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Biocontrol introduction

Target pest: Ageratina riparia (Asterales: Asteraceae), mist flower

Agent introduced: Procecidochares alani (Diptera: Tephritidae), mist flower gall fly


1998, 1999, 2000

Import source:

Mexico via Hawai'i

Import notes:

Imported 1998/99 for host testing, 2000 for release.

Released: 2001

Release details:

Barton et al. (2007) - released at 34 sites across the north of the North Island from February 2001 to June 2004. In total 11,630 flies were released, with the sizes of individual releases varying from 30 to 600 flies.


Winks (2007a), Barton et al. (2007) - established readily at release sites but dispersal slow.

Landcare Research (2015i) - common now at many sites.

Impacts on target:

Winks (2007a), Barton et al. (2007) - may yet contribute to the suppression of mist flower, but too early to assess impact.

Hayes et al. (2013) - a preliminary analysis of financial savings from no longer having to control mist flower by conventional means in the upper North Island suggests a cost reduction of $80,000 to $90,000 per year from the introduction of the fungus Entyloma ageratinae and P. alani in 1998 and 2001 respectively. The net present value for this is more than $3 million with a benefit:cost ratio of 2.5:1; considered very good over a 13 year period.

Landcare Research (2015i) - in conjunction with mist flower fungus (Entyloma ageratinae) provides excellent control of mist flower.

Paynter et al. (2018) - highly parasitised by the wasp Megastigmus sp. (68% parasitism). Impacts only minor. The fungus Entyloma ageratinae, released as a biocontrol agent, controlled A. riparia before P. alani impact could be assessed.

Impacts on non-targets:

Hill (1999), EPA (2000a) - host range testing against 81 species (15 native to New Zealand, of which 12 were in the family Asteraceae) in New Zealand, Hawaii, and Australia showed P. alani is host specific. There were instances of oviposition on two species closely related to mist flower, Ageratina adenophora (Mexican devil weed) and Eupatorium rugosum, but there was no evidence of gall development in either case. The risk of P. alani attacking plants other than mist flower is low, and probably negligible.

Paynter et al. (2004) - surveys record no feeding on Ageratina adenophora, as predicted by lab tests.

Winks (2007a) - extremely unlikely to attack anything but mist flower. In lab tests eggs were very occasionally laid on the closely related Mexican devil weed (Ageratina adenophora), but the larvae never survived and galls were never formed.

EPA Applications:

EPA (1998b) - 21 Sep 1998: application by Auckland Regional Council to import into containment mist flower gall fly (Procecidochares alani), for the purpose of host specificity testing to determine its suitability as a biological control agent for mistflower (Ageratina riparia). EPA Application #NOC98002, approved with controls 14 Nov 1998.

EPA (2000a) - 18 Jun 1999: application by Auckland Regional Council to import for release the mist flower gall fly, Procecidochares alani (Steyskal), for the purpose of biological control of mist flower (Ageratina riparia). EPA Application # NOR99004, approved without controls 23 Sep 2000.


Barton J, Fowler SV, Gianotti AF, Winks CJ, de Beurs M, Arnold GC and Forrester G. (2007). Successful biological control of mistflower in New Zealand: agent establishment, impact, and benefit to the New Zealand flora. Biological control 40:370-385

EPA (1998b). Application to EPA (NOC98002) to import into containment a new organism, the mistflower gall fly (Procecidochares alani), for the purpose of host specificity testing to determine its suitability as a biological control agent for mistflower (Ageratina riparia). Environmental Protection Authority website https://www.epa.govt.nz/database-search/hsno-application-register/view/NOC98002

EPA (2000a). Application to EPA (NOR99004) to release from containment the mist flower gall fly, Procecidochares alani (Steyskal), for the purpose of biological control of mist flower (Argeratina riparia). Environmental Protection Authority website https://www.epa.govt.nz/database-search/hsno-application-register/view/NOR99004

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

Hill RL (1999). Application to EPA (NOR99004) to import for release, or release from containment, the mist flower gall fly, Procecidochares alani. Environmental Protection Authority website https://www.epa.govt.nz/assets/FileAPI/hsno-ar/NOR99004/10224dd6d2/Application-NOR99004.pdf

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

Landcare Research (2015i). Who's who in biological control of weeds? Weed Biocontrol: What's New? 73: 10-11 http://www.landcareresearch.co.nz/publications/newsletters/biological-control-of-weeds/issue-73

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, 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

Winks C (2007a). Mist Flower Gall Fly. In The Biological Control of weeds Book (Landcare Research) https://www.landcareresearch.co.nz/discover-our-research/biosecurity/weed-management/using-biocontrol/the-biological-control-of-weeds-book/