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Ashraf El-Sayed


The orientation behaviour of male codling moth, Cydia pomonella (L.) to a pheromone source (E8,E10-12OH, codlemone) with and without E8,Z10-12OH and/or E8,E10-12Ac was investigated in a flight tunnel using a three dimensional video recording system. Both E8,Z10-12OH and E8,E10-12Ac antagonized male attraction when their ratio to codlemone was increased to 20% and 5% respectively. An additive inhibitory effect was observed when both E8,Z10-12OH and/or E8,E10-12Ac were combined with codlemone. Male codling moth flying upwind showed different flight maneuvers in plumes containing codlemone with either E8,Z10-12OH or E8,E10-12Ac. Increasing the release rate of E8,Z10-12OH in codlemone plume to 10 pg/min (i.e., its ratio relative to codlemone was increased to100%) caused males to significantly reduce their flight speeds and angular velocity, similar effects were observed with E8,E10-12Ac when its release rate was increased only to 0.5 pg/min (i.e., its ratio relative to codlemone was increased to 5%). Both E8,Z10-12OH and E8,E10-12Ac caused males to increase their track angles as their concentrations increased in the codlemone plume. However, this effect was mainly due to the significant increase in the course angle for E8,Z10-12OH, and in the drift angle for E8,E10-12Ac. The relevance of these findings in relation to the orientation disruption of codling moth is briefly discussed.