Zbigniew Sierota

Comparison of three products based on Phlebiopsis gigantea for the control of Heterobasidion annosum in Europe.

The fungus Phlebiopsis gigantea has been used in Europe as a biological agent for the control of conifer root and butt (caused by Heterobasidion annosum ) for nearly 40 years. P. gigantea competes with H. annosum for the woody resource within conifer stumps, and is applied to stump surfaces at felling. Three distinct biological control products based on P. gigantea have been developed: PG Suspension in the UK, PG IBL in Poland and Rotstop in Finland. The formulations are of oidia, which are maintained in a sucrose suspension, sawdust, or a wettable powder, respectively. PG Suspension and PG IBL are applied to pine stumps, while Rotstop is equally as effective on pine as on Norway spruce stumps. For each product, isolates of P. gigantea are selected from the wild and are screened for their competitive ability against H. annosum before formulation. Viability and purity checks are undertaken throughout the production cycle and during routine use. The increasing use of mechanized harvesting machines to fell and process trees is having an impact on this biological control system, the formulations having to be compatible with the mechanical application systems and vice versa. This paper compares the formulation, testing and application of the three products, and considers some aspects of their future development.

New Tuber species found in Poland

New information from a survey of truffles carried out in southern part of Poland in September 2007 is presented. The fruit bodies of Tuber aestivum, T. excavatum, T. rufum and one unidentified Tuber sp. were found. The soil chemistry of the five T. aestivum sites was analysed. Our inventory showed that T. aestivum prefers the mixed forest with host-trees such as: Quercus robur, Corylus avellana, Carpinus betulus, Fagus silvaticus and Tilia cordata. Selection of local inocula of T. aestivum for the propagation of truffles production could be an alternative to the Mediterranean truffles orchards in times when demand for the fungi will be increasing. Fruit bodies of truffles are conserved in the collection of biological material in the Forest Research Institute in Sękocin Stary.

Changes in nitrogen level and mycorrhizal structure of Scots pine seedlings inoculated with Thelephora terrestris

Abstract• We investigated the influence of Thelephora terrestris, an ectomycorrhizal fungus, on the concentration of nitrogen in needles of Pinus sylvestris L. seedlings and their mycorrhizal structure within four seasons of growth.• Seedlings were grown in four treatments: (I) inoculated + 0.030 g N, (II) inoculated + 0.045 g N, (III non-inoculated + 0.030 g N, (IV) non-inoculated + 0.045 g N under laboratory conditions and later planted in post-agricultural land.• For inoculated treatments, statistically significant differences in N concentration of needles were observed for two- and four-year-old seedlings. The number of ectomycorrhizae and concentration of N in needles were negatively correlated. After four seasons of growth the greatest numbers of ectomycorrhizae were present on seedlings from treatment II, and the smallest on seedlings from treatment IV.• Two-year-old seedlings had been colonized by at least six different fungal taxa, i.e. Cenococcum geophilum, Hebeloma crustuliniforme, Rhizopogon sp., Suillus bovinus, Thelephora terrestris and a non-identified one. Treatments I and II were dominated by the ectomycorrhizae of T. terrestris and their number was significantly greater than in treatments III or TV. On four-year-old seedlings ectomycorrhizae of T. terrestris were dominated in all treatments, while ectomycorrhizae of Hebeloma sp. were not found.Résumé• L’influence du champignon ectomycorhizien Thelephora terrestris sur la concentration en azote dans les aiguilles de semis de pin sylvestre et sur la structure mycorhizienne des plants a été suivie durant quatre saisons de croissance.• Les semis ont été cultivés sous quatre traitements : (I) inoculé + 0,030 g N, (II) inoculés + 0,045 g N, (III non inoculés + 0,030 g N, (IV) non inoculés + 0,045 g N, dans les conditions du laboratoire avant d’être plantés sur le terrain.• Dans les traitements d’inoculés, des différences significatives ont été observées dans la concentration des aiguilles en azote pour les semis de deux et quatre ans. Le nombre de mycorhizes et la concentration des aiguilles en azote étaient corrélés négativement. Après quatre saisons de croissance, le plus grand nombre de mycorhizes a été obtenu dans le traitement II et le plus petit dans le traitement IV• Les semis de deux ans avaient été colonisés par au moins six taxons différents de champignon : Cenococcum geophilum, Hebeloma crustuliniforme, Rhizopogon sp., Suillus bovinus, Thelephora terrestris et un autre taxon indéterminé. Dans les traitements I et II, les ectomycorhizes de T. terrestris dominaient et leur nombre était plus élevé que dans les traitements III et IV Pour les semis de quatre ans, les ectomycorhizes de T. terrestris dominaient dans tous les traitements, tandis que celles de Hebeloma sp. étaient absentes.

Characterisation of some Phlebiopsis gigantea isolates with respect to enzymatic activity and decay of Norway spruce wood

Abstract The activity of cellulase, peroxidase, phosphatase and dehydrogenase enzymes, together with the content of protocatechuic and vanillic acids, in samples of Norway spruce wood inoculated with 17 different isolates of Phlebiopsis gigantea was measured. The same isolates were used to compare decay activity in samples of Norway spruce wood after incubation for 3 and 6 months. Significant differences in enzyme activity and phenol production were found between aerial mycelium overgrowing the wood sample and the underlying wood. These differences indicated that the nature of the fungal mycelium appears to change depending on whether it is in contact with wood. After 6 months, highly extensive decomposition of the wood was shown by two British isolates. The results confirm a large difference in P. gigantea inoculum among isolates in natural conditions and reinforce the need for constant evaluation of the most active isolates to use in preparations for biocontrol: a problem for both users and registration bodies.

Evaluating the persistence of Phlebiopsis gigantea (Fr.: Fr.) Jülich mycelium and fruiting bodies in pine stumps after root-rot protection treatments

Ocena występowania grzybni i owocników Phlebiopsis gigantea (Fr.: Fr.) Jülich w pniakach sosnowych po wykonaniu zabiegu ochronnego przed hubą korzeni Evaluating the persistence of Phlebiopsis gigantea (Fr.: Fr.) Jülich mycelium and fruiting bodies in pine stumps after root-rot protection treatments Commercial preparations Rotstop and PgSuspension, used in Scandinavia and the United Kingdom, are EU-licensed biocontrol agents against root rot that contain isolates of the fungus Phlebiopsis gigantea. The composition of these two products differs from that of PgIBL, previously use in Poland, hence the need to verify their effectiveness under Polish site and stand conditions. Stumps were treated with the commercial products and subsequently checked after one year for the persistence of mycelia and fruiting bodies. Molecular methods were used on the mycelia present in the stumps to confirm that their genetic identity was consistent with fungal isolates from the preparations. Treatments with EU-licensed preparations gave satisfactory results - in about 70-80% of the stumps mycelia were present under the bark. Inoculation with Rotstop preparations was most effective during autumn 2008 (effectiveness of 82%), while PgSuspension application was most effective during spring 2008 (effectiveness of 77%). The development of the mycelia in pine stumps from the two preparations investigated (containing preserved dormant spores) was similar to that of preparation PgIBL (formulated from living mycelium within a growing medium), in terms of their relative effectiveness measured as the percentage of stumps supporting under-bark mycelia (which ranged between 70-90%, depending on the treatment term).

Pine sawdust as stimulator of the microbial community in post-arable afforested soil

ABSTRACT Sawdust and wood residues are considered to be stimulators of microbiological change in soil and could be used in post-arable sites designed for afforestation. In this study, we discuss changes in bacteria numbers within selected groups in relation to soil type (arable and forest) and method of sawdust application. Sawdust was spread along planting rows and mixed with the soil or put directly under roots of planted seedlings. Applying sawdust under the roots increased the number of cellulolytic bacteria in all experimental treatments. On post-arable soil, adding sawdust in rows increased the number of copiotrophic bacteria and reduced the number of fluorescent bacteria and actinomycetes (ACT). In control forest soils, the number of copiotrophic, oligotrophic and spore-forming bacteria decreased simultaneously with increased ACT in all treatments. The number of fluorescent bacteria increased when sawdust was applied on forest sites under planted trees and decreased when sawdust was spread in planting rows. Oligotrophic bacteria also decreased in the latter case. We present a list of bacteria identified by DNA – 16S rRNA gene sequences. Adding sawdust to arable soils significantly changed the quantitative and qualitative composition of microbial communities.

Decay indices for evaluating wood decomposition activity

The goal of the current study was to evaluate the efficiency of Norway spruce wood decomposition by the saprotrophic fungus Phlebiopsis gigantea (Fr.) Jülich. We identified the following indices as reliable measures of wood decay: decay acceleration index (DAI), final decay index (FD), and decay intensity index (DI). DAI was used to assess acceleration and deceleration of spruce wood loss, FD to estimate the final wood decay, and DI to evaluate the ability of the fungus to decompose wood, taking into consideration changes in mycelial activity over time. We tested the hypothesis that the wood decay activity of any fungus can be evaluated more objectively when: (i) several isolates of the tested fungus are assessed simultaneously, (ii) tests are performed for at least two time-points, and (iii) samples vary in wood density. Allowing a three-month period for wood decomposition was inadequate for reliable assessment of the wood decay ability of P. gigantea. Conversely, six months after inoculation, the tested isolates showed significant differences in their ability to generate dry wood loss, which depended on wood density. In view of these results, the DAI, FD, and DI indices are practical tools for assessing fungal activity to predict wood loss.

Influence of laser light on mycelial growth of Hebeloma mesophaeum and ectomycorrhizal development on Scots pine

Abstract The effects of exposure to helium-neon (He-Ne) or Argon (Ar) laser light (λ=632.8 nm and 514 nm, respectively) on the growth of Hebeloma mesophaeum mycelium in pure culture were studied. Growth rates were highest after exposure to the He-Ne laser (1×60 s)+Ar laser (2×60 s) and to the He-Ne laser for 3×30. Container-grown Pinus sylvestris (pine) seedlings were inoculated with a water suspension of H. mesophaeum mycelium previously exposed to different kinds of laser light. After 3 months, the percentage of mycorrhizal associations on pine roots was 34.3% higher after He-Ne laser treatment and 47.1% higher after Ar laser treatment than in the controls with untreated fungus. However, seedlings infected with treated fungus were smaller than the control. Overall, laser light stimulated growth of H. mesophaeum mycelia in pure culture and enhanced mycorrhizal development on Scots pine seedlings.

Slow sand filtration for elimination of phytopathogens in water used in forest nurseries

Irrigation water from natural sources can be contaminated by fungi, Oomycota, or bacteria capable of causing serious diseases in seedlings in forest nurseries. Slow sand filtration (SSF) is a cost-effective technique for water decontamination prior to irrigation. The aim of the current study was to assess the effectiveness of SSF as a means of eliminating plant pathogens including Pythium sterilum, Fusarium solani, Xanthomonas campestris, Pseudomonas syringae pv. Syringae and Rhizobium radiobacter from the lake water source used for irrigation. The applied SSF was effective in removing 80–90% of fungal and Oomycota inoculum as well as 70% of the bacteria in the investigated water. Therefore, SSF represents a practical step to lowering the use of pesticides during production of planting stocks in forest nurseries and a valuable element in an integrated plant protection system.

Chemical composition of soils on post-agricultural and forest sites before and after sawdust addition against the background of weather elements

Abstract We analysed changes in soil chemical properties (pH, C:N, N, P, K, Ca, Na) inside two forest areas chosen for renewal (Lubartów A and B) and within one post-agricultural site (Świerczyna) designated for afforestation with Scots pine. The experimental plots were located in areas known as persistent cockchafer grub spots. The Lubartów A site was not fenced and showed signs of wild boar activity. Analyses were carried out in the autumn of 2011 and spring 2012, prior to pine sawdust application to the soil and before tree planting, respectively, and again one year later in May 2013. Precipitation as well as air and soil temperatures were recorded throughout the experimental period. We found that soil temperature and humidity, determined by changes in weather, differences in soil chemical properties between forest and agricultural sites as well as sawdust treatments differentially affected soil reaction, C:N ratios and nutrient content. In the unfenced area (Lubartów A), the content of nutrient forms available to plants decreased no more under sawdust treatment than under control conditions. In the remaining areas, sawdust treatment caused an increase or no change in soil concentrations of the investigated nutrients. Under suitable temperature and humidity conditions, sawdust can represent a significant source of energy-rich compounds promoting diversified edaphone activity, which appears to be the main reason for changes in soil nutrient content.