Project overview
Scotch broom is native to the Mediterranean. It produces dense stands, impeding the establishment of native species. It is present throughout New Zealand.
Five agents have been released to attack broom: the broom gall mite (Aceria genistae), broom leaf beetle (Gonioctena olivacea), broom psyllid (Arytainilla spartiophila), broom seed beetle (Bruchidus villosus), and broom shoot moth (Agonopterix assimilella). In addition, the broom twig miner (Leucoptera spartifoliella) has self-introduced and causes considerable damage in some areas by attacking the foliage. The seed beetle is now destroying much of the seed produced annually. The psyllid damages new growth in spring and is becoming common but damaging outbreaks occur rarely. Of the more recently released agents, the leaf beetle appears to be establishing but the status of the shoot moth is unknown. The gall mite is establishing readily and showing much promise.
Ecological studies suggest that biological control is likely to be able to succeed against broom in the longer term.
