Brown Root Rot of Trees Caused by Phellinus noxius in Windbreaks on Ishigaki Island, Japan. Incidence of Disease, Pathogen and Artificial Inoculation.

Abstract

Extensive wilts of trees have recently occurred in the windbreaks at Okinawa Branch of the Tropical Agricultural Research Center in Ishigaki Island, Okinawa, Japan. Dead or declined trees were observed at 43 points, the total number of dead and declined trees was over 200 and total length of damaged windbreaks was 515m, in about 11% of the total length of windbreaks. Roots of dead and declined trees were collected and many fungus cultures were isolated from them. Most isolates had the following common cultural characteristics:no clamp connections on septa, staghorn-like hyphae and arthroconidia. Two cultures isolated from tissue of diseased trees were artificially inoculated into saplings of Podocarpus macrophyllus. Nine saplings were killed out of 19 inoculated saplings within 13 months and the fungus was reisolated from the dead saplings. As the isolates were considered to be a hymenomycetous fungus, fungal fruiting bodies were collected from windbreaks and from nearby and cultures were isolated from the collected fruiting bodies. One of cultures isolated from the collected fruiting bodies coincided in cultural characteristics with the isolates from dead and declined trees. The fruiting body from which this culture was isolated, was identified as Phellinus noxius (Corner) Cunningham.Taxonomic study revealed that Ph. sublamaenis (Lloyd) Ryvarden, published as a prior name for Ph. noxius, is a synonym of Ph. lamaensis. The fungus reported as Ph. lamaensis by Yasuda from Bonin Island of Japan in 1916, was identified as Ph. noxius.

Hymenochaetaceae (Basidiomycota) in China

“…The fungus is a serious pathogen on numerous angiosperm trees in subtropical China and Japan (Hattori et al 1996), especially on Hevea brasiliensis (Yuan 1997). It causes the so-called "brown root rot" of the trees, and recent studies on its pathogenicity were published by Chang (1995), Abe et al (1995) and Hattori et al (1996). Like all the other species of the family, P. noxium is also a white-rot fungus.…”

Brown root rot caused by phellinus noxius in the Ogasawara (Bonin) islands, southern Japan - current status of the disease and its host plants

“…In Japan, brown root rot was first found on Ishigaki Island, Okinawa Prefecture in 1988 (Abe et al 1995). Since then, the disease has been reported on many islands, causing serious problems in subtropical regions of southern Japan (Sahashi et al 2012).…”

“…LC049950 and LC049951) derived from two P. noxius isolates (WD 1223 obtained from a fruiting body and FFPRI 411142 obtained from a single basidiospore) as reference sequences. These isolates were identified as P. noxius by their morphological characters of fruiting bodies (Abe et al 1995;Corner 1932). Then, representative isolates including FFPRI 411142 collected from each of 38 different tree species were chosen (Table 1), and the DNA sequences of the LSU of the isolates were compared with the P. noxius reference sequences described above.…”

Molecular diagnosis of the brown root rot disease agent Phellinus noxius on trees and in soil by rDNA ITS analysis

“…Despite favoring woody trees, P. noxius can also attack some herbaceous plants [2,5,6] . P. noxius has been found in many tropical and subtropical countries and districts, including Singapore, Japan, Indonesia, Malaysia, Hai-T nan Island in China, Macao, Taiwan, Africa, Australia, Central America, and the Caribbean [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] . The wide geographical distribution of this pathogen and the severe damage it has caused have drawn significant concerns.…”