Biabani et al. (2005), attempted to measure the resistance level of 20 new Iranian
silkworm hybrids to nuclear polyhedrosis virus. In this study, 3rd instar larvae of
B. mori were orally inoculated with B. mori NPV (550 ppm) and reared up to the
spinning stage in summer. The results indicated that lines of 107 K Â 124 K,
107 K Â 108 K, and 101,433 Â 114 had the highest resistance to this virus. Some
hybrid had the highest resistance to this virus.
13.1.2.6 Apis mellifera
At least 18 viruses have been reported in Iranian honeybee colonies, Apis mellifera
(Linnaeus 1758) (Hym.: Apidae). Of those, six viruses cause severe diseases. These
viruses include deformed wing virus (DWV), acute bee paralysis virus (ABPV),
chronic bee paralysis virus (CBPV), sacbrood virus (SBV), Kashmir bee virus
(KBV), and black queen cell virus (BQCV) (Mosadegh 1990; Ghorani et al.
2017). In addition, CBPV was characterized from different regions including
Mazandaran, Razavi Khorasan, Hormozgan, and Kurdistan (Ghorani et al. 2017).
In another study, Sabahi et al. (2018), surveyed 12 apiaries located in the Alborz,
Ardabil, and Guilan province and samples of varroa mite, Varroa destructor
(Anderson and Trueman 2000) (Acari: Varroidae) were taken. Five viruses including
DWV, BQCV, ABPV, Israeli acute paralysis virus (IAPV), and KBV were characterized in V. destructor using RT-PCR. The results indicated that several mite
samples were positive for DWV and BQCV, but all were negative for ABPV,
IAPV, and KBV.
13.1.3 Virus and Natural Condition
Baculoviruses are sensitive to irradiation. Thus, surveying biological activity of
NPVs before and after exposure to sunlight is critically important. In a study by
Mehrvar et al. (2008b), the effects of different radiation dosage (175, 500, 600, 650,
700, and 750 W/m
2 ) and time exposed to simulated sunlight (30, 60, 90, 120,
180, and 240 minutes) were evaluated under laboratory conditions to monitor
NPV virulence in H. armigera. Virulence decreased by a factor of 2.63 against
second instar larvae of H. armigera when exposed to 750 W/m
2 dose for 90 min
(Mehrvar et al. 2008b).
Moreover, application of baculoviruses in biocontrol programs has three major
limitations: they have a high LT 50 , are inactivated by ultraviolet (UV) radiation, and
are difficult to mass produce. To address this, Dezianian et al. (2012), surveyed
additives (including Tinopal, lignin, molasses and skim milk powder) to a suspension of PlxyGV after UV-B irradiation. The material used as the protectant, and the
duration of exposure time (30 or 60 min) significantly affected the larval mortality.
Some combinations, including PlxyGV and Tinopal, PlxyGV and molasses, PlxyGV
and lignin, and PlxyGV and skim milk, increased the viral suspension’s residual
13 Insect Pathogenic Viruses, Microsporidians and Endosymbionts
513
silkworm hybrids to nuclear polyhedrosis virus. In this study, 3rd instar larvae of
B. mori were orally inoculated with B. mori NPV (550 ppm) and reared up to the
spinning stage in summer. The results indicated that lines of 107 K Â 124 K,
107 K Â 108 K, and 101,433 Â 114 had the highest resistance to this virus. Some
hybrid had the highest resistance to this virus.
13.1.2.6 Apis mellifera
At least 18 viruses have been reported in Iranian honeybee colonies, Apis mellifera
(Linnaeus 1758) (Hym.: Apidae). Of those, six viruses cause severe diseases. These
viruses include deformed wing virus (DWV), acute bee paralysis virus (ABPV),
chronic bee paralysis virus (CBPV), sacbrood virus (SBV), Kashmir bee virus
(KBV), and black queen cell virus (BQCV) (Mosadegh 1990; Ghorani et al.
2017). In addition, CBPV was characterized from different regions including
Mazandaran, Razavi Khorasan, Hormozgan, and Kurdistan (Ghorani et al. 2017).
In another study, Sabahi et al. (2018), surveyed 12 apiaries located in the Alborz,
Ardabil, and Guilan province and samples of varroa mite, Varroa destructor
(Anderson and Trueman 2000) (Acari: Varroidae) were taken. Five viruses including
DWV, BQCV, ABPV, Israeli acute paralysis virus (IAPV), and KBV were characterized in V. destructor using RT-PCR. The results indicated that several mite
samples were positive for DWV and BQCV, but all were negative for ABPV,
IAPV, and KBV.
13.1.3 Virus and Natural Condition
Baculoviruses are sensitive to irradiation. Thus, surveying biological activity of
NPVs before and after exposure to sunlight is critically important. In a study by
Mehrvar et al. (2008b), the effects of different radiation dosage (175, 500, 600, 650,
700, and 750 W/m
2 ) and time exposed to simulated sunlight (30, 60, 90, 120,
180, and 240 minutes) were evaluated under laboratory conditions to monitor
NPV virulence in H. armigera. Virulence decreased by a factor of 2.63 against
second instar larvae of H. armigera when exposed to 750 W/m
2 dose for 90 min
(Mehrvar et al. 2008b).
Moreover, application of baculoviruses in biocontrol programs has three major
limitations: they have a high LT 50 , are inactivated by ultraviolet (UV) radiation, and
are difficult to mass produce. To address this, Dezianian et al. (2012), surveyed
additives (including Tinopal, lignin, molasses and skim milk powder) to a suspension of PlxyGV after UV-B irradiation. The material used as the protectant, and the
duration of exposure time (30 or 60 min) significantly affected the larval mortality.
Some combinations, including PlxyGV and Tinopal, PlxyGV and molasses, PlxyGV
and lignin, and PlxyGV and skim milk, increased the viral suspension’s residual
13 Insect Pathogenic Viruses, Microsporidians and Endosymbionts
513