The document discusses biofertilizers and biocontrol agents in agriculture, explaining their types, advantages, and disadvantages. Biofertilizers improve soil health and increase crop yields but come with limitations like specific crop requirements and reduced effectiveness in extreme conditions. Biocontrol agents, which use natural organisms to combat pests and weeds, are eco-friendly and cost-effective, but their effectiveness can be slower and unpredictable compared to chemical methods.

1. SUBMITTED BY:
P.Devadharshini,
II – M.sc., Microbiology,
VIAAS, Sankagiri.
VIVEKANANDHA ARTS AND SCIENCE COLLEGE FOR
WOMEN, SANKAGIRI.
DEPARTMENT OF MICROBIOLOGY
SUBJECT : SOIL AND ENVIRONMENTAL MICROBIOLOGY
TOPIC: BIOFERTILIZERS AND BIOCONTROL AGENTS
SUBJECT INCHARGE:
Dr.R.Dineshkumar,
Assistant Professor,
Department of Microbiology,
VIAAS, Sankagiri.

2. CONTENT
⚫Introduction
⚫Types of Biofertilizers
⚫Advantages of Biofertilizer
⚫Disadvantages of Biofertilizer
⚫Biocontrol Agents
⚫Features of Biological Control
⚫Types of Biocontrol Agents
⚫Advantages of Biocontrol
⚫Disadvantages of Biocontrol
⚫Biocontrol Agents Example
⚫Microbial Biocontrol Agents

3. INTRODUCTION:
⚫Generally, agricultural land gets impoverised after long term
cultivation,if not supplemented properly with inputs.
⚫To supplement the soil nutrient content under conventional
farming system, we need to apply highdoses of agrochemicals
which in turn pollute the ecosystem.
⚫The principle of organic farming also outline the similer concepts
where the soil health and biodiversity is built up to sustain the plant
growth in longer term.
⚫Therefore,in order to make agriculture sustainable,it is necessary to
implements a balanced and responsible use of organic agriculture.

4. TYPES OF BIOFERTILIZER :
⚫The nitrogen fixing bacteria work under two conditions,symbiotically
and as free living bacteria(non-symbiotic).
⚫The symbiotic bacteria make an association with crop plants through
forming nodules in their roots.
⚫The free living bacteria do not form any association but live freely and
fix atmospheric nitrogen.
⚫Now let us examine the features of these microbes in details.
⚫This is called “the principle of cross inculation” which relies on the
assumption that legumes within a particular infection group may be
nodulates by another species of nodule forming bacteria.

6. ADVANTAGES OF BIOFERTILIZER:
⚫Increase crop yield by 20-30%.
⚫Replace chemical nitrogen and phosphorus by 25%
⚫Stimulate plant growth.
⚫Activate the soil biologically.
⚫Restore natural soil fertility.
⚫Provide protection against drought and some soil borne diseases.

7. ⚫Increasing crop production slightly.
⚫Do not replace chemical fertilizers.
⚫For certain crops, specific biofertilizers are necessary.
⚫Mass microbial production contamination.
⚫Light sensitive microbes.
⚫Limited shelf life.
⚫Loose effectiveness in too-hot or too-dry soils.
DISADVANTAGES OF BIOFERTILIZER:

8. ⚫The agents that control the growth of pests or insects by using their
natural living enemy organisms are called biocontrol agents. The
process in which biocontrol agents work is called biological control.
⚫Biological control is an effective method to remove invasive plants
and get pest-free fields. In the biological control process,
the biocontrol agents have been used to control pests, insects, and
pathogens and eradicate unwanted weeds and plants.
⚫The main purpose of biocontrol agents is to increase crop yield by
eradicating pests and insects. They only destroy harmful organisms
such as parasites, pests, and insects and do not harm the useful
organisms present in the soil.
BIOCONTROL AGENTS:

10. FEATURES OF BIOLOGICAL CONTROL :
⚫To approach the biological control process, one must know about
pest management and its life cycle. For example, spraying BT
solution made from seeds on the plant will kill the butterfly
caterpillars. The dried seeds expel toxins from the intestines of
worms and kill them.
⚫The principle used in biological control is predation and parasitism.
It kills the insect without causing any effects to human health—some
of the microbes used as biocontrol agents are the Bacillus
thuringiensis, Trichoderma, Baculoviruses, and
Nucleopolyhedrovirus.
⚫Biological control also falls under organic farming.

11. ⚫The principal attributes of an effective biological control agent are:
efficient searching ability, high parasitism or predation rate, high
reproductive potential, minimal handling time, ability to survive at
low prey densities and ability to adapt to a wide range of
environmental conditions.
⚫It is a natural method to control weeds, pests, insects, and other living
organisms that affect growth. It is used to increase crop yield and
production.
⚫The principle used in biological control is predation and parasitism. It
kills the insect without causing any effects to human health—some of
the microbes used as biocontrol agents are the Bacillus thuringiensis,
Trichoderma, Baculoviruses, and Nucleopolyhedrovirus.

12. ⚫It entails the prey-predator relationship. Examples of classical
biocontrol are aphid, parasitoid, baculovirus, and moths.
⚫A separate relationship is formed between plants and biological
control animals.
⚫It is a natural organic method to control weeds, pests, insects, and
other organisms.
⚫Here pathogens are used as biocontrol agents to kill the enemies that
affect plant growth.
⚫Nematodes are examples of inductive biological control where
nematodes prevent invasive plants from implementations.
TYPES OF BIOCONTROL AGENTS:

14. ADVANTAGES OF BIOCONTROL :
⚫There are plenty of advantages to the biocontrol agents. They are eco-
friendly, prevent soil pollution, and do not harm humans and other
useful organisms in the soil.
⚫They are easy to use, available in all seasons, and cheaper than
agrochemical pesticides and insecticides.
⚫They reduce the impact of chemicals and pesticides on the human
body.
⚫They are cost-effective.

15. ⚫ It is a very slow procedure. It takes a lot of patience and waiting for
the biocontrol agents to work.
⚫Biocontrol agents may not be able to remove the pest completely.
⚫ the disadvantages being it's a time-consuming affair and the speed is
slow in comparison to other processes like chemical processing.
⚫The disadvantages of biological pest control include the risk of
unpredictable and detrimental impacts on non-target species, which
can reduce biodiversity in the agroecosystem.
DISADVANTAGES OF BIOCONTROL :

16. BIOCONTROL AGENTS EXAMPLES :
⚫ spiders
⚫ files
⚫ Ladybugs
⚫ Wasps
⚫ Beetles
⚫ Dragonflies
⚫ Virus
⚫ Bacteria
⚫ fungi

17. MICROBIAL BIOCONTROL AGENTS:
⚫Microbes are used as biocontrol agents in three ways: causing disease
in the host body, fighting with the host, or killing the host organisms.
⚫Ladybirds are common insects that eradicate aphids, and dragonflies
are common insects that eradicate mosquitoes.
⚫ Bacillus Thuringiensis is one of the best biocontrol agents as when
humans spray them on the plants, the fluid fills the spores of the plants
and kills the caterpillars.
⚫These spores intake the Bt bacillus and release the toxin substance to
kill the butterfly caterpillars. They release the toxin in the gut of the
butterfly larvae to kill them.

18. ⚫Pest resistance and disease-resistant plants are developed using
biotechnology. By injecting Bacillus thuringiensis into the plants,
they become resistant to diseases and pests.
⚫Trichoderma (fungus) and Baculoviruses are some of the
microbial biocontrol agents.
⚫Bacillus Thuringiensis controls the larvae of black flies, butterfly
caterpillar larvae, and wax moth larvae.
⚫Beauveria Bassiana (fungus) acts as a biopesticide for bugs, mites,
whiteflies, aphids, etc.