The natural plant toxin asimicin and the standardized extract F020 from Asimina triloba (Annonaceae) were examined for their insecticidal properties using six insect species, encompassing four orders. Growth of Ostrinia nubilalis and Manduca sexta larvae was inhibited at 100 and 500 $\mu$g F020$\cdot$g diet$\sp{-1}$, respectively and mortality was significantly higher than controls at levels as low as 500 and 1 $\mu$g F020$\cdot$g diet$\sp{-1}$, respectively. Antifeedant properties were observed. Toxicity and growth reduction from exposure to F020 were apparent for Oncopeltus fasciatus (Hemiptera) and Tenebrio molitor (Coleoptera). Tenebrio molitor was significantly affected at doses as high as 250 $\mu$g F020$\cdot\mu$l$\sp{-1}$ and at 20 $\mu$g asimicin$\cdot\mu$l$\sp{-1}$. Examination of the effect of F020 on the respiratory rate of third instar O. nubilalis larvae demonstrated that F020 is an effective respiratory inhibitor. Both F020 and asimicin were very effective at inhibiting complex I, the NADH-ubiquinone site of the electron transport chain. The EC$\sb{50}$ values for inhibition of state 3 respiration by asimicin and F020 were 0.546 nmoles$\cdot$mg protein$\sp{-1}$ and 1.656 $\mu$g$\cdot$mg protein$\sp{-1}$, respectively. (Abstract shortened by UMI.)
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/6500 |
| Date | January 1993 |
| Creators | Lewis, Mark Andrew. |
| Contributors | Arnason, J. T., |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Detected Language | English |
| Type | Thesis |
| Format | 154 p. |
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