13.1.8 Mass Production of Entomopathogenic Viruses
For the first time, Izadyar et al. (1998) used a Moldavian NPV isolate in laboratory
conditions on third instar H. armigera larvae. Two concentrations of virus (3 Â 10
9
and 5 Â 10
9 OB/Kg) were added to artificial food. After 10 days, mortality was
observed in the fifth instar larvae. Symptoms of the disease were blackening and
swelling of the larvae. Dead larvae were collected, frozen and purified for assay the
viral virulence on second instar larvae of H. armigera.
Rezapanah and Chitic (1998) evaluated mass rearing potential of two
baculoviruse isolates of C. pomonemlla (CPGV), and Agrothis segetum (AgseNPV).
For this purpose, C. pomonella and Agrotis segetum (Denis and Schiffermüller
1775) (Lep.: Noctuidae) larvae were reared. Then, 2nd and 3rd instar larvae were fed
artificial diets containing viral suspension. Dead larvae were collected, frozen,
homogenized, filtered, and centrifuged, and pellets were formulated with lactose,
glycerin, UV protectant, and conservants in liquid form.
In another study, three main factors affecting virus propagation including larval
stage, inoculation dose, and incubation temperature were surveyed by Mehrvar
(2013). Here, three isolates of Helicoverpa armigera nucleopolyhedrovirus –
Maragheh (MRG), Nebrin (NBN), and Marand (MRD) – collected from tomato
fields in the East Azarbaijan province were used. To select the best larval stage for
virus progration, various H. armigera larval instars were selected and 10 μl of virus
suspension (5 Â 10
5 OB/larva) was added to the diet surface. The early 5th instar
larvae provided the highest yield of the virus inocolum. The optimal inoculation
dose and incubation temperature were 1965.87 OB/mm
2 and 25
C, respectively.
Assemi et al. (2013b) optimized the cost- effective production method of native
isolates of Helicoverpa armigera nucleopolyhedrovirus. Then, Assemi et al.
(2013b), surveyed the effects of seven factors including larval instar, virus isolate,
harvesting time, various artificial diets, different generations, and duration of storage
on some yield characteristics of H. armigera nucleopolyhedrovirus. The maximum
viral yield of 9.499 Â 10
9 OB/larva was obtained when late 5th instar larvae were
individually fed a dose of 5 Â 10
4 OB/ml. Also, a diet without formaldehyde and
ascorbate had the greatest impact on H. armigera performance and was better for
virus production. When the H. armigera larvae were fed a diet containing formaldehyde and ascorbate, controlled with 62.38%, but when formaldehyde and ascorbate was removed from the diet, this percentage was 92.02% (overall 32.21%
increase).
518
M. Mehrabadi et al.
For the first time, Izadyar et al. (1998) used a Moldavian NPV isolate in laboratory
conditions on third instar H. armigera larvae. Two concentrations of virus (3 Â 10
9
and 5 Â 10
9 OB/Kg) were added to artificial food. After 10 days, mortality was
observed in the fifth instar larvae. Symptoms of the disease were blackening and
swelling of the larvae. Dead larvae were collected, frozen and purified for assay the
viral virulence on second instar larvae of H. armigera.
Rezapanah and Chitic (1998) evaluated mass rearing potential of two
baculoviruse isolates of C. pomonemlla (CPGV), and Agrothis segetum (AgseNPV).
For this purpose, C. pomonella and Agrotis segetum (Denis and Schiffermüller
1775) (Lep.: Noctuidae) larvae were reared. Then, 2nd and 3rd instar larvae were fed
artificial diets containing viral suspension. Dead larvae were collected, frozen,
homogenized, filtered, and centrifuged, and pellets were formulated with lactose,
glycerin, UV protectant, and conservants in liquid form.
In another study, three main factors affecting virus propagation including larval
stage, inoculation dose, and incubation temperature were surveyed by Mehrvar
(2013). Here, three isolates of Helicoverpa armigera nucleopolyhedrovirus –
Maragheh (MRG), Nebrin (NBN), and Marand (MRD) – collected from tomato
fields in the East Azarbaijan province were used. To select the best larval stage for
virus progration, various H. armigera larval instars were selected and 10 μl of virus
suspension (5 Â 10
5 OB/larva) was added to the diet surface. The early 5th instar
larvae provided the highest yield of the virus inocolum. The optimal inoculation
dose and incubation temperature were 1965.87 OB/mm
2 and 25
C, respectively.
Assemi et al. (2013b) optimized the cost- effective production method of native
isolates of Helicoverpa armigera nucleopolyhedrovirus. Then, Assemi et al.
(2013b), surveyed the effects of seven factors including larval instar, virus isolate,
harvesting time, various artificial diets, different generations, and duration of storage
on some yield characteristics of H. armigera nucleopolyhedrovirus. The maximum
viral yield of 9.499 Â 10
9 OB/larva was obtained when late 5th instar larvae were
individually fed a dose of 5 Â 10
4 OB/ml. Also, a diet without formaldehyde and
ascorbate had the greatest impact on H. armigera performance and was better for
virus production. When the H. armigera larvae were fed a diet containing formaldehyde and ascorbate, controlled with 62.38%, but when formaldehyde and ascorbate was removed from the diet, this percentage was 92.02% (overall 32.21%
increase).
518
M. Mehrabadi et al.