SURVIVAL OF DIAPREPES ABBREVIATUS (COLEOPTERA: CURCULIONIDAE) LARVAE ON GREEN BUTTONWOOD TREES IN FLOODED MARL SOIL AND POTTING MEDIUM

Survival of Diaprepes root weevil Diaprepes abbreviates (L.) (Coleoptera: Curculionidae) larvae was assessed in flooded marl soil and a flooded nursery potting medium with green buttonwood (Conocarpus erectus L., Combretaceae) as a food source for the larvae. Root-zone flooding may be a viable control option for flood-tolerant ornamental plants including buttonwood. Significantly more larvae survived after 38 d in non-flooded than in flooded marl soil. Similarly, more larvae survived in non-flooded than in flooded potting medium; no larvae were recovered from flooded potting medium. Larval survival rates were significantly higher in flooded marl soil than in flooded potting medium, but there was no difference in survival between non-flooded marl soil and non-flooded potting medium. Larvae recovered from flooded marl soil had significantly smaller head capsule widths and probably were at least 1 instar younger than larvae recovered from non-flooded marl soil or non-flooded potting medium. In summary, flooding marl soil or potting medium reduced survival, and in marl soil flooding slows the growth of D. abbreviatus larvae.