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EPA staff report

Biological control agents for Tradescantia fluminensis November 2012

Advice to the decision making committee on application APP201362: – To import and

release the yellow leaf spot fungus Kordyana sp. as a biological control agent for the

weed tradescantia (Tradescantia fluminensis) under section 34 of the Hazardous

Substances and New Organisms Act 1996

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EPA staff advice: APP201362

November 2012

Executive Summary and Recommendation

In September 2012, Auckland Council made an application to the Environmental Protection

Authority (EPA) seeking to import and release the yellow leaf spot fungus Kordyana sp. as a

biological control agent for the weed tradescantia (Tradescantia fluminensis).

Host range testing shows that no native and/or taonga plants will be adversely affected by this

agent, and we recommend that it be approved for release.

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Table of Contents

Executive Summary and Recommendation ........................................................................................ 2

Table of Contents .................................................................................................................................. 3

1. The application process ............................................................................................................. 4

Purpose of this document .............................................................................................................. 4

Submission process ...................................................................................................................... 4

Application summary ..................................................................................................................... 4

2. The organisms proposed for release ........................................................................................ 5

3. Host-range testing ....................................................................................................................... 6

4. Minimum standards .................................................................................................................... 9

5. Adverse effects .......................................................................................................................... 12

6. Positive effects .......................................................................................................................... 13

7. Conclusion on adverse and positive effects .......................................................................... 15

8. Effects on Māori and their culture and traditions and the principles of the Treaty

of Waitangi (Te Tiriti o Waitangi) ........................................................................................................ 16

9. Recommendation ...................................................................................................................... 19

10. Submissions .............................................................................................................................. 20

11. Comments from DOC and MPI ................................................................................................. 20

12. References ................................................................................................................................. 21

Appendix 1 ........................................................................................................................................... 22

Appendix 2 ........................................................................................................................................... 27

Appendix 3 ........................................................................................................................................... 28

Appendix 4. .......................................................................................................................................... 30

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1. The application process

Purpose of this document

1.1. This document has been prepared by EPA staff; Asela Atapattu (Manager, New

Organisms), Kate Bromfield (Senior Advisor, New Organisms), and Linda Faulkner

(General Manager, Māori Policy and Operations), to advise the HSNO decision making

committee on the results of our risk assessment of an application to import the yellow

leaf spot fungus Kordyana sp. as a biological control agent for the weed tradescantia

(Tradescantia fluminensis). The document discusses information provided in the

application and other readily available sources.

Submission process

1.2. Application ERMA201362 was publicly notified as required by section 53(1)(b) of the

Hazardous Substances and New Organisms (HSNO) Act. The 30 working day

notification period began on 12 September 2012 and closed on 25 October 2012.

1.3. Submitters were asked to provide information, make comments and raise issues,

particularly with regard to, but not limited to the following matters:

methodology of the host-range testing;

adverse effects1, especially adverse effects not identified in the application, and

positive effects2, especially positive effects not identified in the application.

Application summary

1.4. Auckland Council makes this application on behalf of the National Biocontrol Collective,

a collective comprising 13 regional councils and the Department of Conservation

(DOC). Landcare Research was the science provider for the application, and

contracted Professor Robert Barreto (Departamento de Fitopatologia, Universidade

Federal de Viçosa, Brazil) to determine if the yellow leaf spot fungus would be suitable

to release in New Zealand. Landcare Research also contracted Jane Barton to provide

expert input on plant pathology, and Richard Hill & Associates to prepare the

application and manage the application process on behalf of Auckland Council.

1 Adverse effects can include any risks and costs associated with approving the release of these organisms.

2 Positive effects can include any benefits associated with approving the release of these organisms.

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1.5. This application seeks approval to introduce a white smut fungus – the Brazilian yellow

leaf spot fungus (Kordyana sp.) – as a biocontrol agent of tradescantia. The EPA has

already approved the introduction of the chrysomelid beetles Neolema ogloblini

(approval code NOR000043), Lema basicostata and Neolema abbreviata (approval

code ERMA200683) as biocontrol agents for tradescantia. These feed on the leaves,

stems and shoot tips of the weed respectively. The applicant considers that leaf

infection by Kordyana sp. will complement the effects of these insects.

1.6. Tradescantia (sometimes called wandering Willie or wandering Jew) forms thick mats

at many forest margins, in forest clearings, and on stream margins in northern New

Zealand. Mats overshadow and kill low-growing plants, including native tree seedlings

that are essential for forest regeneration. Without intervention, heavy tradescantia

infestations may cause the eventual destruction of small forest remnants and shrinkage

of larger stands over time as forest margins retreat. Tradescantia is a prominent weed

in suburban backyards and civic parks, and commonly causes severe allergic reactions

in dogs that walk in it. Tradescantia has no significant beneficial attributes.

2. The organisms proposed for release

Background on Kordyana sp.

2.1. Kordyana sp. is a white smut fungus that causes distinctive yellow spots on infected

leaves. Molecular analysis has shown that this organism has the following taxonomy:

Kingdom = Fungi

Phylum = Basidiomycota

Sub-phylum= Ustilaginomycotina

Class = Exobasidiomycetes

Order = Exobasidiales

Family = Brachybasidiaceae

Genus = Kordyana

2.2. Phylogenetic analysis showed that the organism is not K. tradescantiae (another

Kordyana species known to infect Tradescantia hosts) and is distinct from any other

Kordyana species (Barreto et al. 2010). We expect it to be formally described using the

specific epithet brasiliensis, the name used in unpublished reports. Until the taxonomy

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is published, the organism remains unnamed and is referred to as Kordyana sp. in this

application.

2.3. There are no inseparable organisms associated with Kordyana sp.

3. Host-range testing

3.1. The applicant has demonstrated that Kordyana sp. poses no threat to native flora

through off-target effects. EPA staff consider that Kordyana sp. is host specific, and will

only act as a pathogen on Tradescantia fluminensis.

3.2. Wapshere (1974) states that the plants most likely to be attacked by a proposed

biocontrol agent are those most closely related to the target weed and growing in the

area where that agent will be used. He developed the centrifugal phylogenetic testing

system for selecting test plants, which accurately predicts the range of hosts that the

control agent will use in its new environment. This system has been universally

adopted by biological control practitioners worldwide and continues to be effective at

preventing unexpected attack of non-target plants in the field, especially for pathogens

(Barton (née Fröhlich) 2004, Barton 2012). The technique was modernised by Briese

(2005), who refined the method, reducing the need for distantly related ―safeguard‖

plants to be included in test lists, as these have been found to add no additional value

to host range testing procedures. Fowler (2007) selected the test-plant species to be

included in host range testing of potential biocontrol agents for

Tradescantia fluminensis (both invertebrates and fungi). The list is presented in table 1

of the application, and his full report is included in Appendix 3.

3.3. Tradescantia fluminensis belongs to the family Commelinaceae (order Commelinales).

There are no plants native to New Zealand belonging to this family (or even to this

order). Exotic plants in the Commelinaceae that occur in New Zealand include a range

of ornamental house and garden plants, some of which have become established in the

wild: Commelina diffusa (climbing dayflower, present in cultivation), Gibasis pellucida

(dotted bridalveil, occasionally found outdoors), Tradescantia albiflora (naturalised),

T. cerinthoides (naturalised), T. virginiana (naturalised) and T. zebrina (in cultivation).

3.4. There are two other families in the Commelinales that occur as exotics in New Zealand;

Haemodoraceae and Pontederiaceae. Within Haemodoraceae there are two

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monospecific genera that occur in New Zealand: Anigozanthos flavidus (kangaroo

paw), a native of Australia, and Wachendorfia thyrsiflora (red root), which has

naturalised here. In Pontederiaceae there are three species: Pontederia cordata

(Pickerelweed), Eichhornia azurea (anchored water hyacinth) and E. crassipes (water

hyacinth, naturalised). Several of these species are well known as ornamental plants in

New Zealand. Most of them are considered undesirable weeds, or as potential weeds

(particularly the Tradescantia and Eichhornia species).

3.5. Less closely related to the Commelinales are the orders Arecales, Poales and

Zingiberales. The only native plant in the Arecales is the endemic palm

Rhopalostylis sapida (Nīkau) and while this is arguably the closest relative to

tradescantia in New Zealand, we are satisfied that it is not closely related to

Tradescantia fluminensis and did not require testing. The fact that the applicant was

unable to source this plant for testing in Brazil does not change the EPA staff

assessment that it is not at risk, and that any risk is therefore negligible.

3.6. There are many plants native to New Zealand in the large order Poales, including

members of the families Typhaceae, Juncaceae, Cyperaceae, Restionaceae and

Poaceae. Landcare Research was able to test other plants that belong to these families

as surrogates, for example, Cyperus rotundus in Cyperaceae and a Juncus species in

Juncaceae, and EPA staff are satisfied that these surrogates accurately reflect the

susceptibility of members of these genera to Kordyana sp.

3.7. There are no plants native to New Zealand in Zingiberales, but there are a few plants in

this family grown here as ornamentals, for example Canna sp. (canna lilies) in

Cannaceae; Musa sp. (bananas) in Musaceae; Strelitzia sp. in Strelitziaceae; and

Zingiber sp. and Hedychium spp. in Zingiberaceae.

3.8. The applicant compiled a final list of 21 plant species (including the target weed) in six

families for host range testing of Kordyana sp. (Table 1 of the application).

3.9. The methods used in host range testing in Brazil, and the results of tests, are given in

detail in three unpublished reports (Barreto et al. 2010; Barreto & Macedo 2011;

Barreto 2012). Since these results are crucial to assessing the risks of Kordyana sp.

attacking non-target plants, a brief summary is also provided here.

3.10. The 20 non-target plants were placed in a shade house with T. fluminensis plants that

had become naturally infected with Kordyana sp. in the field. Tradescantia fluminensis

http://www.landcareresearch.co.nz/__data/assets/pdf_file/0004/39208/barreto_report_8_2010_final.pdfhttp://www.landcareresearch.co.nz/__data/assets/pdf_file/0005/39209/barreto_report_aug_2011.pdfhttp://www.landcareresearch.co.nz/__data/assets/pdf_file/0015/39210/barreto_report_2012.pdf

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plants propagated from material originating in New Zealand were also included as

positive controls (i.e. the test would only be valid if the target plants became infected

under the conditions provided). Tradescantia fluminensis plants developed symptoms

of Kordyana sp. infection one month after they were placed near infected plants in the

shade house, but none of the other test plants developed symptoms during 12 months

of observation (Table 1 of the application). In addition to the 20 test plants required to

define the host range of Kordyana sp., Barreto (2012) monitored a further 42 plant

species of 24 families that were growing in the shade house during the 12 months. No

Kordyana sp. disease symptoms were recorded on these plants.

3.11. Meanwhile, leaves of infected T. fluminensis plants were collected and attached with

Vaseline to the underside of a sheet of glass with the leaf surface pointing downwards

so fungal spores could fall onto test plants below. This sheet of glass was then

suspended over the test plants in a dew chamber where ideal conditions for infection

were provided for 48 hours. Then plants were transferred to a greenhouse for

observation. This direct method was applied to 14 species in the Commelinaceae

family that had already been tested in the shade-house experiment.

3.12. The results were exactly the same as for the shade-house test: Kordyana sp. only

caused symptoms on T. fluminensis of New Zealand origin. These results demonstrate

that under conditions either ideal for the fungus or similar to those it is likely to

experience in the field, the yellow leaf spot is highly host specific, and unlikely to infect

any species other than T. fluminensis. Given the inability of Kordyana sp. to infect

closely related plants, and the taxonomic distance between T. fluminensis and New

Zealand native plants, it is extremely unlikely that Kordyana sp. could damage any non-

target native plants like the Nīkau palm, or ornamental plants in New Zealand (see

section 3.5).

3.13. Both the outdoor and indoor host range tests used field-collected T. fluminensis plants

that had been naturally infected by Kordyana sp. as a source of inoculum.

Consequently, the tests were of a random subset of the Kordyana sp. population, not

just a single strain of the smut. Since all of the material tested gave the same result (it

was unable to infect anything other than T. fluminensis) it seems reasonable to

conclude that the whole species Kordyana sp. is specific to the host species

T. fluminensis. This application therefore seeks to import the whole species, not any

particular strain, as host specificity at the strain level is not a universal characteristic of

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all pathogens. This feature is common in rust fungi and some genera of fungi that can

reproduce asexually (e.g. Colletotrichum species), but the applicants have no

information that would suggest strain-specificity is a typical feature of fungi such as

Kordyana sp. that belong to the Brachybasidiaceae family.

3.14. Host range testing was reviewed by Dr Stan Bellgard, Landcare Research, Auckland

(see page 22 of the application). We respect the authority of Dr Bellgard and his

opinion as an independent expert on this topic.

4. Minimum standards

4.1. Prior to approving any new organism the EPA is required to ensure that if the organism

were to be released, it would meet the minimum standards set out in the in the HSNO

Act.

Section 36 (a): whether Kordyana sp. is likely to cause any significant

displacement of any native species within its natural habitat.

4.2. The applicant has provided evidence that Kordyana sp. can only target

Tradescantia fluminensis. We consider that Kordyana sp. will not out-compete native

fungi on native foliage because it is specific to Tradescantia fluminensis and therefore

will not be found on native plants.

4.3. Winks et al. (2003) surveyed the fungal flora of tradescantia foliage at 14 sites through

New Zealand. Twenty-five fungi were isolated. Most were cosmopolitan saprophytic or

opportunistic pathogens that are likely to be common on the foliage of a range of

plants. A species of Colletotrichum was present in just two of 14 sites, and a species of

Phomopsis was recorded at ten sites. The rate of colonisation of leaves was low (62%),

suggesting that competition for leaf area between fungal species was not high (Winks

et al. 2003). Both Colletotrichum and Phomopsis are genera that include both

saprophytic and pathogenic species. If these are native species then we consider that

they must have existed on plants other than T. fluminensis before the plant was

introduced to New Zealand, and therefore this cannot be their only host. Consequently,

competition on the foliage of T. fluminensis is unlikely to cause a significant decline in

the abundance of these potentially indigenous fungi, and the risk of competitive

displacement is unlikely.

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Section 36 (b): whether Kordyana sp. is likely to cause any significant

deterioration of natural habitats.

4.4. Host range testing indicates that the agent will not attack native plants if released in

New Zealand. Where tradescantia is currently abundant, the natural habitat and its

processes have been degraded. We consider that successful biological control is likely

to help restore those habitats to a more natural state. Where the weed is less

abundant, suppression of tradescantia build-up and dispersal will halt the decline in the

integrity of natural habitats.

4.5. However, there is the potential for biological control to lead to the replacement of

tradescantia exotic species as well as native species. The nature of the replacement

vegetation will vary across habitats. In infested areas with moderate to high incident

light, it is very likely that some replacements will be undesirable species. Studies

indicate that where it occurs, there are unlikely to be any weeds that are as damaging

to biodiversity values as tradescantia (Landcare Research 2012). Overall, we consider

that the vegetation assemblage following successful biological control is likely to

support greater biodiversity than a tradescantia mat, although we acknowledge the role

that supervised forest maintenance will play in this process.

4.6. Tradescantia mats grow in a different way from any native vegetation, and alter the way

infested habitats work. Tradescantia changes how plants succeed each other in natural

habitats and may well adversely affect other native ecosystems. The process of litter

decomposition and nutrient recycling is profoundly different around tradescantia than it

is on open forest floor. Standish et al. (2004) found that the productivity of several sites

examined was high, but that litter breakdown was particularly rapid where tradescantia

occurred. Available nitrogen was higher under weed mats than in non-tradescantia

plots. They concluded that these differences were probably due to differences in

vegetation structure between tradescantia-infested plots and tradescantia-free plots,

and associated differences in microclimate. Introduction of Kordyana sp. is likely to

partially reverse those changes by reducing the biomass of existing mats, providing a

mosaic of new habitat opportunities for native seedlings and limiting the establishment

of new infestations. We therefore consider that rather than causing any deterioration of

natural habitats, introduction of Kordyana sp. will contribute to the restoration of natural

habitats.

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Section 36 (c): whether Kordyana sp. is likely to cause any significant adverse

effects on human health and safety.

4.7. There are no examples of Kordyana sp. acting as a human pathogen or posing a threat

of any kind to human safety. We have not identified any effects on human health and

safety and we therefore consider that Kordyana sp. is not likely to cause significant

adverse effects on human health and safety.

Section 36 (d): whether Kordyana sp. is likely to cause any significant adverse

effect to New Zealand’s inherent genetic diversity.

4.8. The introduction of any new organism to New Zealand has the potential to cause harm

to New Zealand‘s genetic diversity. However, the taxonomic classification of

Kordyana sp. indicates that this potential is unlikely to eventuate.

4.9. There are no close relatives of Kordyana sp. present in New Zealand. There are no

fungi in the same family (Brachybasidiaceae) known in New Zealand. The closest

relatives of Kordyana sp. that do occur in New Zealand are seven species (2 exotic, 5

indigenous) of Exobasidium (Family Exobasidiaceae), which are in the same order as

Kordyana (Exobasidiales). None are found on Tradescantia spp. or on any close

relatives. Also in the same order are two exotic species of Graphiola (family

Graphiolaceae) that have been reported on palm trees in New Zealand.

4.10. Since hybridisation only occurs between close relatives, there is no possibility that

Kordyana sp. would hybridise with a resident fungus. We consider that the evolutionary

changes required for this to occur happen over hundreds and thousands of

generations, even under positive selective pressure. This equates to hundreds, or even

thousands of years, and cannot be considered as part of the HSNO risk assessment.

We therefore consider that Kordyana sp. is unlikely to cause any significant adverse

effects to New Zealand‘s inherent genetic diversity.

Section 36 (e): whether Kordyana sp. is likely to cause disease, be parasitic, or

become a vector for human, animal, or plant disease.

4.11. We note that the purpose of Kordyana sp. is to cause disease in T. fluminensis. Other

than acting as a pathogen for T. fluminensis, we have not identified any scenario under

which Kordyana sp. is likely to cause disease, be parasitic, or become a vector for

human, or animal disease.

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Conclusion on the minimum standards

4.12. We consider that Kordyana sp. is unlikely to cause significant displacement of other

organisms, cause significant deterioration of natural habitats, have any significant

adverse effects on human health and safety, or have significant adverse effects on

New Zealand‘s inherent genetic diversity. It is unlikely to cause disease, be parasitic, or

become a vector for human, animal, or plant disease other than the plant disease for

which it is intended for relase.

4.13. We therefore consider that Kordyana sp. meets the minimum standards as stated in the

HSNO Act.

5. Adverse effects

5.1. The applicant has identified potential adverse effects associated with the release of

Kordyana sp. (see pages 9-18 of the application). In particular, the application identifies

the possible impact of Kordyana sp. on non-target species as a potential risk.

5.2. Host range testing has demonstrated that no native plants are at risk from the release

of Kordyana sp. Both Dr John Liddle from New Zealand Nursery and Garden Industry

Association (NZNGIA) and Nick Hanson from Federated Farmers expressed concern

over the potential impacts of Kordyana sp. on non-native and valued ornamental and/or

agricultural plants. Although we are satisfied that it is extremely unlikely that there will

be any off-target effects from the release of Kordyana sp., we are concerned by the

lack of consultation with these industry groups by the applicant. Consultation early in

the application process would allay industry fears of off-target effects damaging their

valuable economy.

5.3. We consider that host range testing shows that Kordyana sp. will not damage any non-

target species, and is host specific. In the extremely unlikely event that Kordyana sp.

infect any unforeseen plant species, we consider that there are pesticides available

commercially to control the fungi already present in New Zealand, and that these could

be used to control Kordyana sp.

5.4. Dr. Cliff Mason, in his submission, considers that the ―introduction of any alien

organism is intrinsically damaging to our biological integrity‖. He expands on this point

by stating that ―there is always risk from any introduction that is irreducible because of

our incomplete knowledge of the organism and the ecological setting into which it

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would be introduced. This is particularly the case when the proposal is for the

introduction of organisms from phyla that are even less well understood in New

Zealand ecological terms than the Insecta more usually chosen as BCAs”.

5.5. Margaret Hicks expressed concern over the number of agents introduced into New

Zealand to control pests, and how this aligns with New Zealand‘s Biosecurity Act. Since

its inception as a regulator of new organisms in 1998, ERMA and now the EPA has

approved three rust funguses to control pest plants (application ERMA200754 to

control Chilean needle grass, and application APP201171 to control lantana). The

Ministry for Primary Industries (MPI) was advised of both these applications under

section 58(1)(c) of the HSNO Act, and where they have commented on such

applications, their comments are given particular regard by the EPA.

5.6. We consider that the eradication of invasive weeds is aligned with the purpose of the

HSNO Act: to protect the environment. We consider that Kordyana sp. is host specific

and the adverse effects associated with the release of Kordyana sp. are negligible.

6. Positive effects

6.1. The applicant has identified potential positive effects on the environment, on society

and communities, and on the market economy associated with the release of

Kordyana sp. (see pages 9-18 of the application). They consider such effects might halt

or reduce the degradation of forest remnants caused by tradescantia, by:

increasing diversity of native plants and improved regeneration ability in recovering

forests;

improving habitats for native fauna; and

restoring ecosystem processes affected by tradescantia.

6.2. However, the applicant does comment that ―In itself, the introduction of Kordyana sp. is

not expected to have any beneficial environmental effect‖, and we expect it to work in

conjunction with the biocontrol agents previously approved to control tradescantia.

6.3. Cliff Mason questioned a number of assertions made in the application and questioned

the efficacy of the BCA programme. ―In previous submissions on BCAs targeting

tradescantia I have drawn attention to the fact that the agents are unable to produce

sufficient reduction in biomass of the weed to have a beneficial effect on native

seedling germination and growth....it is clear from experimental evidence that a large

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percentage reduction in cover is unachievable by anything other than direct human

intervention by spraying or manual weeding‖. He asks then ―why introduce further

ineffective agents?‖.

6.4. Cliff Mason also questions whether Kordyana sp. will actually work synergistically with

the organisms previously approved by the EPA for release as host-specific biocontrol

agents for tradescantia. ―There does not appear to be any data in the literature to

support the assumption, implicit in this application, that there is a synergistic effect

between BCAs. This assumption suggests that the role of the BCAs in their native

environment is directed toward control of the target that is now a weed in New

Zealand......There is no reason to even suspect synergy against the target and not to

suspect interference of the BCAs with each other‖. He considers that ―In past situations

where multiple agents have been introduced, it seems to have been one of the bunch

that finally emerged as being effective. Is a lottery approach to BCA introduction an

appropriate scientific method?”

6.5. EPA staff are aware of numerous examples of multiple biocontrol agents working

synergistically to control a given weed. For example, agents that attack flowers/flower

buds have been used overseas in tandem with seed feeders to successfully control

Sesbania (Hoffmann and Moran 1998); Hakea (Le Maitre et al. 2008); and

Acacia longifolia (Impson et al. 2004). We consider that as the adverse effects are

negligible in this case, that even if the organism fails to work synergistically with the

other agents or even if one of the ―bunch‖ finally emerges as the one that actually

controls tradescantia, then no harm will have been done to New Zealand‘s native flora

or fauna. If one of the organisms released for control of tradescantia is successful,

either on its own or in conjunction with other agents, then tradescantia will decline in

the environment, reducing the food source for all the agents, and thus reducing their

populations. We do not consider that any of the agents can jump hosts if their food

source collapses, and we do not consider that Kordyana sp. will be able to survive

without this food supply continuing to be present in New Zealand.

6.6. Both Cliff Mason and Margaret Hicks feel that genuine restoration of small remnants of

native vegetation cannot be achieved using biocontrol methods and that active

management of these sites is the only way to avoid inundation by another ―weed‖. Cliff

Mason comments that ―the small plots of bush are under insurmountable threats from a

large suite of invasive plants in which control of any one will only lead to the dominance

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of a successor and in which control of all is clearly impossible by any means other than

continual direct intervention – spraying, manual weeding‖. Margaret Hicks added that

―what has posed a far greater threat to the survival of these forest remnants has been

invasion by cattle‖.

6.7. We consider that introducing effective biocontrol agents is a cost effective way of

managing weed infestations on all affected sites. Often DOC or Council land could be

manually or chemically managed in this way, although they operate with limited funds

and resources, but local land owners may not have the time or resources to manage

invasive weeds. In these cases, weeds continue to invade actively managed land from

adjacent sites, making the problem almost insurmountable. We also consider that

reducing the herbicide use in New Zealand has positive benefits nationally. Even where

there may be no evidence that herbicides cause adverse effects on human health or

the environment, there is a social benefit to be gained through people feeling a sense

of wellbeing by being associated with a reduction in the use of chemicals.

6.8. Despite this, Cliff mason considers that ―It is futile to continue to search for effective

biological control agents. Instead, the message should be understood that small forest

remnants are not a viable means for the maintenance of our biodiversity and that

efforts must be directed towards amalgamation and enlargement of reserves toward a

more sustainable size. I request that the EPA asks the Department of Conservation, as

a member of the Biocontrol Collective, to comment directly on this matter‖. We

submitted this question to DOC and their response is included in Appendix 3.

6.9. Having evaluated the information, we consider that the beneficial effects that can be

accredited to the release of Kordyana sp. are non-negligible.

7. Conclusion on adverse and positive effects

7.1. Margaret Hicks expressed concerns about the risk assessment and the value of

introducing another fungus into New Zealand, in the face of what she considers to be

unknown risks; ―Nothing I have read has persuaded me that there is not a degree of

risk accompanying the release of these biological control organisms. Have the risks

been comprehensively assessed? Can we afford to take such risks at this point in

time?‖.

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7.2. After completing our risk assessment and reviewing the relevent information, we

consider that the adverse effects of releasing Kordyana sp. are negligible and the

positive effects are non-negligible. Therefore the positive effects outweigh the adverse

effects.

8. Effects on Māori and their culture and traditions and the principles of the Treaty of Waitangi (Te Tiriti o Waitangi)

Relationship of Māori to the Environment

8.1. The potential effects on the relationship of Māori with the environment have been

assessed in accordance sections 6(d) and 8 of the Act. Under these sections all

persons exercising functions, powers, and duties under the Act shall take into account

the relationship of Māori and their culture and traditions with their ancestral lands,

water, taonga and the principles of the Treaty of Waitangi (te Tiriti o Waitangi).

8.2. In consideration of these functions and duties, this section of the report provides an

overall evaluation of the consultation process with Māori that was undertaken by the

applicant. From this consultation process, participants signalled there would be an

adverse impact on Māori taonga and their responsibilities as kaitiaki. These aspects will

subsequently be addressed and finally an assessment of the impact this application

may have on the principles of te tiriti o waitangi will be provided by the EPAs Māori

policy and operations unit.

8.3. Of note, other points raised during the consultation process were the effect on native

flora and fauna and monitoring of the effects of the previous and current suite of

controls.

Consultation

8.4. The EPA policy on consultation with Māori requires that consultation be undertaken by

the applicant in the first instance, and that such consultation should lead to the effective

exchange of information between the applicant and iwi/Māori as appropriate. In

addition, another purpose of consultation in this context is to lead to the provision of

information to the decision maker to enable it to evaluate risks, costs and benefits and

make informed decisions in accordance with its legal duty under the Act.

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November 2012

8.5. The detail of the applicant‘s engagement with Māori is outlined in section 5 of the

application and included consulting with the EPA‘s Māori National Network in 2007 and

again in 2010 over their plans to introduce the suite of biological control agents, and the

likely costs and benefits of the biological control strategy for tradescantia.

8.6. In addition to this, the applicant advised that they also intend to discuss the proposal in

face-to-face meetings with Iwi Māori in the Auckland Region. This includes prioritising

iwi/hapu meetings based on rohe where the ―future‖ proposed release sites are situated

e.g. first the Waitakere Ranges (Te Kawerau-A-Maki and Ngati whatua Kaipara), then

extending wider to other iwi. They also propose to work with the Auckland Council

internal Māori relations team to canvas iwi/Māori opinion within their regional networks

that reach 16 iwi/hapu within the Tamaki Makaurau region.

Identification of potential adverse effects to taonga and kaitiakitanga

8.7. Māori perceive natural and native resources such as land, air, water, flora and fauna as

taonga gifted by their tīpūna (ancestors). This gift imposes a responsibility on them as

kaitiaki, to ensure that these resources are conserved and handed on to future

generations in a similar condition. Additional to this, is the belief that everything in the

natural world (both animate and inanimate) has a spiritual life-force (mauri) and these

forces are all bonded together through whakapapa (genealogy). For example, this short

excerpt of a Māori proverb expresses this as:

“When I stand in the shadows of the tree, do I stand in the presence of my brother?

When I gaze upon the glistening waters, do I know that I am the water?”

8.8. This excerpt simply outlines Māori belief that everyone and everything is connected

through an intricate and delicate framework and any disruption to this framework could

pose a significant risk to Māori. As one respondent during the consultation process

stated; ―If resources important to Māori are affected, so are the people‖.

8.9. Therefore, as kaitiaki they must be certain that the mauri of their taonga is healthy and

strong. This has been a concern that has been raised over many years and iwi/Māori

have previously requested assurances that the release of biological control agents

poses no threat to taonga species and ecosystems.

8.10. In response, and as discussed in more detail in section 6.3 of the application, the

applicant has stated that adverse effects on native species are considered highly

unlikely as the agent is host specific to the weed and significant infections will occur

18


November 2012

only where the weed is abundant. Also, it is considered that the introduction of

Kordyana sp. would enhance the current biological control programme and reduce

tradescantia infestations which could halt or reduce the degradation of forest remnants

caused by tradescantia. This in turn would result in an increased diversity of native

plants; improved regeneration ability in recovering forests; improved habitats for native

fauna; and the restoration of ecosystem processes affected by tradescantia.

8.11. In addition, the submission of Te Rūnanga o Ngāi Tahu (who represent over 49,000

members) acknowledges that infestations of the weed have a very damaging impact on

native ecosystems and that biological control offers the most suitable form of weed

management in most situations. Accordingly, they support this application.

8.12. It is considered therefore that the chance for disruption to taonga species and iwi/Māori

kaitiaki responsibilities is low given the highly host specific nature of Kordyana sp. and

the probable subsequent improvement to native ecosystems.

8.13. Given this assessment we anticipate the likelihood of any adverse effects on taonga

species and iwi/Maori kaitiaki responsibilities to be improbable and minimal in

magnitude.

Identification of potential benefits to Taonga and Kaitiakitanga

8.14. Previous consultation identified no significant positive effects other than those accruing

to the general population. Responses highlighted the potential of biological control to

alleviate the increasing effects of tradescantia on native ecosystems, and to reduce any

side-effects of herbicides used to manage tradescantia, both now and in the future.

One response noted the environmental costs associated with doing nothing. Another

sought to collaborate in the project.

Impact on the Principles of the Treaty of Waitangi (Te Tiriti o Waitangi)

8.15. Under section 8 of the Act, all persons exercising powers and functions under the Act

are to take into account the principles of the Treaty of Waitangi (te Tiriti o Waitangi).

8.16. Under previously established case law3 the obligation to take into account is not

intended to be higher than other relevant factors but to give it whatever weight is

3 Bleakley v Environmental Risk Management Authority [2001] 3 NZLR 213, R v Westminster City

(1990) and Haddon v Auckland Regional Council (1993). “The obligation to take into account is not intended to be higher than an obligation to consider the particular factor in making a decision, to weigh it up with the other relevant factors, and to give it whatever weight is appropriate in all the circumstances”. “If the appropriate matters had been to take into account, they must necessarily affect the discretion of the decision maker”.

19


November 2012

appropriate in the circumstances and if the appropriate matters had been to take into

account then they must affect the discretion of the decision maker.

8.17. In reference to the ―principles‖ of the Treaty of Waitangi, as currently accepted by the

Courts and Waitangi Tribunal, we state them to be that of partnership, participation and

protection.

8.18. The principles of partnership and participation refer to the shared obligation on both the

Crown and iwi/Maori to act reasonably, honourably and in good faith towards each

other to ensure the making of informed decisions on matters affecting the interests of

Māori. In fulfilment of these principles, as previously stated, the applicant has

completed an extensive consultation programme for the current suite of biological

controls and has indicated that they intend to continue this throughout the Tamaki

Makaurau region.

8.19. The principle of active protection refers to the Crown‗s obligation to take positive steps

to ensure that Māori interests are protected. Taking into account this principle requires

this application to provide sufficient evidence to show that the introduction of

Kordyana sp. does not pose a significant risk to native or taonga species, ecosystems

and traditional Māori values, practices, health and well-being. The assessments

provided in this section and in other parts of the report, indicate a negligible adverse

biophysical effect to lands, native species and ecosystems.

8.20. Consequently, it is considered that the application provides sufficient information to

take into account the principle of ―active protection‖ and that this application is

consistent with the principles of the Treaty of Waitangi. Given this assessment we

anticipate any effect on the principles of the Treaty of Waitangi to be minimal and the

likelihood of any effect to be highly improbable. The level of effect is therefore

considered negligible.

9. Recommendation

9.1. After weighing the negative and positive effects, we recommend that the release of

Kordyana sp. be approved.

21


November 2012

References

Barreto, RW (2012). Indirect host range testing in shade houses. Unpublished Report. Landcare Research.

Barreto, RW, Macedo, DM, Pereira, OL, Waipara, N and S Dodd (2010). Biological control of

Tradescantia fluminensis with pathogens. Interim report Landcare Research.

Barreto, RW, and DM Macedo (2011). Biological control of Tradescantia fluminensis with pathogens

Unpublished report Landcare Research.

Barton (née Fröhlich), J (2004). How good are we at predicting the field host-range of fungal pathogens used for

classical biological control of weeds? Biological Control 31: 99-122

Barton, J (2012). Predictability of pathogen host range in classical biological control of weeds: an update. BioControl

57: 289–305

Briese, DT (2002). The centrifugal phylogenetic method used to select plants for host-specificity testing of weed

biological control agents: Can and should it be modernised? In. Improving the selection, testing and evaluation of

weed biological control agents. Proceedings of the CRC for Australian Weed Management Biological Control of

Weeds Symposium and Workshop (Eds H. Spafford Jacob and D.T. Briese). 23-33

Fowler SV (2007) Proposed test plant list for the New Zealand biological control programme against Tradescantia

fluminensis. Unpublished report Landcare Research.

Hoffmann JH &and VC Moran (1998). The population dynamics of an introduced tree, Sesbania punicea, in South

Africa, in response to long-term damage caused by different combinations of three species of biological control

agents. Oecologia 114: 343-348

Impson FAC., Moran VC. And JH Hoffmann (2004). Biological control of an alien tree, Acacia cyclops, in South

Africa: impact and dispersal of a seed-feeding weevil, Melanterius servulus. Biological Control 29: 375-381

Le Maitre DC, Krug MR, Hoffmann

JH, Gordon

AJ, and TN. Mgidi (2008). Hakea sericea: Development of a model of

the impacts of biological control on population dynamics and rates of spread of an invasive species. Ecological

Modelling 212 (3-4): 342-358

Standish RJ, Williams, PA, Robertson, AW, Scott NA and DI Hedderley (2004). Invasion by a perennial herb

increases decomposition rate and alters nutrient availability in warm temperate lowland forest remnants. Biological

Invasions 6: 71-81

Wapshire, AJ (1974). A Strategy for evaluating the safety of organisms for biological weed control. Annals of Applied

Biology 11: 201-211

Winks, CJ, Waipara NW, Gianotti AF and SV Fowler (2003). Invertebrates and fungi associated with

Tradescantia fluminensis (Commelinaceae) in New Zealand. LandCare Research report Lo0203/153

22


November 2012

Appendix 1

Submission Submitter/

organisation

Support/

Oppose Submitter comments

102620 West Coast

Regional

Council

Support a number of areas where Tradescantia is a problem;

welcome all viable methods of biocontrol for this pest plant.

102621 DOC Support no reason to dispute the results of the host range testing;

yellow leaf spot fungus (Kordyana sp) poses a negligible risk to

the native flora and fauna of New Zealand;

Tradescantia fluminensis is a significant environmental weed;

and

contributions to successful control will help to protect

conservation values.

102622 Hamilton City

Council

Support Tradescantia fluminensis is a significant weed in Hamilton and

has a negative effect on the city‘s ecological restoration and

significant natural areas;

manual control methods are labour intensive and herbicide

application is undesirable in many restoration settings;

there is potential significant benefit to Hamilton‘s ecology by

using the yellow leaf spot fungus to control the impact of

T. fluminensis.;

if successful, it will also reduce the required frequency and

cost of control efforts; and

the use of this organism in Hamilton could also supplement

introduced beetles in reducing the vigour and impact of

T. fluminensis.

102623 Northland

Regional

Council

Support Tradescantia fluminensis is widespread in Northland;

it forms a thick groundcover under the forest canopy in

reserves on private properties, DOC and council land,

preventing regeneration by native seedlings;

ingress of this weed occurs from the edges of larger native

forest areas, many of which have high ecological values.

invades waterways and wetlands throughout Northland and

has threatened rare endangered plants such as the swamp

Hebe (Hebe aff. bishopiana);

forms dense mats on the margins of rivers, lakes and blocks

23


November 2012


organisation

Support/


drainage channels;

new infestations can be founded from plant fragments spread

by river flow, pest animals, domestic stock and machinery.

Agricultural properties are also colonised by Tradescantia

where the weed is often kept grazed by farmers as a form of

control;

has successfully colonised many of Northland's river systems

and terrestrial habitats and it would be rare to find entire

catchments in the lower and mid north which don't have

Tradescantia;

difficult and expensive to control by manual or mechanical

removal and herbicide treatment can affect non-target plants.

Suppression by artificial shading is impractical for large

infestations;

there are no native plants in New Zealand in the Order

Commelinales to which T. fluminensis belongs;

none of the plants related to T. fluminensis tested for host

specificity in Brazil were found to be infested by Kordyana sp.;

none of the surrogate representatives of relatives of

T. fluminensis tested were hosts of Kordyana sp.; and

biocontrol is considered a sustainable long-term control option

and the introduction of Kordyana sp. is expected to reduce the

vigour of Tradescantia and complement the feeding damage

by three beetle species already released as biocontrol agents.

102624 Cliff Mason Oppose Introduction of new organisms damages our environmental

integrity.

Concerns over the magnitude of the benefits.

Concerns over theoretical foundation for assumed synergistic

effects of a combination of BCAs.

Doubts over the strategy to protect small remnants of

indigenous vegetation.

102625 Te Rūnanga o

Ngāi Tahu

Support reservations about the introduction of exotic species into

Aotearoa New Zealand. However, benefits to the native

environment outweigh the risks;

infestations of the weed have a damaging impact on native

24


November 2012


organisation

Support/


ecosystems, particularly by preventing seedling re-growth of

native species;

vegetation assemblage following successful biocontrol is likely

to support greater biodiversity and more natural ecosystem

processes than a forest-floor mat of tradescantia;

successful biological control relates to the impact of

infestations of the weed on Tuatara populations on

Takapourewa (Stephens Island) by preventing access of the

reptiles and fairy prions to their burrows.

evidence suggests risk to non-target species ranges from

unlikely to extremely unlikely and is regarded as an acceptable

trade-off;

regrettable that the tests could not have included native

species in plant families closest to Commelinaceae; and

test results presented in the application seem clear cut, and do

not provide cause for alarm. Nor is there any indication that

Kordyana will displace, or hybridise with, any native fungus.

102628 Margaret Hicks Oppose tradescantia has extensively colonised stretches of the

Ruakaka River and tributaries and reached pest proportions in

many areas of New Zealand;

tradescantia has not inhibited regeneration of natives species;

expressed concern over the introduction of more foreign

organisms;

considers that there was insufficient testing and that the long

term consequences of the release of Kordyana sp. are

unknown;

concerned that Kordyana sp. has not yet been formally

described;

questioned how release of a plant pathogen aligns with

biosecurity;

recommends mechanical and chemical removal of

tradescantia, although she acknowledges that this is costly,

especially in extensive infestations; and

expressed concern over the risk assessment and whether

New Zealand can afford to risk release of Kordyana sp.

25


November 2012


organisation

Support/


102629 New Zealand

Nursery and

Garden

Industry

Association

Oppose applicant dismisses the economic significance of genera within

the Order Commelinales;

applicant is not objective in their assessment of the status of

the genera particularly Anigozanthos;

Anigozanthos was not included in host testing;

inadequate knowledge as the applicant did not test the related

native toanga species Rhopalostylis sapida (Nīkau); and

lack of consultation with industry.

102630 New Zealand

Biosecurity

Institute

Support provide effective, sustainable and safe control tool for

tradescantia, which is a severe weed in indigenous forest

ecosystems, reserves, public amenity as well as home

gardens;

promote recovery and regeneration of indigenous forest

species currently hindered by thick mats of tradescantia;

help protect key public amenity and environmentally sensitive

areas from tradescantia;

help achieve core biosecurity outcomes for the country;

allow better use of volunteer time in reserve management; and

reduce and prevent allergic reaction health risks to humans

and animals.

102631 Bay of Plenty

Regional

Council

Support tradescantia forms thick mats on forest and clearings, and on

stream margins, and impacts rural and urban areas throughout

the Bay of Plenty Region;

tradescantia overshadows and kills low-growing plants,

including native tree seedlings that are essential for forest

regeneration;

Without intervention, tradescantia severely impacts ecological

integrity of native plant communities;

Spread by fragmentation, it is easily dispersed, and once

established, is difficult to control;

often requires repeated applications of herbicide that have

potential for off target damage of desirable species;

host range tests show that no native plants will be at risk from

Kordyana sp.;

there are valued ornamental house plants related to

26


November 2012


organisation

Support/


tradescantia, but none have been found susceptible to attack

in tests; and

tradescantia modifies natural interactions between species,

and any reduction in the weed will help reverse those impacts;

102362 Federated

Farmers

oppose accept Tradescantia fluminensis as a significantly undesirable

and invasive weed in forestry and conservation;

express concern around the apparent lack of concern given to

the possibility that Kordyana sp. will infect and adversely affect

desirable plants in an agricultural context;

without further assurances on host-specificity, Federated

Farmers does not support this application;

recommends the EPA ensures the applicant adequately

demonstrates that its scientific investigation gave due

consideration to non-native and non-ornamental flora and

proves that there is a negligible risk to all cultivated agricultural

and horticultural crops; and

recommends the EPA ensures that, assuming the above

recommendation is satisfied, the applicant clarifies how their

scientific process achieves that outcome.

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Appendix 2

DOC comments on EPA new organism for release application

Application number: APP201362

Applicant: Auckland Council

Application purpose: to import and release yellow leaf spot fungus (Kordyana sp) as a biological control agent for the weed Tradescantia fluminensis

Thank you for the opportunity to comment on this application. We do not wish to be heard at

a public hearing in support of our comments.

DOC and the National Biological Control Collective

The Department of Conservation is a member of the National Biological Control Collective,

along with the regional councils (and Landcare Research as the science provider/adviser).

The Department provides funding to the Collective to assist with the biological control of

weeds programme.

The Department of Conservation supports this application to import and release yellow leaf

spot fungus (Kordyana sp., yet to be formally described) as a biological control agent for the

weed Tradescantia fluminensis.

Assessment of risk to conservation values

The Department has no reason to dispute the results of the host range testing and it is our

opinion that the yellow leaf spot fungus (Kordyana sp) poses a negligible risk to the native

flora and fauna of New Zealand.

Tradescantia fluminensis is a significant environmental weed and contributions to successful

control via a range of established agents will help to protect conservation values.

Comments co-ordinated on behalf of the Department of Conservation by:

Verity Forbes

(Acting) Technical Advisor Biosecurity; Science and Technical Group; Wellington.

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November 2012

Appendix 3

DOC comments on reasoning of submitter Dr Cliff Mason outlined in paragraph 4 of his

submission (see Appendix 1 for Dr Mason’s submission)

Application number: APP201362

Applicant: Auckland Council

Application purpose: to import and release yellow leaf spot fungus (Kordyana sp) as a biological control agent for the weed Tradescantia fluminensis

The Department has been asked by Dr Cliff Mason to comment on the points made in the

below paragraph, which constitutes part of Dr Mason‘s submission to APP201362:

There is an underlying forlorn hope that some biological magic bullet can be found

that will offer protection to the many small remnants of native vegetation that now

constitute a part of our natural heritage. I contend that this idea that there must be

a solution is wrong. The small plots of bush are under insurmountable threats from

a large suite of invasive plants in which control of any one will only lead to the

dominance of a successor and in which control of all is clearly impossible by any

means other than continual direct intervention – spraying, manual weeding. It is

futile to continue to search for effective biological control agents. Instead, the

message should be understood that small forest remnants are not a viable means

for the maintenance of our biodiversity and that efforts must be directed towards

amalgamation and enlargement of reserves toward a more sustainable size. I

request that the EPA asks the Department of Conservation, as a member of the

Biocontrol Collective, to comment directly on this matter.

The Department agrees that it would be unusual for a single biocontrol agent to control a pest

on its own, let alone offer protection from the suite of existing threats to conservation values in

New Zealand. However, biocontrol agents can be important useful contributors for long-term,

sustained pest control, particularly when used in addition to direct intervention activities for

pest-led or site-led programmes.

As Dr Mason is no doubt aware, most pest plants have arrived in New Zealand without their

natural enemies that may have helped to keep them in check in their own countries.

Biocontrol involves bringing some of those natural enemies to New Zealand (under a strict

testing regime and EPA approval) to help control the pest. Intensive biocontrol follow-up

monitoring that is undertaken by Landcare Research has shown that the agents tested and

released in accordance with accepted best practice remain a low-risk form of pest control,

which is much less damaging than not controlling the pests at all.

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November 2012

Dr Mason has raised issues around the difficulties of halting the decline of biodiversity,

particularly in small forest remnants, and argues ―that small forest remnants are not a viable

means for the maintenance of our biodiversity and that efforts must be directed towards

amalgamation and enlargement of reserves toward a more sustainable size‖. However, the

native vegetation type that tradescantia most commonly invades is lowland

podocarp/broadleaf forest—one of the most fragmented, threatened vegetation types in New

Zealand (Dodd et al. 2011; Ewers et al. 2006). In other words, a large proportion of this type

of forest exists only as remnant populations, which makes it all the more important to protect.

Dr Mason also argues that any weed removed is merely replaced by another. This is not

necessarily the case, particularly for shade tolerant ground cover weeds like tradescantia.

Very few other invasive species are able to invade intact forest and achieve similarly high

levels of biomass in the shade. There is good evidence to show that reducing the biomass of

tradescantia in New Zealand lowland forest is likely to improve native plant regeneration

(Kelly and Skipworth 1984; Standish et al. 2001).

Kind regards,

Verity Forbes

(Acting) Technical Advisor - Biosecurity, Science and Technical Group, Wellington.

Kate McAlpine Science Advisor, Science and Technical Group, Wellington.

References

Dodd M, Barker G, Burns B, et al. (2011). Resilience of New Zealand indigenous forest

fragments to impacts of livestock and pest mammals. New Zealand Journal of Ecology 35:83-

95.

Ewers RM, Kliskey AD, Walker S, et al. (2006). Past and future trajectories of forest loss in

New Zealand. Biological Conservation 133:312-325.

Kelly D & Skipworth JP (1984). Tradescantia fluminensis in a Manawatu (New Zealand)

forest: I. Growth and effects on regeneration. New Zealand Journal of Botany 22: 393-397.

Standish RJ, Robertson AW & Williams PA (2001) The impact of an invasive weed

Tradescantia fluminensis on native forest regeneration. Journal of Applied Ecology 38: 1253-

126.

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November 2012

Appendix 4.

Proposed test plant list for the New Zealand biological control programme against

Tradescantia fluminensis Fowler S. (2007)

Summary test plant list

1/ Family Commelinaceae

Tradescantia fluminensis (control)

T. pallida

T. zebrina

+ T. spathacea?

+ T. x andersonia or varietal?

Gibasis geniculata

Callisia repens

Tripogandra diuretica

Dichorisandra thyrsifolia

Aneilema brasiliense

Commelina benghalensis (or C. diffusa if it can be located)

2/ Add species from other families in the Order Commelinales only if necessary

3/ There are no native New Zealand plant species in the order Commelinales. Candidate

biological control agents will almost certainly be rejected if they cannot be demonstrated to be

host specific to at least the level of family. Consequently, we recommend that New Zealand

native plants are not be included in at least the first stage of the host range testing

programme being considered here.

Introduction

The testing procedure we propose follows the centrifugal system suggested by Wapshere

(1999), although we would also use a hierarchy of testing procedures, starting with the

simpler tests (that are likely to produce ‗false positives‘) and moving on to more sophisticated

(and costly) tests that suffer from the ‗false positive‘ problem to increasingly lesser degrees.

So for example we might start with no-choice feeding and/or development tests (‗starvation

tests) with an insects herbivore species, which can robustly eliminate non-suitable plant

species and define the fundamental host range of plants that the insect can complete its

development on in captivity. For many herbivorous insects this fundamental host range is

31


November 2012

much broader than realised host range under field conditions. If simple experiments to

demonstrate that the fundamental host range in captivity show that the candidate biocontrol

agent is sufficiently safe for release in New Zealand, then costly (and sometimes logistically

difficult, or even impossible, field host range tests would not normally be considered

necessary). In the case of T. fluminensis, this scenario could arise especially because there

are no closely related New Zealand native plant species, and the only members of the plant

family to which T. fluminensis belongs of any significance to New Zealand are several minor

to very minor ornamental species (see Tables 1 & 2).

Taxonomy of the target weed

The target species, Tradescantia fluminensis, is a member of the Family Commelinaceae.

There are no New Zealand native species in this family, or indeed in the Order Commelinales.

It is hard to say what the closest relative to T. fluminensis might be amongst the New Zealand

native plant flora, but Landcare Research botanists suggest it could be the nikau palm (in the

family Arecaleae in the order Arecales). We do not propose testing any New Zealand native

species in this programme because they are so unrelated to the target weed.

Whether to undertake host range testing in New Zealand quarantine or in Brazil?

If testing can be carried out in Brazil, then this is less costly and logistically simpler than

importing and testing agents in quarantine in New Zealand. In addition, realistic testing to

ascertain the field host range can only be carried out in Brazil. Therefore we propose

completing as much host range testing in Brazil as possible under subcontract to the

Universities of Parana and Vicosa.

Test plant species and the rationale for their selection

The classification of the family Commelinaceae on which the following rationale is based in

shown in Table 1.

1/ Within genus Tradescantia: test most/all species of significance to New Zealand.

Tradescantia. fluminensis (controls – from various sources including New Zealand)

T. pallida (Robert has already acquired)

T. zebrina (Robert has already acquired)

Plus T. spathacea (=Rhoeo discolor) could be tested, especially if it is available as

ornamental in Brazil (native range Mexico)

Plus some ornamental varietals of Tradescantia are available in Brazil, and it may be worth

including some of these. Of particular significance might be T. x andersonia (+/- varieties that

are probably either this hybrid, or of parent species of this hybrid) as this does seem to be

quite widely listed as a horticultural plant in New Zealand and other countries.

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November 2012

Note that the current benefits of Tradescantia species (or cultivars) to New Zealand is limited

to minor use as frost intolerant (often indoor) ornamentals, so testing of a comprehensive list

of species/cultivars is not considered essential.

This selection of species/varieties does not consider the classification of Tradescantia into

sections within the genus (Hunt 1981) although it could be extended to involve this if

necessary. However, the species above do in fact represent one species each from 5 of the 9

sections of the genus Tradescantia proposed by Hunt (1981; 1986).

2/ Within sub-tribe Tradescantiinae: test at least one species in each genus containing

species of significance to New Zealand, using a species of significance to New Zealand

where possible.

There are no species of high significance to New Zealand, but the following genera contain

species of minor ornamental use:

Gibasis – suggest G. geniculata

Callisia – suggest C. repens (Robert has already acquired)

Tripogandra – suggest T. multiflora (this species appears to be native to Costa Rica, so

perhaps replace with another that is recorded from Brazil e.g. T. diuretica.

3/ Within the tribe Tradescantieae: test a species in a representative genus of the other

sub tribes, potentially ignoring sub tribes with no species of significance to New

Zealand.

There are no species of high significance to New Zealand, but the following genus contains


sub tribe Dischorisandrinae:

Dichorisandra – suggest D. thyrsifolia (Robert has already acquired)

Suggest ignoring species in other sub tribes, as they are of no relevance to New Zealand i.e.

Palisotinae, Streptoliriinae, Cyanotinae, Coleotrypinae, Thyrsantheminae.

4/ Within the other tribes in the family Commelinaceae (Cartonemateae, Triceratellae,

Commelineae) test a species from representative genera that contain plants of

significance to New Zealand.

There are no species of high significance to New Zealand, but the following genera contain


Tribe Commelineae:

Aneilema – suggest locating a species found in Brazil e.g. Aneilema brasiliense.

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November 2012

Commelina – suggest using a species available in Brazil e.g. C. benghalensis and/or

C. erecta both of which Robert has already located, but perhaps see if C. diffusa could be

located)

Suggest ignoring species in other tribes, as they are of no relevance to New Zealand i.e.

Cartonemateae, Triceratellae.

Use of surrogate species

There are no plant species within the family Commelinaceae of high economic importance to

New Zealand (other than T. fluminensis as a significant weed). However, in general plant

species selected for testing using the above criteria should where possible be those species

of some significance to New Zealand. In some cases (e.g. for Aneilema and Commelina see

above), a closely related, surrogate species can be considered if testing the species of

significance to New Zealand is logistically difficult or impossible.

Inclusion of Australian Commelinaceae

There are several native Australian species in the Commelinaceae (in genera marked in

Table 1) and if there was a realistic risk that biocontrol agents introduced into New Zealand

could accidentally cross the Tasman Sea, then testing some of these species might be

considered (given HSNO Act requirement to take into account international considerations

when assessing risk). For insect herbivores we consider this risk to be negligible, but it might

need to be considered further for some groups of pathogens such as rusts.

Testing plants outside the family Commelinaceae

Prospective biological control agents that included most or all plant species tested in the

family Commelinaceae in their realised host range would probably not be considered further.

However, given the lack of New Zealand native plant species in the entire order

Commelinales, the testing in theory could proceed onto other plant families. If this was the

case, then testing would move onto plant species found in New Zealand in the families shown

in Table 2. The two species in the Pontederiaceae could be tested in Brazil as they are native

to that country. However, they are both floating aquatic plants, so testing many prospective

biological control agents (e.g. terrestrial insect herbivores) would probably be restricted to

feeding trials (as many herbivores would be highly unlikely to rear through on these test

plants because of the aquatic habitat). One species in the Haemodoraceae has been

recorded from Acre, Brazil (Table 2) so in theory might be available for testing. Other species

do not appear to be available in Brazil, so any testing of these would likely have to be

conducted in quarantine confinement in New Zealand. Before undertaking this procedure

(noting that we consider it an unlikely event that a testing programme would proceed to this

stage anyway), it would probably be worth extending the testing to additional plant families in

related plant orders in Brazil (see Appendix 4A).

34


November 2012

Potential for multi-targeting species in the Commelinaceae for biological control: might

we be preventing future weeds?

An analysis of data in the Global Compendium of Weeds (Randall, 2002) suggests that

worldwide the family Commelinaceae contains 14 species that have become invasive alien

weeds when introduced outside their native range (Table 1). A further 12 species have

naturalised in various countries but are not recorded as weeds. Quite a large number of

species in the family are recorded as weeds of agriculture in their native ranges. New Zealand

has only one weedy species in the Commelinaceae, namely the target of this programme

T. fluminensis. Three other species, T. cerinthoides, T. virginiana and Gibasis schiediana are

recorded as naturalised in New Zealand. There are no reports of these species naturalising or

becoming weeds in any other countries.

According to the LCR databases, and recent web searches, New Zealand may have a further

30 species of the Commelinaceae in cultivation. Five of these species are reported as

invasive alien weeds in other parts of the world (excluding T. fluminensis). However, most of

these appear to be invasive in regions with generally warmer climates than New Zealand, so

they may not represent a current weed risk, or if they do then it would only be in the most

northerly parts of New Zealand (and especially the Kermadec Islands). A further three species

of Commelinaceae present in New Zealand have naturalised (but are not reported as alien

weeds) in other countries.

Overall little can be concluded regarding the value of multi-targeting potential weeds in the

Commelinaceae in New Zealand, although given that uses of this plant family in New Zealand

are limited to minor ornamental use (and often indoors), then there don‘t appear to be any

strong reasons to insist on high levels of host specificity of potential biological control agents

e.g. to species, genus or sub tribe/tribe.

35


November 2012

Table 1. The classification of the Family Commelinaceae (nb. sub tribe level only included for the Tribe Tradescantieae). Subfamily, tribes, sub tribes

and genera according to Faden and Hunt (1991) and Stevens (2005).

Subfamily Tribe Sub tribe Genus Species present in New Zealand (A – genus

includes species native to Australia)

+ = naturalised

Species found or

available in Brazil

Species recorded as weeds in

other countries (see Appendix

4 for countries where weedy)

Cartonematoideae Cartonemateae Cartonema A

Triceratellae Triceratella

Commelinoideae Tradescantieae Palisotinae Palisota

Streptoliriinae Streptolirion

Spatholirion

Aetheolirion

Cyanotinae Belosynapsis

Cyanotis A

36


November 2012

Coleotrypinae Coleotrype C. natalensis

Amischotolype

Discorisandrinae Siderasis Yes (Corcovado!)

Dichorisandra D. reginae (uncommon cult., glasshouse), D.

thyrsifolia

D. thyrsifolia*

Cochliostema

Geogenanthus Yes

Thyrsantheminae Tinantia Yes

Thyrsanthemum

Gibasoides

Weldenia W. candida

Elasis

Matudanthus

Tradescantiinae Gibasis G. geniculata, G. pellucida (uncommon cult.,

glasshouse), G. schiediana+

G. geniculata and

others

G. pellucida

Tradescantia T. cerinthiodes+, T. crassula, T. navicularis, T. pallida*, T. zebrina* T. spathacea, T. zebrina, T.

37


November 2012

T. sillamontana, T. zanonia, T. x

andersonia1, T. alba

2, T. pallida, T. zebrina,

T. virginiana+, T. discolor

3, T. spathacea, T.

fluminensis+, T. albida

4, T. albiflora

4, plus

other varieties mentioned e.g. ‗Jazz, Lilac

twist, Osprey‘5

fluminensis

Callisia C. elegans, C. repens (both uncommon cult.,

glasshouse), C. navicularis

C. repens*, C.

warsewicziana*

C. fragans, C. repens

Tripogandra T. multiflora (listed by one NZ nursery) Yes

Uncertain Sauvallea `

Commelineae Stanfieldiella

Floscopa A Yes

Buforrestia Yes

Murdannia A M. keisak, M. loriformis, M.

nudiflora, M. simplex, M.

spirata

Anthericopsis

Tricarpelema

38


November 2012

Pseudoparis

Polyspatha

Dictyospermum

Pollia A

Aneilema A. gramineum (uncommon cult.) Yes

Rhopalephora

Commelina C. diffusa (uncommon cult.), C. tuberosum

(listed by one nursery), C. coelestis, C.

communis, C. dianthifolia, C.erecta

C. benghalensis*, C.

erecta*

C. benghalensis, C. diffusa, C.

virginica

*Species that have already been acquired by Robert Baretto

1This hybrid is reported to have several parent species, most probably T. virginiana, T. ohiensis and T. subaspera

2This probably refers to a white form of T. x andersonia or T. ohiensis

3This appears to be a synonym for T. spathacea which was formerly known as Rhoeo discolor

4These may well be incorrectly applied names to T. fluminensis

5The varieties appear to be large flowered and are probably also developed from USA species and hybrids (T. x andersonia etc)

39

EPA advice Application APP201363

. November 2012

Table 2. Other families in Order Commelinales, and potential species in New Zealand/Brazil that could

be tested if results show that a prospective biological control agent does not show host specificity

confined within the family Commelinaceae. Information provided by the Landcare Research Herbarium

(P. Heenan pers. comm.) and from the New York Botanical Gardens Herbarium website.

Order Family Genus Species Status in New Zealand

Commelinales Philydraceae - -

Pontederiaceae Eichornia crassipes Naturalised (native to

Brazil)

Pontederia cordata* uncommon cult (native to

Brazil)

Haemodoraceae Anigozanthos flavidus* common cult (Australian

native)

Blancoa Uncommon cult

(Australian native)

Xiphidium

caeruleum

Not in New Zealand –

collected in Acre, Brazil

(New York Botanical

Gardens Herbarium)

Wachendorfia thrysiflora* Naturalised (native to

South Africa)

Hanguanaceae - -

40

EPA advice Application APP201363

. November 2012

Appendix 4A Composition of the subclass Commelinids

The commelinids comprise the following four orders and one family (APG 2003) although the

relationships between the main groups are unclear (Stevens 2005):

Order Commelinales

Order Zingiberales

Order Poales

Order Arecales

Family Dasypogonaceae

New Zealand has no native plant species in the Zingiberales or family Dasypogonaceae, and only one

in the Arecales, the endemic nikau palm. However, there are many New Zealand native plants in the

large order Poales including members of the families Typhaceae, Juncaceae, Cyperaceae,

Restionaceae and Poaceae. Any testing of these would need to carried out in quarantine in New

Zealand, but surrogate species could be used in Brazil. Candidates for testing in the Zingiberales in

Brazil could include some well known species: Musaceae - Musa sp (bananas); Cannaceae – Canna

sp (canna lily); Zingiberaceae – Zingiber sp (ginger). Clearly there would be a wide choice of surrogate

species in the Arecales and Poales.

biological control agents for tradescantia fluminensis · leaf spot fungus kordyana sp. as a...

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