Identification of oviposition pheromone of gall midge, Mycodiplosis coniophaga (Winnertz)

A volatile compound, heptyl butyrate, was identified as female oviposition pheromone of gall midge, Mycodiplosis coniophaga (Winnertz) from the fruit of the Chinese crabapple, Malus hupehensis (Pamp.) Rehder (Rosaceae), covered with aecia of cedar apple rust, Gymnosporangium sp. (Uredinales: Pucciniaceae). Preliminary field assays demonstrated that heptyl butyrate itself was significantly attractive than the heptyl isobutarate, an analog of the pheromone. However, attraction could be significantly inhibited by addition of trans-beta-ocimene, which was another component identified from the same volatile source. In a period of 2-wk in 2009, more than 10,000 M. coniophaga females were captured in 10 Jackson traps (Trécé Inc., Salinas, CA) baited with 0.25-1.0 gram of synthetic heptyl butyrate in hedgerow, which made up of many kinds of trees, shrubs and vines, but mainly by M. hupehensis in Beltsville, Maryland.