Leptographium tereforme sp. nov. and other Ophiostomatales isolated from the root-feeding bark beetle Hylurgus ligniperda in California

Abstract

The redhaired pine bark beetle Hylurgus ligniperda (F.) is native to Europe but was discovered in Los Angeles, California, in 2003. This root-and stump-feeding beetle is a common vector of Ophiostomatales, which are potential tree pathogens or causes of blue stain of conifer sapwood. In this study Ophiostomatales were isolated on a cycloheximide-amended medium from 118 adult H. ligniperda collected from infested logs of Pinus halepensis and P. pinea at two sites in California. In total eight species of Ophiostomatales were identified and seven species that occasionally were isolated were unidentified. The most frequently isolated species were Ophiostoma ips and Grosmannia galeiforme, which were isolated respectively from 31% and 23% of the 118 beetles. The other species isolated included O. piceae (isolated from 9% of the beetles), O. querci (8%) and Leptographium tereforme sp. nov. (6%). Grosmannia huntii, L. serpens, three Sporothrix species, O. floccosum, O. stenoceras, two unidentified Hyalorhinocladiella sp. and a sterile fungus each were isolated from fewer then 5% of beetles. Most of the identified species already were known in USA and have been found in association with H. ligniperda in other countries. However the new species, L. tereforme, and G. galeiforme were recorded from USA for the first time, and this is the first report of L. serpens from western North America.

Grosmannia and Leptographium spp. associated with conifer-infesting bark beetles in Finland and Russia, including Leptographium taigense sp. nov.

“…The ITS sequence of an isolate recently obtained from Hylurgus ligniperda (Fabr.) infesting P. halepensis L. and P. pinea L. in California (Kim et al 2011), and an unpublished ITS sequence from P. radiata L. in Spain (AJ538334), both labelled as G. galeiformis, also grouped with G. radiaticola.…”

“…in Sweden (Mathiesen-Käärik 1953), Hylastes ater Payk. and H. ligniperda on pines in Chile (Zhou et al 2004a), H. ligniperda in South Africa (Zhou et al 2001) and California (Kim et al 2011), stained P. radiata in Spain, Korea and NZ Thwaites et al 2005), and possibly D. valens Le Conte on P. tabuliformis Carr. in China (Lu et al 2009b).…”

“…The fungus was originally described from roots of non-native Pinus species in South Africa, infested by Hylastes angustatus Herbst, presumably introduced from Europe ( Wingfield and Marasas 1983;Wingfield 1985). Similarly, L. truncatum has repeatedly been found on non-native pines in New Zealand Reay et al 2005;Thwaites et al 2005;Kim et al 2011), and with T. piniperda introduced into Canada from Europe (Hausner et al 2005). However, L. truncatum does not appear to be a common associate of beetles in Europe, as it has only been reported from the UK and Spain (Romón et al 2007) on this continent.…”

Ophiostomatoid fungi associated with root‐feeding bark beetles onScots pine inPoland

“…; Kim et al. ). According to Kirisits (), host tree species can be an important determinant of the relationship between beetles and their associated fungi.…”

“…; Kim et al. ), none of the European studies have so far explored the relationships between ophiostomatoid fungi and Hg. ligniperda .…”