Bioassay of the Nucleopolyhedrosis Virus of Neodiprion sertifer (Hymenoptera: Diprionidae)

Abstract

Linear regression analysis of probit mortality versus several concentrations of nucleopolyhedrosis virus of Neodiprion sertifer resulted in the equation Y = 2.170 + 0.872X. An LC₅₀ was calculated at 1758 PIB/ml. Also, the incubation time of the virus was dependent on its concentration. Most insect viruses possess the potential of causing 100% mortality when employed against some pest species populations (Bailey 1973). However, Franz (1964) pointed out that such a result is not always desirable. For instance, if the virus proves persistent and capable of being transmitted by the target species, one would ideally like a small section of the population to survive, serving as a focus for future epizootics. Not only would this serve to reduce the environmental load of virus, if continuous application of virus was planned, but it would also serve to ensure that predator and parasitoid populations would remain intact. Though studies on mortality as a function of virus concentrations are only one of many aspects ensuring proper usage of these pathogens, they give us some predictive basis to achieve some of the aforementioned results. This paper reports on two aspects of the nucleopolyhedrosis virus (NPV) of Neodiprion sertifer (Geoffroy): first, the LC₅₀; and second, mortality as a function of time at fixed concentrations.

Citation

Mohamed, M.A.; Coppel H.C.; Podgwaite, J.D. 1982. Bioassay of the Nucleopolyhedrosis Virus of Neodiprion sertifer (Hymenoptera: Diprionidae). Great Lakes Entomologist. 15: 93-96.