VOLATILE EMISSIONS FROM ACTIVELY-GROWING GYNANDROPSIS GYNANDRA AND CLEOME HASSELERIANA TO CONTROL SPIDER MITES IN PROTECTED ROSE CULTIVATION
Foliage of the African spider plant, Gynandropsis gynandra L. (Briq) is traditionally used in rural Eastern Africa as a repellent against livestock ticks, and this characteristic extends to repellence of another Acarid, the two-spotted spider mite (Tetranychus urticae Koch). The repellent effect on this major, global pest in protected rose cultivation is due to the foliar emission of acetonitrile (methyl cyanide), that is also toxic to the mites if they cannot escape it. Additionally, G. gynandra leaves contain a number of other substances that are toxic to spider mites at low concentrations and are emitted following foliar disruption e.g., from herbivory. The potential of this repellent activity in rose production in temperate regions might be viewed with limited enthusiasm if it involves the need to maintain a repellent plant, G. gynandra, of tropical origin. Consequently, a taxonomically close relative of G. gynandra, Cleome hassleriana Chod., also from the family Cleomaceae and widely-grown in Europe and N. America has been investigated. It has comparable acetonitrile emission and foliar content of miticidal compounds to G. gynandra, indicating their parallel potential to repel spider mites. Either of these plants could be considered as a contributor when constructing spider mite control strategies, apotential source of effective, natural miticides and, possibly, as a potential gene donor for genetic manipulation.
Nyalala, S. and Grout, B.W.W. (2015). VOLATILE EMISSIONS FROM ACTIVELY-GROWING GYNANDROPSIS GYNANDRA AND CLEOME HASSELERIANA TO CONTROL SPIDER MITES IN PROTECTED ROSE CULTIVATION. Acta Hortic. 1064, 299-302
spider mite, Tetranychus urticae, rose, Gynandropsis gynandra, Cleome hassleriana, repellent volatiles, toxicity