12th botany neet school

Biocontrol of insect pests Bacterial pesticides

Biocontrol of insect pests

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1. The manufacture of methyl isocynate (MIC) was started in 1980 in
India to make Serin (carbaryl), a powerful pesticide that can kill more
than 100 types of insects attacking 100 different crops.

2. Many of the chemical pesticides, which are used to control several
crop pests also affects the beneficial organisms.

3. They also bring about considerable damages to living organisms
because of their hazardous effects in the environment.

There was an enmasse killing of more than 4,000 people, many animals and plants, when methyl isocyanate (MIC) gas leaked out in the night of 2nd and 3rd December, 1984 from the underground reservoir of Union Carbide Factory at Bhopal.

This is mentioned as Bhopal Tragedy. Many of the people exposed to this poisonous gas are suffering even today.

4. Majority of microorganisms such as viruses, bacteria, fungi,
protozoa and mycoplasma are known to kill insect pests.

The suitable preparations of such microorganisms for control of insects are called as ‘microbial insecticides’. These are non-hazardous, non-phytotoxic and are selective in their action.

They are eco-friendly not responsible for environmental degradation. The most frequently used bio-control agent is Bacillus thuringiensis and Pyrethrum extracted from the inflorescence of Chrysanthemum belonging to Asteraceae.

Bacterial pesticides

B. thuringiensis is a widely distributed bacterium. It is a saprophytic bacterium and can be isolated from soils, litters and dead insects. It is a spore-forming bacterium and produces several toxins such as exotoxins and endotoxins in crystallized forms.

The bacterium is harmful to lepidoptera insects. After infection of spore, larvae are damaged due to the secretion of a single large crystal in the cell. This crystal (toxin) is proteinaceous in nature.

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Other links 

Plant physiology – photosynthesis and its significance

BIOLOGY IN HUMAN WELFARE Introduction & Food production

Aims of plant breeding

Aspects of plant breeding and Types

Hybridization in plant breeding

Polyploid breeding, Mutation breeding, Breeding for disease resistance

Genetic engineering, Improved varieties, Role of biofertilizers

Green manuring, Mycorrhiza as biofertilizer

Benefits from biofertilizers

Crop diseases and their control, Rice – Oryza sativa

Groundnut or peanut – Arachis hypogea

Citrus canker, Tungro disease of rice

Genetically modified food

Bio war, Genetically Modified Organisms (GMO) in biological warfare

Biopiracy, Bioresources, Biomolecules, Biopatent, Biotechnology

Sustainable agriculture

Medicinal plants including microbes

Commonly Available Medicinal Plants

Microbes in medicine

Economic importance of Food plant Rice

Oil plant Groundnut Economic importance

Fibre plant – Cotton Economic importance

Timber yielding plant Teak Economic importance

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