Granens rotröta orsakar stora förluster för skogsbruket

201

Juurikääpä eri-ikäisrakenteisessa kuusikossa – riskit ja torjunta

Tieteen tor

Tallens rotröta

201

Kuusen tyvilaho aiheuttaa suuria tappioita metsätaloudelle

201

Männyn tyvitervastauti – tunnistaminen ja torjunta

201

Pilottikoe tyvitervastaudin leviämisen estämiseksi sairaissa männiköissä

Posteri201

Identifiering och bekämpning av rotröta, 2019

201

Juurikääpätuhojen tunnistaminen ja torjunta, 2019

201

Significance of Heterobasidion species among wood decay fungi in northern peatland forests

In Nordic countries, Heterobasidion root rot is known as a widespread and severe disease affecting conifer trees on mineral soils, while our understanding of its occurrence in peatland forests is more limited. This study investigated the prevalence of Heterobasidion parviporum and H. annosum, along with common coexisting fungi in disease centers, in six Norway spruce-dominated and two Scots pine-dominated drained peatland forests in southern Finland. Among the 590 trees examined, Heterobasidion species were the most common fungi responsible for root rot in both spruce and pine stands. In mature spruce stands, Heterobasidion sp. had infected an average of 5.4 trees per hectare, and in pine stands, 4.5 trees per hectare. However, our results showed that compared to mineral soils in the same region, Heterobasidion sp. was neither as frequent nor as dominant in Norway spruce stands on peat soil. Furthermore, the absence of large multi-tree Heterobasidion genets in peatland forests indicated restricted progression of Heterobasidion infections. Instead of Heterobasidion sp., Armillaria sp. was the predominant decay fungus in three spruce stands and one pine stand, while Resinicium bicolor was dominant in one spruce stand. Interestingly, Armillaria cepistipes, less pathogenic than A. borealis and rarely causing decay on spruce on mineral soil, was the most common Armillaria species at peatland sites. Further in-vitro-tests revealed that certain fungal isolates from the disease centers were highly competitive against H. parviporum. These isolates included both basidiomycetes, such as Stereum sanquinolentum and Amylostereum aerolatum, as well as the ascomycetes, Acocoryne sp., Leptodontidium elatius, and Rutstroemia calopus. Our findings led us to speculate that the competitive ability of Heterobasidion sp. against coexisting fungi might be lower in peatland conditions compared to mineral soils. Moreover, the potential risks and benefits of continuous cover forestry (CCF) regarding Heterobasidion root rot are discussed. Considering the relatively low prevalence of the pathogen in peatland forests and the more beneficial environmental effects of CCF compared to clear-cut-based rotation forestry, CCF appears to be a viable management option in spruce-dominated stands on drained peat soil. However, to ensure the health of peatland forests in the future, controlling Heterobasidion root rot is as crucial on peatland as it is on mineral sites