Why Does Phlebiopsis gigantea not Always Inhibit Root and Butt Rot in Conifers?

Abstract

This review aims to identify possible causes of differing effectiveness of artificial biological control of Heterobasidion root rot by the saprotrophic fungus Phlebiopsis gigantea. We describe published information in terms of pathogen–competitor relationships and the impact of environmental and genetic factors. We also revisit data from original research performed in recent years at the Forest Research Institute in Poland. We hypothesized that, in many cases, competition in roots and stumps of coniferous trees between the necrotrophic Heterobasidion spp. and the introduced saprotroph, Phlebiopsis gigantea, is affected by growth characteristics and enzymatic activity of the fungi, the characteristics of the wood, and environmental conditions. We concluded that both wood traits and fungal enzymatic activity during wood decay in roots and stumps, and the richness of the fungal biota, may limit biological control of root rot. In addition, we identify the need for research on new formulations and isolates of the fungal competitor, Phlebiopsis gigantea, as well as on approaches for accurately identifying the infectious threat from pathogens.

Control of Heterobasidion in Norway Spruce Stands: The Impact of Stump Cover on Efficacy of Urea and Phlebiopsis gigantea and Implications for Forest Management

“…Furthermore, Wang et al [29] found that treatment of Larix x eurolepis stumps with urea resulted in more stable effects in control of Heterobasidion than using BCA. The average air temperature during experiment establishment was close to the optimal for P. gigantea development [57], and our data indicate that, although the total precipitation in the three-week period following establishment of the experiments was low, it was sufficient to ensure favorable conditions for fungal growth.…”

“…These results are in agreement with those obtained in other studies, where the efficacy of urea and P. gigantea were similar [5,20,29]; however, urea has been documented to have higher efficacy in comparison to P. gigantea in some studies [26,33,34]. Moreover, development of P. gigantea depends on (i) stump treatment coverage quality [28,30,53]; (ii) stump and root wood moisture content, which in turn depend on the humidity during the treatment period [53], weather conditions and seasonality [54][55][56]; (iii) growth characteristics of different P. gigantea isolates [43]; (iv) enzymatic activity of the fungi; (v) the characteristics of the wood; and (vi) the richness of the fungal biota [57]. Furthermore, Wang et al [29] found that treatment of Larix x eurolepis stumps with urea resulted in more stable effects in control of Heterobasidion than using BCA.…”

Afforestation of Land Abandoned by Farmers Poses Threat to Forest Sustainability Due to Heterobasidion spp.

“…This phenomenon is called hyphal interference. When the hyphae of these fungi come into contact, the Heterobasidion hyphae are rapidly destroyed locally [87].…”

Efficacy of Biological and Chemical Control Agents against Heterobasidion Spore Infections of Norway Spruce and Scots Pine Stumps on Drained Peatland

“…[ 28 ]. Environmental conditions, stump size, and properties of stump wood, including wood moisture content, have also been shown to have a decisive influence on the control result [ 23 , 24 , 25 , 29 , 30 ].…”