The patterns of gorse pod production, the phenology of Exapion ulicis and its impact on gorse seed production were assessed in a field study conducted at two sites over 20 months in Tasmania, Australia. The production of gorse pods varied considerably between the two sites as did the impact of E. ulicis on mature gorse seed production. At Stonehenge, a site in Tasmania's eastern midlands, green pods were produced in spring and summer and black pods were produced in late spring, summer and early autumn, the timing of which was well synchronised with E. ulicis seed feeding activity. At Lymington, a coastal site in southern Tasmania, both green and black pods were produced almost all year, the timing of which was not well synchronised with E. ulicis seed feeding activity. As a result, the average percentage of mature seeds that were damaged by E. ulicis was 2.7 times higher at Stonehenge (45.5%) than at Lymington (16.7%). These levels of seed destruction were much lower than the levels (i.e. 75-85%) that were considered necessary by previous workers to cause a decline in gorse densities. The results show that additional agents are needed to act in combination with E. ulicis and reduce seed production further if seed feeding biological control agents are to have an impact on plant densities in Tasmanian gorse populations.

Item Type:	Refereed Article
Research Division:	Agricultural, Veterinary and Food Sciences
Research Group:	Crop and pasture production
Research Field:	Crop and pasture protection (incl. pests, diseases and weeds)
Objective Division:	Environmental Management
Objective Group:	Terrestrial systems and management
Objective Field:	Control of pests, diseases and exotic species in terrestrial environments
UTAS Author:	Davies, JT (Mr Jamie Davies)
UTAS Author:	Ireson, J (Dr John Ireson)
UTAS Author:	Allen, GR (Associate Professor Geoff Allen)
ID Code:	48800
Year Published:	2008
Web of Science® Times Cited:	10
Deposited By:	Agricultural Science
Deposited On:	2008-04-09
Last Modified:	2014-12-12
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