title: Effect of root feeding by Diaprepes abbreviatus (Coleoptera: Curculionidae) larvae on leaf gas exchange and growth of three ornamental tree species.
abstract: Diaprepes abbreviatus L. (Coleoptera: Curculionidae), feeds on a variety of ornamental plants grown in southern Florida. Studies were conducted to evaluate the effects of root feeding by D. abbreviatus larvae on leaf gas exchange and growth of three ornamental tree species commonly grown in southern Florida that are known hosts of this weevil: green buttonwood, Conocarpus erectus L.; live oak, Quercus virginiana Mill.; and pygmy date palm, Phoenix roebelenii O'Brien. These hosts were grown in containers and infested with weevil larvae. Net CO2 assimilation, transpiration, and stomatal conductance of CO, were measured monthly. Leaf, stem, and root fresh and dry weights of each species also were determined. In one of two tests, larval root feeding significantly reduced net CO2 assimilation, transpiration, and stomatal conductance of CO2 of infested green buttonwood trees. Leaf gas exchange of live oak was not affected by larval infestation. In addition to testing cumulative effects of multiple infestations of larvae, the effects of incremental infestations on leaf gas exchange and fresh and dry weights also were tested for each plant species. Net CO2 assimilation, transpiration, stomatal conductance of CO2, and dry weights of green buttonwood were reduced as a result of larval root feeding, whereas there was no effect of incremental larval infestations on leaf gas exchange of live oak or pygmy date palm within the experimental time frame. There was no effect of incremental larval infestations on dry weights of live oak, but leaf, stem, and dry root weight of pygmy date palm were lower for infested plants than for noninfested plants. Overall, green buttonwood was more susceptible to larval root feeding damage than either live oak or pygmy date palm.
authors.affiliation: Tropical Research and Education Center, University of Florida, 18905 SW 280 Street, Homestead, FL 33031, USA.
authors.forename: Alex P
authors.initials: AP
authors.lastname: Diaz
authors.forename: Catharine
authors.initials: C
authors.lastname: Mannion
authors.forename: Bruce
authors.initials: B
authors.lastname: Schaffer
mesh_terms: D000818:Animals; D028023:Arecaceae / Q000254:growth & development / Q000469:parasitology; D001517:Coleoptera / Q000502:physiology*; D029764:Combretaceae / Q000254:growth & development / Q000469:parasitology; D006790:Host-Parasite Interactions; D007814:Larva / Q000502:physiology*; D018515:Plant Leaves / Q000502:physiology*; D018517:Plant Roots / Q000254:growth & development / Q000469:parasitology*; D029963:Quercus / Q000254:growth & development / Q000469:parasitology; D014197:Trees / Q000254:growth & development / Q000469:parasitology*