Author
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SHAPIRO, MARTIN |
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Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 8/27/1998 Publication Date: N/A Citation: N/A Interpretive Summary: The fall armyworm is a major pest on corn and sorghum in the United States, Mexico, and Latin America. A virus was found more than 30 years ago, but it is not very potent against this insect. Several other insect viruses (NPVs) were tested against fall armyworm larvae, but they were totally ineffective. The addition of some optical brighteners increased the killing powers of all viruses, including the fall armyworm NPV. Five of these brightener (Blankophor BBH, Blankophor HRS, Blankophor P167, Blankophor RKH, and Tinopal LPW) not only lowered the amount of virus needed to kill the armyworm but speeded up the kill process. These same 5 brighteners also improved the potencies of the gypsy moth NPV, the corn earworm NPV, and the beet armyworm NPV. These results show that the same brighteners that increase the "killing power" of the fall armyworm NPV could also be used to increase the potencies of viruses against the corn earworm and the beet armyworm. Thus these materials should be considered by Entomologists as adjuvants for insect pathogenic viruses to control pest insect species. Technical Abstract: The nuclear polyhedrosis virus (NPV) from S. frugiperda (SfMNPV) was the most active virus tested against fall armyworm, Spodoptera frugiperda (J.E. Smith), larvae (LC(50) = 10,900 PIB per 30-ml cup). No LC(50s) could be obtained for the alfalfa looper, Autographa californica (Speyer), NPV (AcMNPV), the celery looper, Anagrapha falcifera (Kirby), NPV (AfMNPV), the wax moth, Galleria mellonella (L.), NPV (GmMNPV), or the bollworm, Helicoverpa armigera (Hubner), NPV (HaMNPV). The addition of an optical brightener, Tinopal LPW (1%) significantly enhanced the activities of all NPVs. The most activie NPV/Tinopal LPW combination was SfMNPV, followed by AcMNPVm HaMNPV, AfMNPV, and GmMNPV. In terms of speed of kill, SfMNPV was the most active virus tested. When Tinopal LPW was added the LT(50) was reduced by more than 35%. The addition of Tinopal LPW to the heterologous NPVs resulted in LC(50) and LT(50) values that were comparable to SfMNPV alone. Five of 8 brighteners acted as activity enhancers for SfMNPV (i.e., Blankophor BBH, Blankophor HRS, Blankophor P167, Blankophor RKH, and Tinopal LPW), whereas Blankophor BSU, Blankophor DML, and Blankophor LPG did not enhance virus activity. |
