The chlamydospore is a survival spore produced by 35 of the 75 described species of Phytophthora. Phytophthora ramorum Werres, de Cock & Man in't Veld, the causal agent of Sudden Oak Death (SOD), produces abundant chlamydospores in artificial culture and plant tissue. The chlamydospore is likely the most important survival...
Decomposing logs in Douglas-fir - western hemlock forests in the Pacific Northwest are systems in which many organisms interact. Fungi in these systems include both mycorrhizal fungi associated with hemlock seedlings and many species of saprotrophic wood decomposer fungi. It is very likely that these two groups of fungi interact...
Disease is often overlooked as a natural disturbance agent in plant communities. This study examines what effects, if any, a disease-mediated disturbance has on the plant community as a whole in old-growth and mature forests of western Oregon. Phellinus weirii (Murrill) Gilbertson (Family: Hymenochaetaceae) is a native root-rotting pathogen that...
Tall fescue is thought to have co-evolved with the fungal endophyte Acremonium coenophialum to form a mutualistic relationship. Endophyte-infected (EI) plants can have increased growth and survival when compared with endophyte-free (EF) plants. Responses to endophyte-infection vary and are host-genotype and fungal-biotype specific. Mechanism(s) by which endophyte-infection confers increased growth...
Mycorrhizae are important for plant growth, particularly in nutritionally poor soils. Vesicular-arbuscular mycorrhizae (VAM) are the primary form of mycorrhizae found in tropical plants, and their persistence in the soil as colonizing fungal propagules following deforestation cannot be directly
measured. Utilizing the "most probable number" (MPN) method for estimating infective...
Post-fire Pezizales often fruit seasonally approximately six weeks after a fire in successional groups over the course of two years. Two methods, pure culture synthesis and PCR-based identification, were used to determine if some of these species were mycorrhizal. Eleven fungal isolates, Anthracobia melaloma, Gyromitra infula, Helvella compressa, Morchella sp.,...
The Demonstration for Ecosystem Management Options (DEMO) study originated out of the changing management priorities associated with federal forest lands in the Pacific Northwest which included an objective to maintain mature and old-growth forest characteristics in managed stands. The DEMO project examines the effects that different levels and patterns of...
Concerns over the possibility of exotic pest
introductions from eastern Russia to the West Coast of the United States due to proposed log imports raises the question of the effectiveness of possible mitigation measures. Toxicity of methyl bromide to representative pathogenic fungi was tested by exposing Armillaria ostoyae, Heterobasidion annosum,...
Seedlings of Gaultheria shallon, Pseudotsuga menziesii, Rhododendron macrophyllum and Tsuga heterophylla were grown together in the greenhouse in soils from three young managed Douglas-fir forests in the Oregon Coast Range. The main objectives were 1 )to evaluate the ability of ericaceous plants and overstory conifers to share compatible mycorrhizal fungi...
The coniferous forests of the Pacific Northwest are
affected by a variety of endemic fungal root pathogens. Forest
disease surveys have noted the presence of two or more of
these root pathogens infecting the same stump or root, and it
has been suggested that these fungi may be interacting
synergistically....
Wood degrading ability and tolerance to wood-preserving chemicals
of several fungi isolated from Douglas-fir utility poles were
investigated by the agar-stick and soil-block methods. Birch (Betula.
sp. ) wood sticks and western hemlock (Tsuga heterophylla) wood blocks
were used.
The soil-block and agar-stick tests provided identical weight
loss rankings of...
The biocontrol potential of Trichoderma harzianum Rifai,
Trichoderma polysporum (Link.:Pers.) Rifai, Scytalidium aurantiacum
Klingstr. et Beyer or a Penicillium sp. against Trametes versicolor
(L. :Fr.) Pilat, Neolentinus lepideus (Fr.) Redh. et Ginns, Postia
placenta (Fr.) M.Lars. et Lomb. and Irpex lacteus Fr. was evaluated
using agar plate, soil bottle and...
The potential of 9 bacterial and 6 fungal isolates to
protect wood against wood staining microorganisms was
studied using small sapwood samples of unseasoned Ponderosa
pine [Pinus ponderosa Laws] sapwood. Bacillus subtilis Cohn,
isolate 733 A , Gliocladium virens J.H. Miller, J.E. Giddens
& A.A. Foster isolate H 3 and...
Studies of physiological effects of fungicides on fungi are critical for understanding
modes of action and mechanism of resistance; however, studies are difficult to perform
on filamentous fungi because of the inability to produce homogeneous a biological
system using a mass of mycelium. Moreover, the presence of rigid cell wall...
The biocontrol potential of Trichoderma harzianum strains
B-2A, B-8A, B-4B, B-15B, and B-41 and Serratia plymuthica was
evaluated using agar plates and wood wafers of unseasoned
ponderosa pine (Pinus ponderosa laws). All five isolates of
Trichoderma harzianum and Serratia plymuthica could inhibit
stain fungi growth in agar plates and exhibited...
The fungi that cause mold and stain of freshly sawn lumber result in millions of dollars in losses to the forest products industry. Stain and mold are typically prevented by either kiln drying or by application of a topical fungicide. While these treatments are effective, kiln drying is costly and...
Phaeocryptopus gaeumannii is a pathogenic fungus on Douglas-fir needles which has become a serious threat to timber production in the last decade along the Oregon coast This research was undertaken to describe the general biology and pathology of F. gaeumannii on Douglas-fir needles and how environmental variables affect fungal development....
Stem rust, caused by the fungus Puccinia graminis subsp. graminicola, can cause yield reductions exceeding 90% on perennial ryegrass (Lolium perenne L.) crops grown for seed if not treated with fungicide in the spring. There is evidence that late-spring stem rust epidemics are initiated by populations that survived the winter....
Although chemical fungicides are commonly used to control fungal soil-borne
diseases of Easter lilies, Lilium longiflorum Thunb., in field production and
greenhouse forcing, cultural and biological controls may be alternatives or
complementary to chemicals for control of pathogens.
The influence of inoculations with beneficial, symbiotic, and biocontrol
microorganisms to enhance...
Thesis research focused on: 1) Water and fertilizer gradients
within the plant root zone, and effects of chemical and physical
gradients on Trichoderma harzianum populations. 2) Regulation of root
growth physically with permeable fabric containers and chemically with
copper compounds. 3) Effects of copper coatings for fabric containers
on Glomus...
Using ¹³C cross polarization magic angle spinning nuclear magnetic resonance techniques on 5 species of dead trees from the northwest (western hemlock, Douglas fir, Sitka spruce, lodgepole pine and ponderosa pine) I tracked the lignin and cellulose content over a 22 to 36 year period in order to determine the...
Previous research on coarse woody debris (CWD) indicated that moisture content and initial heterotrophic colonization of decaying wood can affect the decomposition process. Six heterotrophic treatments were created to simulate the effects of physical penetration of the bark and wood and the transmission of ascomycetes versus basidiomycetes into CWD. In...
The hypothesis that inoculation of transplants with vesicular-arbuscular mycorrhizal (VAM) fungi before planting into saline soils would alleviate salt effects on growth and productivity was tested on lettuce (Lactuca sativa L.) and onion (Allium cepa L.). A secondary hypothesis was that the fungi isolated from a saline soil would be...
Eight phylloplane yeasts were isolated from backyard apple trees in Corvallis, OR. Yeast isolates were classified to genus or species level. All isolates were tested in vitro for antagonistic activity against the postharvest pathogens Botrytis cinerea and Penicillium expansum. Of these isolates, Aureobasidium pullulans, Sporobolomyces roseus Rhodotorula sp., consistently reduced...
The effects of natural preconditioning (source wood), wood species, and previous
exposure of wood to two types of fungi on the feeding rates and protozoa survival in the
Pacific dampwood termite Zootermopsis angusticollis (Isoptera: Termospidae) were
examined under laboratory conditions. Termites were exposed to four wood species that
had been...
Western Oregon is home to native Rhododendron species and is the center for cultivated
Rhododendron production in the United States. These Rhododendron spp. are known to
be infected with fungal endophytes. However, the community structure of these
endophytes in native and cultivated Rhododendron is poorly understood. Our study
targeted the...
The influence of atmospheric humidity and free water on germination and germ tube growth of Botrytis cinerea Pers. ex Fr. was studied. Relative humidities (RH) were maintained inside insulated humidity chambers with sulfuric acid solutions of the appropriate concentrations. Insulation was necessary to reduce the incidence of condensation caused by...
Experiments were conducted to determine both the influence of wood
moisture content on the fungitoxicity of methylisothiocyanate (MIT) to the
wood-decay fungus Poria carbonica, and the ability of gelatin to safely en-capsulate MIT for efficient treatment of wood products.
The fungitoxicity of MIT was studied by determining the product of...
A glaze storm of exceptional severity was seen in the Corvallis
area, January, 1942. The weight of ice that accumulated in the
crowns of young-growth Douglas-fir trees caused widespread top
breakage in many stands lying in the broad path of this storm.
Early research on this phenomenon showed the majority...
Background information is presented that provides historical perspectives on the field of mycology in the Pacific Northwest and its role in forest management. The series of events and decisions that have led to previous studies (or lack of studies) in the field also dictate the directions of current research. Culture,...
Phyllopane microorganisms on the leaf surfaces of bean
(Phaseolus vulgaris L. ), hop (Humulus lupulus L. 'Fuggle-H'),
mint (Mentha piperita L. 'Mitcham') and tomato (Lycopersicon
esculentum Mill. ) has been observed by cultural methods. A leaf
impression method was used to examine both actively growing and
inactive propagules present on...
The free amino acid content of the intracellular pools in higher
marine fungi was determined by thin-layer and gas-liquid chromatography.
The organisms investigated include:
Ascomycetes; Nais inornata, Leptosphaeria oraemaris, Corollospora
maritima, Haligena elaterophora, Halosphaeria mediosetigera, Halosphaeria
appendiculata, Halosphaeria quadriremis, Lignincola Laervis
and Remispora hamata, and Fungi Imperfecti; Zalerion maritimum and...
The fungus Verticillium dahliae Kleb. causes a wilt disease of
peppermint, Mentha pipertita L. Propane flaming of peppermint
stubble is widely used to control Verticillium wilt in the Willamette
Valley of Oregon, but little is known about the temperature required
for effective control of the fungus.
The purposes of this...
Engineered wood composites are used in many structural applications and are intended for dry use. However, these materials may encounter significant amounts of wetting while in service, which can lead to structural failures. This study combined aspects of wood science, mechanics, structural engineering, and mycology to assess changes in material...
Bumble bees (Hymenoptera: Apidae) are important native pollinators in wild and agricultural systems, and are one of the few groups of native bees commercially bred for use in the pollination of a range of crops. In recent years, declines in bumble bees have been reported globally. One factor implicated in...
Ectomycorrhizal fungi (EmF) form symbioses with trees. These symbioses profoundly influence forest ecology. Certain EmF form specialized profusions of hyphae, known as ectomycorrhizal fungal mats (mats) which are visible to the naked eye, alter forest soil biogeochemistry, substantially contribute to soil microbial biomass/respiration and support unique microbial communities. Piloderma and...
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David D. Myrold Jane E. Smith
Ectomycorrhizal fungi (EmF) form symbioses with
Sodium polypectate (SPP) was added to an ethanol-streptomycin
agar (ESA) medium to determine if it would provide a selective
substrate for the growth of Verticillium dahliae and for isolation of
the fungus from soil and plant tissues in the presence of saprophytic
fungi. Sodium polypectate improved greatly the formation and...
A study was undertaken to determine the reliability of the formation
of a line of demarcation between paired cultures of Fomes
cajanderi Karst. as an indicator of dissimilar compatibility genotypes.
The results were applied to an assay of the number and location of
compatibility genotypes in each of four glaze-damaged,...