Diseases, pathogens and parasites of Undaria pinnatifida

filiformis, P. lanceolata, Pterocladiella capillacea and Schizymenia dubyi (Cantacuzene 1930;
Apt 1988b; Apt & Gibor 1989; Rheinheimer 1992; Ashen & Goff 1996, 1998, 2000).
A number of bacterial diseases of Porphyra have been reported, particularly in relation to
farmed Porphyra, including “green spot rotting-like deterioration” (Ryokuhan-byo) of
Porphyra yezoensis (Nakao et al. 1972), "filament bacterial felt" disease (agent not specified)
(Song et al. 1993), and "white wasting disease"/ white spot"/ "Gijishirogusare-sho" (Tsukidate
1971, 1977). Tsukidate (1983) examined the symbiotic relationship between Porphyra species
and attached bacteria that occurred in conjunction with white rot, the disease which has
caused the most serious damage to the Porphyra cultivation industry in Japan. Anaaki-disease
causes severe damage to the red alga Porphyra yezoensis; Hayashi et al. (1984) identified the
agent as Vibrio fischeri and reported on how it attaches to host thalli (Porphyra sp.), digests
host cells and makes holes in the thalli. Sunairi et al. (1995) reported Flavobacterium sp. to
be the causative agent of Anaaki-disease, as a result of several repeated single-colony
isolations and infection experiments. In order to ascertain the role of bacteria in the process of
rotting or decaying of cultured laver, Fujita et al. (1972) examined 24 strains of bacteria
isolated from diseased fronds of Porphyra yezoensis, including species of Pseudomonas,
Vibrio, Beneckea.
Weinberger et al. (1994) quantified the bacterial epiphytes of Gracilaria conferta and found
that saprophytic bacteria reached 350 times and agar degraders 25,000 times higher numbers
per gram of wet weight on tissues infected with the “white tips disease”, as compared to
healthy tissues. Jaffray & Coyne (1996) developed an in situ assay to detect bacterial
pathogens of the red alga Gracilaria gracilis responsible for causing lesions, thallus
bleaching, and Jaffray et al. (1997) examined bacterial epiphytes on Gracilaria gracilis. The
cause for the “white canopy disease” or “colourless disease” described from Gracilaria
tenuistipitata cultivated in Vietnam is not known (Phap & Thuan 2002) although it is
probably similar to “ice-ice disease” in farmed Eucheuma/Kappaphycus species.
Uyenco et al. (1977) isolated strains of Pseudomonas, Flavobacterium, and Actinobacterium
associated with "ice-ice disease" in diseased Eucheuma striatum. The symptoms of this
disease include the presence of a white powdery growth on the thallus which causes loss of
pigments, and the gradual consumption and subsequent fragmentation of the host. Largo et al.
(1995a), found that pathogenic bacteria identified as Vibrio sp. and Cytophaga sp. promoted
ice-ice disease in stressed host branches in the carrageenan-producing red algae Kappaphycus
alvarezii and Eucheuma denticulatum. Largo et al. (1999) examined the time-dependent
attachment mechanism of bacterial pathogens during ice-ice infection in Kappaphycus
alvarezii.
Ghirardelli (1998) reported on small sheathed Cyanophyta that occur in the cell walls of live
and dead crustose rhodophytes, collected in the lower intertidal zone in the Gulf of Trieste
(Northern Adriatic Sea, Italy). Pectonema terebrans is a cyanobacterium that grows in the
calcified cell walls of coralline algae in Italy, such as Hydrolithon sp., Lithophyllum sp.,
Sporolithon sp. and Titanoderma sp., and it leaves characteristic holes behind and thus can be
identified even in ancient host material (Ghirardelli 1998). The endophytic cyanobacterium
Pleurocapsa sp. is associated with galls and the “deformative disease” in Chilean Mazzaella
laminarioides (Correa et al. 1993, 1997, 2000; Sanchez et al. 1996; Buschmann et al. 1997;
Faugeron et al. 2000). Pleurocapsa triggers the development of tumours that can result in
major changes in frond morphology and texture and negatively affect the number of spores,
settlement rates, germination success and offspring survival (Correa et al. 2000).
An unspecified bacterium is the cause of “Coralline Lethal Orange Disease” (CLOD) in the
crustose coralline alga Hydrolithon onkodes from central west Pacific. CLOD is characterised
MAF Biosecurity New Zealand Diseases, pathogens and parasites of Undaria pinnatifida • 21