Chamaecyparis Lawsoniana Research Articles

Biocidal Activity of Three Wood Essential Oils Against <I>Ixodes scapularis</I> (Acari: Ixodidae), <I>Xenopsylla cheopis</I> (Siphonaptera: Pulicidae), and <I>Aedes aegypti</I> (Diptera: Culicidae)

The biocidal activity of three steam distilled wood essential oils-incense cedar, Calocedrus decurrens (Torr.) Florin; Port-Orford-cedar, Chamaecyparis lawsoniana (A. Murr.) Parl.; and western juniper, Juniperus occidentalis (Hook)--were evaluated against adult Aedes aegypti (L.) (Diptera: Culicidae) and Xenopsylla cheopis (Rothchild) (Siphonaptera: Pulicidae) and nymphal Ixodes scapularis Say (Acari: Ixodidae). In vitro laboratory bioassays were conducted to establish baseline dose-mortality data through 24 h. Incense cedar heartwood was the most toxic to all three vector species followed in order of activity by western juniper and Port-Orford-cedar based on LC50 and LC90 values. Ae. aegypti were substantially more susceptible to the oils than either I. scapularis or X. cheopis.

Biocidal Activity of Three Wood Essential Oils Against Ixodes scapularis (Acari: Ixodidae), Xenopsylla cheopis (Siphonaptera: Pulicidae), and Aedes aegypti (Diptera: Culicidae)

The biocidal activity of three steam distilled wood essential oils—incense cedar, Calocedrus decurrens (Torr.) Florin; Port-Orford-cedar, Chamaecyparis lawsoniana (A. Murr.) Parl.; and western juniper, Juniperus occidentalis (Hook)—were evaluated against adult Aedes aegypti (L.) (Diptera: Culicidae) and Xenopsylla cheopis (Rothchild) (Siphonaptera: Pulicidae) and nymphal Ixodes scapularis Say (Acari: Ixodidae). In vitro laboratory bioassays were conducted to establish baseline dose–mortality data through 24 h. Incense cedar heartwood was the most toxic to all three vector species followed in order of activity by western juniper and Port-Orford-cedar based on LC50 and LC90 values. Ae. aegypti were substantially more susceptible to the oils than either I. scapularis or X. cheopis.

Antioxidant activity of extracts from the wood and bark of Port Orford cedar

Heartwood, sapwood, and inner and outer bark of Port Orford cedar were extracted with methanol, and the extracts evaluated for antioxidant activity. The total phenol content (TPC) of the extracts was determined by the Folin-Ciocalteu method and expressed as gallic acid equivalent (GAE). Butylated hydroxytoluene was used as a positive control in the free-radical-scavenging activity tests and ethylenediaminetetraacetic acid dihydrate disodium salt served as a positive control in the metal-chelating activity assay. All wood extracts showed significant freeradical-scavenging activity. In the radical-scavenging assay of 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (the ABTS assay), the inner bark extracts exhibited the strongest free-radical-scavenging activity. The 50% inhibitory concentrations (IC50) in the radical-scavenging assay against 1,1-diphenyl-2-picrylhydrazyl hydrate radical (DPPH) of the heartwood, sapwood, and inner and outer bark extracts were 64.77, 29.03, 10.31, 19.87 μg·ml−1, respectively. In the metal-chelating activity system, the sapwood extract demonstrated significant activity. The greatest TPC, 537.5 mg GAE/g dry extract, was detected in the inner bark. The lowest TPC of 136.9 mg GAE/g dry extract was observed in the heartwood dry extract. The results indicate that the antioxidant activities of the extracts are in accordance with the amounts of phenolics present; the inner and outer barks of Port Orford cedar are rich in phenolics and may provide good sources of antioxidants.

Antibacterials and modulators of bacterial resistance from the immature cones of Chamaecyparis lawsoniana

As part of an on-going project to characterize compounds from immature conifer cones with antibacterial or modulatory activity against multidrug-resistant (MDR) strains of Staphylococcus aureus, eight compounds were isolated from the cones of Chamaecyparis lawsoniana. The active compounds were mainly diterpenes, with minimum inhibitory concentrations ranging from 4 to 128 μg/ml against MDR effluxing S. aureus strains and two epidemic methicillin-resistant (EMRSA) clinical isolates. The compounds extracted were the diterpenes ferruginol, pisiferol and its epimer 5-epipisiferol, formosanoxide, trans-communic acid and torulosal, the sesquiterpene oplopanonyl acetate and the germacrane 4β-hydroxygermacra-1(10)-5-diene. Some of these compounds also exhibited modulatory activity in potentiating antibiotic activity against effluxing strains and ferruginol, used at a sub-inhibitory concentration, resulted in an 80-fold potentiation of oxacillin activity against strain EMRSA-15. An efflux inhibition assay using an S. aureus strain possessing the MDR NorA efflux pump resulted in 40% inhibition of ethidium bromide efflux at 10 μM ferruginol (2.86 μg/ml). We report the 1H and 13C NMR data for the cis A/B ring junction epimer of pisiferol which we have named 5-epipisiferol. We also unambiguously assign all 1H and 13C NMR resonances for trans-communic acid.

Port‐Orford‐cedar resistant to Phytophthora lateralis

Summary Phytophthora lateralis, an exotic root pathogen, is the primary cause of Port‐Orford‐cedar (Chamaecyparis lawsoniana) mortality throughout its native range in southwest Oregon and northwest California. Most trees in the field are very susceptible, but genetic resistance to this pathogen has been demonstrated. Since the late 1980s, the USDA Forest Service and the Bureau of Land Management in cooperation with Oregon State University have conducted an intensive programme to identify and test resistant trees from the field, and propagate them in a seed orchard with the goal of providing resistant seedlings for regeneration. Susceptible families showed only 0–10% survival using a variety of inoculation techniques. Rooted cuttings of resistant parents are seldom killed, and seedling families of these parents exhibit 25–100% survival, depending on family and inoculation technique. Symptom development on resistant trees, including sunken lesions, and resinosis as well as reduced colonization and re‐isolation success, was consistent with a hypersensitive reaction. In a long‐term field test, five resistant families had 20–80% survival after 16 years, while three susceptible families had 0–8% survival in the same interval.

First Report of Phytophthora citricola on False Cypress in Hungary.

In May 2005, an estimated 10 to 15% mortality of various cultivars of false cypress (also named Lawson cypress or Port-Orford-cedar [Chamaecyparis lawsoniana]) with severe wilt was observed in field stands of an ornamental nursery in western Hungary. Wilted plants had rot-associated reduction of their root system. Root discoloration and occasional chlorosis of lower leaves commenced on potted 3-year-old plants that were held in the open air for 10 to 12 months before planting. Four species of Phytophthora (P. lateralis, P. eriugena, P. hibernalis, and P. cinnamomi) have been reported on this host (2). Direct plating of discolored roots from the most susceptible cultivar (Silver Globus) onto a selective potato dextrose agar or carrot agar medium yielded pure cultures that developed white, stellate colonies with sparse aerial mycelia. The hyphal growth was optimal at 25°C, but the growth above 32°C and below 4°C was completely inhibited. Single, terminal sporangia on simple (occasionally sympodial) sporangiophores formed abundantly in nonsterile soil filtrate but not in agar. Sporangia, 31 to 67 μm (59.1 ± 9.3 μm) long and 25 to 39 μm (31.5 ± 4.0 μm) wide, were noncaducous and semipapillate, variable in shape, mostly obpyriform, rarely obovoid, ovoid-ellipsoid and spherical or bifurcated and distorted, and the exit pore was narrow (7.2 ± 0.8 μm). No external or internal proliferation and no hyphal swellings or chlamydospores were observed. The isolates were homothallic with smooth-walled oogonia (27.3 ± 3.4 μm in diameter) and paragynous antheridia. The oospores (24.7 ± 2.1 μm in diameter) were plerotic. The morpho-physiological features suggested that our isolates belonged to Waterhouse's Group III, and in particular, represented P. citricola. This was confirmed by cellulose acetate electrophoresis of malate dehydrogenase; the isozyme pattern of false cypress isolate was identical to that of the ITS-sequenced (NCBI Accession No. AY366193) P. citricola isolate from a Hungarian alder forest (1). Pathogenicity tests on four 3-year-old potted false cypress (cv. Silver Globus) plants in the greenhouse resulted in rapidly developing (within 2 weeks) sunken, necrotic lesions at the stem base around the site of wound inoculation with a 5-mm-diameter mycelial agar plug. After 12 weeks, each inoculated plant wilted and died. The causal agent was consistently reisolated from necrotic tissues. In Hungary, P. citricola was first isolated and identified from alder forest soil (1). Nonetheless that false cypress has been listed as the host of P. citricola in Norway and Poland (3,4), to our knowledge, this report is the first definitive description of this Phytophthora sp. on this host.

Antioxidant activity of extracts from the bark of Chamaecyparis lawsoniana (A. Murray) Parl.

Abstract The bark of Chamaecyparis lawsoniana (A. Murray) Parl. was extracted with methanol and sequentially partitioned with n-hexane, ethyl acetate, n-butanol and deionized water. The antioxidant activities of the four extracts were evaluated using the DPPH• and ABTS+• methods. The total phenolic content of the extracts was determined using the Folin-Ciocalteu method and expressed as gallic acid equivalents (GAE). Butylated hydroxytoluene was used as a positive control in the radical-scavenging activity tests. All the bark extracts showed significant radical-scavenging activity. In the ABTS+• assay, n-butanol extracts exhibited the strongest radical-scavenging activity, followed by ethyl acetate, water, and n-hexane extracts. The greatest total phenolic content was 428.54 mg GAE per gram of dry extract and was detected in the n-butanol extract, followed by the ethyl acetate and n-hexane extracts. The antioxidant activities correlate with the amount of phenolics present in these extracts. The ethyl acetate and n-butanol extracts were rich in phenolics and may represent a good source of antioxidants.

First Report of Root Rot and Stem Canker Caused by Phytophthora cambivora on Noble Fir (Abies procera) for Bough Production in Norway.

In 2004, damages resembling those caused by Phytophthora spp. were observed in a 15-year-old bough plantation of noble fir (Abies procera). When removing bark upward from the roots and base of a diseased tree, a reddish brown discoloration with distinct borders to surrounding wood appeared. The discoloration extended approximately 1.5 m above ground, but only on one side of the stem. This resulted in dead basal branches (flagging) on the cankered side of the tree. Other dying trees in the same field did not show flagging symptoms but turned chlorotic to brown after being girdled by the expanding stem canker. Approximately 25% of the trees were dead or dying. Isolations were carried out from the area between healthy and diseased tissue both from roots and base of the stem of the tree with flagging symptoms. Samples were rinsed in running tap water and plated on the Phytophthora selective medium PARP (17 g of cornmeal agar, 10 mg of pimaricin, 250 mg of ampicillin, 10 mg of rifampicin, and 100 mg of pentachloronitrobenzene (PCNB) in 1 liter of water), with and without hymexazol added (50 mg/l). Morphological characters of the isolated Phytophthora sp. included nonpapillate sporangia (37 to 64 μm), internal proliferation, and characteristic hyphal swellings. The isolate was heterothallic and produced amphigynous antheridia when crossed with tester strains of P. cryptogea. The mating type was A2. The internal transcribed spacer (ITS) rDNA sequences were identical to P. cambivora (GenBank Accession No. AY880985). Thus, both morphological characters and DNA analysis supported the species identification. A pathogenesis test to fulfill Koch's postulate was carried out during 2005. Inoculation was done by placing agar with culture in the growth medium close to the roots of noble fir seedlings. Eleven weeks after inoculation, clearly visible stem canker symptoms were observed. The ITS sequences of the reisolated Phytophthora sp. were determined and found identical to P. cambivora. P. cambivora was reported to cause root rot and stem canker in a noble fir Christmas tree plantation in the United States (1). P. citricola and P. citrophthora are known to cause problems on Lawson Falsecypress/Port-Orford-cedar (Chamaecyparis lawsoniana) in Norway, but damages by Phytophthora spp. have never been reported in Abies spp. plantations or forest stands in Norway. Currently, we are also working on Phytophthora problems discovered in two different Christmas tree plantations (A. lasiocarpa and A. nordmanniana). Reference: (1) G. A. Chastagner et al. Plant Dis. 79:290, 1995.

Resistance breeding against nonnative pathogens in forest trees — current successes in North America

Nonnative invasive pathogens have decimated North American forests for over 100 years, and additional pathogens continue to arrive. These pathogens are destined to be permanent fixtures in the ecosystem. In many cases, management activities have been unsuccessful in slowing the spread of these pathogens or in restoring forests. Genetic resistance potentially provides an invaluable management tool for restoring these species or using them in plantations. Although native tree species are highly susceptible to some nonnative pathogens, a low frequency of resistance is present in even those North American host species most affected. Classical breeding methods can produce genetically diverse and resistant populations for reforestation or restoration of natural forests. However, any operational program for developing resistant populations of forest trees must contend with relatively long generation times, as well as the long-lived nature of trees and the potential of the pathogen to evolve. Western white pine (Pinus monticola), Port-Orford-cedar (Chamaecyparis lawsoniana), American chestnut (Castanea dentata), and American elm (Ulmus americana) are examples of species for which there are successful breeding programs for disease resistance. Examples from these species, with a particular focus on western white pine and white pine blister rust [Cronartium ribicola] resistance, will be used to illustrate some of the successes in operational programs, as well as to discuss some of the research needs and current unknowns in developing durable resistance. Some of these programs have been ongoing for 50 years, while the Port-Orford-cedar program began only in the last decade. Resistant seedlings from several programs are now being used in reforestation and restoration.

Heterogeneity Shapes Invasion: Host Size And Environment Influence Susceptibility To A Nonnative Pathogen

Theoretical study of invasion dynamics has suggested that spatial heterogeneity should strongly influence the rate and extent of spreading organisms. However, empirical support for this prediction is scant, and the importance of understanding heterogeneity for real-world systems has remained ambiguous. This study quantified the influence of host and environmental heterogeneity on the dynamics of a 19-year disease invasion by the exotic and fatal pathogen, Phytophthora lateralis, within a stream population of its host tree, Port Orford cedar (Chamaecyparis lawsoniana). Using dendrochronology, we reconstructed the invasion history along a 1350-m length of infected stream, which serves as the only route of pathogen dispersal. Contrary to theoretical predictions, the temporal progression of the disease invasion was not related to a host's downstream spatial position, but instead was determined by two sources of heterogeneity: host size and proximity to the stream channel. These sources of heterogeneity influenced both the epidemic and endemic dynamics of this pathogen invasion. This analysis provides empirical support for the influence of heterogeneity on the invasion dynamics of a commercially important forest pathogen and highlights the need to incorporate such natural variability into both invasion theory and methods aimed at controlling future spread.

Spontaneous changes a basis for new ornamental woody plant cultivars

In nursery stock production of some ornamental woody plants the appearance of spontaneous variability was identified in the form of atypical pigmentation of leaves (albinism, variegated, red colored), leaves shape (jaggy) and dwarfs. Mutated plants with variegated leaves were observed among hybrid plane (Platanus x acerifolia (Ait.) Willd.), Siberian elm (Ulmus pumila L.), laurel cherry (Prunus laurocerasus L.) and Lawson false-cypress (Chamaecyparis lawsoniana (Murr.) Parl.) Seedlings. The type of variegation and frequency were analyzed. Among plane tree and Siberian elm seedlings there were observed red colored leaves. Atypical, jaggy shaped leaves were found among laurel cherry seedlings. Dwarf growth was identified at Siberian elm and birch (Betula pendula Roth.) where also found fruits at one year seedling. There were not significant differences in some morphological and physiological properties in plane tree seedlings with various pigmented leaves. .

CLIMATIC ASSESSMENT OF A 580-YEAR CHAMAECYPARIS LAWSONIANA (PORT ORFORD CEDAR) TREE-RING CHRONOLOGY IN THE SISKIYOU MOUNTAINS, USA

Tree-ring data from Chamaecyparis lawsoniana (A. Murr.) Parl. (Port Orford cedar; Cupressaceae) were used to create a standardized chronology, assess the local, limiting factors on radial growth, and investigate the extent of a unique climatic event. We produced a 580-year tree-ring chronology (A.D. 1420 to 2000) from a large number of cedars (n = 1537) sampled in one 37 km2 area in the Siskiyou Mountains of southwestern Oregon and northern California. This chronology represents an area with few long-term climatic studies and a species with no dendrochronological data. We found radial growth to be positively correlated with year-round soil moisture conditions, specifically with cool, wet conditions in summer and warm, wet conditions in winter. The year 1739 stood out as a climatic pointer year with the smallest ring width index for the entire chronology and anatomically distinctive damage to the latewood of 1738 and earlywood of 1739. This pointer year was consistently identified across watersheds, topographic position (e.g., streamside, hillslope), and the range of the cedar, corresponding to an extreme, single-year drought occurring throughout the Pacific Northwest.

Toxicity studies on western juniper oil ( Juniperus occidentalis) and Port-Orford-cedar oil ( Chamaecyparis lawsoniana) extracts utilizing local lymph node and acute dermal irritation assays

The essential oil extracts of western juniper oil ( Juniperus occidentalis) and Port-Orford-cedar oil ( Chamaecyparis lawsoniana) were evaluated for possible dermal toxic effects on mice and rabbits. Mice were tested for their response to both extracts utilizing a local lymph node assay. Western juniper oil extract at 0.5% and 5% concentrations did not show a stimulation index (SI) greater than normal (3.0); however, a 50% concentration did show a positive response at 3.3. Port-Orford-cedar oil extract did not show a positive response at concentrations of 0.5%, 5% or 50%. An acute dermal irritation study using rabbits had a primary irritation index (PII) of 3.3 with 100% Port-Orford-cedar oil extract. This was reduced to a PII of 0.625 when diluted 1:1 with olive oil. Undiluted western juniper oil extract had a PII score of 2.7. While a 5.0% solution had a PII score of 0.3, a 0.5% solution of western juniper oil was a non-irritant. It would appear that animals bedded on wood shavings have contact with essential oils at concentrations far less than the 2% maximum by weight obtained by steam distillation extraction. These concentrations did not elicit a hypersensitivity response.

Height Control of Picea spp. and Chamaecyparis lawsoniana with Uniconazole and 6-Benzyladenine

Abstract The use of plant growth retardants (PGRs) could benefit conifer growers by enabling them to produce more uniform, live tabletop Christmas tree specimens. We applied two PGRs to determine effectiveness on height control and terminal bud density for the following species of conifer seedlings: Black Hills spruce (Picea glauca var. densata), Serbian spruce (P. omorika), Colorado blue spruce (P. pungens), and Port Orford cedar (Chamaecyparis lawsoniana). The chemicals were applied at 2-week intervals throughout an 8-week period for a total of four applications. Uniconazole was applied as a foliar spray and soil drench (5 and 1 ppm, respectively), 6-benzyladenine (BA) was applied as a foliar spray (500 and 1000 ppm), and the control did not receive a PGR application. Uniconazole was generally effective on the spruces but not on Port Orford cedar, whereas BA reduced height of all species and increased spruce bud densities. However, BA treatments were phytotoxic in all species tested. The drench of uniconazole caused minor phytotoxicity in Black Hills spruce, whereas foliar applications to Port Orford cedar had minor phytotoxic effects.

Phytophthora cinnamomi

<i>Phytophthora cinnamomi</i>

Controlling Growth of Tabletop Christmas Trees with Plant Growth Retardants

Tabletop Christmas tree growers whose greenhouse-grown conifers have undesirable shoot growth may alleviate this problem by applying plant growth retardants (PGRs). Some of the most common PGRs in the horticulture industry were evaluated to determine their effectiveness in controlling plant height: ancymidol at 100 μL·L-1 (ppm), daminozide at 5000 μL·L-1, paclobutrazol at 60 μL·L-1, chlormequat at 1500 μL·L-1, uniconazole at 15 μL·L-1, and ethephon at 500 μL·L-1 compared to a nontreated control. The following conifer species were used: colorado blue spruce (Picea pungens), black hills spruce (P. glauca var. densata), serbian spruce (P. omorika), noble fir (Abies procera), grand fir (A. grandis), fraser fir (A. fraseri), concolor fir (A. concolor), arborvitae (Thuja occidentalis), port orford cedar (Chamaecyparis lawsoniana), and douglas-fir (Pseudotsuga menziesii). Chlormequat was the only PGR that caused phytotoxicity and damage to the foliage was minimal. Noble fir, douglas-fir, colorado blue spruce, and arborvitae were unaffected by any PGR treatment. Daminozide reduced growth of port orford cedar and concolor fir; uniconazole reduced growth of black hills spruce and serbian spruce; paclobutrazol reduced growth of fraser fir; and ethephon reduced growth of grand fir.

EFFECT OF WATER STRESS ON INFECTION BY SPECIES OF HONEY FUNGUS (ARMILLARIA MELLEA AND A. GALLICA)

Summary Isolates of Armillaria mellea and A. gallica that differed in virulence to healthy blackcurrant, strawberry, Lawson cypress and privet were used to inoculate plants exposed to different watering regimes. Host plants from which water had either been withheld or their roots kept constantly flooded with water, both showed increased susceptibility compared to those plants, which had been watered regularly. At the end of the period of stress, roots from randomly selected plants from each treatment were harvested. Following chemical analysis of the roots for protein, lipids, and carbohydrates including starch, in vitro assays were carried out with these substances. The increased amounts of these nutrients in both groups of stressed plants are sufficient to stimulate the growth of both A. mellea and A. gallica and enhance their virulence.

Evaluating Recovery of Cupressaceae Taxa After Flooding at Contrasting Temperatures

Abstract Chamaecyparis are ornamental plants that are used extensively in temperate-zone landscapes worldwide. However, due to their low tolerance to environmental stresses Chamaecyparis often perform poorly in urban landscapes. The objective of this research was to evaluate rootstocks of selected Cupressaceae taxa to determine their adaptability to poor drainage and high temperatures found commonly in urban landscapes. To accomplish this objective, 10 taxa (Chamaecyparis, Platycladus, Thuga spp., and x sCupressocyparis leylandii) were grown in 2.8 liter (#1) black plastic containers with a pinebark:sand (8:1 by vol) medium for 19 weeks in two greenhouses with 9/15 hr day/night temperatures of either 22/18C (72/64F) or 30/26C (86/79F). Half the plants in each greenhouse were flooded for 4 weeks. Root relative growth rate (RGR) was a better indicator of plant performance under flooded conditions compared to shoot RGR. At 22/18C (72/64F), root RGR of Chamaecyparis thyoides and Thuja ‘Green Giant’ only declined 10% and 11% between nonflooded and flooded plants, respectively. Chamaecyparis obtusa and x Cupressocyparis leylandii had the largest percentage decline in root RGR from nonflooded to flooded plants with 71% and 213%, respectively. Chamaecyparis thyoides had the highest root RGR at 30/26C (86/79F) in both nonflooded and flooded conditions with a 19% decrease in root RGR between nonflooded and flooded. Chamaecyparis lawsoniana and T. ‘Green Giant’ were ranked 2 and 3 in flooded conditions at 30/26C (86/79F); however, percentage decline increased to 43% and 46%, respectively. At this temperature, the remaining seven taxa had greater than 50% decline in root RGR in flooded conditions compared to nonflooded plants. In nonflooded conditions, shoot and root RGR of all species decreased from 22/18C (72/64F) to 30/26C (86/79F) except for Chamaecyparis thyoides. The shoot and root RGR of Chamaecyparis thyoides grown in 22/18C (72/64F) and 30/26C (86/79F) were similar in nonflooded conditions. Chamaecyparis thyoides demonstrated excellent tolerance to flooding and temperature and could be a desirable understock for other Chamaecyparis when grown in poorly drained locations.

The most frequent parasitic and saprophytic fungi on some species in the fam. Cupressaceae

The parasitic and saprophytic mycoflora was inventoried on three species in the fam. Cupressaaceae (Cupressus sempervirens, Chamaecyparis lawsoniana and Juniperus virginiana) in Serbia and Montenegro. The greatest number of fungi was recorded on eastern red cedar, but they were mainly the parasites of weakness or saprophytes. The greatest damage on cypress is caused by the pathogenic fungus Seiridium cardinale - agent of bark necrosis and canker. Sphaeropsis sapinea, the pathogen of many coniferous species, was identified on all three hosts on which it does not cause great harm. The study of the morphological characteristics of the fungus on these host plants and the comparative analysis with the morphological characteristics of the same fungus on Pinus spp. shows a difference between them. The study of S. sapinea pathogenicity by artificial inoculations of Austrian pine seedlings in the controlled conditions shows that the isolate of the fungus from cypress can cause infection of uninjured P. nigra shoots.

Fungi isolated from soil with quicksets of Chamaecyparis lawsoniana and their influence on the growth of Phytophthora cinnamomi and Rhizoctonia solani

Chamaecyparis lawsoniana is often attacked by other pathogens (from genera: Phytophthora, Pythium, Fusarium, Rhizoctonia) both when the quicksets are taken root and later, when the young plants are planted. The aim of the study was to determine an effect of saprobiotic fungi isolated from soil with quicksets Chamaecyparis lawsoniana on the growth of Phytophthora cinnamomi and Rhizoctonia solani. In our experiment, method series biotic was used (MAŃKA 1974). This method allowed to determine index of impendence for plants by Phytophthora cinnamomi and Rhizoctonia solani with the help of summary biotic effect. The results of observation on the biotic interaction of saprobiotic fungi isolated from soil with quicksets Chamaecyparis lawsoniana, analysed as biotic series and Phytophthora cinnamomi and Rhizoctonia solani showed, that this of fungal community did not limited growth of these pathogens. Summary biotic effects were negative. Environment of saprobiotic fungi more promoted growth of Rhizoctonia solani than Phytophthora cinnamomi. It means, that in the soil under Chamaecyparis lawsoniana crop, Rhizoctonia solani could have a better of conditions for growth than Phytophthora cinnamomi.