Treesearch

The prevalence of large wildfires has increased in recent years. In many cases, agency personnel have little prior experience to draw from to organize their postfire response to uncharacteristically large events. However, local residents look to resource managers to provide the necessary leadership to work through these difficult decisions. In particular, methods to create meaningful discussion of management priorities with local citizens are essential. This article reports results from a telephone survey of participants in a US Forest Service-led tour after the Booth and Bear Butte...

Occupancy analysis and its ability to account for differential detection probabilities is important for studies in which detecting echolocation calls is used as a measure of bat occurrence and activity. We examined the feasibility of remotely acquiring bat encounter histories to estimate detection probability and occupancy. We used echolocation detectors coupled o digital recorders operating at a series of proximate sites on consecutive nights in 2 trial surveys for the Hawaiian hoary bat (Lasiurus cinereus semotus). Our results confirmed that the technique is readily amenable for use in...

Phytophthora ramorum is a unique organism in many ways, having a broad host range and both soilborne and aerial infection stages. This makes mplementing effective control measures very complex. The use of biological control has been demonstrated against various Phytophthora spp. in general, but not specifically against P. ramorum. One aspect of biological control considered for use in this study was the use of microorganisms. Over 100 fungi, bacteria, and actinomycetes were isolated from natural field soil, leaf surfaces, and plant parts (endophytes). Some soil organism and endophyte...

Identification of appropriate phytosanitary treatments that can be used for certifying solid wood packing material movement from areas infested or threatened by actionable plant pests and pathogens into uninfested areas is mportant. Heat treatment has been used on commodities to control fungal diseases and insect infestations for many years. The restricted use of methyl bromide has revived the interest on heat disinfestation for commodities. The purpose of this research is to determine the efficacy of heat treatment to control Phytophthora ramorum in wood species. Artificially inoculated...

The knowledge on latency is of great importance to prevent the spread of Phytophthora ramorum with healthy looking plant material. To learn more about the tissue colonisation in Rhododendron, histological studies with epifluorescence microscopy have been started. Epifluorescence images showing P. ramorum structures in different tissues are presented. A first idea of P. ramorum development in Rhododendron root, twig and leaf tissue is offered for discussion. To improve and simplify the specific detection of P. ramorum structures under controlled conditions a method for the genetic transforma...

Within the European project ?Risk Analysis for Phytophthora ramorum? (RAPRA), susceptibility of economically and ecologically important plants in Europe towards P. ramorum was tested via in vitro inoculation methods. In these studies different species and/or cultivars of Buxus, Calluna, Erica, Hedera, Rhododendron, and Vaccinium were tested using a detached leaf or twig assay. Zoospore suspensions of five isolates, three European and two North American, were produced for inoculation by immersion of detached leaves and twigs, some of which had been wounded prior to the treatment. After...

As part of the project European Phytophthora ramorum Pest Risk Analysis (RAPRA) a wide range of fungicides was tested for in vitro activity against mycelial growth and zoospore germination of P. ramorum. A preliminary set of experiments was performed to study the effect of nine common fungicides specific for Phytophthora spp. Dimethomorph, copperoctanoate, and the combination of mancozeb and fenamidone inhibited mycelium growth and zoospore germination of P. ramorum isolates in vitro. Mancozeb alone did not inhibit mycelial growth effectively. Propineb, azoxystrobin, propamacarb, and...

Effective monitoring and identification of areas of hardwood mortality is a critical component in the management of sudden oak death (SOD). From 2001 to 2005, aerial surveys covering 13.5 million acres in California were conducted to map and monitor hardwood mortality for the early detection of Phytophthora ramorum, the pathogen responsible for SOD. To assess the spatial accuracy of the aerial detection survey (ADS) program data, we used a mortality stem map generated from aerial photo interpretation (Meentemeyer and others 2007) within the Big Sur ecoregion of California. Although results...

Chlamydospores were produced as described by Colburn and Shishkoff (Phytopathology 96:S25). Samples (5cc) of chlamydospores in sand inoculum were placed in 15 ml conical plastic test tubes and incubated at selected temperatures for 1, 2, 3, 4, and 7 days. Following incubation, tube contents were resuspended in 0.2 percent water agar and 1 ml was plated onto PARPH selective medium amended with 4 percent clarified V8 juice. Numbers of colonies resulting from germinated chlamydospores were assessed microscopically. High temperature treatments included 30, 35, and 40°C while low temperature...

Stream monitoring using leaf baits for early detection of P. ramorum is an important part of the Oregon sudden oak death program. About 50 streams in and near the Oregon quarantine area in the southwest corner of the state are currently monitored. Rhododendron and tanoak leaf baits in mesh bags are exchanged every two weeks throughout the year. Leaves are sent to Corvallis for isolation and PCR diagnosis using the Winton and Hansen ITS primers. P. ramorum is regularly recovered from streams draining infested sites 5 years after eradication treatment. Because there has been a very good...