Bioassay of nucleopolyhedrosis virus against larval instars of Malacosoma neustria
1975; Elsevier BV; Volume: 25; Issue: 3 Linguagem: Inglês
10.1016/0022-2011(75)90092-0
ISSN1096-0805
Autores Tópico(s)Entomopathogenic Microorganisms in Pest Control
ResumoThe relative susceptibility of third- and fourth-instar Malacosoma neustria larvae to a nucleopolyhedrosis virus was studied by bioassay in the laboratory. Larval mortality increased with increased dosage, whereas the dosage-incubation relationship was reversed. Larval age inversely affected mortality and incubation. The computed LD50's for third- and fourth-instar larvae were 1,405 and 12,320 polyhedral inclusion bodies (PIB's)/larva. The median lethal doses calculated as number of PIB's/mg body weight showed that third-instar larvae were only twice more susceptible to virus than fourths. The LT50 values for 3 × 105, 3 × 104, and 3 × 103 PIB's/larva were 5.9, 6.58, and 8.15 days, respectively, in third-instar assay; the corresponding figures for the two highest concentrations were 9.3 and 10.7 days in the older larvae. Lethally infected individuals died after one or, exceptionally, two molts. No correlation was found between pupal weight or adult emergence of survivors and the virus dose administered to the larvae.
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