2. MICROBIAL INSECTICIDE
Microbial insecticides are single
celled organisms such as bacteria,
virus,fungi,protozoan and nematodes.
Microbial insecticides are those micro
organisms or their products that are
capable of attacking and killing pest
insects.
3. The available microbial insecticides are prepared
from Bacillus thuringiensis ,Baculo virus.
They applied as conventional insecticidal sprays,
dusts,liquid drenches, liquid concentrates, wettable
powders or granules.
They are essentially non toxic and non pathogenic to
wild life, humans and not closely related to target
pests.
4. BACILLUS THURINGIENSIS
Bacillus thuringiensis was discovered by
ishiwatari in 1901 in diseased silkworms .
Bacillus thuringiensis(bt) is a natural occurring
soil borne bacteria and since 1950 it is used as a
natural insect control.
5. TARGET PESTS OF BACILLUS THURINGIENSIS
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7. .
Bt genes are engineered into plants to make
crop resistant to insects .
“Bt toxin” produces a protein that is toxic to
specific insects .
Bt toxin were produced to kill like insects such
as caterpillars,potato beetles,cabbage
worms,moth,butterflies,mosquito and Black fly.
8. MODE OF ACTION
There are many bt proteins but there mechanism
of action are similar ,
Bt protein is absorbed by insect specific
receptor in tha lining of gut.
The activated proteins form a complex
Which bores into the gut of the insect Causing
the content of the gut to spill out .This eventually
kills the insect.
10. ADVANTAGES
The use of insect resistant Bt plants can
potentially reduce use of chemical insecticidal
sprays, which are extremely toxic and expensive.
It will not Kill beneficial insects such as
honeybees and other pollinator.
The advantage of bt is that its nontoxic to
humans and wildlife or pets.
11. DISADVANTAGES
Many strains are susceptible to the sunlight and
their potency will degrade within a week.
Some strains used on leaf beetles Can become
ineffective within 24 hours.
The optimal storage conditions for bt products
were cool,dry air and out of sunlight.