Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2012
Publication Date: 2/1/2013
Publication URL: http://handle.nal.usda.gov/10113/56614
Citation: Harrison, R.L. 2013. Concentration- and time-response characteristics of plaque isolates of Agrotis ipsilon multiple nucleopolyhedrovirus derived from a field isolate. Journal of Invertebrate Pathology. 112(2):159-161. Interpretive Summary: A pest called the black cutworm infests many crops around the world. The use of chemical insecticides to kill this pest is not desirable due to negative ecological, environmental, and health consequences. Baculoviruses are a group of insect viruses that can be used to kill insect pests without the problems of chemical insecticides. In this study, baculoviruses isolated from the black cutworm were tested for their ability to infect and kill black cutworm larvae. Doses of the viruses required to kill the black cutworm were determined, along with the length of time that the larvae survived after being infected. A mixture of different viruses was tested to see if it killed larvae more efficiently than individual viruses. Viruses with superior insecticidal properties were identified. The information in this study contributes to progress towards identifying and developing baculoviruses that can be used as biopesticides against the black cutworm and similar pests. Baculoviruses have a wide range of applications in addition to their use as biopesticides, and this study will be of interest to scientists in academia, government, and industry who work with this group of viruses.
Technical Abstract: Plaque isolates derived from the Illinois field isolate of Agrotis ipsilon multiple nucleopolyhedrovirus are distinguished by the presence or absence of a small deletion in the baculovirus egt (ecdysteroid UDP-glucosyltransferase) coding sequence. Dose-response and time-response bioassays were performed with both plaque and field isolates to assess their relative pathogenicity and characterize the contributions of the two genotypes to the virulence of the field isolate. Plaque isolates with a mutated egt gene were less virulent against A. ipsilon larvae than other isolates, but killed larvae faster. An additive or synergistic effect on virulence was not observed in mixed infections with isolates representing the two different egt genotypes.