Rubber vine is in the family Asclepiadaceae, sub-family Periploicoideae,
and is closely related to the family Apocynaceae. Australia has many native plants in these two families, some of which
(Hoya, Stephanotis) are also important ornamentals. A biological control program started in 1985, with searches in Madagascar where the plant is native. Unfortunately, few potential agents were found, and none were host specific to the genus
Cryptostegia. In tests, two of the species also damaged other native and ornamental plants in the families Apocynaceae or
Asclepiadaceae, and were rejected for this reason (McFadyen and Marohasy
1993b).
The leaf-feeding moth E. whalleyi was the most host specific of the insects found. In both laboratory tests and in the field, it fed and developed on plants in several genera of the subfamily
Periplocoideae, but on none outside of this family (McFadyen and Marohasy
1993a). There are only five species in this subfamily in Australia, only one of which is common and found in the same areas as
rubber vine. This plant is also a vine, and grows in the same riverine habitats of northern Australia as
rubber vine. Where rubber vine invades an area, the native vine is displaced and becomes locally extinct.
