Pollen on corn earworm moths,Helicoverpa zea(Boddie), can provide an indication of their host plant visitations and migratory activities. Our study was conducted to determine the origin ofCitrussp. pollen-contaminated moths captured in Atoka County, Oklahoma, during 1990 and the host plant feeding range of moths present in Hidalgo County, Texas, and Atoka County. Captured moths were analyzed for pollen with scanning electron microscopy.H. zeamoths captured in January 1989 in the Lower Rio Grande Valley of Texas when citrus was not blooming were not contaminated withCitrusspp. pollen. Sixty percent of those captured on 17 March 1989 during the citrus blooming period were contaminated withCitrussp. pollen. None of the moths sampled in that area between 21 March and 2 April 1990 were contaminated withCitrusspp. after a major freeze in December 1989. Citrus blooming during 1990 was drastically reduced or eliminated in South Texas, northeastern Mexico, Louisiana, and central Florida. However,Citrussp. pollen accounted for 3% of all pollen detected on migratoryH. zeacollected in Atoka County between 27 February and 24 April 1990. Lack ofCitrusspp. pollen-contaminatedH. zeain Hidalgo County after the severe freeze suggests theH. zeacontaminated withCitruspollen was collected in Atoka County during April 1990 originated elsewhere. Evaluation of calculated trajectories, synoptic weather maps, and upper-air transport opportunities suggests southern Florida, the Bahamas, Cuba, Yucatán Peninsula, and northern Central America as potential source areas 1,515 km from the capture site. This would require the moths to be in flight over water for 72 h or have very limited diurnal resting periods on seaweed (Sargassumspp.), ships, oil platforms, or the sea surface.