Biopestides are being manufactured all across the world but due to limited resources the research in biopesticides is not upto the mark. however advancement has been made in recent decades to protect crops from the attack of different insect pest in order to meet the agricultural productivity.
Forensic Biology & Its biological significance.pdf
Recent Advances in Biopesticides BY Ghulam Murtaza
1.
2. Pesticide
A pesticide is any substance or mixture of substances intended for
preventing , destroying , repelling , or mitigating any pest.
Pest include insects, plant pathogens, weeds, birds, and microbes
etc.
3. History
Since before 2000 BC, humans have utilized pesticides.
The first known pesticide was elemental sulfur.
In 15 century toxic chemicals such as arsenic, mercury and lea
were being applied.
In 17th century use of nicotine sulphate started.
In 19th century use of natural pesticides started.
Until 1950 Ar- based pesticides were common.
Paul Muller discovered DDT as effective pesticide.
In 1975 organochlorines were replaced by organophosphates and
Carbamates.
In 1960 herbicides became common.
Pesticide use has increased 50 folds since 1950.
2.3 million tons of industrial pesticides are used each year.
4. Classification on the basis of Targeted
Organism
Pesticides
Algicides
Virucides
Rodenticide
Fungicides
Herbicides
insecticide
Avicides Bactericide
miticidesnematicide
6. Chemical Pesticides
1. Organochlorides, which have a high persistence in the
environment of up to about 15 years (DDT, dieldrin and aldrin
2. Organophosphates, which have an intermediate persistence of
several months (parathion, carbaryl and malathion)
3. Carbamates, which have a low persistence of around two weeks
(Tenik, Zectran and Zineb)
4. Synthetic pyrethroids, which are nonpersistent, contact and
residual acting insecticides (cypermethrin, permethrin), suitable for
a wide range of crops and target insect
7. Prominent Families of Herbicides
Phenoxy and Benzoic Acid Herbicides e.g. 2,4-D
Triazines e.g. ( Atrazine) interfere with photosynthesis
Ureas e.g Diuron
Chloroacetanilides e.g alachor
8. Biopesticides
Biopesticides are certain type of pesticides derived from such
natural materials as plants, animal and microbes like bacteria,
fungi etc.
9.
10. Microbial Pesticides
Microbial pesticides are composed of microscopic living organisms (viruses,
bacteria, fungi, protozoa, or nematodes) or toxin produced by these organisms
Applied as conventional insecticidal sprays, dusts, or granules.
Their greatest strength is their specificity as most are essentially nontoxic and
non pathogenic to animals and humans.
Microbial pesticides includes insecticides, fungicides, herbicides and growth
regulators of microbial origin.
11. Some of the important microbial pesticides
a. Bacillus thuringiensis
Discovered in Japan in early 20th century and first become a
commercial product in France in 1938.
Control lepidopterous pests like
American bollworm in cotton
and stem borers in rice.
Fig: Bacillus thuringiensis
When ingested by pest larvae, Bt releases toxins which damage the mid
gut of the pest, eventually killing it.
Main sources for the production of Bt preparations are the strains of the
subspecies kurstaki, galeriae and dendrolimus
12. b. Agrobacterium radiobacter (Agrocin)
Agrobacterium radiobacter is used to treat roots during transplanting,
that checks crown gall.
Crown gall is a disease in peaches, grapevine, roses and various plants
caused by soil borne pathogen Agrobacterium tumefaciensm.
The effective strains of A. radiobacter posses two important features:
They are able to colonize host roots to a higher population density.
They produce an antibiotic, agrocin, that is toxic to A. tumefaciens.
13. c. Pseudomonas fluorescens (Phenazine)
•This bacteria is used to control damping off caused by Pythium sp., Rhizoctonia
solani, Gaeumannomyces graminis.
•It has ability to grow quickly in the rhizosphere
d. Trichoderma Fig: Pseudomonas
•Trichoderma is a fungicide effective against soil born diseases such as root rot.
•This is also used against Necteia
galligena, that causes silver leaf
disease of fruit trees by entering
through pruning wounds.
Fig. spores of Trichoderma
14. e. Metarizium anisopliae
•It infects spittlegbugs, rhinoceros beetles.
f. Beauveria bassiana
• Controls Colorado potato beetle.
g. Verticillum lecanii:
•Controls aphids and whiteflies.
h. Nomuraea riley:
• Controls soybean caterpillars.
i.Baculoviruses (Bvs)
• Control lepidopterous and hymenopterous pests.
•Rod shaped, circular double stranded super coiled DNA.
Fig: Metarhizium anisopliae
Fig: Beauveria
15. Pesticides derived from plants
Generally act in one of two ways
Contact poison
Stomach poison
About 250000 plant species evaluated
2121 useful in pest management
1005 exhibited insecticidal activity
384antifeedants
297 repellents
27 attractants
31 growth inhibiting properties
16. Plant-incorporated-protectants (PIPs)
Pesticidal substances that plant produce from the genetic material that
has been added to the plant.
As the pest feed on such plants they will eventually die.
Botanical pesticides:
These are naturally occurring plant material that may be crude
preparation of the plant parts ground to produce a dust or powder that
can be used in full strength or dilute form in a carrier such as clay, talc
or diatomaceous earth.
“Azadirachtin” effects the reproductive and digestive procees of pest.
Several plant based insecticides as nicotinoids, natural pyrethroids,
rotenoids, neem products etc are used.
18. Common name Scientific name Plant parts used Active principle
Castor Ricinus communis Leaves and oil Ricin , ricinnie
Onion Allium cepa bulb
Oleic acid ,
cepocoded , α
asarone , β asarone
Custard apple Annona squamosa Leaves and bark Annonin ,
squamocin
19.
20. Tobacco plant
• Nicotina tobaccum
• Family: Solonaceae
• Part used: dried leaves
• Annual herb
• Habitat: America and cultivated in many countries
• Active constituents
– Nicotine
– Nor nicotine
21. Nicotine
Colorless, Bitter, Pyridine like flavor, Very toxic
Turns brown when exposed to sunlight
Soluble in non-polar solvents like chloroform, alcohol, ether and
CCl4
Miscible with water
It is present in plat as: 18% stem, 64% leaves, 13% root and 5%
flower
Seeds don’t contain nicotine
It cause death by convulsions
Effective against soft pests
22. Pyrethrum
• Family: Compositae
• Parts used: Dry flower
• Active constituents
– Pyrithrine
– Linoleic acid
– Volatile oil
– Palmitic acid
• Perennial herb
• Drying is done by sunlight
• Habitat: Cultivated in Yugoslavia, Brazil, Africa etc.
23. Cont....
• Flowers are collected from 4-5 years plant. Closed flowers
contain more toxic principles
• These are mainly stomach poisons. But when flying insect’s skin
come in contact with them. They penetrate through skin and
cause death due to convulsions and respiratory failure
• Used along with DDT, ethylene glycol mixture to form aerosol
which is sprayed on fly and mosquito
• Used to preserve cotton during storage
24. Derris elliptica
• Family: Leguminosae
• Parts used: dried root
• Active constituents
– Rotenone
• Cultivation
• Philippines, Malaysia, Indonesia and Burma
• Rotenone
– Soluble in non-polar solvents
– Insoluble in water
– Used for both biting and sucking insects
– It leaves no harmful residues
25. 4.Biochemical pesticides
They are naturally occurring substance to control pest by non-toxic
mechanisms.
Biochemical pesticides include substances as insect sex pheromones, that
interfere with
mating that attract insect pest
to traps.
The synthetic attractants-
are used in one of four ways:
i. As a lure in traps used to monitor pest populations;
ii. As a lure in traps designed to “trap out” a pest population;
iii. As a broadcast signal intended to disrupt insect mating
iv. As an attractant in a bait containing an insecticide
Fig: weevil pheromone trap
26. Biopesticides are usually inherently less toxic than conventional
pesticides.
Biopesticides generally affect only the target pest and closely
related organisms,
Biopesticides often decompose quickly, avoiding the pollution
problems caused by conventional pesticides.
Biopesticides can greatly decrease the use of conventional
pesticides, while crop yields remain high.
Cheap, renewable can be handled safely.
Difficult for insects to develop resistance to these pesticides.
27. Slow effect
Lack persistence and wide spectrum activity
Rapidly degraded by UV lights so residual action is slow.
Seasonal availability of plants products indicates the needs for storage.
They are not available easily
Poor water solubility and generally not systemic in nature
All products applied followed by growers have not been scientifically
verified.
28. Fate of Pesticides
Once a pesticide is applied, several things may happen.
It may be taken up by plants and/or ingested by animals, insects,
worms, or microorganisms in the soil
It may move downward in the soil and adhere to soil particles, or it
may dissolve
It may volatilize
It may be broken down into less toxic compounds
It may be leached or moved out of the plants root zone by rain or
irrigation water or
It may be carried away by runoff water or erosion
29. Factors Affecting Fate Of Pesticides
There are four major factors which affect the fate of pesticides.
They are as follows:
1. Properties of the pesticide
2. Properties of the soil
3. Conditions of the site
4. Management practices
30. Case Study: Use of DDT
An October 2007 study has linked breast cancer from exposure to
DDT before puberty.
Scientists estimated that DDT and other chemicals in
organophosphate class have saved 7 million human lives since 1945
by preventing the transmission of diseases such as Malaria, bubonic
plague, sleeping sickness and typhoid.
A study from WHO in 2000 from Vietnam established that non-
DDT malaria controls were significantly more effective than DDT
use.
The US National Academy of Sciences stated that the DDT
metabolite DDE causes eggshell thinning and that the bald eagle
population in the United States declined primarily because of
exposure to DDT and its metabolites
31. Case Study: Impacts on Human Health
An estimated 2.2 million people are at risk due to exposure from
agricultural pesticides, with the majority of this population being
locating in developing nations.
In 2004, carbofuran pesticide residues found on several batches of
noodles manufactured in Nigeria may have resulted in 23
reported cases of vomiting and one death.
32. Case Study : Environmental Impacts
Methyl bromide (CH3Br) is a broad spectrum agricultural
pesticide that has been used on more than 100 crops worldwide—
mainly in strawberry, bell pepper and tomato production.
Its primary use is as a soil fumigant
It has been found to cause stratospheric ozone layer depletion
and to be associated with serious health effects.
The U.S. Environmental Protection Agency (US EPA) placed it
under the U.S. Clean Air Act of 1990 for regulation. Under the
1998 amendment to this Act, the importation and production of
methyl bromide was to be reduced by 50% by the year 2001, 70%
by 2003, and total phase-out by 2005
33. Pesticide poisoning a case study
Potato farmers in the province of Carchi in northern
Ecuador suffer a number of health problems caused by high
exposure to chemical insecticides mostly carbofuran and
methamidophos.
The annual number of deaths resulting from pesticide
exposure is 4 per every 10,000 citizens
Questionnaire data, meanwhile, reveals that 4 out of every
100 rural people suffer pesticide poisonings that are not
reported to the medical authorities.
34. Case Study: Health effects
A study on workers (N=356) in four units manufacturing HCH in
India revealed neurological symptoms (21%) which were related to
the intensity of exposure
Observations confined to health surveillance in male formulators
engaged in production of dust and liquid formulations of various
pesticides (malathion, methyl parathion, DDT and lindane) in
industrial settings of the unorganised sector revealed a high
occurrence of generalised symptoms (headache, nausea, vomiting,
fatigue, irritation of skin and eyes) besides psychological,
neurological, cardiorespiratory and gastrointestinal symptoms
coupled with low plasma ChE activity (Gupta et al., 1984).
35. Case Study: Wheat poisoning
In India the first report of poisoning due to pesticides was from
Kerala in 1958, where over 100 people died after consuming wheat
flour contaminated with parathion (Karunakaran, 1958).
Special Committee on Harmful Effects of Pesticides collected
samples to assess the pesticide residues in selected food
commodities (Surveillance of Food Contaminants in India, 1993)
DDT residues were found in about 82% of the 2205 samples of
bovine milk collected from 12 states. About 37% of the samples
contained DDT residues above the tolerance limit of 0.05 mg/kg
(whole milk basis). The highest level of DDT residues found was
2.2 mg/kg.
36. Case Study: Barbasco Biopesticide
The Peruvian rainforests are home to promising plant barbasco.
Roots are used as natural poison
Active substance of barbasco rotenone is extremely poisonous to
insects and can be use to kill lice and flees on livestock
It’s a still poison but the positive thing is that it breaks naturally .
Rotenone loses its effectiveness in a week time and does not leave
harmful residues.
37. Conclusion
Biopesticides are typically microbial biological pest control that are
applied in a manner similar to chemical pesticides.
Available in different formulations
Also used to control soil borne and seed borne fungal pathogens
Disadvantages of them are, high specificity, slow speed of action and
their requirement of suitable condition for their survival.
Even though, biopesticides are best for controlling the pests of
agriculture then the chemicals
Therefore there should be more works on production on biopesticides
and encourage people to use biopesticides to control the pests.
