Summary In December 2009 and January 2010 an outbreak of Uraba lugens Walker (Lepidoptera: Nolidae), the gumleaf skeletonizer (GLS) that affects jarrah, Eucalyptus marginata, became apparent in south-western Western Australia in the vicinity of Yanmah (34°9'S, 116°1'E), Carter (34°05'S, 116°02'E) and Quinninup (34°23'S, 116°17'E) forest blocks. By the end of January 2011 the outbreak severely affected more than 250 000 ha of jarrah forest. This study is a preliminary field trial of the Desire® GLS pheromone lure and trap system that compares trap results with larval populations determined from branch-clip samples. Thirteen of 19 sites for deployment of the trap and lure system were selected from an array of 61 sites from which GLS larval density data from November 2010 had been collected, and trap sites included six FORESTCHECK sites, for which long-term monitoring of forest condition had been undertaken. These 19 sites were across a rainfall gradient, and provided a strong contrast in outbreak severity between eastern and western sites. The GLS lure was highly specific for GLS, with a mean capture rate of 55 male moths per site. However, a trap at a site with a thick tall understorey that had supported a large larval population captured only four moths. The trap and GLS lure system are effective for monitoring both outbreak and basal populations of GLS in jarrah forest with an open understory. Moth captures from lure traps are an effective alternative to monitoring GLS larval populations, with the reservation that the trap system has impaired effectiveness in locations with thick understory that exceeds the trap height.