Entomopathogens – including insect pathogenic viruses – can be utilized in all
three categories of biological control including classical, conservational and augmentative. Moreover, they can be easily used as an ideal tool in sustainable agriculture and integrated pest management (IPM) strategies for the following reasons:
(i) they are environmentally safe; (ii) many of them have a narrow host range and are
virulent against their insect hosts; (iii) based on their specificity, there is very little
effect on non-target organisms; and (iv) they promote biodiversity. Therefore,
microbial pesticides are attractive alternatives to chemical pesticides for application
in plant protection and pest control.
Insect viruses may contain double or single-stranded DNA (dsDNA and ssDNA,
respectively) or double or single-stranded RNA (dsRNA and ssRNA, respectively).
Some viruses are contained in a protein matrix called an occlusion body (OB).
Baculoviruses are the most important insect viruses due to their applications in
biological control of insect pests. Baculoviruses are a family of large rod-shaped
viruses that mainly infect insects and have dsDNA circular genomes ranging from
80 to 180 kb in size (Ayres et al. 1994; Grzywacz 2017). The Baculoviridae
comprise four genera including Alphabaculovirus (the lepidopteran
polyhedroviruses), Betabaculoviruses (the granoloviruses), Gammabaculovirus
(the hymenopteran polyhedroviruses) and Deltabaculovirus (the dipteran
polyhedrovirus) (Jehle et al. 2006).
Baculoviruses have attractive characteristics making them good candidates for
use in pest control, particularly in the natural environment (Inceoglu et al. 2006). The
most important feature of these viruses is their narrow host range; there are species
that infect only one insect host or a few species. This narrow host range makes them
suitable for insect pest control without side effects on other non-target insects such as
beneficial groups. Baculoviruses are highly pathogenic against their insect hosts;
they can kill the insect host within a few days by propagation within the host’s body
but not through production of toxins.
The study of entomopathogenic viruses in Iran began in 1998 in which case
studies on the effect of Nuclear Polyhedrosis Virus (NPVs) on some pests such as
Heliothis armigera (Hübner 1808), Spodoptera exigua (Hübner 1808), Plutella
xylostella (Linnaeus 1758), and Cydia pomonella (Linnaeus 1758) were performed.
Issues regarding histopathology and mass rearing were also surveyed during
this time.
Although considerable effort has been made in characterization of microbial
diversity across the country, there has been little progress in the area of insect
pathogenic microorganisms particularly entomopathogenic viruses. Considering
the importance of insect pathogens in microbial control programs and their diversity
in Iran, more studies need to be done on isolation and characterization of native
insect pathogens.
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M. Mehrabadi et al.
three categories of biological control including classical, conservational and augmentative. Moreover, they can be easily used as an ideal tool in sustainable agriculture and integrated pest management (IPM) strategies for the following reasons:
(i) they are environmentally safe; (ii) many of them have a narrow host range and are
virulent against their insect hosts; (iii) based on their specificity, there is very little
effect on non-target organisms; and (iv) they promote biodiversity. Therefore,
microbial pesticides are attractive alternatives to chemical pesticides for application
in plant protection and pest control.
Insect viruses may contain double or single-stranded DNA (dsDNA and ssDNA,
respectively) or double or single-stranded RNA (dsRNA and ssRNA, respectively).
Some viruses are contained in a protein matrix called an occlusion body (OB).
Baculoviruses are the most important insect viruses due to their applications in
biological control of insect pests. Baculoviruses are a family of large rod-shaped
viruses that mainly infect insects and have dsDNA circular genomes ranging from
80 to 180 kb in size (Ayres et al. 1994; Grzywacz 2017). The Baculoviridae
comprise four genera including Alphabaculovirus (the lepidopteran
polyhedroviruses), Betabaculoviruses (the granoloviruses), Gammabaculovirus
(the hymenopteran polyhedroviruses) and Deltabaculovirus (the dipteran
polyhedrovirus) (Jehle et al. 2006).
Baculoviruses have attractive characteristics making them good candidates for
use in pest control, particularly in the natural environment (Inceoglu et al. 2006). The
most important feature of these viruses is their narrow host range; there are species
that infect only one insect host or a few species. This narrow host range makes them
suitable for insect pest control without side effects on other non-target insects such as
beneficial groups. Baculoviruses are highly pathogenic against their insect hosts;
they can kill the insect host within a few days by propagation within the host’s body
but not through production of toxins.
The study of entomopathogenic viruses in Iran began in 1998 in which case
studies on the effect of Nuclear Polyhedrosis Virus (NPVs) on some pests such as
Heliothis armigera (Hübner 1808), Spodoptera exigua (Hübner 1808), Plutella
xylostella (Linnaeus 1758), and Cydia pomonella (Linnaeus 1758) were performed.
Issues regarding histopathology and mass rearing were also surveyed during
this time.
Although considerable effort has been made in characterization of microbial
diversity across the country, there has been little progress in the area of insect
pathogenic microorganisms particularly entomopathogenic viruses. Considering
the importance of insect pathogens in microbial control programs and their diversity
in Iran, more studies need to be done on isolation and characterization of native
insect pathogens.
506
M. Mehrabadi et al.