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Biocontrol introduction

Target pest: Jacobaea vulgaris (Asterales: Asteraceae) = Senecio jacobaea, ragwort

Agent introduced: Botanophila jacobaeae (Diptera: Anthomyiidae) = Pegohylemyia jacobaeae, ragwort seed fly

Imported: 1928-1939

Import source: England

Import notes: Cameron et al. (1989) - imported as puparia along with the seedfly Botanophila seneciella.

Released: 1936-1940

Release details: Gourlay (2007) - released at Nelson and a number of North Island sites.

Establishment: Gourlay (2007) - established on the central volcanic plateau, Bay of Plenty and and southern Waikato.

Impacts on target: Gourlay (2007) - does not impact seed production enough to reduce ragwort populations. A high proportion of first seedheads are infested, but this declines throughout the summer when the majority of plants flower. Studies show 80-90% of seeds escape attack. Paynter et al. (2017) - asynchrony with host plant limits effectiveness.

Impacts on non-targets: Paynter et al. (2004) - surveys record no feeding on Senecio bipinnatisectus and S. vulgaris, consistent with lab tests that predicted no non-target feeding.


Cameron PJ, Hill RL, Bain J and Thomas WP (1989). A Review of Biological Control of Invertebrate Pests and Weeds in New Zealand 1874-1987. Technical Communication No 10. CAB International Institute of Biological Control. DSIR Entomology Division. 424p.

Gourlay H (2007). Ragwort Seedfly. In the Biological Control of Weeds Book (Landcare Research) http://www.landcareresearch.co.nz/research/biocons/weeds/book/documents/Ragwort_SeedFly.pdf

Landcare Research (2007). New Zealand Arthropod Collection (NZAC) Biological Control Voucher Collection. http://www.landcareresearch.co.nz/resources/collections/nzac/holdings/biological-control-voucher-collection

Paynter Q, Fowler SV, Groenteman R. (2017). Making weed biological control predictable, safer and more effective: perspectives from New Zealand. BioControl (First online: 8 Aug 2017). https://doi.org/10.1007/s10526-017-9837-5

Paynter, Q.E., Fowler, A.H., Gourlay, M.L., Haines, M.L., Harman, H.M., Hona, S.R., Peterson, P.G., Smith, L.A., Wilson-Davey, J.R.A., Winks, C.J. and Withers, T.M. (2004). Safety in New Zealand weed biocontrol: A nationwide survey for impacts on non-target plants New Zealand Plant Protection 57: 102-107