protective effect of different additives and natural polymers on the stability of helicoverpa armigera npv (hanpv) against ultraviolet radiation

Microbial biopesticides because of their less environmental impact ensure the management of agro–ecosystems. among the microbial biopesticides, baculoviruses have been interested. because of the low stability of baculoviruses against sunlight, preparation of uv protectant formulations is being focused in this study. accordingly, the ultraviolet protective effect of some natural and chemical additives (green tea, black tea, coffee, cocoa, tween 80, sodium lignin sulfonate and titanium dioxide) at two concentration levels (0.5% and 3% w/v) for the helicoverpa armigera nucleopolyhedrovirus was evaluated. the investigation was expanded to include three natural polymers (sodium alginate, gelatin, starch) which have recently been used for microencapsulation of biopesticides. results are based on larval insecticide bioassays to test original activity remaining (oar). the results showed that titanium dioxide (3% w/v) had no protective effect after 8 hours exposure to uva (26.66± 3.33). after 48 hours exposure, although titanium dioxide (3% w/v) provided a very little protection against uva radiation (30.00± 6.35), it still remained the less effective additive. unlike some reports, titanium dioxide did not provide adequate protection against uva radiation in our study. in addition, it reduced the activity of occlusion bodies (obs) in the absence of uv rays. after eight hours exposure to uva radiation, sodium alginate (3% w/v) was an excellent uva protectant (93.33± 3.33), whereas the mentioned polymer provided inadequate protection, 48 hours post uva radiation (50.00± 3.46). the other applied polymers provided medium protection against uva radiation. after 48 hours, the concentrations of 3% w/v of green tea and coffee provided significant uv protection on stability of helicoverpa armigera nucleopolyhedrovirus activity at 80.00± 1.54 and 83.33± 3.33, respectively. lignin at both concentration levels was a proper uv protectant after 48 hours (83.33± 6.66).

Protective effect of different additives and natural polymers on the stability of Helicoverpa armigera NPV (HaNPV) against ultraviolet radiation

Microbial biopesticides because of their less environmental impact ensure the management of agro–ecosystems. Among the microbial biopesticides, baculoviruses have been interested. Because of the low stability of baculoviruses against sunlight, preparation of UV protectant formulations is being focused in this study. Accordingly, the ultraviolet protective effect of some natural and chemical additives (green tea, black tea, coffee, cocoa, Tween 80, sodium lignin sulfonate and titanium dioxide) at two concentration levels (0.5% and 3% w/v) for the Helicoverpa armigera nucleopolyhedrovirus was evaluated. The investigation was expanded to include three natural polymers (sodium alginate, gelatin, starch) which have recently been used for microencapsulation of biopesticides. Results are based on larval insecticide bioassays to test original activity remaining (OAR). The results showed that titanium dioxide (3% w/v) had no protective effect after 8 hours exposure to UVA (26.66± 3.33). After 48 hours exposure, although titanium dioxide (3% w/v) provided a very little protection against UVA radiation (30.00± 6.35), it still remained the less effective additive. Unlike some reports, titanium dioxide did not provide adequate protection against UVA radiation in our study. In addition, it reduced the activity of occlusion bodies (OBs) in the absence of UV rays. After eight hours exposure to UVA radiation, sodium alginate (3% w/v) was an excellent UVA protectant (93.33± 3.33), whereas the mentioned polymer provided inadequate protection, 48 hours post UVA radiation (50.00± 3.46). The other applied polymers provided medium protection against UVA radiation. After 48 hours, the concentrations of 3% w/v of green tea and coffee provided significant UV protection on stability of Helicoverpa armigera nucleopolyhedrovirus activity at 80.00± 1.54 and 83.33± 3.33, respectively. Lignin at both concentration levels was a proper UV protectant after 48 hours (83.33± 6.66).