Design and elevation of sex-attractant traps for pea moth, Cydia nigricana (Steph.) and the effect of plume shape on catches

• 1 Catches of male pea moths in six designs of trap, each containing (E,E)-8,10-dodecadienyl acetate as an attractant, were compared; triangular-shaped traps caught most moths.
• 2 The vertical distribution of moths within a pea crop and the size of catches at different levels varied in different wind speeds. Three-quarter crop height is probably the optimum height for monitoring.
• 3 Five trap designs (including the triangular type) captured only 20–30% of individuals landing on them; water traps were slightly more efficient.
• 4 There was an eight-fold range in the number of moths caught depending on the sticky material used. ‘Bird-Tanglefoot’ was most effective.
• 5 Smoke plumes, emitted from different trap designs in the field to simulate plumes of attractant, were photographed and measured. The effect of trap design on plume shape was confirmed in wind tunnel tests.
• 6 Field tests showed that the more elongated the mean plume emitted from a trap the greater the catch.
• 7 The tracks of individual moths flying to traps are discussed in relation to current views on orientation to odour sources.