This document discusses biopesticides, which are pesticides derived from natural materials like plants, bacteria, and minerals. It describes different types of biopesticides including microbial biopesticides which use microorganisms like bacteria and fungi to control pests. The document outlines advantages like lower toxicity compared to chemical pesticides as well as disadvantages like limited effectiveness against multiple pest types. It also discusses recent advances in biopesticide development through recombinant DNA technology.

1. Microbes as
Biopesticides
Vivek Kumar
Department of Biosciences
Swami Rama Himalayan University
Jolly Grant, Dehradun

2. Introduction
• Biopesticides are certain types of pesticides derived from
natural materials such as animals, plants, bacteria, and
certain minerals.
• For example, canola oil and baking soda have pesticidal
applications and are considered biopesticides.
• As of April 2016, there are 299 registered biopesticide active
ingredients and 1401 active biopesticide product
registrations.
• Even a chilli powder solution is a biopesticide.
• Crushed leaves, bark in solution act as excellent biopesticide.

3. Types of Biopesticides
• Biochemical pesticides
• These are naturally occurring substances that control pests by non-
toxic mechanisms.
• Conventional pesticides, by contrast, are generally synthetic materials
that directly kill or inactivate the pest.
• Biochemical pesticides include substances that interfere with mating,
such as insect sex pheromones, as well as various scented plant
extracts that attract insect pests to traps.
• Because it is sometimes difficult to determine whether a substance
meets the criteria for classification as a biochemical pesticide, EPA has
established a special committee to make such decisions.

4. Microbes as biopesticides
• They come from naturally occurring or genetically altered
bacteria, fungi,algae, viruses or protozoans.
• Microbial control agents can be effective and used as
alternatives to chemical insecticides.
• A microbial toxin can be defined as a biological toxin material
derived from a microorganism, such as a bacterium or
fungus.
• Pathogenic effect of those microorganisms on the target
pests are so species specific.

5. • The effect by microbial entomopathogens occurs by invasion
through the integument or gut of the insect.
• This is followed by multiplication of the pathogen resulting in
the death of the host, e.g., insects.
• Studies have demonstrated that the pathogens produce
insecticidal toxin important in pathogenesis.
• Most of the toxins produced by microbial pathogens which
have been identified are peptides, but they vary greatly in
terms of structure, toxicity and specificity.

6. • Microbial pesticides consist of a microorganism (e.g., a
bacterium, fungus, virus or protozoan) as the active
ingredient.
• Microbial pesticides can control many different kinds of
pests, although each separate active ingredient is relatively
specific for its target pest[s].
• For example, there are fungi that control certain weeds and
other fungi that kill specific insects.
• The most widely used microbial pesticides are subspecies
and strains of Bacillus thuringiensis, or Bt.

7. • Each strain of this bacterium produces a different mix of
proteins and specifically kills one or a few related species of
insect larvae.
• While some Bt ingredients control moth larvae found on
plants, other Bt ingredients are specific for larvae of flies and
mosquitoes.
• The target insect species are determined by whether the
particular Bt produces a protein that can bind to a larval gut
receptor, thereby causing the insect larvae to starve.

8. Insect Control
• Bacteria - Bacillus thuringiensis, B. sphaericus, Paenibacillus popilliae,
Serratia entomophila
• Viruses - nuclear polyhedrosis viruses, granulosis viruses, non-
occluded baculoviruses
• Fungi - Beauveria spp, Metarhizium, Entomophaga, Zoopthora,
Paecilomyces fumosoroseus, Normuraea, Lecanicillium lecanii
• Protozoa - Nosema, Thelohania, Vairimorpha
• Entomopathogenic nematodes - Steinernema spp, Heterorhabditis
spp
• Others - Pheromones, parasitoids, predators, microbial by-products

9. Weed Control
• Fungi - Colletotrichum gloeosporioides,
Chondrostereum purpureum, Cylindrobasidium laeve
• Bacteria - Xanthomonas campestris pv. Poannua
• Plant Disease Control
• Fungi - Ampelomyces quisqualis, Candida spp.,
Clonostachys rosea f. catenulate, Coniothyrium
minitans, Pseudozyma flocculosa, Trichoderma spp

10. • Competitive and Soil Inoculants - Bacillus pumilus, B. subtilis,
Pseudomonas spp, Streptomyces griseoviridis, Burkholderia
cepacia
• Nematicides etc.
• Nematode Trapping Fungi - Myrothecium verrucaria,
Paecilomyces lilacinus
• Bacteria - Bacillus firmus, Pasteuria penetrans
• Mollusc parasitic nematode - Phasmarhabditis
hermaphrodita

11. Plant-Incorporated-Protectants
• Plant-Incorporated-Protectants (PIPs) are pesticidal
substances that plants produce from genetic material that
has been added to the plant.
• For example, scientists can take the gene for the Bt pesticidal
protein and introduce the gene into the plant's own genetic
material.
• Then the plant, instead of the Bt bacterium, manufactures
the substance that destroys the pest.
• The protein and its genetic material, but not the plant itself,
are regulated by EPA.

12. Advantages of using biopesticides
• Biopesticides are usually inherently less toxic than conventional
pesticides.
• Biopesticides generally affect only the target pest and closely related
organisms.
• In contrast to broad spectrum, conventional pesticides that may
affect organisms as different as birds, insects and mammals.
• Biopesticides often are effective in very small quantities and often
decompose quickly.
• Which results in lower exposures and largely avoiding the pollution
problems caused by conventional pesticides.

13. • When used as a component of Integrated Pest Management
(IPM) programs, biopesticides can greatly reduce the use of
conventional pesticides, while crop yields remain high.
• To use biopesticides effectively (and safely), however, users
need to know a great deal about managing pests and must
carefully follow all label directions.

14. • The organisms used in microbial insecticides are essentially
nontoxic and nonpathogenic to wildlife, humans, and other
organisms not closely related to the target pest.
• The safety offered by microbial insecticides is their greatest
strength.
• The toxic action of microbial insecticides is often specific to a
single group or species of insects.
• And this specificity means that most microbial insecticides
do not directly affect beneficial insects (including predators
or parasites of pests) in treated areas.

15. • Because their residues present no hazards to humans or
other animals, microbial insecticides can be applied even
when a crop is almost ready for harvest.
• In some cases, the pathogenic microorganisms can become
established in a pest population or its habitat and provide
control during subsequent pest generations or seasons.
• They also enhance the root and plant growth by way of
encouraging the beneficial soil microflora.
• By this way they take a part in the increase of the crop yield.

17. Disadvantages of microbial insecticides
• Because a single microbial insecticide is toxic to only a specific species
or group of insects, each application may control only a portion of the
pests present in a field and garden.
• If other types of pests are present in the treated area, they will
survive and may continue to cause damage.
• Conventional insecticides are subject to similar limitations because
they too are not equally effective against all pests.
• This is because of selectivity indeed and this negative aspect is often
more noticeable for both general predators, chemicals and
microbials.
• On the other hand predators and chemicals may be danger for other
beneficial insects in threatened area.

18. • Heat, desiccation (drying out), or exposure to ultraviolet
radiation reduces the effectiveness of several types of microbial
insecticides.
• Consequently, proper timing and application procedures are
especially important for some products.
• Special formulation and storage procedures are necessary for
some microbial pesticides.
• Although these procedures may complicate the production and
distribution of certain products, storage requirements do not
seriously limit the handling of microbial insecticides that are
widely available.

19. • Because several microbial insecticides are pest-
specific, the potential market for these products may
be limited.
• Their development, registration, and production costs
cannot be spread over a wide range of pest control
sales.
• Consequently, some products are not widely available
or are relatively expensive (several insect viruses, for
example).

20. Present Status of biopesticides
• Presently, biopesticides cover only 2% of the plant
protectants used globally.
• However, its growth rate shows an increasing trend in
past two decades.
• Global production of biopesticides has been estimated
to be over 3,000 tons per year, which is increasing
rapidly.

21. • Increasing demand of residue-free agricultural produce,
growing organic food market and easier registration than
chemical pesticides are some of the key drivers of the
biopesticide market.
• Globally, the use of biopesticides is increasing steadily by
10% every year.
• About 90% of the microbial biopesticides are derived from
just one entomopathogenic bacterium, Bacillus thuringiensis.

22. • More than 200 products are being sold in the US market, compared
to only 60 comparable products in the EU.
• More than 225 microbial biopesticides are manufactured in 30
OECD (Organisation for Economic Co-operation and Development)
countries.
• The NAFTA (North American Free Trade Agreement) countries (USA,
Canada, and Mexico) use about 45% of the biopesticides sold, while
Asia lacks behind with the use of only 5% of biopesticides sold
world over.

23. Recent Advances
• The science of biopesticide is still considered to be
young and evolving.
• In-depth research is needed in many areas such as
production, formulation, delivery and
commercialization of the products.
• Some of the biopesticides, currently under
development, may prove to be excellent alternatives
to the chemical pesticides.

24. • Many of them are based on the locally available plants like
beshram (Ipomoea carnea - the pink morning glory), neem,
garlic, triphala, Pinus kesiya etc.
• These can be easily processed and made available to the
farmers to improve biopesticide consumption.
• In addition to the continuous search for new biomolecules
and improving efficiency of the known biopesticides,
recombinant DNA technology is also being deployed for
enhancing efficacy of biopesticides.

25. • The technology allows a toxin (not toxic to higher
animals) to be combined with a carrier protein which
makes it toxic to insect pests when consumed orally,
while it was toxic only when injected into a target prey
by a predator.
• The fusion protein may be produced as a recombinant
protein in microbial system, which can be scaled up
for industrial production and commercial
formulations.