An integrated pest management trap: Discovering the pheromone of the celery leaftier (Udea rubigalis)

The celery leaftier (Udea rubigalis, Lepidoptera: Crambidae) is a generalist herbivore, attacking horticultural and vegetable crops. It is a pest of celery in the United States, but is lacking monitoring and adequate control methods. Michigan is among the top three states for celery production, with about a $20 million value crop in 2013. Our objective was to identify the semiochemical cues utilized for intraspecies communication. We conducted field trials to determine the sex of the pheromone-emitting moth by creating different virgin moth baits, which were made of wire tea infusers hung in white delta traps. Traps were placed in the field in a randomized, replicated design at multiple commercial celery farms in the 2014 growing season in west Michigan. Bait treatments included: 1) virgin female moths of varying numbers per bait, 2) two virgin female moths of different ages, 3) virgin male moths and, 4) empty baits. Traps were left out for 48 hrs and then the sex of the leaftiers attracted to the traps and the number of moths trapped was recorded. This data was analyzed with an analysis of variance. Virgin female moths attracted males to traps; the empty baits and baits with males did not attract any leaftier moths in the field. The identity of the pheromone was determined by placing virgin female moths in round bottom flasks overnight and collecting the residue left on the glass for GC-MS analysis. The information gathered from this project can be used to develop monitoring traps for commercial celery growers.