Leaf Gas Exchange and Damage of Mahogany and Pond Apple Trees from Adult Diaprepes abbreviatus (Coleoptera: Curculionidae) Feeding and Soil Flooding

Cliff G. Martin, Catharine Mannion, Bruce Schaffer

Abstract


The effects of feeding on leaves by adult Diaprepes root weevil, Diaprepes abbreviatus L. (Coleoptera: Curculionidae), and flooding on leaf gas exchange [net CO 2 assimilation (A), transpiration (E), and stomatal conductance (gs)], plant growth (root, stem, leaf, and total plant dry weights, stem diameter, and plant height) and adult host plant preference (feeding damage and oviposition) were determined on mahogany, Swietenia mahagoni Jacq., and pond apple, Annona glabra L., trees in outdoor screen cages. Flooding reduced leaf gas exchange, plant growth, and D. abbreviatus feeding damage of mahogany trees. Leaf gas exchange of infested and non-infested trees of both mahogany and pond apple were similar except for one measurement date for mahogany. Leaf dry weights were greater for non-infested than infested mahogany trees. There was no effect of infestation on dry weights of pond apple trees. Based on feeding injury to leaves, adults preferred non-flooded to flooded mahogany trees. The lack of response in leaf damage or oviposition to flooding for pond apple was attributable to the avoidance of leaves by adult D. abbreviatus of this plant species despite it being a host for root weevil larvae. The results indicate that while flooding of the root zone adversely affects growth and physiology of mahogany trees, it does not predispose trees to greater damage from adult D. abbreviatus. In fact, adult insect damage was greater for non-flooded than flooded trees. Pond apple was not greatly affected by root zone flooding and was not a preferred host of adult D. abbreviatus under flooded or non-flooded conditions.

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