Paralobesia viteana (Clemens) (Lepidoptera:Tortricidae), the grape berry moth, is a major economic pest of cultivated grapes in eastern North America. Although pheromone lures and traps are available for monitoring this pest, male moth captures in these traps decline as the infestation risk increases through the multiple generations that occur during a season. This makes it difficult to use traps to monitor this pest's population dynamics and complicates the timing of pest management

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... To test whether seasonal changes in the plant canopy affect captures of male grape berry moth, we manipulated grapevine fruit density or canopy structure in multiple growing seasons, and measured male captures under these conditions. Removal of either 50 or 100% of the fruit clusters from vineyard plots did not consistently affect captures in pheromone traps. In 2013, significantly more males were captured in traps in plots where clusters were not removed compared to captures in traps in plots where 50 or 100% of clusters were removed, but this effect was not seen in 2014 or 2015. In the first year of a separate experiment, there were no differences in male captures between unaltered canopies and those held open artificially. In subsequent years we detected significant differences in male captures for some sample periods, and there was a prevailing trend of arithmetically more male captures in unaltered than in open canopies. We conclude that fruit presence, fruit density and canopy fullness do not reduce male P. viteana captures late in the season, and that other factors are driving this pattern.