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Biocontrol introduction

Target pest: Alternanthera philoxeroides (Caryophyllales: Amaranthaceae), alligator weed

Agent introduced: Macrorrhinia endonephele (Lepidoptera: Pyralidae) = Vogtia malloi, Arcola malloi, alligator weed moth


1982, 1983, 1984, 1987

Import source:

South America via Florida and Australia

Import notes:

Cameron et al. (1989) - the first shipment [as Vogtia malloi, subsequently reclassified as Arcola malloi and then Macrorrhinia endonephele - see taxonomic note in 'General comments' section] was received from Brisbane in January 1982, consisting of alligator weed stems containing larvae and pupae. This shipment was destroyed because many stems were rotten and the larvae infected with the fungus Aspergillus flavus. The second shipment was received from Sydney in December 1983; the emerging insects bred prolifically and after more than two generations in quarantine larvae were released in the field. However, these larvae were the progeny of only 47 imported individuals, so to increase variability, a third shipment was requested, arriving from Sydney in March 1984. Some of these were found to be infected by a microsporidian and were destroyed; the progeny of the others were released. However, no released M. endonephele survived their first winter in the field, and in March 1987 further pupae were collected near Sydney. From the resulting colony, only offspring from adults in which no infection was found were released.



Release details:

Cameron et al. (1989) - between late-February and early-April 1984 infested stems containing approximately 10,000 larvae from the second importation (see ‘Import notes’ section) were released at four sites near Woodhill (Auckland), Dargaville and Whangarei (Northland). In early spring 1984 further field releases were made from the third importation. Between August 1987 and February 1988, 12 releases, each consisting of approximately 5,000 eggs and/or neonate larvae or 1,000-2,000 second or third instar larvae, from the fourth importation, were made at ten sites in Northland and Auckland.


Cameron et al. (1989) - none of the 1984 releases survived their first winter in the field. Each of the ten 1987-88 release sites were visited the following autumn and M. endonephele was recovered from seven of them. At five of these sites, at least one field generation had been completed. However, it is too early yet to determine if they have successfully established.

Harman et al. (1996) - Macrorrhinia endonephele has established well.

Winks (2007c)/Gourlay (2021d) - patchily established in Northland and Auckland but not as common as the alligator weed beetle (Agasicles hygrophila).

Impacts on target:

Harman et al. (1996) - Macrorrhinia endonephele is suppressing areas of weed.

Winks (2007c)/Gourlay (2021d) - large populations cause considerable damage to alligator weed and give control in some lakes and ponds. Larvae are unable to control the weed in running water that is regularly flooded and are not suited to low temperatures. Inhabits terrestrial populations of alligator weed but cannot exert sufficient control there.

Landcare Research (2017e) - it is estimated that the biocontrol agents (M. endonephele and the beetle Agasicles hygrophila) are saving around $505,000 per year in Auckland and Northland, with a resulting benefit to cost ratio of 101:1.

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. Damaging impacts of M. endonephele, a stem-boring moth, have been reported in its native range (although considerable damage has only been reported from one stand of A. philoxeroides), 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 M. endonephele only feeding on the target plant, although laboratory tests predicted minor non-target damage on Alternanthera sessilis.

General comments:

Taxonomic note (31 December 2023) - Pastrana (1961) established the monotypic genus Vogtia Pastrana and described V. malloi Pastrana from Buenos Aires, Argentina. Shaffer (1995) proposed Arcola as a replacement name for Vogtia (preoccupied by Vogtia Kölliker, 1853, Cnidaria). Hayden & Landry (2020) recognised Arcola malloi (Pastrana, 1961) as a junior subjective synonym of Macrorrhinia endonephele (Hampson, 1918), and synonymised the genera Vogtia Pastrana, 1961 and Arcola Shaffer, 1995 with Macrorrhinia Ragonot, 1887. (All information from Hayden & Landry 2020.)


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.

Gourlay H (2021d). Alligator weed moth: Marcrorrhinia endonephele. The Biological Control of Weeds Book - Te Whakapau Taru: A New Zealand Guide (Landcare Research) [Update of Winks (2007c)] https://www.landcareresearch.co.nz/discover-our-research/biodiversity-biosecurity/weed-biocontrol/projects-agents/biocontrol-agents/alligator-weed-moth/

Harman HM, Syrett P, Hill RL, Jessep CT. (1996). Arthropod introductions for biological control of weeds in New Zealand, 1929 - 1995. New Zealand Entomologist, 19(1): 71-80

Hayden JE, Landry JF (2020). Arcola malloi (Pastrana), the alligatorweed stemborer, a new synonym of Macrorrhinia endonephele (Hampson) (Lepidoptera: Pyralidae: Phycitinae). Insecta Mundi 0768: 1-25 https://journals.flvc.org/mundi/article/view/122883

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 (2017e). Alligator weed: a financial snapshot. Weed Biocontrol: What's New? 81: 4 http://www.landcareresearch.co.nz/publications/newsletters/biological-control-of-weeds/issue-81

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 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

Winks C (2007c). Alligator weed moth: Marcrorrhinia endonephele. The Biological Control of Weeds Book - Te Whakapau Taru: A New Zealand Guide (Landcare Research) [Updated 2021 - see Gourlay (2021d)] https://www.landcareresearch.co.nz/discover-our-research/biodiversity-biosecurity/weed-biocontrol/projects-agents/biocontrol-agents/alligator-weed-moth/