BIOCONTROL POTENTIAL OF HYPERA-RUMICIS (L) (COLEOPTERA, CURCULIONIDAE) ON CURLY DOCK (RUMEX-CRISPUS L)

When Hypera rumicis L. was added to caged curly dock (Rumex crispus L.), plants lost herbaceous green tissue and in the longer experiment produced no seed. Height was less for regrowth and greater evapotranspiration was seen with plants previously defoliated by this weevil. In a natural field infestation, heavily infested plants were lower in height and aerial biomass than lightly infested plants 2 to 7 m away. No seed was produced by heavily infested plants. No-choice feeding on rhubarb (Rheum rhaponticum L.) leaf disks resulted in < 2% leaf area loss. Mating adults and egg masses were observed in both caged rhubarb to which H. rumicis was added, and naturally infested rhubarb in the field, but no larvae, pupae, or cocoons were observed. Most larvae feeding on rhubarb petioles failed to develop into adults.