Mesocriconema onoensis (Luc, 1959) Loof & De Grisse, 1989)
[Syn.: Criconemella onoensis (Luc, 1959); Macroposthonia onoensis (Luc, 1959)]
[Criconematidae]
Ring nematode
Yes – Has been reported on taro in Fiji (Orton Williams 1980). Association with taro seems to be minor.
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Yes. Recorded in NT and Qld (McLeod et al. 1994; Stirling et al. 2001).
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No
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Meloidogyne arenaria (Neal, 1889)
[Heteroderidae]
Peanut root-knot nematode
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No – May be present in the soil around the taro plant feeding on the roots, but not likely to present on or in the corm.
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Yes. Recorded in NSW, Qld, SA, Tas., Vic. and WA (McLeod et al. 1994).
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No
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Meloidogyne graminicola Golden & Birchfield, 1965
[Heteroderidae]
Rice root knot nematode
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No – Taro is reported as a host (Luc et al. 1990). May be present in the soil around the taro plant feeding inside the roots, but not likely to present on or in the corm. Infested soil is a greater risk than corms. Second-stage juveniles invade the roots, just behind the root tips and may migrate within the root cortex (Luc et al. 1990).
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No record found.
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No
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Meloidogyne hapla Chitwood, 1949
[Heteroderidae]
Root-knot nematode
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No – May be present in the soil around the taro plant feeding on the roots, but not likely to present on or in the corm.
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Yes. Recorded in NSW, Qld, SA, Tas., Vic. and WA (McLeod et al. 1994).
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No
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Meloidogyne incognita (Kofoid & White, 1919)
[Heteroderidae]
Root-knot nematode
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No – May be present in the soil around the taro plant feeding on the roots, but not likely to present on or in the corm.
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Yes. Recorded in NSW, NT, Qld, SA, Tas., Vic. and WA (McLeod et al. 1994).
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No
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Meloidogyne javanica (Treub, 1885)
[Heteroderidae]
Sugarcane eelworm
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No – May be present in the soil around the taro plant feeding on the roots, but not likely to present on or in the corm.
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Yes. Recorded in ACT, NSW, NT, Qld, SA, Tas., Vic. and WA (McLeod et al. 1994).
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No
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Ogma melanesicum (Andrassy, 1979)
[Syn.: Syro melanesicus (Andrassy, 1979)]
[Criconematidae]
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No – Reported feeding on roots of taro in Samoa (Orton Williams 1985). May be present in the soil around the taro plant feeding on the roots, but not likely to present on or in the corm.
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Yes. Recorded in WA (as Ogma melanesica) (McLeod et al. 1994).
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No
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Pratylenchus brachyurus (Godfrey, 1929)
[Pratylenchidae]
Root-lesion nematode
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Yes – Migratory endoparasite of roots. The nematode tunnels through the root cortex as it feeds. In some hosts it can enter the plant’s vascular system (Payan 1989). Reported from taro in Fiji, Samoa and Tonga (Orton Williams 1980).
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Yes. Recorded in NSW, NT, Qld and WA (McLeod et al. 1994).
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No
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Pratylenchus coffeae (Zimmermann, 1898)
[Pratylenchidae]
Banana root nematode
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Yes – Reported from taro in Fiji (Orton Williams 1980). Mainly found in the roots and in the soil, but some Pratylenchus coffeae nematodes may also be present in the corm skin (Luc et al. 1990). Nematodes may be present on poorly cleaned taro corms.
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Yes. Recorded in northern Australia, NSW, Qld, SA, Vic. and WA (McLeod et al. 1994).
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No
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Pratylenchus penetrans (Cobb, 1917)
[Pratylenchidae]
Northern root lesion nematode
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Yes – Pratylenchus spp. mainly feed on the root cortical tissues, but they are known to also attack potato and yam tubers, resulting in surface lesions (Luc et al. 1990). Nematodes may be present on poorly cleaned taro corms.
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Yes. Recorded in NSW, Qld, SA, Tas., Vic. and WA (McLeod et al. 1994).
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No
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Pratylenchus pratensis (deMan, 1880) Filipjev, 1936
[Pratylenchidae]
Lesion nematode
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Yes – Reported on taro in Egypt (Ibrahim et al. 2010). Pratylenchus spp. mainly feed on the root cortical tissues, but they are known to also attack potato and yam tubers, resulting in surface lesions (Luc et al. 1990). Nematodes may be present on poorly cleaned taro corms.
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Yes. Recorded in NSW and Vic. (McLeod et al. 1994).
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No
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Pratylenchus zeae Graham, 1951
[Pratylenchidae]
Root-lesion nematode
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Yes – Reported from taro in Fiji (Orton Williams 1980). Pratylenchus spp. mainly feed on the root cortical tissues, but they are known to also attack potato and yam tubers, resulting in surface lesions (Luc et al. 1990). Nematodes may be present on poorly cleaned taro corms.
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Yes. Recorded in NSW, NT, Qld, Vic. (McLeod et al. 1994) and WA (Riley and Kelly 2002).
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No
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Radopholus similis (Cobb, 1893)
[Pratylenchidae]
Burrowing nematode; Banana root nematode
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Yes – Radopholus spp. are migratory endoparasites of root and corm tissues (Luc et al. 1990). Reported on taro in Fiji and Samoa (Orton Williams 1980).
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Yes. Recorded in NSW, NT, Qld, SA and WA (McLeod et al. 1994; EPPO 2011c).
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No
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Rotylenchulus reniformis Linford & Oliveira, 1940
[Syn.: Tetylenchus nicotiana Yokoo & Tanaka, 1954; Rotylenchulus nicotiana (Yokoo & Tanaka, 1954]
[Hoplolaimidae]
Reniform nematode
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No – Rotylenchulus spp. are sedentary root feeding nematodes (Luc et al. 1990). Not expected to feed on corm tissues. Reported on taro in Fiji, Samoa, Solomon Islands and Tonga (Orton Williams 1980).
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Yes. Recorded in NT and WA (Sauer 1981).
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No
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Scutellonema bradys (Steiner & Le Hew, 1933) Andrassy, 1958
[Hoplolaimidae]
Yam nematode
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Yes – Scutellonema bradys has been reported on taro in the Caribbean, so could potentially be present on corms from that region. However, taro is considered to be a poor host (Bridge et al. 2005), so this nematode is unlikely to be commonly associated with imported taro corms.
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No record found.
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No – This nematode is unlikely to establish via trade in taro corms. While small numbers can survive on some plant hosts for short periods, populations only thrive and increase on yams, cowpea, melon and sesame (Bridge et al. 2005). It mostly spreads via movement of yam tubers for planting (CABI 2011).
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No
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Tylenchulus semipenetrans Cobb, 1913
[Tylenchulidae]
Citrus root nematode
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No – Tylenchulus spp. are sedentary root feeding nematodes (Luc et al. 1990). Not expected to feed on corm tissues.
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Yes. Recorded in NSW, NT, Qld, SA, Vic. and WA (McLeod et al. 1994).
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No
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Xiphinema brevicolle Lordello & Da Costa, 1961
[Longidoridae]
Dagger nematode
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No – May be present in the soil around the taro plant feeding on the roots, but not likely to present on or in the corm.
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Yes. Recorded in NSW, Qld, Vic. and WA (McLeod et al. 1994).
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No
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Xiphinema elongatum Schuurmans Stekhoven & Teunissen, 1938
[Longidoridae]
Dagger nematode
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No – May be present in the soil around the taro plant feeding on the roots, but not likely to present on or in the corm.
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Yes. Recorded in NSW, NT, Qld and WA (McLeod et al. 1994).
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No
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Xiphinema ensiculiferum (Cobb, 1893)
[Syn.: Tylencholaimus ensiculiferus Cobb, 1893]
[Longidoridae]
Dagger nematode
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No – May be present in the soil around the taro plant feeding on the roots, but not likely to present on or in the corm.
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Yes. Recorded in NSW and Qld (McLeod et al. 1994).
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No
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Xiphinema insigne Loos, 1949
[Syn.: Xiphinema indicum Siddiqi, 1959]
[Longidoridae]
Dagger nematode
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No – May be present in the soil around the taro plant feeding on the roots, but not likely to present on or in the corm.
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Yes. Recorded in NSW, NT, Qld and WA (McLeod et al. 1994).
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No
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BACTERIA
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Bacillus megaterium De Bary, 1884
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Yes – Reported on taro in the Solomon Islands (McKenzie and Jackson 1986).
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Yes. Recorded in Australia (CABI 2011).
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No
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Bacillus subtilis (Ehrenberg, 1835) Cohn, 1872
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Yes – Reported on taro in the Solomon Islands (McKenzie and Jackson 1986).
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Yes. Recorded in NSW, Qld and SA (APPD 2009).
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No
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Erwinia carotovora subsp. carotovora (Jones, 1901) Bergey et al., 1923
Bacterial root rot of sweet potato
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Yes – Reported on taro in French Polynesia (Hammes et al. 1989), Papua New Guinea (Muthappa 1987) and Solomon Islands (McKenzie and Jackson 1986).
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Yes. Recorded in NSW (Letham 1995), Qld, Vic. (APPD 2009), NT, Tas. and WA (CABI 2011).
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No
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Dickeya sp.
[Syn.: Erwinia chrysanthemi (Burkh.) Young et al., 1978]
Bacterial soft rot
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Yes – Causes a storage rot in taro corms (Jackson and Gollifer 1975).
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Not verified but likely. Soft rot identified as Erwinia chrysanthemi has been reported in taro crops in Queensland (Daniells et al. 2009).
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Yes – Bacteria survive in the soil. Other closely related strains or species are already present and widespread in Australia. Taro host plants are common in parts of Australia.
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No – Only a minor problem in the field. It has little effect on the number of corms produced or the development of corm rots in healthy plants, but can be a problem in wounded corms (Daniells et al. 2009). Predominantly a secondary storage rot (Jackson and Gollifer 1975). The pathogen associated with taro in the Solomon Islands is phylogenetically distinct from the disease of pineapple and potato (Dickeya zeae) (Parkinson et al. 2009).
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No
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Xanthomonas axonopodis pv. dieffenbachiae (McCulloch & Pirone, 1939) Vauterin et al., 1995
Bacterial blight of aroids
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Yes – The bacterium is in the leaves and in decaying dead leaf material in the soil. However, infection may be systemic, and bacteria may be present in the corm tissues.
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No. A strain of Xanthomonas axonopodis has been recorded in Qld on glycine (Neonotonia wightii) (APPD 2009). No record of the strain associated with taro in Australia.
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Yes – Suitable host plants are present in many parts of northern Australia. While the strains affecting taro have relatively narrow host ranges, they may be able to infect other Araceae species.
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Yes – Leaf blight disease caused extensive damage to a taro crop in India (Phookan et al. 1996).
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Yes
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CHROMALVEOLATA
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Peronosporales (Albugo, Phytophthora)
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Peronospora trichotoma Massee
Corm rot
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No – Type specimen collected on taro in Jamaica in 1886, but other records of this species do not appear to exist. Peronospora trichotoma is probably based on a hyphomycete that may have overgrown an initial attack of Phytophthora colocasiae (Constantinescu 1991).
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No record found.
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No
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Phytophthora botryosa Chee
Phytophthora leaf fall
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No – Primarily a disease of rubber trees, causing premature leaf fall. Only one record associated with taro (CABI 2011). There is no evidence to suggest corms are infected by or are likely to carry infectious propagules. Trimming of leaves during harvest and the cleaning of soil from corms will remove Phytophthora botryosa chlamydospores from the pathway.
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No record found.
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No
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Phytophthora cinnamomi Rands
Root rot
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Yes – Reported causing root and corm rot in taro in Fiji (Dingley et al. 1981).
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Yes. Recorded in NSW (Letham 1995), Qld (Simmonds 1966), SA (Cook and Dube 1989), Tas. (Sampson and Walker 1982) and WA (Shivas 1989).
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No
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Phytophthora colocasiae Raciborski
Taro leaf blight
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Yes – Pathogen survives as mycelium in corm until replanted. Oospores may also survive in corm and leaf tissue (CABI 2011). Reported causing taro corm rots in the Solomon Islands (Jackson and Gollifer 1975).
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No record found.
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Yes – Primarily a foliar pathogen, but petioles and corms can be infected (Brooks 2005). Mycelium in corms is thought to be a pathway for transmission, although Phytophthora colocasiae also causes fast developing (5-10 days) hard corm rots (Brooks 2005). Although the species is heterothallic, oospore development has not been demonstrated in nature, and reproduction is by mycelium and zoospores.
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Yes – Crop losses of 30-50 percent are reported from affected countries (Brooks 2005).
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Yes
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Phytophthora nicotianae Breda de Haan
Black shank
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Yes – Reported causing root and corm rot in taro in Fiji (Dingley et al. 1981).
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Yes. Recorded in NSW (Letham 1995), Qld (Simmonds 1966), SA (Cook and Dube 1989), Tas. (Sampson and Walker 1982) and WA (Shivas 1989).
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No
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Phytophthora palmivora (E.J. Butler) E.J. Butler
Budrot
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Yes – Reported on taro in French Polynesia (Hammes et al. 1989).
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Yes. Recorded in NSW (Letham 1995) and Qld (Simmonds 1966).
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No
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Phytophthora sp. (not yet defined at species level)
Taro pocket rot
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Yes – A slow growing rot formed near the top of the corm. It is homothallic, and forms thick-walled sexual spores which may persist in paddies for long periods (CTAHR 2002).
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No record found.
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Yes – Early stages of the disease are hard to spot, and the rot is slow growing. The species is self-fertile and will form thick-walled sexual spores that can remain in the soil for long periods (CTAHR 2002).
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Yes – Only known in Hawaii on taro. Caused severe crop damage from mid-1990s (Uchida 1998). Similar rots can be caused by Phytophthora colocasiae (CTAHR 2002).
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Yes
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Pythium adhaerens Sparrow
Corm soft rot
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Yes – Taro has been recorded as a host in Palau (McKenzie and Jackson 1990). No specific data available, but mode of action similar to Pythium carolinianum.
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No record found.
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Yes – Similar to Pythium carolinianum (below).
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No – Not considered to be of economic importance (AQIS 1999).
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No
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Pythium aphanidermatum (Edson) Fitzpatrick
Damping off
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Yes – Taro is reported as a host in the Federated States of Micronesia (Ecoport 2011) and Samoa (Gerlach 1988).
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Yes. Recorded in NSW (Letham 1995), Qld (Simmonds 1966), SA (Cook and Dube 1989) and WA (Shivas 1989).
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No
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Pythium arrhenomanes Drechsler
Root rot
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Yes – Reported causing taro corm rot in the Cook Islands (Dingley et al. 1981).
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Yes. Recorded in NSW (Cother and Gilbert 1992) and Qld (Simmonds 1966).
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No
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Pythium carolinianum V.D. Matthews
Root rot, Corm soft rot
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Yes – Rots usually start with roots but spread to corm, and can be transmitted by planting of infected corms (Jackson and Gerlach 1985; Carmichael et al. 2008). The pathogen may invade the corm through cuts and harvesting damage (Erwin and Ribeiro 1996)
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No record found.
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Yes – Has been reported to have a minimum, optimal and maximum growth at 10 °C, 30 °C and more than 40 °C respectively (Abdelzaher and Elnaghy 1998), so could establish in parts on northern Australia.
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Yes – Both wetland and dryland taro crops are affected, the former most severely (Carmichael et al. 2008). Crop losses range from 10-100 percent with an average of about 25 percent (Jackson and Gerlach 1985).
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Yes
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Pythium debaryanum R. Hesse
Damping-off
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Yes – Reported on taro in the Solomon Islands (McKenzie and Jackson 1986).
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Yes, Recorded in Qld (Simmonds 1966), SA (Cook and Dube 1989), Tas. (Sampson and Walker 1982) and WA (Shivas 1989).
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No
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Pythium deliense Meurs
Damping-off
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Yes – Reported on taro in Samoa (Gerlach 1988).
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Yes. Recorded in Qld (Vawdrey and Peterson 1990) and Tas. (Sampson and Walker 1982).
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No
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Pythium graminicola Subramaniam
Root rot
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Yes – Reported causing taro corm rot in Hawaii (Raabe et al. 1981).
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Yes. Recorded in NSW, Qld (APPD 2009) and SA (Cook and Dube 1989).
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No
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Pythium irregulare Buisman
Dieback
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Yes – Reported causing corm rot in the Cook Islands (Dingley et al. 1981) and French Polynesia (Hammes et al. 1989).
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Yes. Recorded in NSW (Letham 1995), Qld (Simmonds 1966), SA (Cook and Dube 1989), Tas. (Sampson and Walker 1982) and WA (Shivas 1989).
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No
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Pythium middletonii Sparrow
Damping-off
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Yes – Reported causing corm rot in the Cook Islands (Dingley et al. 1981), Palau (McKenzie and Jackson 1990), Samoa (Gerlach 1988) and the Solomon Islands (McKenzie and Jackson 1986).
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Yes. Recorded in NSW (Letham 1995), Tas. (Sampson and Walker 1982) and WA (Shivas 1989).
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No
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Pythium myriotylum Drechsler
Brown rot
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Yes – Reported on taro in the Solomon Islands (McKenzie and Jackson 1986).
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Yes. Recorded in NSW (Letham 1995), Qld (Simmonds 1966), SA (Cook and Dube 1989) and WA (Shivas 1989).
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No
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Pythium splendens Hans Braun
[Including: Pythium splendens var. hawaianum Sideris; Pythium splendens Hans Braun var. splendens]
Blast
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Yes – Reported causing taro corm rot in Fiji, Samoa (Dingley et al. 1981) and the Solomon Islands (McKenzie and Jackson 1986).
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Yes. Recorded in Qld (Simmonds 1966), SA (Cook and Dube 1989), Tas. (Sampson and Walker 1982) and WA (Shivas 1989).
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No
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Pythium ultimum Trow
Pythium rot
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Yes – Soil pathogen responsible for root and corm rots. May be present in infected corms.
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Yes. Recorded in NSW (Letham 1995), Qld (Simmonds 1966), SA (Cook and Dube 1989), Tas. (Sampson and Walker 1982) and WA (Shivas 1989).
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No
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Pythium vexans de Bary
[Including: Pythium vexans var. minutum G.S. Mer & Khulbe; Pythium vexans de Bary var. vexans]
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Yes – Reported causing taro corm rot in Fiji (Dingley et al. 1981), Samoa (Gerlach 1988) and Solomon Islands (McKenzie and Jackson 1986).
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Yes. Recorded in NSW (Letham 1995), Qld (Simmonds 1966), SA (Cook and Dube 1989) and WA (Shivas 1989).
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No
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