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1.
Two Rotstop® preparations, one containing a Phlebiopsis gigantea strain from Finland (Rotstop F) and the other one from Sweden (Rotstop S), were used in different concentrations to treat thinning stumps of Picea abies against spore infections by Heterobasidion spp. in southern Sweden. Trees were cut on three sites during the summer of 2004, and 285 stumps were treated manually ensuring 100% coverage. Spore concentrations in the treatment suspensions were ca 5 × 106 and 10 × 106 spores/l, and approximately 10 ml of suspension was applied per 100 cm2 of stump surface. An additional 31 stumps on one of the sites were treated mechanically with Rotstop S; in this treatment the spore concentration was high, about 20 × 106 spores/l, but the coverage was incomplete. Three months later there was a significant reduction in frequency and relative areas of Heterobasidion spp. infections on stumps with manual treatment compared with the untreated stumps. However, there was no significant difference between the preparations or the concentration of active ingredient in terms of their reduction of Heterobasidion infection. Mechanical treatment with incomplete coverage failed to control infection. Therefore, in conditions of moderate Heterobasidion spore load in the environment there seems to be no reason to use higher concentrations of P. gigantea in the treatment of spruce stumps.  相似文献   

2.
Natural colonization by the root and butt rot causing fungi Heterobasidion spp. on Norway spruce (Picea abies) stumps following thinning and treatment with the biological control agent Phlebiopsis gigantea was investigated on three sites in southern Sweden 6 years after treatment. The fully treated stumps and control stumps were excavated and sampled to compare the survival of Heterobasidion spp. in the long term. Six years post‐treatment, 47 and 11% of untreated and treated stumps, respectively, had Heterobasidion infection. There was no difference in the relative infected area in discs collected from the butt and the roots for the different treatments. Control efficacy was 83% for treated stumps. After 6 years, there were no apparent differences between the remaining infections in treated compared with those in untreated stumps regarding the number of colonies, their size or relative infection area. Although infections, 3 months after treatment with P. gigantea, were significantly fewer and smaller than in untreated stumps, Heterobasidion inoculum can survive for at least 6 years in the stump and, when it does, constitute a risk for neighbouring trees.  相似文献   

3.
The efficacy of stump treatment with 40% urea solution and spore suspension of Phlebiopsis gigantea against primary infection by Heterobasidion spp. on hybrid larch (Larix × eurolepis) was tested in two field studies in southern Sweden. In the first study, stumps treated with urea or P. gigantea were sampled by cutting a cross‐section disc after 3 months following exposure to natural conditions, and in the second study, stumps treated with only P. gigantea were sampled after 2 months. Spore traps made from hybrid larch, Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) were used to estimate the abundance of ambient spores of Heterobasidion spp. in the second study. Urea significantly reduced infection frequency of Heterobasidion spp. compared to the control. Phlebiopsis gigantea was less effective at reducing infection frequency in the first study than in the second study. Infections were caused by both H. parviporum and H. annosum sensu stricto. The amount of H. annosum infection in proportion to Heterobasidion spp. was significantly lower on the stumps treated with P. gigantea compared to the control; however, the proportion of H. parviporum on the treated stumps was not higher than the control in the first study. Spore traps made of Scots pine had a significantly higher frequency of infection than Norway spruce and hybrid larch. Only the spore traps made of hybrid larch showed significant correlation with the control stumps in terms of relative infected area. Conclusively, it seems prudent to protect hybrid larch stumps from primary infection by Heterobasidion spp., and both urea and P. gigantea can be recommended as stump treatment agents on hybrid larch, even if urea seemed to present more stable results.  相似文献   

4.
Fungal isolations and genetic fingerprinting were used to determine whether Phlebiopsis gigantea stump treatment against Heterobasidion annosum sl. using a single genotype (Rotstop) would affect the genetic diversity of P. gigantea populations. The survival time of P. gigantea was longer in Norway spruce (Picea abies) stumps compared to Scots pine (Pinus sylvestris) as no isolates were obtained from pine stumps 6 years after treatment, whereas in about half of the spruce stumps the fungus was still present. The usage of Rotstop did not seem to increase the occurrence of the fungus 5 years after the treatment in fresh (1‐year‐old) untreated stumps within the same forest stands. All the isolates from the 6‐year‐old treated spruce stumps were identical in genotype with the Rotstop‐strain, whereas all isolates from the fresh untreated spruce and pine stumps differed from it. Within the treated pine stand, the biocontrol usage seemed to have caused a slight reduction in genetic markers not related to Rotstop, but there were no statistically significant differences between the marker frequencies and the local natural population. Thus, Rotstop is not likely to cause any immediate threat to the genetic diversity of P. gigantea.  相似文献   

5.
Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.  相似文献   

6.
The properties of 64 heterokaryotic strains of Phlebiopsis gigantea, isolated mostly from Norway spruce stumps, were tested for asexual spore production, growth rate and competitive ability against Heterobasidion spp. on agar medium, and for growth rate in spruce wood. Eighteen isolates were also tested for the efficacy of control against Heterobasidion spp. in stem pieces of spruce. The results revealed high variation in traits between different P. gigantea isolates. The efficacy of control against Heterobasidion spp. and the growth rate in spruce wood were closely related to each other (r = 0.727, p < 0.001). These preliminary tests indicate that the growth rate of a P. gigantea strain in spruce wood is the most important characteristic determining its efficiency in controlling the infection and spread of Heterobasidion spp. in spruce stumps.  相似文献   

7.
In an experiment established on three Norway spruce sites in southern Sweden, the ability of five strains of Phlebiopsis gigantea, including the commercial strain Rotstop®, and two Trichoderma formulations to control natural Heterobasidion spp. spore infections was compared. At each site 160 trees were felled, and the resulting stumps were treated with spore suspensions of the seven fungal preparations. Twenty stumps at each site were left untreated as control stumps. When sampled 9 months after treatment, two of the P. gigantea strains (1984 and 1985) were the most effective at preventing infection by Heterobasidion spp. The other three P. gigantea strains were less effective, and two Trichoderma formulations did not significantly reduce Heterobasidion spp. infections.  相似文献   

8.
The natural establishment of the root and butt rot causing fungus Heterobasidion annosum s.l. on Norway spruce (Picea abies) thinning stumps treated with Phlebiopsis gigantea was investigated on seven sites in southern Sweden. The trees were cut during summertime and the stumps were treated with different patterns simulating the effect of mechanical stump treatment with a single‐grip harvester. Sampling was conducted 3 and 12 months after treatment. At both samplings, the best control was obtained when 100% of the stump surface was covered by P. gigantea: in contrast, untreated control stumps showed the highest incidences of H. annosum s.l. infection at both sampling times. However, 30 and 26% of the fully covered stumps at the first and second samplings, respectively, were diseased, and question the efficacy of treating Norway spruce stumps with this biological control agent in Sweden.  相似文献   

9.

The spread of Heterobasidion parviporum Niemelä & Korhonen in roots of Norway spruce was studied in three unthinned first rotation stands of Norway spruce [Picea abies (L.) Karst.] on former agricultural land in south-western Sweden. Heterobasidion parviporum was inoculated at stump height into the trunk of 135 standing trees in a randomized block design. One year after inoculation, two-thirds of the trees were thinned out and one-third was left standing. Half of the stumps left by thinning were treated with spores of Phlebiopsis gigantea (Fr.) Jül and half were left untreated. The spread of H. parviporum was examined both 3 and 5 yrs after inoculation. The rate of spread of H. parviporum and the proportion of infected roots were found to be significantly higher in the root systems of the stumps than in those of the standing trees. Treatment with P. gigantea had no significant effect on the development of H. parviporum in the stumps. There was a tendency 5 yrs after inoculation, however, for a lower proportion of H. parviporum-infected roots in the stumps treated with P. gigantea than in the untreated stumps. In conclusion, thinning of infected Norway spruce was found to increase the rate of spread of H. parviporum in the root systems of the infected trees, which could increase the risk of a rapid build-up of infection in the remaining stand.  相似文献   

10.
Abstract

Pine stumps are not being treated against Heterobasidion spp. in Sweden. To determine whether they should be, the frequency of stump infections and the species of Heterobasidion involved were investigated in nine newly thinned pure Scots pine (Pinus sylvestris L.) stands in southern Sweden. The incidence of Heterobasidion was measured in roots of standing Scots pine in another 15 stands. Infections by both H. annosum (Fr.) Bref. s.s. and H. parviporum Niemelä & Korhonen were numerous in stumps six months after a summer thinning. The pathogen, mostly H. annosum, was found in 44 of 60 sampled root systems, from 14 of the 15 stands. Twenty of the infected pines were assessed as healthy on the basis of crown symptoms while 24 trees had defoliated crowns. Infected root systems were most frequent among trees with thin crowns in stands on former agricultural land, where previous thinnings had been carried out during the growing season when airborne spores are plentiful. The study suggests that stump treatment may be a profitable way to reduce disease development in Scots pine monocultures on sandy soils as well as in mixtures with Norway spruce [Picea abies (L.) Karst.] on any soil.  相似文献   

11.
The relationship between the proportion of the stump surface covered by the biological stump treatment agent PG Suspension, containing Phlebiopsis gigantea and its efficacy against the pathogen Heterobasidion annosum sensu stricto was studied during a first thinning of Corsican pine (Pinus nigra ssp. laricio) in Thetford Forest, UK. PG Suspension was manually applied to 100%, 75%, 50% or 0% of the surface of 150 stumps. Spores of H. annosum were inoculated onto 75 of the stumps, and the remaining stumps exposed to natural airborne spore deposition. The relationship between coverage and efficacy was found to be quantitative. Covering all the stump surface with PG Suspension completely excluded the pathogen, whereas stumps not treated with PG Suspension (the 0% treatment) became infected with H. annosum. Partial (75%) PG Suspension coverage resulted in the pathogen colonizing 40% of stumps following artificial inoculation with H. annosum, and just 7% of stumps exposed to ambient H. annosum spore infection. Decreasing levels of coverage allowed increasing areas of the stump surface to be colonized by H. annosum. Some small gaps in coverage were closed by lateral growth of P. gigantea, but it is recommended that operators aim for full stump coverage to give complete protection against H. annosum.  相似文献   

12.
The effectiveness against Heterobasidion natural airborne infections on Norway spruce stumps was tested for six treatments: aqueous suspension of Phlebiopsis gigantea oidiospores, 10%, 20% and 30% aqueous urea solutions, 4% copper oxychloride aqueous solution, and borax powder. The experiment was carried out in four naturally regenerated forests in the western Alps, each characterized by a different airborne inoculum potential. Within each stand, all treatments, with the exception of urea 10%, were effective and resulted in colonized areas of stumps significantly lower than controls. The effect of ambient spore loads on the stump colonization is discussed.  相似文献   

13.
Management of a Norway spruce stand planted on a site infected by Heterobasidion coll. is problematic because the fungus spreads vegetatively from the colonized stumps of the previous generation to the new seedlings. Growing of mixed stand with more resistant tree species has been suggested to decrease the economic losses caused by butt rot in Norway spruce trees. The mechanistic simulation model Rotstand describing the spread of Heterobasidion coll. in coniferous stands of southern Finland was used to study the effect of planting Scots pines around colonized clear‐felling stumps of Norway spruce of the previous generation. Planting of Scots pines in clusters around colonized stumps markedly decreased the butt rot of Norway spruce trees at the age of 20 years and at clear felling. If the same number of Scots pines were planted randomly, the effect was weak. When the average diameter of colonized clear‐felling stumps was 30 cm, a Scots pine circle with a radius of 3 m resulted in the highest soil expectation value (SEV) at 2% discounting rate, whereas with 40‐cm stump diameter, a 4‐m radius produced the highest SEV. When the proportion of Heterobasidion parviporum in the old colonized stumps was 50% instead of 95%, planting pines around colonized stumps still clearly decreased the butt rot at the age of 20 years and in final felling.  相似文献   

14.
In the Western Italian Alps (WIA), the three European species of the forest pathogen Heterobasidion spp. can coexist in the same area. Heterobasidion parviporum Niemelä & Korhonen and Heterobasidion abietinum Niemelä & Korhonen are normally found in areas with a significant presence of their respective primary hosts, spruce (Picea spp.) and fir (Abies spp.). The host/niche occupied by Heterobasidion annosum (Fr.) Bref. in the region still remains unclear. Although Scots pine (Pinus sylvestris), a major host for this fungal species in other parts of Europe, is abundant in the region, little or no evidence of disease caused by H. annosum is visible in this tree species. Two different, but not mutually exclusive, hypotheses can explain the presence of H. annosum: (1) Scots pines are infected but largely asymptomatic and (2) H. annosum has adapted to different hosts. An analysis of Heterobasidion species was performed in two natural, mixed‐conifer forests using traditional isolation techniques and novel direct molecular diagnosis from wood. In a subalpine stand of mixed spruce (Picea abies), larch (Larix spp.), and Swiss stone pine (Pinus cembra), 18 naturally infected spruces and larches only yielded H. parviporum. A Swiss stone pine in the same stand was extensively colonized by both H. parviporum and H. annosum. In a second subalpine stand, an analysis of 18 spruce stumps and nine Swiss stone pine stumps yielded both H. parviporum and H. annosum isolates. Pine stumps had been mostly colonized by H. parviporum prior to tree felling, suggesting that this species may be secondarily infected by the locally predominant Heterobasidion species (i.e. H. parviporum). Results of our analysis also indicated that primary colonization of spruce stumps (e.g. through basidiospores) was caused by both H. parviporum and H. annosum, while secondary infection of such stumps was mostly because of H. parviporum.  相似文献   

15.
Fomes annosus is the most important root pathogen in British forestry. In pine crops, F. annosus is often checked when stumps are naturally colonised by Peniophora gigantea. Experimental inoculation of stumps with P. gigantea reduced infection by F. annosus in first rotation crops and was as effective as chemical stump treatments. In severely diseased pine crops, P. gigantea inoculation reduced but did not eliminate F. annosus. P. gigantea is produced commercially and is used in many pine forests in Britain.  相似文献   

16.
The efficacy of a native isolate of Phlebiopsis gigantea in protecting the stumps of Pinus pinea against spore infection by Heterobasidion annosum s.str. was investigated. In preliminary tests carried out in stem pieces of P. pinea in confined environment, the efficacy of the isolate was compared with Rotstop®, the commercial formulation prepared from a north European P. gigantea strain. Both showed a fully protective effect against artificial inoculation of H. annosum. Moreover, in stump treatment experiments carried out in a coastal P. pinea forest close to Rome, the native P. gigantea was effective against heavy airborne inoculum of H. annosum. Some natural infection by P. gigantea occurred in the stumps, but it was unable to control the pathogen. Random amplified microsatellite analysis allowed to recognize the presence of different P. gigantea strains in the forest.  相似文献   

17.
Fruiting of Heterobasidion on cull pieces and stumps of Norway spruce was investigated in cutting areas and mature spruce stands located in southern Finland. Cull pieces of variable size and showing butt rot were left on three clear‐cut areas and in one thinned stand. Additionally, a part of the cull pieces was transported to mature forest sites with closed canopy. During the succeeding 3–4 years the cull pieces were investigated annually for sporocarps of Heterobasidion, and the area of actively sporulating pore layer of each sporocarp was measured. Root bases of spruce stumps in the logging areas were excavated and sporocarps found on the stumps also measured. At the onset of the experiment, Heterobasidion spp. were isolated from 76% of the cull pieces showing butt rot; 85% of the isolates were identified as H. parviporum and 15% as H. annosum s.s. During the following 3–4 years sporocarps were found on 20% of the 1938 cull pieces where Heterobasidion butt rot was initially detected visually. Sporocarp formation was promoted by advancement of butt rot, increasing cull piece diameter and end‐to‐end ground contact, but restricted by the colonization of the cull piece by Stereum sanguinolentum. Between‐site differences were significant but could not be explained by differences in tree cover. At the end of the investigation period the average sporulating area of Heterobasidion sporocarp per metre of cull piece was higher than the average sporulating area per stump at three of four logging sites. Hence, leaving cull pieces containing Heterobasidion butt rot at logging areas in southern Finland can considerably increase local production of Heterobasidion spores.  相似文献   

18.
Heterobasidion annosum (Fr.) Bref. s. l. colonization following thinning was studied in 1246 stumps of Picea abies (L.) Karst. trees from 14 previously unthinned stands in Sweden. Treatments included mechanized and manual application of (1) 35% urea solution, (2) Phlebiopsis gigantea (Fr.) Jül. spores, and (3) 5% solution of disodium octaborate tetrahydrate (DOT), and untreated stumps, cut in the summer and winter. Compared with untreated stumps cut in the summer, all stump treatments and winter cuttings significantly reduced the colonized stump area 6–7 weeks after thinning by 88–99%. Mechanized stump treatment provided as good protection as manual treatment against H. annosum infections. The probability of spore infection (p ij ) was reduced by 53–83% in mechanized treatment and 79–98% in manual treatment compared with untreated summer thinning. In terms of p ij , urea had significantly higher control efficacy than P. gigantea and manual treatment performed better than mechanized treatment.  相似文献   

19.
The occurrence of Heterobasidion annosum in stumps and growing trees was investigated on 15 forest sites in southern Finland where the previous tree stand had been Norway spruce (Picea abies) infected by H. annosum, and the present stand was either Scots pine (Pinus sylvestris), lodgepole pine (Pinus contorta), Siberian larch (Larix siberica), silver birch (Betula pendula) or Norway spruce 8–53 years old. Out of 712 spruce stumps investigated of the previous tree stand, 26.3% were infected by the S group and 0.3% by the P group of H. annosum. The fungus was alive and the fruit bodies were active even in stumps cut 46 years ago. In the subsequent stand, the proportion of trees with root rot increased in spruce stands and decreased in stands of other tree species. On average, one S type genet spreading from an old spruce stump had infected 3.0 trees in the following spruce stand, 0.5 trees in lodgepole pine, 0.3 trees in Siberian larch, 0.05 trees in Scots pine and 0.03 trees in silver birch stand. Although silver birch generally was highly resistant to the S type of H. annosum, infected trees were found on one site that was planted with birch of a very northern provenance.  相似文献   

20.
Spatial distribution of Heterobasidion genets over a period of ca 50 years in two successive generations of Norway spruce (Picea abies) was unravelled. The genets were first identified in 1993 in a naturally regenerated 43‐year‐old spruce stand that had been thinned the previous winter. Heterobasidion parviporum was found in 17.5% of the old stumps of the previous spruce generation. Nine genets were identified on the study plot; seven of them were present in old stumps of the previous tree generation and two only in the new spruce generation. Eighteen spruce trees of the new generation were infected, 15 of them by vegetative growth of genets originating from the old stumps. The study plot was investigated again in 2005. No new genets had been established after thinning, and three old genets had died out. The remaining genets had infected five new trees, most likely from the thinning stumps of diseased trees. At the age of 56 years, 16.1% of the residual spruces were infected by Heterobasidion. The results of this study suggest that if spore infection to stumps of spruce can be prevented, the decay frequency caused by H. parviporum will not necessarily increase in successive generations.  相似文献   

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