Parasitic association of the mycetophagous wood nematode, Bursaphelenchus fraudulentus with the honey fungus Armillaria ostoyae

Abstract

Honey fungi, Armillaria spp. are common and economically important pathogens of a wide range of tree species grown both in the forest and orchard cultures worldwide.Our field research in 73 forest stands across Poland has shown a common association of the mycetophagous wood nematode, Bursaphelenchus fraudulentus with Armillariainfected trees. The data reported here provide the first insight into the parasitic interaction of a nematode and Armillaria ostoyae. In laboratory conditions, B. fraudulentus reproduced on A. ostoyae, caused substantial damage to its mycelium and, finally, killed the whole colony within a short time. In ageing cultures, the nematode produced resting (dauer) juveniles. After artificial inoculation to Armillaria-infected trees, the nematode population persisted under the bark, continued feeding and mass reproduction on the mycelium, and dispersed over the mycelial fans. The ability of B. fraudulentus to develop and reproduce on the surface and inside the fungal rhizomorphs suggests that these structures could facilitate the nematode dispersion in the environment. Since B. fraudulentus is not pathogenic to the host tree, its parasitic association with A. ostoyae may contribute to natural regulation of this fungus in the environment.The observed characteristics of this nematode suggest that it could potentially be used as a biocontrol agent of honey fungi in forest and orchard trees.

Bursaphelenchus crenati Rühm, 1956 (Tylenchina: Aphelenchoididae), a nematode associated with the Greater ash bark beetle, Hylesinus crenatus Fabricius, in dying ash, Fraxinus excelsior L., in Europe

“…Wood-inhabiting nematodes in Bursaphelenchus are usually transported to new breeding trees with the aid of insect vectors (Rühm, 1956;Massey, 1974), although alternative means of transmission by direct contact with infected wood particles and roots or in/on rhizomorphs of tree-pathogenic fungi have been also suggested in the literature (Halik & Bergdahl, 1992;Tomalak, 2017). In our study, B. crenati was found associated exclusively with trunks of older F. excelsior infested with H. crenatus.…”

Assessment of the PCR technique for identification of Bursaphelenchus mucronatus Mamiya & Enda 1979, B. xylophilus Steiner & Buhrer 1934 (Nickle 1970) and B. fraudulentus Rühm 1956 (Nematoda, Aphelenchoididae) in crude extract of nematodes isolated from wood

“…Drugim, blisko spokrewnionym z poprzednimi jest również niepatogeniczny B. fraudulentus. W przeciwieństwie do obu wcześniej wymienionych gatunków nicień ten związany jest głównie z drzewami liściastymi, lecz okazyjnie może występować również w sośnie (Tomalak 2017). Morfologicznie gatunki te są trudne do odróżnienia i wymagają szczególnej uwagi w trakcie analizy materiału pobranego z drewna, gdzie występuje również wiele innych nicieni.…”

The Threat of Pests and Pathogens and the Potential for Biological Control in Forest Ecosystems

“…Many nematodes are used in tree crops as biocontrol agents [116][117][118]. The parasitic association between the nematode Bursaphelenchus fraudulentus and the fungus Armillaria ostoyae helps to maintain Armillaria populations at sublethal levels [119].…”