Sex attractant-based monitoring of a biological control agent of gorse

Cydia succedana (Denis dt Schiffermuller) has been introduced into New Zeal and for the biological control of gorse seeds (Ulex europaeus). Traps baite d with a sex attractant were developed for monitoring the flight timing and number of adult male moths and were used as a new tool for monitoring the establishment, phenology and efficacy of the agent. The best hare tested wa s (E,E)-8,10-dodecadien-1-yl acetate, although high catches were also made with the E,Z isomer. There was no difference in the total catch across a ra nge of doses from I to 300 mu g/lure (7151 insects caught). Male flight was recorded at the bottom, middle and top of a hillside between 280 and 370 m altitude, along with the percentages of plants at each site bearing flower s and seed pods. There was an initial seasonal linkage between the catch of males and plans phenology, but a lack of synchrony was evident between the insect and the plant in the second generation, indicating a potentially im portant limitation for biological control at this site. The prospects for u sing sex attractants in traps as an aid for monitoring populations of weed biological control agents are excellent. Other potential applications inclu de the cost-effective detection of establishment and the determination of t he optimal size of founding populations to ensure establishment of control agents.