Leaf Gas Exchange and Growth Responses of Green Buttonwood and Swingle Citrumelo to Diaprepes Abbreviatus (Coleoptera: Curculionidae) Larval Feeding and Flooding

Cliff G. Martin, Catharine Mannion, Bruce Schaffer

Abstract


Effects of flooding and herbivory by Diaprepes abbreviatus L. (Coleoptera: Curculionidae) larvae on leaf gas exchange [net CO2 assimilation (A), transpiration (E), and stomatal conductance (gs)] and growth of green buttonwood (Conocarpus erectus L.) and Swingle citrumelo [Poncirus trifoliata (L.) Raf. × Citrus paradisi Macf.] trees were tested. Growth and survival of the larvae were also examined. For each plant species, there were 2 larval infestation treatments (infested and non-infested) and 2 flooding treatments (flooded and nonflooded). Beginning 6 d after larval infestation, plants were flooded in three 1-wk cycles each with 2 d of flooding followed by 5 d of non-flooding. For green buttonwood, E was higher for non-flooded than flooded plants on the third of 5 measurement dates and A and gs were higher for non-flooded than flooded plants on the fifth (final) measurement date. For Swingle citrumelo, E and gs were higher for non-infested than infested plants on the fifth (final) measurement date. Root dry weight of Swingle citrumelo was higher for flooded, infested than for non-flooded, infested plants and for non-flooded, non-infested than for non-flooded, infested plants. Larval survival rate, head capsule width, and root damage rating of Swingle citrumelo were lower for flooded than for non-flooded plants, whereas flooding did not affect larval survival or growth on green buttonwood. Thus, short-term cyclical flooding of three 2-d cycles may control D. abbreviatus larvae on Swingle citrumelo but did not control larval populations or reduce damage on green buttonwood.

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