Genetic variation in Picea abies (L.) Karst. and Fomes annosus (Fr.) Cke. shown by growth of the fungus on wood dust

Growth of Fomes annosus is studied by a test based on growth of previously starved hyphae on sawdust of heartwood of Picea abies as the only nutrition. Our observations show that the method can be used to distinguish beween different spruce individuals or clones, between different Fomes annosus strains and between different growing sites of the trees.     

Stamm- und Wurzelfäulen in Douglasien,Pseudotsuga menziesii (Mirb.) Franco1

Stem and root rot of Douglas fir, Pseudotsuga menziesii (Mirb.) Franco. In 20 year old Douglas fir most of the butt rot was caused by Fomes annosus. Stem decay was central as well as eccentric reaching the sap wood in either case. The side roots of 20 year old Douglas fir were compared with those of a 40 year old stand with butt rot. In individual trees with decay there were less roots with Fomes annosus decay in the younger stand. Calocera viscosa was more abundant in the older stand. Soil conditions which might have favoured root rot in the young stand are discussed.     

Incidence and severity of annosus root rot in Loblolly pine plantations in Virginia

Fourteen plots of 25 loblolly pines each were excavated by bulldozers in order to determine incidence and severity of Heterobasidion annosus in asymptomatic loblolly pine in Virginia. Of the 350 trees sampled, 85% were infected with H. annosus. Basidiocarps were found on 9% of the sampled trees. The average frequency of roots infected per tree with H. annosus, for all measured trees (trees with > 1% infection evident), was 30% of the primary roots and 31% of the secondary roots. The average root length infected for all the measured trees was 14% for primary roots and 15% for secondary roots.     

Fomes annosus (Fr.) Cke. und andere Stammfäulepilze in einem Douglasienbestand,Pseudotsuga menziesii (Mirb.) Franco1

Fomes annosus (Fr.) Cke. and other decay fungi in a Douglas fir stand, Pseudotsuga menziesii (Mirb.) Franco. 40% of the trees in a 40 years old Pseudotsuga menziesii stand showed butt rot. 85 trees were analysed for decay fungi. Fomes annosus, the most frequent fungus, also invaded the sap wood. Factors of the soil favourable to the rot and the possibility of transmission of the most frequent decay fungus, Fomes annosus, from (a) neighbouring spruce stands, (b) from the roots of Scots pine from the previous crop arc discussed. Caniophora puteana was isolated from about 10% of the butt rots. The importance of Calocera viscosa which grew out of the central decay of twelve trees as a decay fungus is still under investigation.     

A comparison of isolation methods for determining the incidence of Fomes annosus in living loblolly pine1

Several methods were utilized to determine the disease incidence of Fomes annosus (Fr.) Karst. in selected 0.02 hectare plots established in five thinned loblolly pine (Pinus taeda L.) plantations. A total of 79 trees were sampled. Infection as determined by the presence of conks was 2.5 percent. Increment borer samples (two/tree) removed from the root collar zone revealed 10.1 percent infection. Root chip isolations from two, 45 cm long roots per tree indicated 31.6 percent infection. In a random sampling of 10 trees in each of the five plantations, 18 percent infection was found using the two root method. These results indicate that F. annosus may be more prevalent than previously reported.     

Fomannoxin production by different spruce isolates of Fomes annosus

In vitro production by five isolates of Fomes annosus obtained from diseased spruce trees in Irish Forestry plantations is compared. Identification of these isolates as five distinct strains is based on quantitative differences in fomannoxin production, differences in linear growth rate and mycelial interaction between isolates in paired culture.     

A Study of Losses in Scots Pine caused by Fomes annosus

Data are presented from unreplicated Scots pine {Pinus sylvestrisL.) sample plots in Thetford Forest which have been differentiallyattacked by Fomes annosus (Fr.) Cooke. Volume production ofseverely infested crops differs markedly from that forecastby management tables. The volume of dead trees may not representthe total loss of volume in these plots as there appears alsoto be a reduction in the growth of the remaining live trees.These observations may have considerable significance in forecastingfuture volume production from stands attacked by F. annosusand also in deciding the optimum time for their replacement.     

Fomannoxin,a phytotoxic metabolite of Fomes annosus: in vitro production,host toxicity and isolation from naturally infected Sitka spruce heartwood

The effect of different culture conditions on growth and production of fomannoxin and the sesquiterpene phytotoxin fomannosin by a single isolate of Fomes annosus was studied. Whereas fomannoxin was produced by actively growing hyphae, fomannosin production was associated with the declinning growth phase of the fungus. The presence of fomannoxin in chloroform extracts from the stained stein heartwood zone of Fomes annosus diseased Sitka spruce trees was established. Fomannosin however was not detected. Toxicity of fomannoxin to germinating seeds and young seedlings of Sitka spruce was demonstrated.     

Inoculation of pine stumps with Peniophora gigantea by chainsaw felling

By adding oidia of Peniophora gigantea to the lubricating oil of a chainsaw, stumps were automatically inoculated as the trees were felled. An experiment on Pinus sylvestris showed that direct chainsaw inoculation gave comparable results in terms of abundance of P. gigantea and control of Fames annosus, as conventional inoculation of stumps after felling.     

The influence of chemical factors on the selectivity of Pinus resinosa stumps for Fomes annosus

Fresh pine stump surfaces act selectively for primary invaders such as Fomes annosus that competes successfully against other microorganisms. However, a series of chemical reactions on the stump surface due to aeriation and the hosts response to wounding may be implicated in the selectivity of the host for certain microorganisms. The theory of stump selectivity of coniferous trees for F. annosus as well as the theory of wound reaction and protection wood are discussed. The sequence of events after wounding is complicated and the present investigation concentrates on the processes associated with the host response to wounding.     

Influence of acidity on the growth of Trichoderma viride Pers. ex Fr. and on the inhibitory effect of its filtrates against Fomes annosus (Fr.) Cke. in artificial cultures

This work reports results of observations on mycelial dry weight yield, pH changes and the inhibitory effect of filtrates of Trichoderma viride on linear growth of the mycelium of Fomes annosus. The maximum mycelial yield of T. viride, derived from spores was obtained within the pH range 2,5–3,1. The greatest inhibitory effect of filtrates on the mycelial growth of F. annosus occurred at an initial pH of the Trichoderma cultures from 2,0-3,5. At other pH-values, no inhibition was found.     

Modern aspects of biological control of Fomes and Armillaria1

Biological methods can help to control root-infecting fungi such as Fomes annosus and Armillaria mellea. For example, inoculation of pine stumps with the fungus Peniophora gigantea is widely used against F.annosus in Britain. Experiments arc in progress to determine whether similar methods can be used for stumps of other conifers. The main sources of infection by Armillaria are stumps of broad-leaved trees, which are often treated chemically to prevent regrowth. Some of these treatments promote colonization by saprophytic fungi that compete well with Armillaria. In experiments, direct inoculation of stumps combined with chemical treatment has given encouraging results.     

Wundfäule in Fichtenwaldungen mit alten Schälschäden

Wound decays in spruce stands following bark stripping . 2083 trees in 91 sample plots on four trial areas (24 ha) were examined for bark stripping and decay. Only 25% of trees showed no injury. Of the injured trees, 73% showed some degree of decay, 10% discoloration. and 17% neither decay nor discoloration. Of the wood destroying fungi isolated Fomes annosus was dominant and appeared to be the most important and widespread of the wound inhabiting fungi in the test area. Besides the Basidiomycetes a considerable number of other fungi was isolated. The most frequent was Cylindrocarpon cylindroides var. tenue.     

Fomes annosus Butt-Rot of Sitka Spruce IV. Observations on the Distribution of Cryptosporiopsis abietina (Petrak) in the Stems of Rotted Trees

Cryptosporiopsis abietina was isolated from the heartwood of12 out of 18 Sitka spruce suffering from butt rot caused byFomes annosus, but from none of eight healthy trees from thesame plantations. C. abietina was present in a distinct zoneabove the tissue colonised by F. annosus. It was present inboth sound wood, and in wood with stain or incipient decay. C. abietina inhibited the growth of F. annosus on malt agar,and to a lesser extent in autoclaved Sitka spruce heartwood.The possible influence of this potentially antagonistic funguson infection by F. annosus is briefly discussed.     

Relative susceptibility of selected pure and hybrid pines to Fomes annosus (Fr.) Cke.

Eight strains of Fomes annosus (Fr.) Cke. were grown on malt and potato dextrose agar to determine their growth rates. Pine wood from several locations in P. resinosa trees was tested to ascertain which sample area was best-suited for fungal growth studies. Fifteen pines were ranked according to relativc susceptibility to two strains of F. annosns. Pinus densiflora Sieb. and Zucc. and P. rigida × radiata were most “resistant” and “susceptible” respectively.     

Inhibitory effect of Trichoderma viride Pers. ex Fr. filtrates on Fomes annosus (Fr.) Cke. In relation to some carbon sources

The mycelial yield of Trichoderma viride on a number of carbon sources and the inhibitory effect of its filtrates on Fomes annosus were investigated. d-Xylose and d-glucose as carbon sources in the media gave the highest degree of inhibition when their filtrates were directly tested against F. annosus mycelium. The protection of pine wood blocks with filtrates was most effective when these were derived from cellulose and d-xylose.     

Zum Vorkommen von Fomes annosus (Fr.) Karst. im Boden von Fichtenbeständen (Picea abies Karst.)1

Occurrence of Fomes annosus in the soil of spruce stands (Picea abies Karst) . In stands of spruce Fomes annosus was found to occur in a viable state in the litter and soil to a depth of 25 cm. Successful isolations were obtained from 153 samples out of a total of 216. In ca. 40% of the 153 samples Fomes annosus could be isolated from 9 mg of soil; in the remaining samples it was found either in 90 mg, 230 mg or in 900 mg. The results raise the possibility of direct infection of the roots of spruce by Fomes annosus from the soil.     

An Experiment to Control Fomes annosus in Second Rotation Pine Crops

Stump removal was found to singnificantly reduce killing byFomes annosus in second rotation crops of pine. Poisoning andgirdling of trees prior to felling and also stump poisoningfailed to control the disease. In this experiment no significantdifferences were detected in the susceptibility of Scots andCorsican pine to attack. Increasing periods of delay beforereplanting resulted in less mortality. An equation is presented,based on factors of the first rotation crop which may be usedto predict losses likely to occur when a site is replanted.Root attack by F. annosus results in reduced growth and yieldas well as mortality. The results from the experiment are discussed in trems of themangement of pine crops attacted by F. annosus in Theford Chase.     

Die Wirkung wäßriger Streuextrakte verschiedener Waldbäume auf Mycelwachstum und Konidiosporenkeimung von Fomes annosus (Fr.) Cke.

The effect of water extracts of leaf and needle litter from different forest trees on the mycelial growth and the germination rate of conidia of Fomes annosus (Fr.) Cke. Litter extracts from various forest trees and stands have distinct effects on mycelial growth and germination rate of conidia of Fomes annosus. The effects depend on concentration of the extract, period of extraction and on date of collecting the litter samples.     

Biological control of Fomes annosus by Peniophora gigantea1

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.