Enhancement in Activity of Homologous and Heterologous Baculoviruses Infectious to Beet Armyworm (Lepidoptera: Noctuidae) by an Optical Brightener

Abstract

The nuclear polyhedrosis virus (NPV) from the beet armyworm, Spodoptera exigua (Hübner) (SeMNPV), was the most active virus tested against the beet armyworm (LC50 = 4.1 PIBs/mm2), followed by nuclear polyhedrosis viruses from the alfalfa looper, Autographa californica (Speyer) (AcMNPV; LC50 = 92.6 PIBs/mm2), and the celery looper, Anagrapha falcifera (Kirby) (AfMNPV; LC50 = 195.7 PIBs/mm2). In the case of the nuclear polyhedrosis virus from the bollworm, Helicoverpa armigera (Hübner), LC50s could only be obtained for five/six replicates, whereas LC50s could only be obtained for two/six replicates for the nuclear polyhedrosis virus from the wax moth, Galleria mellonella (L.) (GmMNPV). When an optical brightener Tinopal LPW was added to virus suspensions, LC50 values were reduced by 130-fold for both SeMNPV and AcMNPV and by 300-fold for AfMNPV. The addition of Tinopal LPW greatly increased the activities of HaMNPV and GmMNPV. In terms of speed of kill, Tinopal LPW reduced the LT50s for all nuclear polyhedrosis viruses by 30-40%.

Improved insecticidal activity of a genetically modified baculovirus expressing the immunosuppressive CrV1 protein from a polydnavirus againstSpodoptera exigua

“…The LC50 was lower using the AcMNPV-C6-CrV1 (1,000 OBs/cm 2 ) than that of the wild type of 10,000 OBs/cm 2 (Table 1; Fig. 2 Panel B); the LT50 was also similar to 9,141 OBs/cm 2 for an AcMNPV wild-type baculovirus as reported by Shapiro, (2000). All bioassays produced significant non-zero slopes A c c e p t e d M a n u s c r i p t with t-ratios ranging from 14.15 to 16.00.…”

“…The LT50 was shorter using the AcMNPV-C6-CrV1 virus (214 h) than that of the wild-type virus of 139 h (Table 1; Fig. 2 Panel A); the LT50 was similar to 151 h for an AcMNPV wild-type baculovirus using 4,300 OBs/cm 2 (Shapiro, 2000). The relationship between dose (OBs/cm 2 ) -and time (h) -mortality of recombinant and wild-type baculoviruses for the control of S. exigua is summarized in Fig.…”

Potential of <I>Agrotis ipsilon</I> Nucleopolyhedrovirus for Suppression of the Black Cutworm (Lepidoptera: Noctuidae) and Effect of an Optical Brightener on Virus Efficacy

“…The addition of 0.5% M2R to AgipMNPV treatments signiÞcantly reduced LD 50 estimates in thirdinstar A. ipsilon by Ϸ160-fold to Ϸ2 OBs per larva. This magnitude of viral enhancement by an optical brightener compares with 116 Ð303,000-fold seen in Spodoptera frugiperda (J. E. Smith) (Hamm and Shapiro 1992;Shapiro and Hamm 1999), 42Ð1,670-fold seen in L. dispar (Shapiro and Robertson 1992;Farrar et al 1995;Shapiro and Argauer 1995;Argauer and Shapiro 1997), 15Ð1,584-fold seen in Pseudoplusia includens (Walker) (Zou and Young 1996), 119-fold seen in Spodoptera exigua (Hü bner) (Shapiro 2000), and 3.3-fold in Choristoneura occidentalis Freeman (Li and Otvos 1999).…”

A Stilbene Optical Brightener can Enhance Bacterial Pathogenicity to Gypsy Moth (Lepidoptera: Lymantriidae) and Colorado Potato Beetle (Coleoptera: Chrysomelidae)

“…Stilbene optical brighteners enhance the activity of viruses in a number of Lepidoptera (Dougherty et al ., 1996;Shapiro, 2000). Would stilbene optical brighteners similarly enhance the activity of bacteria?…”