Relationships Between Patterns of Defoliation by the Fruittree Leafroller (Lepidoptera: Tortricidae) and Foliage Morphology of Baldcypress in Forested Wetlands of Louisiana

Baldcypress, Taxodium distichum (L.) Richard, has been threatened recently by a new insect herbivore, the fruittree leafroller, Archips argyrospila (Walker) (Lepidoptera: Tortricidae). Baldcypress foliage varies from long-leaved, open-faced branchlets with leaves arranged in two-ranked fashion to short-leaved, appressed, imbricate branchlets. Field surveys revealed that the tallest trees contained 72 – 85% appressed foliage, whereas intermediate and small-sized trees contained 55–92% open type foliage. Over a three-year period, open morphology trees repeatedly exhibited significantly higher levels of defoliation (percentage of crown loss) by the fruittree leafroller, compared with appressed morphology trees. There was no ovipositional preference (number of egg masses) associated with morphology type. Differences in defoliation levels, therefore, were attributed to morphologically related influences on foliage suitability for larval stages.