Diseases, pathogens and parasites of Undaria pinnatifida

pacifica, Sparlingia pertusa, and Weeksia sp. (Sussmann et al. 1999, 2005, Sussmann &
DeWreede 2001, 2002, 2005). Acrosiphonia sporophytes also occur in Palmaria mollis and
Polyides rotundus from the Northeast Atlantic (Sussmann & DeWreede 2002).
Spongomorpha aeruginosa occurs in Haemescharia hennedyi from Germany, and the related
species S. mertensii in Mastocarpus papillatus from Canada (Sussmann & DeWreede 2001).
Two endophytic green algae observed in Curdiea racovitzae and Iridea cordata from the
Antarctic Peninsula were not further identified (Peters 2003).
Endophytic brown algae in red algae
Brown algae living as endophytes in red algae are from three orders of the Phaeophyceae:
Ectocarpales, Laminariales and Desmarestiales. Setchell & Gardner (1922) described a
number of new species of Streblonema, both epiphytic and endophytic taxa, including the
endophytes S. corymbiferum (in Cumagloia andersonii) and S. investiens (in Helminthocladia
calvadosii). Microspongium tenuissimum occurs in Aeodes orbitosa from South Africa,
Grateloupia doryphora from Canary Islands, and Grateloupia intestinalis from Chile (Peters
2003). A second Microspongium species, M. radians, which has been described from Chilean
Grateloupia doryphora and also grows in Mazzaella laminarioides from South Africa
(Burkhardt & Peters 1998; Peters 2003) is considered synonymous to M. tenuissimum
(Heesch 2005). Another endophyte, genetically identified as Microspongium sp., was isolated
from Polysiphonia elongata growing in the Western Baltic Sea (Burkhardt & Peters 1998).
This species may be synonymous with Mikrosyphar polysiphoniae described from Baltic
Polysiphonia stricta. Pedersen (1976) reported Mikrosyphar polysiphoniae in Polysiphonia
arctica in collections from Greenland. Other Mikrosyphar species, such as M. porphyrae, an
endophyte of Porphyra sp. in the Baltic Sea, may likewise belong to the genus
Microspongium (Heesch 2005).
Kelp gametophytes have recently been discovered living endophytically in filamentous and
foliose red algae. Most of the hosts belong to the order Ceramiales, such as Antithamnion
densum, Callithamnion acutum, C. biseriatum, Ceramium gardneri, Delesseria decipiens,
Griffithsia pacifica, Herposiphonia plumula, Irtugovia pacifica, Membranoptera platyphylla,
Pleonosporium vancouverianum, Polyneura latissima, Polysiphonia paniculata,
Pterosiphonia dendroidea, Pterosiphonia sp., Pterothamnion pectinatum and Scagelia
pylaisei. Kelp gametophytes are furthermore hosted by Fryeella gardneri (Rhodymeniales)
and Euthora cristata, Orculifilum denticulatum (Gigartinales). In earlier studies, the species
of Laminariales involved were not identified further (Garbary et al. 1999a, b, Garbary & Kim
2000), although more recently Sasaki et al. (2003) were able to identify Agarum clathratum in
Orculifilum denticulatum and Hubbard et al. (2004) identified gametophytes of Alaria
esculenta and Nereocystis luetkeana growing in a number of hosts. Gametophytes of
Desmarestia antarctica grow in Antarctic Curdiea racovitzae (Moe & Silva 1989; Peters
2003).
Although some taxa are predominantly epiphytic, they may also affect the host through some
endophytic development, as found in the epiphyte Elachista antarctica which is anchored
within its Antarctic host Palmaria decipiens by endophytic filaments (Peters 2003).
Endophytic diatoms
Diatoms may either live as endo- or epiphytes in/on red algae. Diatoms such as Achnanthes
longipes, Melosira nummoloides, Synedra gracilis and Ligmophora sp. heavily epiphytise
Porphyra species, e.g. P. yezoense, in Japan and South Korea. The epiphyte load inhibits
normal growth of the basiphyte, leading to a condition called “diatom felt disease” (Tsukidate
1983, 1991; Fujita 1990; Song et al. 1993). Examples of endophytic diatoms are Gyrosigma
coelophilum, which has been observed in Coelarthrum opuntia in Japan (Okamoto et al.
26 • Diseases, pathogens and parasites of Undaria pinnatifida MAF Biosecurity New Zealand