|Strawberry Root Weevil|
|AN ABSTRACT OF THE THESIS
Donald Brian Emenegger
for the degree of Master of Science in Entomology
presented on February 13 1976,
Oregon State University
Title: BIOLOGY AND POPULATION REGULATION OF THE STRAWBERRY ROOT WEEVIL, OTIORHYNCUS OVATUS ( L . ) COLEOPTERA: CURCULIONIDAE
The life history of the strawberry root weevil, Otiorhynchus ovatus (L. ), on peppermint was studied in the Willamette Valley of Oregon to provide the information necessary to develop effective control measures.
Adult weevils emerged from the soil from late May until mid-June and were active in the field until late July. Active feeding by adults occurred between one and seven hours after sunset. No significant migration for the purpose of feeding or oviposition was observed and no adults were found to overwirlter. Oviposition occurred from mid-June until September in the laboratory but ceased by late July in the field. Egg incubation periods averaged 13 days in the laboratory with fertility rates of 70 to 80 percent. Fertility declined substantially in the laboratory after late July. Larvae occurred in the peppermint root systems from early June until late May of the following year with pupation occurring from mid-April until the first of June. Carabid beetles, Omaseus melanarius, were found to be predaceous on adult strawberry root weevils but no other predators or parasites were discovered. Laboratory studies indicate that desiccation is a potential mortality factor acting on all immature stages.