Tiphia vernalis

Below-ground soil environments where scarabaeid beetle larvae occur; established in agricultural areas, nurseries, turfgrass, golf courses, sod farms, and residential lawns. Survey sites in Connecticut included managed landscapes with high Japanese beetle populations.

Native to Korea; introduced to and established in eastern North America including Ohio, Connecticut, Missouri, and Kentucky. Detected at multiple survey sites across Connecticut and found in ornamental tree nurseries in northern Ohio.

Adult activity detected from July through September in Connecticut, with peak captures in August. Seasonal occurrence noted in Kentucky, with phenology tied to host larval availability.

• Popillia japonica - parasitoidJapanese beetle; primary target of introduction. Females parasitize third-instar larvae.
• Anomala orientalis - parasitoidOriental beetle; up to 31% parasitism rate observed in Ohio nurseries.
• Cyclocephala spp. - parasitoidMasked chafers; host association documented for related species Tiphia pygidialis, with T. vernalis noted in same habitats.

Females parasitize scarabaeid larvae by locating grubs in soil, stinging them into temporary paralysis, and laying eggs externally on the host. Larval wasps feed externally on the grub, eventually killing it. Developmental timing is synchronized with host larval stages, particularly third-instar grubs.

Females engage in directed below-ground movement along residual body odor trails made by dragging host grubs through soil. Trail-following behavior is elicited by contact kairomones in grub frass, with stronger responses to host frass than non-host frass. The combination of host frass and body odor produces the strongest trail-following response. Presence of a grub is not necessary for trail-following to occur.

Biological control agent of invasive scarab beetles, particularly Japanese beetle. Contributes to population suppression of soil-dwelling scarab larvae in managed landscapes. Parasitism rates of up to 60% have been documented for Japanese beetle populations in some Ohio nurseries.

Intentionally introduced to North America by USDA entomologists in the 1920s–early 1930s for classical biological control of Japanese beetle. Now naturalized and established in multiple states. Provides non-chemical pest management option in turfgrass, nursery, and agricultural systems.

• Tiphia pygidialisAlso a parasitoid of scarabaeid grubs (masked chafers), but shows species-specific responses to host kairomones. T. vernalis can be distinguished by host association with Popillia japonica and Anomala orientalis versus Cyclocephala hosts for T. pygidialis.

• parasitoid
• biological control
• Japanese beetle
• scarabaeidae
• soil-dwelling
• introduced species
• kairomone
• trail-following

• BugGuide
• Wikipedia
• iNaturalist taxon
• Bug Eric: What is, and is NOT, a Japanese Beetle
• Friday Flower – Ozark Witch Hazel | Beetles In The Bush
• Life History of Oriental Beetle and Other Scarabs, and Occurrence of Tiphia vernalis in Ohio Nurseries
• Kairomones from scarabaeid grubs and their frass as cues in below‐ground host location by the parasitoids Tiphia vernalis and Tiphia pygidialis
• Survey of Tiphia Vernalis (Hymenoptera: Tiphiidae), a Parasitoid Wasp of Popillia japonica (Coleoptera: Scarabaeidae), in Connecticut
• Biology ofTiphia pygidialis(Hymenoptera: Tiphiidae), a Parasitoid of Masked Chafer (Coleoptera: Scarabaeidae) Grubs, with Notes on the Seasonal Occurrence ofTiphia vernalisin Kentucky
• Preovipositional Behaviors of <I>Tiphia pygidialis</I> and <I>Tiphia vernalis</I> (Hymenoptera: Tiphiidae), Parasitoids of White Grubs (Coleoptera: Scarabaeidae)
• Establishment of Tiphia vernalis (Hymenoptera: Tiphiidae), a Naturalized Parasitoid of the Japanese Beetle, Popillia japonica (Coleoptera: Scarabaeidae), in Meramec State Park, Sullivan, Missouri, USA