Rubber vine is believed to have a potential range in Australia from about Coen in
Cape York Peninsula to
Port Hedland in the
Pilbara. It has not yet moved much beyond Queensland. It is a major threat to
gallery forests along rivers in northern Australia, because it can strangle and kill the native trees by climbing over them and eliminating access to light. It can also do the same thing in
savanna woodlands away from watercourses. Rubber vine is also extremely toxic to all livestock: less than 10 grams of rubber vine leaves can kill a 400 kilogram
horse within six days, and it is also highly toxic to
cattle,
sheep and
goats. However, it is extremely unpalatable and only causes death in dry seasons when green
grass is very scarce, although in Queensland it is believed that two or three deaths of human children may have occurred via ingesting rubber vine. Control of rubber vine has relied on importing biological agents from its native habitat in southwestern Madagascar, the most important of which is the “rubber vine rust” (
Uredo (= Maravalia) cryptostegiae). In some areas near
Charters Towers, this rust has infected most rubber vine plants, but its effect has not been great enough to stop the spread of the plant westwards. The “rubber vine moth” (
Euclasta gigantalis) was introduced earlier than the rust (in 1988) but has not proved very effective. The extreme remoteness of most rubber vine infestations rules out mechanical and chemical control for dealing with the plant. ==Africa==