An insect virus, called Manawatu virus (MwV), was isolated from a larva of the New Zealand grass grub Costelytra zealandica (White) (Coleoptera: Scarabaeidae). MwV was serologically related, but not identical, to several insect nodaviruses. The single capsid protein of MwV was 40,000 MW, the same as black beetle virus (BBV), but virus particles had a different electrophoretic mobility from BBV. The bipartite RNA genome, like other nodaviruses, consisted of two species of MW 1.1 and 0.46 million. MwV particles sedimented at 142 S and had an estimated density in neutral CsCl of 1.366 g/ml compared with 1.352 g/ml for BBV. The serological and physico-chemical properties, compared with other nodaviruses, indicate that MwV is unique.
The effects on housefly (Musca domestica) of six norditerpene lactones (nagilactones B, D, E, podolide, hallactone B and 14‐epi‐ponalactone A) in a defined diet were tested. Nagilactone D was the most active, with an LD50 of 0.7 ppm. Nagilactones C and D were also toxic to light‐brown apple moth (Epiphyas postvittana) and codling moth (Laspeyresia pomonella).
The relationship between lactone structure and toxicity to housefly is discussed.
ZUSAMMENFASSUNG
INSEKTIZIDWIRKUNG VON NORDITERPENLACTONEN
Viele aus Podocarpus‐Arten isolierte Norditerpenlactone sind für Stubenfliegen toxisch. Es wird über die Resultate der Fütterung von sechs Lactonen an die Stubenfliege in einem definierten Nährboden berichtet und die LD50 von zwölf Verbindungen werden verglichen. Der aktivste Stoff ist Nagilacton mit einer LD50 von 0,7 ppm. Nagilacton C und D sind auch toxisch fur Epiphyas postvittana und für den Apfelwickler Die wirksamsten Verbindungen haben eine kurze nichtpolare Seitenkette und eine elektronenreiche, funktionelle Gruppe bei C‐8, ferner sind sie Epoxyalkohole in Ring‐A. Diese in der Natur vorkommenden Lactone spielen wahrscheinlich eine Schutzrolle in der Pflanze.
Two nodaviruses, both isolated from New Zealand scarab beetles, replicated in DSIR-HA-I 179 (HA) cells derived from the black beetle, Heteronychus arator (Coleoptera: Scarabaeidae). Black beetle virus and Flock House virus, isolated from the grass grub (Costelytra zealandica) produced a characteristic cytopathic effect in cells.
The moulting hormone activity of 13 ecdysteroids has been determined using a housefly ligature bioassay and the effects on fly development of 11 of these when incorporated !n a defined diet have been tested. The most active compounds in the moulting hormone assay were 20-hydroxyecdysone and 5,20-dihydroxyecdysone 2-(3',4'-methylenedioxy)-cinnamate while in the diet test 20-hydroxyecdysone and 5,20-dihydroxyecdysone gave 84% and 77% larval mortality, respectively at 100 ppm. 5,20-Dihydroxyecdysone 2-(3',4'methylenedioxy)-cinnamate severely inhibited adult emergence.
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