens against sucking insects and mites.
 Rotenone is extracted from the roots of the legumes, Derris sp grown in Malaysia and the
East Indies.
 Rotenone is used as an insecticide and also as a fish poison.
 It is also used as a fish poison for reclaiming lakes and ponds.
 Ryania is a botanical extracted from the stem and roots of Ryania speciosa, a shrub grown
in Trinidad.
 It is effective against insects like the European corn borer, Ostrinia nubilalis and many
other insect pests.
Neem Extract
 Neem (Azadirachta indica) is an indigenous tree. It has good medicinal and insecticidal
properties. Leaves and leaf-extracts have been used to repel insect pests of crops and stored
grains. The active principle of this tree is azadirachtin.
 Neem products are active against more than 300 insect species, a large number of nematodes
and other plant pathogens
 It is also eco-friendly. Hence, neem is an eco- friendly and a versatile botanical pesticide.
 The oil cake is used as a manure-cum- pesticide. Powdered oil-cake applied to the soil is a
good source of plant nutrients. Extracts from several other plants are also used as pest
control agents. A few of them are: seed extract of Pongamia glabra , leaf extract of Ipomea
carnea, Vrtex negundo (nochi), Andrographis paniculataetc.
Garlic Extract as a Fungicide
 Garlic (Allium sativum) has medicinal and some insecticidal properties.
 Garlic extracts also have fungicidal properties.
Plant Products to Protect Stored Grains from Insect Attack
 Pudina (Mentha piperata) leaf extracts can inhibit and destroy the rice brown leaf spot
fungus present on the surface of seeds.
 Several plant products are used to protect stored grains from insect attack, it is environment
friendly, non-toxic and also economic.
 Layers of neem and Pongamia leaves are spread inside the storage bins of grains.
 Crushed neem leaves and fruits were used to plaster the walls of mud bins.
Biological Control of Pests and Weeds
Any substance used for controlling, preventing, destroying, disabling or repelling a pest is called as
pesticide. Several chemical pesticides h.r been used by man to control pests., such pesticides has
certain disadvantages.
Disadvantages of Pesticides
1. Pesticides are expensive and dangerous to the handler, the environment and the consumers of
plant products.
2. Pesticides make the pests more resistant to chemical pesticides.
3. Pesticides often cause one species to be replaced by another sometimes the second pest may be
more virulent.
4. Chemical pesticides not only kill the pests but also their natural enemies in the fields.
5. Sometimes, the use of pesticides will kill the major pests and the natural enemies of certain
minor pests.
Biological Control of Pests – Biopesticides
"Biopesticides" are naturally occurring substances (biochemical pesticides) that control pests,
microorganisms that control pests (microbial pesticides), and pesticidal substances produced by
Characteristics of an Ideal Biological Control Organism
It should be able to survive for an extended period in the field either in an active or inactive
It should contacts the pathogen either directly or indirectly by diffusion of chemicals.
Multiplication of the control organism in the laboratory should be simple and inexpensive.
It should be a simple, efficient and inexpensive process of packaging, distribution and
It should be specific for the target organism.
It should not be a health hazard in its preparation and handling.
It should be environment friendly.
t should be active under the appropriate environmental conditions.
It should control the target pathogen efficiently and economically.
Three major classes of Biopesticides
Microbial or biological pesticides may consist of bacteria, fungi or viruses
Plant-incorporated protectants, (PIPs) (i.e. GM crops).
Biochemical pesticides are naturally occurring substances that control pests by nontoxic
Several bacteria which kill certain insects are used as biopesticides. Some of them are : 1. Bacillus
thuringiensis, 2. B.popilliae, 3. B. lentimorbus, 4. B.sphaericus, 5. Pseudomonas sp. and 6.
Agrobacterium radiobacter.