1.25.2Management for taro leaf blight
Phytophthora colocasiae has been assessed to have an unrestricted risk estimate of ‘moderate’ for taro corms imported from countries hosting this pathogen, and additional measures are therefore required to manage this risk.
The major risk from Phytophthora colocasiae is the importation of corms bearing viable sporangia or zoospores (particularly between petiole bases) that are subsequently diverted from their intended use for human consumption and used as planting material. Infected and rotting corms bearing viable hyphae or spores could also be discarded near susceptible hosts.
The proposed risk management measure for countries where this pathogen is present is:
-
area freedom from Phytophthora colocasiae. Taro corms must only be sourced from areas declared free of taro leaf blight.
Alternative measures proposed by exporting countries, e.g. systems approach, pest free place of production etc., will be considered on a case-by-case basis.
The objective of this measure is to reduce the likelihood of importation for Phytophthora colocasiae to at least ‘very low’. The restricted risk would then be reduced to ‘very low’, which would achieve Australia’s ALOP.
1.25.3Management for Colocasia bobone disease, Taro vein chlorosis and Tomato zonate spot
Colocasia bobone disease virus, Taro vein chlorosis virus and Tomato zonate spot virus have been assessed to have an unrestricted risk estimates of ‘low’ for taro corms imported from countries hosting these pathogens, and additional measures are therefore required to manage these risks.
The major risks from these viruses are from the import of infected corms, their diversion from their intended use of human consumption to planting material, sprouting of the corms, and transmission of the viruses to other plants by their insect vectors.
The proposed risk management measures for taro from countries where these viruses are present are:
-
topping of corms of large corm taro to remove the petiole bases and the apical growing points to reduce the likelihood that infected plants establish, either from discarded corm waste or corms that are used for propagation
-
prohibition of corms of small corm taro, which could grow into infected plants due to their ease of propagation.
All petiole material and growing points of the corm must be removed, and the corm must be free of lateral shoots, suckers and daughter corms. Topping of large taro corms may take place either in the country of origin, or on arrival, before phytosanitary inspection of the corms.
The objective of these measures is to reduce the likelihood of importation for Colocasia bobone disease virus, Taro vein chlorosis virus and Tomato zonate spot virus to at least ‘low’. The restricted risk would then be reduced to ‘very low’, which would achieve Australia’s ALOP.
1.25.4Operational system for the maintenance and verification of phytosanitary status
A system of operational procedures is necessary to maintain and verify the phytosanitary status of imported fresh taro corms. This is to ensure that the proposed risk management measures have been met and are maintained. The components of the proposed operational system are described below.
Phytosanitary certification by a NPPO, or other relevant agency nominated by the NPPO
The objectives of phytosanitary certification are to ensure that:
-
an International Phytosanitary Certificate (IPC) is issued for each consignment, consistent with ISPM 12 Guidelines for Phytosanitary Certificates (FAO 2001b), to provide formal documentation to AQIS verifying the relevant measures have been undertaken offshore
-
each IPC includes a description of the consignment (including the taro variety and country of origin).
Additional Phytosanitary Certificate declarations
Each consignment must be accompanied by an original IPC endorsed with the following additional declarations:
-
The taro in this consignment is Colocasia esculenta var. esculenta and not Colocasia esculenta var. antiquorum
AND
-
The tubers are sourced from [name of country], which is free of taro leaf blight (Phytophthora colocasiae)
AND
-
The tubers have been inspected and found to be topped and free from all foliage including petiole bases, and free from sprouts, suckers and attached daughter corms
OR
-
The taro in this consignment was sourced from [name of country], which is free of taro planthopper (Tarophagus proserpina), Colocasia bobone disease virus, Taro vein chlorosis virus and Tomato zonate spot virus.
Packaging and labelling
The objectives of the requirement for packaging and labelling are to ensure that:
-
fresh taro exported to Australia is not contaminated by quarantine pests or regulated articles (e.g. trash, soil and weed seeds)
-
unprocessed packing material (which may vector pests not identified as being on the pathway) is not imported with the taro corms
-
all wood used in the packing of the commodity complies with AQIS conditions (see AQIS publication ‘Cargo containers: Quarantine aspects and procedures’).
On-arrival phytosanitary inspection and clearance by AQIS
The objectives of this procedure are to ensure that:
-
on arrival in Australia, each consignment as defined by a single phytosanitary certificate is inspected by AQIS at the first port of entry for quarantine pests and regulated articles
-
inspection lots are inspected using the standard AQIS inspection protocol, which includes optical enhancement where necessary
-
a sample size for taro corms of 600 units (a unit is a single taro corm) is inspected from each consignment. If a consignment has less than 1000 units, then 450 units are to be inspected. For consignments of less than 450 units, all units must be inspected
-
if no live quarantine pests or other regulated articles are detected in the inspection lot, the consignment will be released from quarantine
-
inspection lots will fail if quarantine pests and/or regulated articles are detected by AQIS during on-arrival inspections. Remedial action is to be taken when this occurs
-
if the product continually fails inspection, the export program may be suspended and audited by AQIS, with reinstatement after AQIS is satisfied that appropriate corrective action has been taken.
Policy on unidentified disease symptoms
Australia has a long standing policy of requiring treatment for diseased material where identification of the pathogens responsible is not possible. Where diseased taro corms are detected and identification of the pathogens is not possible, or cannot be provided within a practical time, then the product is deemed to pose a disease risk to Australia and remedial action is required.
Definition of large and small corm taro
For the purposes of imports of taro into Australia, the following conditions will be imposed to distinguish between large and small corm taro:
Large corm taro will meet all of the following conditions. Individual corms will:
a) be at least 15 cm long or be at least 7 cm in diameter at the widest point
b) be at least 300 g in weight
c) be free of lateral buds or shoots
d) lack shaggy hairs.
Corms not meeting these conditions will be deemed to be small corm taro.
Remedial action for non-compliance – on-arrival verification
The objectives of the proposed requirements for remedial action(s) for non-compliance during on-arrival verification are to ensure that any quarantine risk is addressed by remedial action, as appropriate, for consignments that do not comply with import requirements.
1.26Review of policy
Australia collects data on pests intercepted in trade and uses this information to validate import policy. Depending on the level and type of pest interceptions at the border, Biosecurity Australia may consider further revisions of this policy and the operational requirements.
Conclusion
This draft review of import conditions supports the continuation of existing import conditions for fresh large corm taro, with an additional condition to mitigate the risks posed by Phytophthora colocasiae. The prohibition of small corm taro (Colocasia esculenta var. antiquorum), adopted as an emergency measure in 2006, will remain until further notice. Countries that are able to demonstrate freedom from Colocasia bobone disease virus, Taro vein chlorosis virus and Tomato zonate spot virus may apply for access for small corm taro. This will be assessed on a case-by-case basis.
The findings of this draft report are based on a comprehensive analysis of relevant scientific literature. Biosecurity Australia considers that the risk management measures proposed in this report will provide an appropriate level of protection against the pests identified in this risk analysis. Various risk management measures may be suitable to manage the risks associated with fresh taro from all countries. Biosecurity Australia will consider any other measures suggested by stakeholders that provide an equivalent level of phytosanitary protection.
Appendices
Appendix A: Initiation and pest categorisation for pests of taro
Initiation (columns 1 – 2) identifies the pests of taro that have the potential to be on fresh corms produced using commercial production and packing procedures.
Pest categorisation (columns 3 - 6) identifies which of the pests with the potential to be on taro corms are quarantine pests for Australia and require pest risk assessment.
The steps in the initiation and categorisation processes are considered sequentially, with the assessment terminating at the first ‘No’ for columns 2, 4 or 5 or ‘Yes’ for column 3.
Details of the method used in this IRA are given in Section 2: Method for pest risk analysis.
Pest
|
Potential to be on taro corms
|
Present within Australia
|
Potential for establishment and spread
|
Potential for economic consequences
|
Pest risk assessment required
|
ARTHROPODA: Arachnida: Acari
|
Acariformes (mites)
|
Rhizoglyphus minutus Manson, 1972
[Acaridae]
Taro mite
|
Yes – Frequently intercepted in Australia and New Zealand on taro corms from the Pacific (Zhang 2003, 2004).
|
No record found. However, the taxonomy of Rhizoglyphus in Australia is confused due to a lack of detailed taxonomic study (Fan and Zhang 2003).
|
Yes – At least three other Rhizoglyphus species are found in Australia (Fan and Zhang 2003). The main host is taro, which is found in parts of Australia. Other hosts include yam and coconut (Zhang 2003), which are present in Australia. Taro has been imported for many years and there have been many mite interceptions. However, there are no records of establishment in Australia.
|
No – Rhizoglyphus minutus affects root crops such as taro and yams after harvest. It is most often associated with damaged tissue and with fungal attack (Trade Forum 2002). Fiji does not consider the mite to be a pest as such, because it does not damage the corm (Vinning 2003). It is not listed as one of the Rhizoglyphus species known to be agricultural pests in Diaz et al. (2000).
|
No
|
Tetranychus cinnabarinus (Boisduval, 1867)
[Tetranychidae]
Carmine spider mite
|
No – Adults and nymphs feed primarily on the undersides of the leaves. The mites tend to feed in ‘pockets’ often near the midrib and veins (Mau et al. 2007). Leaf trimming during harvest should exclude this pest from the pathway.
|
Yes (Halliday 2000).
|
|
|
No
|
Tetranychus lambi Pritchard & Baker, 1955
[Tetranychidae]
Banana spider mite
|
No – Feeds on leaves and fruit of host plants (Gutierrez and Schicha 1983). Leaf trimming during harvest should exclude this pest from the pathway.
|
Yes. Has been recorded in NSW and Qld (AICN 2011).
|
|
|
No
|
Tetranychus marianae McGregor, 1950
[Tetranychidae]
Spider mite
|
No – Colonies are found on the underside of leaves (Ochoa et al. 1994). Leaf trimming during harvest should exclude this pest from the pathway.
|
Yes. Has been recorded in Qld (AICN 2011).
|
|
|
No
|
MOLLUSCA: Gastropoda
|
Achatina fulica Bowditch, 1822
[Syn.: Lissachatina fulica (Bowditch, 1822)]
[Achatinidae]
Giant African snail
|
No – Giant African snail is a polyphagous feeder that is reported to eat taro plants, but only when pest populations are high. It is principally a foliar feeder, but will eat any live or dead plant tissue (Carmichael et al. 2008). Eggs are laid in the soil, so the main risk is hitchhiking juveniles or adults. Removal of leaves and soil will remove this pest from the pathway.
|
No record found.
|
|
|
No
|
Pomacea canaliculata (Lamarck, 1822)
[Ampullariidae]
Golden apple snail
|
No – Voracious consumers of plant material. Egg masses are laid on any available surface, in wet conditions. These would normally be removed by cleaning methods employed to remove soil and surface contaminants in packing houses, and detected during routine entry inspection for contaminants. Removal of leaves and soil will remove this pest from the pathway.
|
No record found.
|
|
|
No
|
ARTHROPODA: Insecta
|
Coleoptera (beetles)
|
Adoretus sinicus Burmeister, 1855
[Scarabaeidae]
Chinese rose beetle
|
No – Adults feed on leaves at night, and larvae feed on rotting material in the soil and rarely attack living roots (Hawaii Department of Agriculture 2009). Reported eating taro leaves in Micronesia (Nafus 1997). Leaf trimming during harvest should exclude this pest from the pathway.
|
No record found.
|
|
|
No
|
Adoretus versutus Harold, 1869
[Syn.: Adoretus vestitus Boheman, 1858; Adoretus vitiensis Nonfried, 1891; Adoretus insularis Fairmaire, 1897]
[Scarabaeidae]
Rose beetle
|
No – Adult beetles feed on leaves at night and shelter in the soil or under leaf litter during the day. The larvae feed on rotting material in the soil. They may attack living roots, but damage is only slight (Ecoport 2011). Leaf trimming during harvest and removal of soil and roots should exclude this pest from the pathway.
|
No record found.
|
|
|
No
|
Apirocalus ebrius Faust, 1892
[Anthribidae]
Horned weevil
|
No – Herbivorous leaf-feeding weevil (Smith 1978). Adult weevils attack soft growing points and leaves of taro and a range of other crops. Damage is often not serious (French 2006). Leaf trimming during harvest should exclude this pest from the pathway.
|
No record found.
|
|
|
No
|
Apirocalus terrestris Thompson, 1977
[Anthribidae]
Horned weevil
|
No – Adult weevils attack soft growing points and leaves of taro and a range of other crops. Damage is often not serious (French 2006). Leaf trimming during harvest should exclude this pest from the pathway.
|
No record found.
|
|
|
No
|
Araecerus fasciculatus (De Geer, 1775)
[Syn.: Araecerus coffeae (Fabricius, 1801)]
[Anthribidae]
Cocoa weevil
|
Yes – This weevil has been reported as a storage pest in tuber products. Larvae tunnel through the corm (CABI 2007).
|
Yes. Has been recorded in NSW, Qld, Tas., Vic., SA (Zimmerman 1994).
|
|
|
No
|
Caedius demeijerei Gebien, 1920
[Tenebrionidae]
|
No – Beetles have been reported damaging beans, taro and radish. Adults are found on the ground under beans (French 2006). Leaf trimming during harvest and cleaning of corms should exclude this pest from the pathway.
|
No record found.
|
|
|
No
|
Dermolepida noxium Britton, 1957
[Scarabaeidae]
Chafer beetle
|
No – Leaf feeder on banana, but has been reported damaging taro (French 2006). Should be eliminated by normal packing procedures.
|
No record found.
|
|
|
No
|
Elytroteinus subtruncatus (Fairmaîre, 1881)
[Circulionoidea]
Fiji ginger weevil
|
Yes – The larval stage burrows into the corm (Mau and Martin Kessing 1992).
|
No record found.
|
Yes – Host plants, including avocado, sugarcane, lemon and taro (Follett et al. 2007) are present in many parts of Australia, so some spread could be anticipated.
|
Yes – Host plants include economic crops. Feeding of the larvae results in wilting and loss of vigour. If feeding is extensive, the host may die (Mau and Martin Kessing 1992).
|
Yes
|
Eucopidocaulus tridentipes (Arrow, 1911)
[Syn.: Papuana tridentipes Arrow, 1911]
[Scarabaeidae]
Taro beetle
|
Yes – Adult beetles tunnel into corms, eventually destroying them. Larvae feed on rotting vegetation, sawdust etc. (Macfarlane 1987; Carmichael et al. 2008).
|
No record found.
|
Yes – Potential hosts include ornamental and native aroids. However damage is readily apparent and should be discovered on packing/ import inspection.
|
Yes – This species of taro beetle is a serious pest of taro, burrowing into the corms and making smooth-sided, round tunnels (Adams 2006b).
|
Yes
|
Glyptoporopterus sharpi (Faust, 1898)
[Circulionoidea]
Weevil
|
No – Has been reported on taro (French 2006), but leaf trimming during harvest should exclude this pest from the pathway.
|
No record found.
|
|
|
No
|
Henosepilachna guttatopustulata (Fabricius, 1775)
[Syn.: Epilachna guttatopustulata (Fabricius, 1775); Coccinella guttatopustulata Fabricius, 1775]
[Coccinellidae]
Large leaf eating ladybird
|
No – Both larvae and adults feed on foliage (Li 1993). Leaf trimming during harvest should exclude this pest from the pathway.
|
Yes. Has been recorded in NSW, NT, Qld, Tas. and Vic. (Li 1993; AICN 2011).
|
|
|
No
|
Melanhyphus clypealis (Arrow, 1937)
[Scarabaeidae]
Beetle
|
No – Scarab beetles are occasionally reported on taro (French 2006). Leaf trimming during harvest should exclude this pest from the pathway.
|
No record found.
|
|
|
No
|
Oryctes rhinoceros (Linnaeus, 1758)
[Syn.: Oryctes stentor Castelnau, 1840; Scarabaeus rhinoceros Linnaeus, 1758]
[Scarabaeidae]
Rhinoceros beetle
|
No – Larvae live in rotting logs, tree stumps, compost heaps, sawdust etc. Adult beetles burrow into the growing points of coconut and oil palms (CABI 2007). Only incidentally associated with taro, and not noted as a pest for that species.
|
No. Has previously been recorded in Qld (CABI 2007).
|
|
|
No
|
Papuana biroi Endrödi, 1969
[Scarabaeidae]
Taro beetle
|
Yes – Adult beetles tunnel into corms, eventually destroying them. Larvae feed on rotting vegetation, sawdust etc. (Macfarlane 1987; Carmichael et al. 2008).
|
No record found.
|
Yes – Potential hosts include ornamental and native aroids. However damage is readily apparent and should be discovered on packing/ import inspection.
|
Yes – Burrows into corm forming large tunnels and cavities that eventually destroy product (Carmichael et al. 2008).
|
Yes
|
Papuana cheesmanae Arrow, 1941
[Scarabaeidae]
Taro beetle
|
Yes – Adult beetles tunnel into corms, eventually destroying them. Larvae feed on rotting vegetation, sawdust etc. (Macfarlane 1987; Carmichael et al. 2008).
|
No record found.
|
Yes – Potential hosts include ornamental and native aroids. However damage is readily apparent and should be discovered on packing/ import inspection.
|
Yes – Burrows into corm forming large tunnels and cavities that eventually destroy product (Carmichael et al. 2008).
|
Yes
|
Papuana huebneri Fairmaire, 1879
[Scarabaeidae]
Taro beetle
|
Yes – Adult beetles tunnel into corms, eventually destroying them. Larvae feed on rotting vegetation, sawdust etc. (Macfarlane 1987; Carmichael et al. 2008).
|
No record found.
|
Yes – Potential hosts include ornamental and native aroids. However damage is readily apparent and should be discovered on packing/ import inspection.
|
Yes – Burrows into corm forming large tunnels and cavities that eventually destroy product (Carmichael et al. 2008).
|
Yes
|
Papuana inermis Prell, 1912
[Scarabaeidae]
Taro beetle
|
Yes – Adult beetles tunnel into corms, eventually destroying them. Larvae feed on rotting vegetation, sawdust etc. (Macfarlane 1987; Carmichael et al. 2008).
|
No record found.
|
Yes – Potential hosts include ornamental and native aroids. However damage is readily apparent and should be discovered on packing/ import inspection.
|
Yes – Burrows into corm forming large tunnels and cavities that eventually destroy product (Carmichael et al. 2008).
|
Yes
|
Papuana japenensis Arrow, 1941
[Scarabaeidae]
Taro beetle
|
Yes – Adult beetles tunnel into corms, eventually destroying them. Larvae feed on rotting vegetation, sawdust etc. (Macfarlane 1987; Carmichael et al. 2008).
|
No record found.
|
Yes – Potential hosts include ornamental and native aroids. However damage is readily apparent and should be discovered on packing/ import inspection.
|
Yes – Burrows into corm forming large tunnels and cavities that eventually destroy product (Carmichael et al. 2008).
|
Yes
|
Papuana laevipennis Arrow, 1911
[Syn.: Papuana woodlarkiana subsp. laevipennis (Arrow, 1911)]
[Scarabaeidae]
Taro beetle
|
Yes – Adult beetles tunnel into corms, eventually destroying them. Larvae feed on rotting vegetation, sawdust etc. (Macfarlane 1987; Carmichael et al. 2008).
|
No record found.
|
Yes – Potential hosts include ornamental and native aroids. However damage is readily apparent and should be discovered on packing/ import inspection.
|
Yes – Burrows into corm forming large tunnels and cavities that eventually destroy product (Carmichael et al. 2008).
|
Yes
|
Papuana semistriata Arrow, 1911
[Scarabaeidae]
Taro beetle
|
Yes – Adult beetles tunnel into corms, eventually destroying them. Larvae feed on rotting vegetation, sawdust etc. (Macfarlane 1987; Carmichael et al. 2008).
|
No record found.
|
Yes – Potential hosts include ornamental and native aroids. However damage is readily apparent and should be discovered on packing/ import inspection.
|
Yes – Burrows into corm forming large tunnels and cavities that eventually destroy product (Carmichael et al. 2008).
|
Yes
|
Papuana szentivanyi Endrodi, 1971
[Scarabaeidae]
Taro beetle
|
Yes – Adult beetles tunnel into corms, eventually destroying them. Larvae feed on rotting vegetation, sawdust etc. (Macfarlane 1987; Carmichael et al. 2008).
|
No record found.
|
Yes – Potential hosts include ornamental and native aroids. However damage is readily apparent and should be discovered on packing/ import inspection.
|
Yes – Burrows into corm forming large tunnels and cavities that eventually destroy product (Carmichael et al. 2008).
|
Yes
|
Papuana trinodosa Prell, 1912
[Scarabaeidae]
Taro beetle
|
Yes – Adult beetles tunnel into corms, eventually destroying them. Larvae feed on rotting vegetation, sawdust etc. (Macfarlane 1987; Carmichael et al. 2008).
|
No record found.
|
Yes – Potential hosts include ornamental and native aroids. However damage is readily apparent and should be discovered on packing/ import inspection.
|
Yes – Burrows into corm forming large tunnels and cavities that eventually destroy product (Carmichael et al. 2008).
|
Yes
|
Papuana uninodis Prell, 1912
[Scarabaeidae]
Taro beetle
|
Yes – Adult beetles tunnel into corms, eventually destroying them. Larvae feed on rotting vegetation, sawdust etc. (Macfarlane 1987; Carmichael et al. 2008).
|
No record found.
|
Yes – Potential hosts include ornamental and native aroids. However damage is readily apparent and should be discovered on packing/ import inspection.
|
Yes – Burrows into corm forming large tunnels and cavities that eventually destroy product (Carmichael et al. 2008).
|
Yes
|
Papuana woodlarkiana Montrouzier, 1855
[Syn.: Papuana woodlarkiana subsp. woodlarkiana (Montrouzier, 1855)]
[Scarabaeidae]
Taro beetle
|
Yes – Adult beetles tunnel into corms, eventually destroying them. Larvae feed on rotting vegetation, sawdust etc. (Macfarlane 1987; Carmichael et al. 2008).
|
Yes. Has been recorded in Qld and WA (Brooks 1965).
|
|
|
No
|
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