Citrus pollen retention by adult Helicoverpa zea (Lepidoptera: Noctuidae) after exposure to citrus blooms.

Abstract

In previous migration studies, the presence of citrus pollen on adult Helicoverpa zea (Boddie), in conjunction with synoptic weather systems and 72-h backtrack trajectories, were used to identify source zones of migrants. However, data are lacking regarding the retention of citrus pollen for 72-h by H. zea adults. We exposed laboratory-reared and feral H. zea adults to citrus blooms for a 12-h period in laboratory and field studies and examined insects for the external presence of citrus pollen (i.e., marking) at 12-h intervals through 72 h. Citrus pollen marking was higher for females than males at the time of removal from citrus blooms. Fifteen to 100% of H. zea adults were marked with citrus pollen at 72 h after removal from citrus blooms. Pollen loads ranged from rare (< or = 10 pollen grains) to moderate (101 to 500 grains) during 1995; only rare and light (11 to 100 grains) pollen loads were detected during 1996. Citrus pollen marking of H. zea adults through 72 h after removal from citrus blooms has not been previously confirmed. These data provide evidence of H. zea using available blooming citrus groves in the absence of a host crop and will impact current perspectives regarding H. zea and host plant interactions and timing of pest management tactics.