A Review of Biopesticides and Their Mode of Action Against Insect Pests - Environmental Sustainability: Role of Green Technologies - page 48

actions, therefore reaching importance all over the
world. Biopesticides and their by-products are
mainly utilized for the management of pests inju-
rious to plants (Mazid et al. 2011 ).
Biopesticides are classifi ed into three different
categories: (1) plant-incorporated protectants, (2)
microbial pesticides, and (3) biochemical pesti-
cides. They do not have any residue problem,
which is a matter of substantial concern for con-
sumers, specifi cally for edible fruits and vegeta-
bles. When they are used as a constituent of
insect pest management, the effi cacy of biopesti-
cides can be equal to that of conventional pesti-
cides, particularly for crops like fruits, vegetables,
nuts, and fl owers. By combining synthetic pesti-
cide performance and environmental safety,
biopesticides execute effi caciously with the trac-
tability of minimum application limitations and
with superior resistance management potential
(Kumar 2012 ; Senthil-Nathan 2013 ).
Copping and Menn ( 2000 ) reported that
biopesticides have been gaining attention and
interest among those concerned with developing
environmentally friendly and safe integrated crop
management (ICM)-compatible approaches and
tactics for pest management. In particular, farm-
ers' adoption of biopesticides may follow the
recent trend of “organically produced food” and
the more effective introduction of “biologically
based products” with a wide spectrum of biologi-
cal activities against key target organisms, as well
as the developing recognition that these agents
can be utilized to replace synthetic chemical pes-
ticides (Menn and Hall 1999 ; Copping and Menn
2000 ; Chandrasekaran et al. 2012 ;

lems seen with chemical pesticides. Biopesticides
are frequently target specifi c, are benign to
benefi cial insects, and do not cause air and water
quality problems in the environment, and also
agricultural crops can be reentered soon after
treatment. Microorganisms from nature can also
be used in organic production, and risks to human
health are low. In addition, the usage of biopesti-
cides has other several advantages; e.g., many
target pests are not resistant to their effects
(Goettel et al. 2001 ; EPA 2006 ).
Biopesticides derived from bacteria like
Bacillus thuringiensis (Bt), a large array of fungi,
viruses, protozoa, and some benefi cial nematodes
have been formulated for greenhouse, turf, fi eld
crop, orchard, and garden use (Hom 1996 ; Butt
et al. 2001a , b ; Grewal et al. 2005 ; EPA 2006 ).
Biocontrol microbials, their insecticidal meta-
bolic products, and other pesticides based on
living organisms are sorted as biopesticides by
the EPA. There are hundreds of registered products
enlisted in EPA ( 2013 ).

2 Microbial Pesticides

2.1 Bacteria

2.1.1 Bacillus thuringiensis
Beginning in the 1980s and continuing to the
present, a different molecular approach has been
employed to develop market acceptance of
biopesticides. Earlier, several efforts were
aimed at establishing microbial insecticides,
like Bt , which has been used commercially over
40 years (Gelernter and Schwab 1993 ). Later,
some Bacillus species such as Bacillus thuringi-
ensis israelensis Bti and Bacillus sphaericus
2362 ( Bs ) were found particularly effective
against mosquito (Revathi et al. 2013 ) and other
dipteran larvae. Bti was fi rst discovered to have
increased toxicity against mosquito larvae in
1975 (Goldberg and Margalit 1977 ).
Various bacterial species and subspecies,
especially Bacillus , Pseudomonas , etc., have
been established as biopesticides and are primar-
ily used to control insect and plant diseases. Most
salient among these are insecticides based on

Senthil-

Nathan 2013 ).
Insecticides from microorganisms extend a
unique chance to developing countries to
research, and they have possessed to develop
natural biopesticide resources in protecting crops.
The utilization of biopesticide programs would
be required to prevent the development of resis-
tance in target insect pests to synthetic chemical
pesticides and toxins from biopesticides (Copping
and Menn 2000 ; Senthil-Nathan 2006 ; Senthil-
Nathan et al. 2006 , 2009 ).
Compared with chemical pesticides, biopesti-
cides do not present the same regulatory prob-