| The objective of this research was to determine effects of herbivory by Diaprepes abbreviatus (L.) (Coleoptera: Curculionidae) and flooding on the physiology and growth of select ornamental plant species in south Florida. Susceptibility to larval feeding was greatest for green buttonwood and Surinam cherry, followed by mahogany, then pond apple. Pond apple supported Diaprepes larvae to pupation and represents a new host plant and family (Annonaceae). Under flooded conditions and/or planted in marl soil, pond apple performed optimally, whereas buttonwood, mahogany, and Surinam cherry had reduced leaf gas exchange and growth. Surinam cherry had the greatest "preference" of potting medium over marl soil, followed by buttonwood, then mahogany, then pond apple. Pond apple and buttonwood tolerated flooding the best, followed by mahogany, then Surinam cherry. When flooded 38 days, larval survival was lowest in flooded potting medium, followed by flooded marl soil, then non-flooded marl soil and non-flooded potting medium. Larvae from flooded marl soil had smaller head capsule widths and instars than non-flooded larvae in marl soil or potting medium. Flooding more than soil type influenced larval survival, though both factors affected it. Effects on leaf gas exchange and plant growth were cumulative for flooding in green buttonwood and for infestation in Swingle citrumelo. Contrary to similar studies, buttonwood was not flood-adaptated and was the most flood-sensitive species, possibly because of short flood periods, while Swingle citrumelo was the most sensitive species to larval feeding. Flooding with three 2-d cycles seemed more likely to control larvae in Swingle citrumelo than in green buttonwood. In an adult Diaprepes study, green buttonwood adapted to flooding rendering leaf gas exchange, growth, and adult preference the same under flooded and non-flooded conditions. For Surinam cherry and mahogany, leaf gas exchange, growth, and adult feeding damage in infested cages was higher for non-flooded than flooded plants. Pond apple had the lowest adult feeding damage and egg clusters per plant, hence, it seems unlikely to become infested. Surinam cherry was most susceptible to flooding, followed by mahogany, with buttonwood and pond apple least affected, whereas buttonwood and mahogany were most susceptible to adult Diaprepes, followed by Surinam cherry, then pond apple. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)... |
