Abstract

A grease matrix was loaded with pheromone components for Pandemis pyrusana and Choristoneura rosaceana (Lepidoptera: Tortricidae), two synchronic and sympatric species affecting apple orchards in Washington, USA. The chemicals used were a 5-blend of cis-11- tetradecenyl-acetate (Z11-14Ac), trans-11-tetradecenyl-acetate, cis-11-tetradecenyl-1-ol, cis-11-tetradecanal, and cis-9-tetradecenyl-acetate (Z9-14Ac) (90.05:1.89:1.42:0.95:5.69 ratio), or a 2-blend of Z11-14Ac and Z9-14Ac (94:6 ratio). Experiments to test each blend separately in a wind tunnel (at 0.16% and 16% pheromone), or in field trials (1.6% and 16%), indicated that significantly more P. pyrusana males responded to the higher concentration within any blend, and that a source containing the 5-pheromone blend caused significant reduction in attractiveness to this species. Source contact was significantly reduced within the P. pyrusana male behavioral sequence. This is the first report for P. pyrusana pheromone inhibitor, but further research is needed to identify whether one or more specific components elicit this response. The inhibitory effect observed probably helps to avoid interspecific matings in nature, and might be useful to develop some strategies against this pest, but it impedes to developing an attracticide formulation targeting simultaneously P. pyrusana and any other sympatric and synchronic species using these chemicals (as C. rosaceana) within their pheromone blends.