Location: Biological Control of Pests ResearchTitle: Potential utilization of Stethorus punctillum to control Tetranychus cinnabarinus on strawberry in greenhouses and high tunnels
Submitted to: Entomological Society of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/5/2019
Publication Date: N/A
Technical Abstract: The effectiveness of mass-reared ladybird beetles to control spider mites in greenhouse crop cultivation is poorly known. The hypothesis that the spider mite predatory ladybird Stethorus (S.) punctillum (Coleoptera: Coccinellidae) can control the carmine spider mite Tetranychus (T.) cinnabarinus (Acari: Tetranychidae) was tested. S. punctillum adults were purchased from a biocontrol company and released in a climate-controlled greenhouse to combat a natural infestation of T. cinnabarinus. Predator and pest populations were monitored weekly via non-destructive visual observations. Results indicated that T. cinnabarinus population density declined drastically in two weeks after releasing S. punctillum. In 3-4 weeks, post-release, T. cinnabarinus density was often less than 1 nymph (or adult) per leaflet/plant. The presence of S. punctillum offspring (larvae and pupae) on plants confirmed that released adults were reproductively active. Eventually, released adults and their offspring (adults) died, because of a lack of food, i.e., spider mites. Consequently, T. cinnabarinus population density rebounded. Thus, repeated releases of S. punctillum were necessary to maintain T. cinnabarinus at low densities for extended time periods. In conclusion, this study demonstrates the effectiveness of S. punctillum, but multiple releases are necessary to prevent T. cinnabarinus resurgence.