BEHAVIORAL OBSERVATIONS AND MEASUREMENTS OF AERIAL PHEROMONE IN A MATING DISRUPTION TRIAL AGAINST PEA MOTH CYDIA-NIGRICANA F (LEPIDOPTERA, TORTRICIDAE)

Synthetic sex pheromone of the pea moth Cydia nigricana, (E,E)-8,10-do decadien-1-yl acetate (E8,E10-12:Ac), was applied in a 3-ha pea field at a rate of 17 g/ha, in two different dispenser formulations. Aerial concentrations within pea canopy, as determined by a field electroante nnogram (EAG) apparatus, were 2 and 3 ng/m(3) in the two dispenser tre atments. The validity of the EAG measurements was corroborated by samp ling of field air, followed by gas chromatographic quantification of E 8,E10-12:Ac. Males were attracted to fresh dispensers releasing E8,E10 -12:Ac plus less than 2% of the antagonistic E, Z; Z, E; and Z, Z isom ers. Two days after placement, the proportion of these isomers had inc reased to 6%. Males were then no longer attracted to the dispensers, b ut were observed to fly out of the treated field. Male attraction to c alling females was almost entirely suppressed, and attraction to traps baited with synthetic pheromone was significantly reduced. Larval inf estation in the pheromone-treated field was 2%, compared to 36% in a c ontrol field.