| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4568295 | Scientia Horticulturae | 2011 | 5 Pages |
The African spider plant (Gynandropsis gynandra L. (Briq)) has repellent properties against spider mite on roses (Rosa hybrida L.) when grown as a companion plant. Gas chromatography–mass spectrometry (GC–MS) has been used to identify potential volatile compounds in the foliar emissions of this plant that may contribute to the anti-mite properties. Acetonitrile (methyl cyanide) was the most abundant compound emitted by entire plants and detached leaves of five lines of both glasshouse- and field-grown G. gynandra, with only trace levels emitted by roses grown under similar conditions. A toxicity bioassay was conducted to evaluate the bioactivity of acetonitrile against spider mite, and ≥2.5 μL/L of air rendered 100% of the mites inactive. Removal of the compound after an initial exposure of up to 5.0 μL/L of acetonitrile allowed some 10% of the mites to recover mobility, but above this level no mobility was observed. This study provides a very strong indication that foliar emissions of acetonitrile by G gynandra are responsible, to a significant degree, for the spider mite repellent activity of the plant when used as an intercrop with roses.
Research highlights► Gynandropsis gynandra L. (Briq) has repellent properties against spider mite on roses. ► Acetonitrile is the major volatile emitted by G. gynandra L. (Briq) and not roses. ► Depending upon the concentration, acetonitrile can be repellent or toxic to spider mites. ► Emitted acetonitrile from G. gynandra is a major factor in repelling spider mite.
