Efficiency of flight interception traps for adult Colorado potato beetles (Coleoptera : Chrysomelidae)

Interception traps have been used to monitor and sample Colorado potato bee tle, Leptinotarsa decemlineata (Say), populations in flight, but the effici ency of these traps was unknown. The efficiency of interception window trap s is limited because flying adults avoid the traps and may bounce off the t rap without being collected. All trap types tested were avoided in night ch amber tests, including those constructed of transparent Plexiglas or yellow wood boards. A larger screen trap and a harp trap designed to reduce detec tion were also avoided by the beetles in night. None of the traps provide a direct estimate of the number of adults randomly flying in the trap area. The highest level of efficiency for window traps was obtained with the yell ow trap, which caught 16% of the expected flying population. Harp and scree n traps without frames intercepted 60-62% of the expected flying population . The presence of a frame did not increase significantly the avoidance of t he screen and harp traps by beetles in night. Recommendations are made to m aintain or increase the efficiency of some traps.