Biocontrol introduction
Target pest: Ageratina adenophora (Asterales: Asteraceae), Mexican devil weed
Agent introduced: Procecidochares utilis (Diptera: Tephritidae), Mexican devil weed gall fly
Imported:
1958
Import source:
Mexico via Queensland, Australia
Import notes:
Cameron et al. (1989) - three shipments of P. utilis adults were received from Queensland in October 1958, on the 15th (300 sent, of which 288 survived), 21st (188 sent, 165 survived) and 29th (133 sent, 127 survived). In total, 621 were sent, 580 survived and were released.
Landcare Research (2007a) - specimens of P. utilis from Brisbane, Australia, dated 1958, are present in the Biological Control Voucher Collection of the New Zealand Arthropod Collection [indicating an importation from that source in that year].
Released:
1958
Release details:
Cameron et al. (1989) - five hundred and eighty adults were released in October 1958 within 72 hours of being sent from Brisbane (and one day after arriving in New Zealand) at two sites near Colville on the Coromandel Peninsula in the North Island. Three releases were made, from shipments arriving on the 15th (288 released), 21st (165 released) and 29th (127 released). After establishment on the Coromandel Peninsula, relocations were made from that region in 1963 to all large stands of A. adenophora in New Zealand.
Establishment:
Cameron et al. (1989) - within three months of release, galls could be found 45 m away from one of the release sites, and by July 1959, 280 m away. By 1963 P. utilis had spread throughout the Coromandel Peninsula. After relocations from that region in 1963, P. utilis established in all large stands of A. adenophora in New Zealand.
Impacts on target:
Cameron et al. (1989) - it appears that P. utilis caused significant damage to stands of A. adenophora for approximately five years after its introduction. The severity of P. utilis attack recorded in the 10 years following its release suggests the decline in importance of A. adenophora in that time may have been caused by P. utilis, assisted by the accidentally-introduced fungus Ragnhildiana perfoliati [see the Ragnhildiana perfoliati introduction entry], but no detailed evaluation has been carried out and changes in land management may have also played a part. For many years P. utilis appeared to be free of parasitoids in New Zealand, but in the early 1970s the chalcid parasitoid Megastigmus sp (first recorded in New Zealand in 1972) was found parasitising it at levels of up to 71%. The abundance of P. utilis today appears less than observed soon after its release; this may reflect decreased abundance of A. adenophora or the effects of the parasitoid. Ageratina adenophora remains a common plant in the North Island but is less economically important now than in 1957, and is rarely a problem on agricultural land.
Landcare Research (2008d) - a nationwide survey and literature review investigating the toll that parasitism is taking on weed biocontrol agents has found several agents, including P. utilis, for which parasitism levels of more than 60% have been measured. Procecidochares utilis is parasitised by one exotic species: Megastigmus sp. [a chalcid wasp]. Biocontrol agents are likely to be adversely affected by such levels of parasitism; however, there is anecdotal evidence that P. utilis and a fungus, Ragnhildiana perfoliati [see the Ragnhildiana perfoliati introduction entry], significantly suppress A. adenophora.
Hayes et al. (2013) - Mexican devil weed is not a serious problem today; this can be attributed, at least in part, to biocontrol agents [P. utilis was deliberately released, the fungus Ragnhildiana perfoliati probably accidentally introduced with it].
Landcare Research (2014f) - Ageratina adenophora is generally considered to be a minor weed in New Zealand. It is believed that an introduced gall fly (Procecidochares utilis) and the leaf blight fungus R. perfoliati are exerting some level of control, although this has not been formally measured.
Landcare Research (2015i) - initially P. utilis had a high impact but the impact is now reduced considerably by an Australian parasitic wasp.
Paynter et al. (2018) - highly parasitised by the wasp Megastigmus sp. (up to 100% parasitism) and galls also gnawed or pecked open by an unknown predator. The impact of P. utilis is unclear; it may contribute to partial control, but it's importance relative to the fungus Ragnhildiana perfoliati is unknown.
Paynter (2024) - factors influencing the success of weed biocontrol agents released and established in New Zealand were investigated. Each agent’s impact on the target weed in New Zealand was assessed as ‘heavy’, ‘medium’, ‘variable’, ‘slight’ or ‘none’, where a ‘heavy’, ‘medium’ or ‘variable’ impact have all been observed to reduce populations or percentage cover of their target weed in all or part of their respective target weed ranges in New Zealand. Results showed that: (i) agents that are highly damaging in their native range were almost invariably highly damaging in New Zealand; (ii) invertebrate agents with a closely related ‘native analogue’ species are susceptible to parasitism by the parasitoids that attack their native analogues and failed to have an impact on the target weed, and (iii) agent feeding guild helped predict agent impact - in particular, agents that only attack reproductive parts of the plant (e.g., seed and flower-feeders) are unlikely to reduce weed populations. The impacts of P. utilis, a gall-forming fly, in its native range are unknown (no reports could be found), it does not have a New Zealand native ecological analogue and its impact in New Zealand is assessed as ‘variable’.
Impacts on non-targets:
Paynter et al. (2004) - surveys record no feeding on Ageratina riparia (mist flower), consistent with laboratory specificity testing, which predicted no non-target feeding.
References
Cameron PJ, Hill RL, Bain J, 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.
Hayes L, Fowler SV, Paynter Q, Groenteman R, Peterson P, Dodd S, Bellgard S (2013). Biocontrol of weeds: achievements to date and future outlook. In: Dymond JR (ed) Ecosystem services in New Zealand: conditions and trends. Manaaki Whenua Press, Lincoln, pp 375-385 https://www.landcareresearch.co.nz/__data/assets/pdf_file/0005/77054/2_8_Hayes.pdf
Landcare Research (2007a). New Zealand Arthropod Collection (NZAC) Biological Control Voucher Collection. Landcare Research website [Updated 2020] https://www.landcareresearch.co.nz/tools-and-resources/collections/new-zealand-arthropod-collection-nzac/databases-and-holdings/new-t2-landing-page/
Landcare Research (2008d). Parasitism - a major or minor cause of biocontrol failure? What’s New In Biological Control of Weeds? August 2008, 45: 4-5 https://www.landcareresearch.co.nz/assets/Publications/Weed-biocontrol/wtsnew45.pdf
Landcare Research (2014f). International weed biocontrol symposium. What’s New In Biological Control of Weeds? May 2014, 68: 2-4 https://www.landcareresearch.co.nz/assets/Publications/Weed-biocontrol/Whatsnew68.pdf
Landcare Research (2015i). Who's who in biological control of weeds? Weed Biocontrol: What's New? 73: 10-11 https://www.landcareresearch.co.nz/assets/Publications/Weed-biocontrol/Weed_Biocontrol_73.pdf
Paynter Q (2024). Prioritizing candidate agents for the biological control of weeds. Biological Control, Volume 188, January 2024, Article Number 105396 https://doi.org/10.1016/j.biocontrol.2023.105396
Paynter Q, Fowler SV, Groenteman R. (2018). Making weed biological control predictable, safer and more effective: perspectives from New Zealand. BioControl 63: 427-436 (first published online 8 Aug 2017) https://doi.org/10.1007/s10526-017-9837-5 https://link.springer.com/article/10.1007/s10526-017-9837-5
Paynter QE, Fowler AH, Gourlay AH, Haines ML, Harman HM, Hona SR, Peterson PG, Smith LA, Wilson-Davey JRA, Winks CJ, Withers TM (2004). Safety in New Zealand weed biocontrol: A nationwide survey for impacts on non-target plants. New Zealand Plant Protection 57: 102-107 https://journal.nzpps.org/index.php/nzpp/issue/view/vol57
