Citrus pollen marking and population activity of adult Helicoverpa zea (Boddie) (Noctuidae: Lepidoptera) in the lower Rio Grande Valley of Texas

Helicoverpa zea activity was documented in citrus groves of the Lower Rio Grande Valley. H. zea behavior included feeding, flying, mating, and resting postures. Results agree with certain previous works on H. zea behavior in corn and cotton and expand the knowledge base on nocturnal behavior of this pest in non-host crops.;Scanning electron microscopy indicates citrus pollen grains can be readily identified with distinguishing morphological characteristics among species. These data contribute to the current knowledge base on citrus pollen morphology. Feral and laboratory-reared H. zea adults exposed to citrus blooms in laboratory and field conditions verified H. zea feeding behavior in citrus groves and provides insight regarding pollen marking and retention rate. Males and females were marked with citrus pollen after 12-h exposure to citrus blooms. Insects retained pollen through 72 hours after removal from citrus blooms. These data aid in documenting movement of H. zea to more temperate areas where citrus is not grown.;The Lower Rio Grande Valley has ∼14,250 ha of citrus plantings on which empirical modeling suggests ∼171,000 to 1,951,000 H. zea adults utilize citrus groves as foraging resources and reproductive activity. During 1994 and 1995, ∼94% and 73%, respectively, of adults captured in citrus groves were marked with citrus pollen. H. zea adults collected in sex pheromone traps in the Lower Rio Grande Valley and locations ≤ 661 km north of the Lower Rio Grande Valley support previous studies using citrus pollen as a natural marker. These data demonstrate the utility of citrus pollen as a natural marker for migratory lepidopterous field crop pests. These results provide further insight regarding H. zea nocturnal behaviors and population dynamics in the Lower Rio Grande Valley with emigration to more temperate areas.