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.