Is there treatment for phytophthora ramorum?

Detection of "P. ramorum" in watercourses has emerged as the earliest of early detection methods. This technique employs pear or rhododendron baits suspended in the watercourse using ropes, buckets, mesh bags, or other similar devices. If plants in the watershed are infected with "P. ramorum", zoospores of the pathogen (as well as other "Phytophthora" spp.) are likely present in adjacent waterways. Under conducive weather conditions, the zoospores are attracted to the baits and infect them, causing lesions that can be isolated to culture the pathogen or analyzed via PCR assay. This method has detected "P. ramorum" at scales ranging from small, intermittent seasonal drainages to the Garcia, Chetco, and South Fork Eel Rivers in California and Oregon (144, 352, and 689 mi2 drainage areas, respectively). It can detect the existence of infected plants in watersheds before any mortality from the infections becomes evident. Of course, it cannot detect the exact locations of those infected plants: at the first sign of "P. ramorum" propagules in the stream, crews must scour the watershed using all available means to find symptomatic vegetation.

Phytophthora ramorum

Phytophthora ramorum is the oomycete plant pathogen known to cause the disease sudden oak death (SOD). The disease kills oak and other species of trees and has had devastating effects on the oak populations in California and Oregon, as well as being present in Europe. Symptoms include bleeding cankers on the tree's trunk and dieback of the foliage, in many cases eventually leading to the death of the tree.

"P. ramorum" also infects a great number of other plant species, significantly woody ornamentals such as "Rhododendron", "Viburnum", and "Pieris", causing foliar symptoms known as ramorum dieback or ramorum blight. Such plants can act as a source of inoculum for new infections, with the pathogen-producing spores that can be transmitted by rainsplash and rainwater.

"P. ramorum" was first reported in 1995, and the origins of the pathogen are still unclear, but most evidence suggests it was repeatedly introduced as an exotic species. Very few control mechanisms exist for the disease, and they rely upon early detection and proper disposal of infected plant material.

The disease is known to exist in California's coastal region between Big Sur (in Monterey County) and southern Humboldt County. It is confirmed to exist in all coastal counties in this range, as well as in all immediately inland counties from Santa Clara County north to Lake County. It has not been found east of the California Coast Ranges, however. It was reported in Curry County, Oregon just north of the California border, in 2001. Sonoma County has been hit hardest, having more than twice the area of new mortality of any other county in California.

About the same time, a similar disease in continental Europe and the UK was also identified as "Phytophthora ramorum".

It was first discovered in California in 1995 when large numbers of tanoaks ("Notholithocarpus densiflorus") died mysteriously, and was described as a new species of "Phytophthora" in 2000. It has subsequently been found in many other areas, including Britain, Germany, and some other U.S. states, either accidentally introduced in nursery stock, or already present undetected.

In tanoaks, the disease may be recognized by wilting new shoots, older leaves becoming pale green, and after a period of two to three weeks, foliage turning brown while clinging to the branches. Dark brown sap may stain the lower trunk's bark. Bark may split and exude gum, with visible discoloration. After the tree dies back, suckers try to sprout the next year, but their tips soon bend and die. Ambrosia beetles ("Monarthrum scutellare") will most likely infest a dying tree during midsummer, producing piles of fine white dust near tiny holes. Later, bark beetles ("Pseudopityophthorus pubipennis") produce fine, red boring dust. Small black domes, the fruiting bodies of the "Hypoxylon" fungus, may also be present on the bark. Leaf death may occur more than a year after the initial infection and months after the tree has been girdled by beetles.

In coast live oaks and Californian black oaks, the first symptom is a burgundy-red to tar-black thick sap bleeding from the bark surface. These are often referred to as bleeding cankers.

In addition to oaks, many other forest species may be hosts for the disease; in fact, it was observed in the USA that nearly all woody plants in some Californian forests were susceptible to "P. ramorum". including rhododendron, madrone ("Arbutus menziesii"), evergreen huckleberry ("Vaccinium ovatum"), California bay laurel ("Umbellularia californica"), buckeye ("Aesculus californica"), bigleaf maple ("Acer macrophyllum"), toyon ("Heteromeles arbutifolia"), manzanita ("Arctostaphylos spp."), coast redwood ("Sequoia sempervirens"), Douglas fir ("Pseudotsuga menziesii"), coffeeberry ("Rhamnus californica"), honeysuckle ("Lonicera hispidula"), and Shreve oak ("Quercus parvula"). "P. ramorum" more commonly causes a less severe disease known as ramorum dieback/leaf blight on these hosts. Characteristic symptoms are dark spots on foliage and in some hosts the dieback of the stems and twigs. The disease is capable of killing some hosts, such as rhododendron, but most survive. Disease progression on these species is not well documented. Redwoods exhibit needle discoloration and cankers on small branches, with purple lesions on sprouts that may lead to sprout mortality.

In Europe, "Ramorum" blight was first observed on rhododendron and viburnum in the early 1990s, where it was initially found mainly on container-grown plants in nurseries. The principal symptoms were leaf and twig blight. By 2007, it had spread throughout nurseries and retail centers in 16 European countries, and had been detected in gardens, parks, and woodlands in at least eight countries. It has not caused significant harm to European oak species.

In 2009, the pathogen was found to be infecting and killing large numbers of Japanese larch trees ("Larix kaempferi") in the United Kingdom at sites in the English counties of Somerset, Devon, and Cornwall. It was the first time in the world that "Phytophthora ramorum" had been found infecting this species. Since then, it has also been found extensively in larch plantations in Wales and in southwest Scotland, leading to the deliberate felling of large areas. The UK Forestry Commission noted that eradication of the disease would not be possible, and instead adopted a strategy of containing the disease to reduce its spread. Symptoms of the disease on larch trees include dieback of the tree's crown and branches, and a distinctive yellowing or ginger colour beneath the bark. In August 2010, the disease was found in Japanese larch trees in Counties Waterford and Tipperary in Ireland. It had spread to Japanese larch plantations across the south of the country by February 2014. Coillte, who owned twenty forests where the disease was present, felled 16,000 trees in one of its forests, having already felled 150 hectares to contain the disease.

The closely related "Phytophthora kernoviae" causes similar symptoms to "P. ramorum", but infects the European beech ("Fagus sylvatica").

"P. ramorum" produces both resting spores (chlamydospores) and zoospores, which have flagella enabling swimming. "P. ramorum" is spread by air; one of the major mechanisms of dispersal is rainwater splashing spores onto other susceptible plants, and into watercourses to be carried for greater distances. Chlamydospores can withstand harsh conditions and are able to overwinter. The pathogen will take advantage of wounding, but it is not necessary for infection to occur.

As mentioned above, "P. ramorum" does not kill every plant that can be used as a host, and these plants are most important in the epidemiology of the disease as they act as sources of inoculum. In California, California bay laurel ("Umbellularia californica") seems to be the main source of inoculum. Green waste, such as leaf litter and tree stumps, are also capable of supporting "P. ramorum" as a saprotroph and acting as a source of inoculum. Because "P. ramorum" is able to infect many ornamental plants, it can be transmitted by ornamental plant movement.

Hikers, mountain bikers, equestrians, and other people engaged in various outdoor activities may also unwittingly move the pathogen into areas where it was not previously present. Those travelling in an area known to be infested with SOD can help prevent the spread of the disease by cleaning their (and their animals') feet, tyres, tools, camping equipment, etc. before returning home or entering another uninfected area, especially if they have been in muddy soil. Additionally, the movement of firewood could introduce sudden oak death to otherwise uninfected areas. Both homeowners and travelers are advised to buy and burn local firewood.

"P. ramorum" is heterothallic and has two mating types, A1 and A2, required for sexual reproduction. The European population is predominantly A1 while both mating types A1 and A2 are found in North America. Genetics of the two isolates indicate that they are reproductively isolated. On average, the A1 mating type is more virulent than the A2 mating type, but more variation occurs in the pathogenicity of A2 isolates. It is currently not clear whether this pathogen can reproduce sexually in nature and genetic work has suggested that the lineages of the two mating types might be isolated reproductively or geographically given the evolutionary divergence observed.

"P. ramorum" is a relatively new disease, and several debates have occurred about where it may have originated or how it evolved.

Evidence suggests "P. ramorum" may be an introduced species, and these introductions occurred separately for the European and North American populations, hence why only one mating type exists on each continent – this is called a founder effect. The differences between the two populations are thus caused by adaptation to separate climates. Evidence includes little genetic variability, as "P. ramorum" has not had time to diversify since being introduced. Existing variability may be explained by multiple introductions with a few individuals adapting best to their respective environments. The behavior of the pathogen in California is also indicative of being introduced; it is assumed that such a high mortality rate of trees would have been noticed sooner if "P. ramorum" were native.

Where "P. ramorum" originated remains unclear, but most researchers feel Asia is the most likely, since many of the hosts of "P. ramorum" originated there. Since certain climates are best suited to "P. ramorum", the most likely sources are the southern Himalayas, Tibet, or Yunnan province.

Species of "Phytophthora" have been shown to have evolved by the interspecific hybridization of two different species from the genus. When a species is introduced into a new environment, it causes episodic selection. The invading species is exposed to other resident taxa, and hybridization may occur to produce a new species. If these hybrids are successful, they may outcompete their parent species. Thus, "P, ramorum" is possibly a hybrid between two species. Its unique morphology does support this. Also, three sequences studied to establish the phylogeny of "Phytophthora": ITS, cox II and nad 5, were identical, supporting "P. ramorum" having recently evolved.

"P. ramorum" may be native to the United States. Infection rates could have previously been at a low level, but changes in the environment caused a change to the population structure. Alternatively, the symptoms of "P. ramorum" may have been mistaken for that of other pathogens. When SOD first appeared in the United States, many other pathogens and conditions were blamed before "P. ramorum" was found to be the causal agent. With many of the most seriously affected plants being in the forest, the likelihood of seeing diseased trees is also low.

In relation to human ecology, the loss of tanoak as the pathogen spreads to culturally sensitive indigenous lands represents a loss of tanoak acorn as one of the most important traditional and ceremonial foods still used in Northern California such as among Yurok people, Hupa, Miwok, and Karuk peoples. Similar impact applies to the decline of other native plant species that are traditional food sources in tanoak and oak regimens infected by the pathogen.

In forest ecology, the pathogen contributes to loss of environmental services provided by diversity of plant species and interdependent wildlife.

The mortality caused by this emerging disease is expected to cause many indirect effects. Several predictions of long-term impacts have been discussed in the scientific literature. While such predictions are necessarily speculative, indirect impacts occurring on shorter time scales have been documented in a few cases. For instance, one study demonstrated that redwood trees ("Sequoia sempervirens") grew faster after neighboring tanoaks were killed by sudden oak death. Other studies have combined current observations and reconstruction/projection techniques to document short-term impacts while also inferring future conditions. One study used this approach to investigate the effects of SOD on the structural characteristics of redwood forests.

Additional long-term impacts of SOD may be inferred from regeneration patterns in areas that have experienced severe mortality. These patterns may indicate which tree species will replace tanoak in diseased areas. Such transitions will be of particular importance in forest types that were relatively poor in tree species diversity before the introduction of SOD, e.g., redwood forest., the only study to comprehensively examine regeneration in SOD-impacted redwood forests found no evidence that other broadleaf tree species are beginning to recruit. Instead, redwood was colonizing most mortality gaps. However, they also found inadequate regeneration in some areas and concluded that regeneration is continuing. Since this study only considered one site in Marin County, California, these results may not apply to other forests. Other impacts to the local ecology include, among others, the residual effects of spraying heavy pesticides (Agrifos) to treat SOD symptoms, and the heavy mortality of the native pollinator community that occurs as a result. Bee hives situated in areas of heavy Agrifos spraying have incurred significant losses of population in direct correlation to the application of these chemicals. Counties such as Napa and Sonoma may be doing significant damage to their native pollinator populations by virtue of adopting broad-based prophylactic pesticide policies. Such damage to the pollinator populations may have tertiary negative effects on the entire local plant community, compounding the loss of biodiversity, and thus environmental value, attributable to SOD.

Early detection of "P. ramorum" is essential for its control. On an individual-tree basis, preventive treatments, which are more effective than therapeutic treatments, depend on knowledge of the pathogen’s movement through the landscape to know when it is nearing prized trees. On the landscape level, "P. ramorum’s" fast and often undetectable movement means that any treatment hoping to slow its spread must happen very early in the development of an infestation. Since "P. ramorum’s" discovery, researchers have been working on the development of early detection methods on scales ranging from diagnosis in individual infected plants to landscape-level detection efforts involving large numbers of people.

Detecting the presence of "Phytophthora" species requires laboratory confirmation. The traditional method of culturing is on a growth medium selective against fungi (and, in some cases, against other oomycetes such as "Pythium" species). Host material is removed from the leading edge of a plant tissue canker caused by the pathogen; resulting growth is examined under a microscope to confirm the unique morphology of "P. ramorum". Successful isolation of the pathogen often depends on the type of host tissue and the time of year that detection is attempted.

Because of these difficulties, researchers have developed some other approaches for identifying "P. ramorum". The enzyme-linked immunosorbent assay test can be the first step in nonculture methods of identifying "P. ramorum", but it can only be a first step, because it detects the presence of proteins that are produced by all "Phytophthora" species. In other words, it can identify to the genus level, but not to the species level. ELISA tests can process large numbers of samples at once, so researchers often use it to screen out likely positive samples from those that are not when the total number of samples is very large. Some manufacturers produce small-scale ELISA “field kits” that the homeowner can use to determine if plant tissue is infected by "Phytophthora".

Researchers have also developed numerous molecular techniques for "P. ramorum" identification. These include amplifying DNA sequences in the internal transcribed spacer region of the "P. ramorum" genome (ITS polymerase chain reaction, or ITS PCR); real-time PCR, in which DNA abundance is measured in real time during the PCR reaction, using dyes or probes such as SBYR-Green or TaqMan; multiplex PCR, which amplifies more than one region of DNA at the same time; and single strand conformation polymorphism (SSCP), which uses the ITS DNA sequence amplified by the PCR reaction to differentiate "Phytophthora" species according to their differential movement through a gel.

Additionally, researchers have begun using features of the DNA sequence of "P. ramorum" to pinpoint the minuscule differences of separate "P. ramorum" isolates from each other. Two techniques for doing this are amplified fragment length polymorphism, which through comparing differences between various fragments in the sequence has enabled researchers to differentiate correctly between EU and U.S. isolates, and the examination of microsatellites, which are areas on the sequence featuring repeating base pairs. When "P. ramorum" propagules arrive in a new geographic location and establish colonies, these microsatellites begin to display mutation in a relatively short time, and they mutate in a stepwise fashion. Based on this, researchers in California have been able to construct trees, based on microsatellite analyses of isolates collected from around the state, that trace the movement of "P. ramorum" from two likely initial points of establishment in Marin and Santa Cruz Counties and out to subsequent points.

Early detection of "P. ramorum" on a landscape scale begins with the observation of symptoms on individual plants (and/or detecting "P. ramorum" propagules in watercourses; see below). Systematic ground-based monitoring has been difficult within the range of "P. ramorum" because most infected trees stand on a complex mosaic of lands with various ownerships. In some areas, targeted ground-based surveys have been conducted in areas of heavy recreation or visitor use such as parks, trailheads, and boat ramps. In California, when conducting ground-based detection, looking for symptoms on bay laurel is the most effective strategy, since "P. ramorum" infection of true oaks and tanoaks is almost always highly associated with bay laurel, the main epidemiological springboard for the pathogen. Moreover, on many sites in California (though not all), "P. ramorum" can typically be detected from infected bay laurel tissues via culturing techniques year-round; this is not the case for most other hosts, nor is it the case in Oregon, where tanoak is the most reliable host.

As part of a nationwide USDA program, a ground-based detection survey was implemented from 2003 to 2006 in 39 U.S. states to determine whether the pathogen was established outside the West Coast areas already known to be infested. Sampling areas were stratified by environmental variables likely to be conducive to pathogen growth and by proximity to possible points of inoculum introduction such as nurseries. Samples were collected along transects established in potentially susceptible forests or outside the perimeters of nurseries. The only positive samples were collected in California, confirming that "P. ramorum" was not yet established in the environment outside the West Coast.

Aerial surveying has proven useful for detection of "P. ramorum" infestations across large landscapes, although it is not as “early” a technique as some others because it depends on spotting dead tanoak crowns from fixed-wing aircraft. Sophisticated GPS and sketch-mapping technology enable spotters to mark the locations of dead trees so that ground crews can return to the area to sample from nearby vegetation.

A less technical means of detecting "P. ramorum" at the landscape level involves engaging local landowners across the landscape in the search. Many local county agriculture departments and University of California Cooperative Extension offices in California have been able to keep track of the distribution of the pathogen in their regions through reports and samples brought to them by the public. In 2008, the Garbelotto Laboratory at University of California, Berkeley, along with local collaborators, hosted a series of educational events, called "SOD Blitzes", designed to give local landowners basic information about "P. ramorum" and how to identify its symptoms; each participant was provided with a sampling kit, sampled a certain number of trees on his or her property, and returned the samples to the lab for analysis. This kind of citizen science hopefully can help generate an improved map of "P. ramorum" distribution in the areas where the workshops are held.

The course that "P. ramorum" management should take depends on a number of factors, including the scale of the landscape upon which one hopes to manage it. Management of "P. ramorum" has been undertaken at the landscape/ regional level in Oregon in the form of a campaign to completely eradicate the pathogen from the forests in which it has been found (mostly private, but also USDA Forest Service and USDI Bureau of Land Management ownership). The eradication campaign involves vigorous early detection by airplane and watercourse monitoring, a U.S. Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) and Oregon Department of Agriculture-led quarantine to prevent movement of host materials out of the area where infected trees are found, and immediate removal of "P. ramorum" host vegetation, symptomatic or not, within a buffer around each infected tree.

The Oregon eradication effort, which began near the town of Brookings in southwest Oregon in 2001, has adapted its management efforts over the years in response to new information about "P. ramorum". For example, after inoculation trials of various tree species more clearly delineated which hosts are susceptible, the Oregon cooperators began leaving nonhost species such as Douglas fir and red alder on site. In another example, after finding that a small percentage of tanoak stumps that were resprouting on the host removal sites were infected with the pathogen—whether these infections were systemic or reached the sprouts from the surrounding environment is unknown—the cooperators began pretreating trees with very small, targeted amounts of herbicide to kill the root systems of infected tanoaks before cutting them down. The effort has been successful in that while it has not yet completely eradicated the pathogen from Oregon forests, the epidemic in Oregon has not taken the explosive course that it has in California forests.

California, though, faces significant obstacles that preclude it from mounting the same kind of eradication effort. For one thing, the organism was too well established in forests in the Santa Cruz and San Francisco Bay areas by the time the cause of sudden oak death was discovered to enable any eradication effort to succeed. Even in still relatively uninfested areas of the north coast and southern Big Sur, regionally coordinated efforts to manage the pathogen face huge challenges of leadership, coordination, and funding. Nevertheless, land managers are still working to coordinate efforts between states, counties, and agencies to provide "P. ramorum" management in a more comprehensive manner.

Several options exist for landowners who want to limit the impacts of SOD death on their properties. None of these options is foolproof, guaranteed to eradicate "P. ramorum", or guaranteed to prevent a tree from becoming infected. Some are still in the initial stage of testing. Nevertheless, when used thoughtfully and thoroughly, some of the treatments do improve the likelihood of either slowing the spread of the pathogen or of limiting its impacts on trees or stands of trees. Assuming that the landowner has correctly identified the host tree(s) and symptom(s), has submitted a sample to a local authority to send to an approved laboratory for testing, and has received confirmation that the tree(s) are indeed infected with "P. ramorum"—or, alternatively, assuming that the landowner knows that "P. ramorum"-infected trees are nearby and wants to protect the resources on his or her property—he or she can attempt control by cultural (individual-tree), chemical, or silvicultural (stand-level) means.

The best evidence that cultural techniques might help protect trees against "P. ramorum" comes from research that has established a correlation between disease risk in coast live oak trees and the trees’ proximity to bay laurel. In particular, this research found that bay laurel trees growing within 5 m of the trunk of an oak tree were the best predictors of disease risk. This implies that strategic removal of bay laurel trees near coast live oaks might decrease the risk of oak infection. Wholesale removal of bay laurel trees would not be warranted, since the bay laurels close to the oak trees appear to provide the greatest risk factor. Whether the same pattern is true for other oaks or tanoaks has yet to be established. Research on this subject has been started for tanoak, but any eventual cultural recommendations will be more complicated, because tanoak twigs also serve as sources of "P. ramorum" inoculum.

A promising treatment for preventing infection of individual oak and tanoak trees—not for curing an already established infection—is a phosphonate fungicide marketed under the trade name Agri-fos. Phosphonate is a neutralized form of phosphorous acid that works not by direct antagonism of "Phytophthora", but by stimulating various kinds of immune responses on the part of the tree. It is mostly environmentally benign if not applied to nontarget plants and can be applied either as an injection into the tree stem or as a spray to the bole. When applying Agri-fos as a spray, it must be combined with an organosilicate surfactant, Pentra-bark, to enable the product to adhere to the bole long enough to be absorbed by the tree. Agri-fos has been very effective in preventing tree infections, but it must be applied when visible symptoms of "P. ramorum" on other trees in the immediate neighborhood are still relatively distant; otherwise, the tree to be treated likely is already infected, but visible symptoms have not yet developed (especially true for tanoak).

Trials of silvicultural methods for treating "P. ramorum" began in Humboldt County in northwest coastal California in 2006. The trials have taken place on a variety of infested properties both private and public and have generally focused on varying levels and kinds of host removal. The largest () and most replicated trials have involved removal of tanoak and bay laurel by chainsaw throughout the infested stand, both with and without subsequent underburning designed to eliminate small seedlings and infested leaf litter. Other treatments included host removal in a modified “shaded fuelbreak” design in which all bay laurel is removed, but not all tanoaks; bay and tanoak removal using herbicides; and removal of bay laurel alone. The results of these treatments are still being monitored, but repeated sampling has so far detected only very small amounts of "P. ramorum" in the soil or on vegetation in the treated sites.

Research and development in managing "P. ramorum" in nursery settings extends from "P. ramorum" in the individual plant, to "P. ramorum" in the nursery environment, to the pathogen’s movement across state and national borders in infected plants.

An array of studies have tested the curative and protective effects of various chemical compounds against "P. ramorum" in plants valued as ornamentals or Christmas trees. Many studies have focused on the four main ornamental hosts of "P. ramorum" ("Rhododendron", "Camellia", "Viburnum", and "Pieris"). Several effective compounds have been found; some of the most effective include mefenoxam, metalaxyl, dimethomorph, and fenamidone. Many of these studies have converged upon the following conclusions: chemical compounds are, in general, more effective as preventives than as curatives; when used preventively, chemical compounds must be reapplied at various intervals; and chemical compounds can mask the symptoms of "P. ramorum" infection in the host plant, potentially interfering with inspections for quarantine efforts. In general, these compounds suppress but do not eradicate the pathogen, and some researchers are concerned that with repeated use the pathogen may become resistant to them. These studies and conclusions are summarized by Kliejunas.

Another area of research and evolving practice deals with eliminating "P. ramorum" from nursery environments in which it is established to prevent human-mediated pathogen movement within the ornamental plant trade. One way of approaching this is through a robust quarantine and inspection program, which the various federal and state regulatory agencies have implemented. Under the federal "P. ramorum" quarantine program implemented by USDA APHIS, nurseries in California, Oregon, and Washington are regulated and must participate in an annual inspection regimen; nurseries in the 14 infested counties in coastal California, plus the limited infested area in Curry County, Oregon, must participate in a more stringent inspection schedule when shipping out of this area.

Much of the research into disinfesting nurseries has focused on the voluntary best management practices (BMPs) that nurseries can implement to prevent "P. ramorum’s" introduction into the nursery and movement from plant to plant. In 2008, a group of nursery industry organizations issued a list of BMPs that includes subsections on pest prevention/management, training, internal/external monitoring/audits, records/traceability, and documentation. The document includes such specific recommendations as “Avoid overhead irrigation of high-risk plants”; “After every crop rotation, disinfect propagation mist beds, sorting area, cutting benches, machines and tools to minimize the spread or introduction of pathogens”; and “Nursery personnel should attend one or more "P. ramorum "trainings conducted by qualified personnel or document self-training”.

Research on control of "P. ramorum" in nurseries has also focused on disinfesting irrigation water containing "P. ramorum" inoculum. Irrigation water can become infested from bay trees in the forest (if the irrigation source is a stream), from bay trees overhanging irrigation ponds, from runoff from infested forests, or from recirculated irrigation water. Experiments in Germany with three types of filters—slow sand filters, lava filters, and constructed wetlands—showed that the first two removed "P. ramorum" from the irrigation water completely, while 37% of the post-treatment water samples from the constructed wetland still contained "P. ramorum".

Since "P. ramorum" can persist for an undetermined period of time within the soil profile, management programs in nurseries should also deal with delineating the pathogen’s distribution in nursery soil and eliminating it from infested areas. A variety of chemical options has been tested for soil disinfestation, including such chemicals as chloropicrin, metham sodium, iodomethane, and dazomet. Lab tests indicated that all of these chemicals were effective when applied to infested soil in glass jars. Additionally, tests on volunteer nurseries with infested soil demonstrated that dazomet (trade name Basamid) fumigation followed by a 14-day tarping period successfully removed "P. ramorum" from the soil profile. Other soil disinfestation practices under investigation, or in which interest has been expressed, include steam sterilization, solarization, and paving of infested areas.

One of the most important aspects of "P. ramorum" control involves interrupting the human-mediated movement of the pathogen by ensuring that infested materials do not move from location to location. While enforceable quarantines perform part of this function, basic cleanliness when working or recreating in infested areas is also important. In most cases, cleanliness practices involve ridding potentially infested surfaces—such as shoes, vehicles, and pets—of foliage and mud before leaving the infested area. The demands of implementing these practices become more complex when large numbers of people are working in infested areas, as in construction, timber harvesting, or wildfire suppression. The California Department of Forestry and Fire Protection and USDA Forest Service have implemented guidelines and mitigation requirements for the latter two situations; basic information about cleanliness in "P. ramorum"-infested areas can be found at the California Oak Mortality Task Force web site (www.suddenoakdeath.org) under the “Treatment and Management” section (subsection “Sanitation and Reducing Spread”).

In England in 2009, the Forestry Commission, DEFRA, the Food and Environment Research Agency, Cornwall County Council, and Natural England are working together to record the locations and deal with this disease. Natural England is offering grant funding through its Environmental Stewardship, Countryside Stewardship, and Environmentally Sensitive Area schemes to clear rhododendron. In 2011, the Forestry Commission started felling of larch forest in the south-west of England, as an attempt to halt the spread of the disease. In Northern Ireland at the end of 2011, the Department of Agriculture and Rural Development’s Forest Service began felling 14 hectares of affected Larch woodland at Moneyscalp, on the edge of Tollymore Forest Park in County Down.

Phytophthora ramorum

Phytophthora ramorum is the oomycete plant pathogen known to cause the disease sudden oak death (SOD). The disease kills oak and other species of trees and has had devastating effects on the oak populations in California and Oregon, as well as being present in Europe. Symptoms include bleeding cankers on the tree's trunk and dieback of the foliage, in many cases eventually leading to the death of the tree.

"P. ramorum" also infects a great number of other plant species, significantly woody ornamentals such as "Rhododendron", "Viburnum", and "Pieris", causing foliar symptoms known as ramorum dieback or ramorum blight. Such plants can act as a source of inoculum for new infections, with the pathogen-producing spores that can be transmitted by rainsplash and rainwater.

"P. ramorum" was first reported in 1995, and the origins of the pathogen are still unclear, but most evidence suggests it was repeatedly introduced as an exotic species. Very few control mechanisms exist for the disease, and they rely upon early detection and proper disposal of infected plant material.

The disease is known to exist in California's coastal region between Big Sur (in Monterey County) and southern Humboldt County. It is confirmed to exist in all coastal counties in this range, as well as in all immediately inland counties from Santa Clara County north to Lake County. It has not been found east of the California Coast Ranges, however. It was reported in Curry County, Oregon just north of the California border, in 2001. Sonoma County has been hit hardest, having more than twice the area of new mortality of any other county in California.

About the same time, a similar disease in continental Europe and the UK was also identified as "Phytophthora ramorum".

It was first discovered in California in 1995 when large numbers of tanoaks ("Notholithocarpus densiflorus") died mysteriously, and was described as a new species of "Phytophthora" in 2000. It has subsequently been found in many other areas, including Britain, Germany, and some other U.S. states, either accidentally introduced in nursery stock, or already present undetected.

In coast live oaks and Californian black oaks, the first symptom is a burgundy-red to tar-black thick sap bleeding from the bark surface. These are often referred to as bleeding cankers.

In Europe, "Ramorum" blight was first observed on rhododendron and viburnum in the early 1990s, where it was initially found mainly on container-grown plants in nurseries. The principal symptoms were leaf and twig blight. By 2007, it had spread throughout nurseries and retail centers in 16 European countries, and had been detected in gardens, parks, and woodlands in at least eight countries. It has not caused significant harm to European oak species.

The closely related "Phytophthora kernoviae" causes similar symptoms to "P. ramorum", but infects the European beech ("Fagus sylvatica").

"P. ramorum" produces both resting spores (chlamydospores) and zoospores, which have flagella enabling swimming. "P. ramorum" is spread by air; one of the major mechanisms of dispersal is rainwater splashing spores onto other susceptible plants, and into watercourses to be carried for greater distances. Chlamydospores can withstand harsh conditions and are able to overwinter. The pathogen will take advantage of wounding, but it is not necessary for infection to occur.

As mentioned above, "P. ramorum" does not kill every plant that can be used as a host, and these plants are most important in the epidemiology of the disease as they act as sources of inoculum. In California, California bay laurel ("Umbellularia californica") seems to be the main source of inoculum. Green waste, such as leaf litter and tree stumps, are also capable of supporting "P. ramorum" as a saprotroph and acting as a source of inoculum. Because "P. ramorum" is able to infect many ornamental plants, it can be transmitted by ornamental plant movement.

"P. ramorum" is a relatively new disease, and several debates have occurred about where it may have originated or how it evolved.

Where "P. ramorum" originated remains unclear, but most researchers feel Asia is the most likely, since many of the hosts of "P. ramorum" originated there. Since certain climates are best suited to "P. ramorum", the most likely sources are the southern Himalayas, Tibet, or Yunnan province.

"P. ramorum" may be native to the United States. Infection rates could have previously been at a low level, but changes in the environment caused a change to the population structure. Alternatively, the symptoms of "P. ramorum" may have been mistaken for that of other pathogens. When SOD first appeared in the United States, many other pathogens and conditions were blamed before "P. ramorum" was found to be the causal agent. With many of the most seriously affected plants being in the forest, the likelihood of seeing diseased trees is also low.

In relation to human ecology, the loss of tanoak as the pathogen spreads to culturally sensitive indigenous lands represents a loss of tanoak acorn as one of the most important traditional and ceremonial foods still used in Northern California such as among Yurok people, Hupa, Miwok, and Karuk peoples. Similar impact applies to the decline of other native plant species that are traditional food sources in tanoak and oak regimens infected by the pathogen.

In forest ecology, the pathogen contributes to loss of environmental services provided by diversity of plant species and interdependent wildlife.

Detecting the presence of "Phytophthora" species requires laboratory confirmation. The traditional method of culturing is on a growth medium selective against fungi (and, in some cases, against other oomycetes such as "Pythium" species). Host material is removed from the leading edge of a plant tissue canker caused by the pathogen; resulting growth is examined under a microscope to confirm the unique morphology of "P. ramorum". Successful isolation of the pathogen often depends on the type of host tissue and the time of year that detection is attempted.

Aerial surveying has proven useful for detection of "P. ramorum" infestations across large landscapes, although it is not as “early” a technique as some others because it depends on spotting dead tanoak crowns from fixed-wing aircraft. Sophisticated GPS and sketch-mapping technology enable spotters to mark the locations of dead trees so that ground crews can return to the area to sample from nearby vegetation.

Research and development in managing "P. ramorum" in nursery settings extends from "P. ramorum" in the individual plant, to "P. ramorum" in the nursery environment, to the pathogen’s movement across state and national borders in infected plants.


Is Death in Discworld?

Death is a fictional character in Terry Pratchett's "Discworld" series and a parody of several other personifications of death. Like most Grim Reapers, he is a black-robed skeleton usually carrying a scythe. His jurisdiction is specifically the Discworld itself; he is only a part, or minion, of Azrael, the universal Death. He has been generally used by Pratchett to explore the problems of human existence, and has become more sympathetic throughout the series.

Death (Discworld)

Death has appeared in every Discworld novel, with the exception of "The Wee Free Men" and "Snuff", and had a possible cameo at the end of "Johnny and the Dead" (the character was not identified, but spoke in unquoted small caps). The Discworld books with Death as a leading character, starting with "Mort" in 1987, are:

Death's hollow, peculiar voice is represented in the books by unquoted ; since he is a skeleton, he has no vocal cords to speak with, and therefore the words enter the head with no involvement from the ears. His "voice" is often described using a morbid metaphor, such as two slabs of granite being rubbed together, or the slamming of coffin lids; these descriptions have become less frequent in later novels. In the first Discworld novel, "The Colour of Magic", as well as in "Eric", all pronouns referring to Death are capitalized; thus, for example, "he" is written as "He". This is usually reserved for the Discworld gods and is not featured in any of the other novels.

Death is not invisible; however, most people's brains refuse to acknowledge him for who he is, unless he insists. Under normal circumstances, only those of a magical disposition (e.g. witches and wizards), children, and cats can see him, or allow themselves to see him. Due to his eternal nature, Death can ignore such things as walls and magic spells; he exists throughout all time, so things lasting merely centuries are not as real as he is. He can adjust time with regard to himself and others near him, completing tasks very rapidly from a normal perspective. He can only go where people believe in death and can only see people who can die. In this sense, he is similar to the gods of the Discworld, in that he is powered by mortals' collective belief in him.

Wizards, witches, and significant figures such as kings have the prerogative of being collected by Death himself, rather than one of the lesser entities. Most other souls are collected by another functionary, such as the anthropomorphic personification of scrofula. Death himself must collect some minimum number of souls, worked out by a system called the "nodes", in order to keep the momentum of dying going. His selection of ordinary deaths may be based on the showiness of the death, such as a common thief being incinerated by a dragon. In addition to wizards and kings, he has shown up for numerous ordinary people, at least two dogs, at least two kittens, a swan, and a red, flower-like sea creature. These events are usually of importance within the story, so Death's appearance may simply be considered a plot device. He has also appeared in situations where characters are in mortal peril; for example, Death has appeared before Rincewind on numerous nearly-fatal occasions. Similarly, in "Thud!" Samuel Vimes has a near-death experience, which means that Death has a corresponding "near-Vimes experience", in which he appears before the stricken Vimes sitting in a deckchair reading a mystery novel.

He is fond of cats, who can see him at all times, and curry, the consumption of which he describes as like biting a red-hot ice cube.

Death is fascinated by humanity. His interest is coupled with bafflement: it's a favorite point of Pratchett's that the habits and beliefs that are grown into instead of being rationally acquired are an essential part of being human. As Death is an outside observer, his imitations of humanity are intricate but marked by a fundamental lack of comprehension. When acting as a stand-in for the Hogfather (a figure similar to Santa Claus) he starts by greeting the children with from force of habit, until reminded not to do so. He is especially intrigued by humanity's ability to complicate their own existence, and their ability to actually get up in the morning without going insane from the sheer prospect of what life entails (from his perspective).

This fascination with humanity extends to the point of sympathy towards them, and he will often side with humans against greater threats, notably the Auditors of Reality. He has on a number of occasions bent the rules to allow a character extra life (e.g., the little girl rescued from the fire in "Reaper Man"). Death has also indicated that he will oblige dying humans by playing a game with them for their lives, much like the personification of Death in "The Seventh Seal"; the games he offers include chess, though he consistently has trouble remembering how the knights move, and another game (referred to by Death as "Exclusive Possession" in the book, presumably based on Monopoly), which the challenger lost despite having "three streets and all the utilities". Granny Weatherwax was able to play cards against Death in a successful bid to save a child's life, Granny's hand having four queens while Death's had only four "ones". (A hand of four aces would generally beat a hand of queens in poker, but Death chose to consider them low, giving the old witch a "wink" in the process.)

In the same way that his granddaughter, Susan, has been described as ""Helpfulness Personified"" in terms of her personality, Death, by his own admission, could very well be described as 'Duty Personified' in terms of personality; in "Hogfather", in a discussion with Albert, Death comments He does not cause people to die, nor does he concern himself with their goodness or badness in life; it is simply his job to collect their souls at the appointed time. Somewhat like a garbage man making his rounds emptying the trash cans, Death performs a vital but thankless task.

In many ways, he epitomizes the bleakness of human existence. In "Reaper Man", in which he is rendered temporarily mortal (or at least the imagination of being mortal, since his state of being "it/death" is, as mentioned in Discworld Noir, constant), he becomes frustrated and infuriated with the unfair inevitability of death, a theme that continues through later books. In "Soul Music" he expresses misery at the fact that he is capable of preventing deaths but is forbidden to do so; during his time as the Hogfather, he uses his new dual role to save a little match girl from dying of the cold by giving her the 'gift' of a future, thus allowing him to avoid the usual complications that arise from him breaking the rules. Despite his general lack of emotion, the Auditors of Reality are one of the few things actually capable of angering him. He also gets angry upon hearing of Rincewind: In "Eric", for example, his eyes turn red at the mention of Rincewind. Pratchett even says in "The Art of Discworld" that he has received a number of letters from terminally ill fans in which they hope that Death will resemble the Discworld incarnation (he also says that those particular letters usually cause him to spend some time staring at the wall).

Death has developed considerably since his first appearance in "The Colour of Magic". In this, he was quite a malicious character and follows Rincewind around wanting him to die after circumstances resulted in Rincewind'missing' their scheduled 'appointment'. At one point he deliberately stops a character's heart, though this may have been Death's stand-in, Scrofula. By the time of "Mort" he had gained the sympathetic and humorous personality he has in later books. In later novels, he has been used to examine developments in theoretical physics as, being supernatural, he is able to witness such events firsthand, although being a cat lover, he is not fond of the Schrödinger's cat thought experiment, believing it cruel to the cats involved.

Death resides in an extra-dimensional realm called Death's Domain. Within the domain, his home looks like a Victorian house with a garden and is well tended, but is predominantly in shades of black and decorated with a skull and crossbones motif. It is called "Mon Repos", (Quirmian for "my place of rest"), and is much larger on the inside, because Death has not quite mastered the art of scale. Similarly, because he does not quite understand real distance compared to perspective, the surrounding terrain is actually relatively close, but blurred to appear farther away. Death adds a large golden wheat field to the grounds after the events of "Reaper Man". There is also a tree swing, created by Death for his granddaughter Susan, which swings through the trunk of the tree. (There is a joke common among engineers that pictures a rope-and-board swing as envisioned by various corporate entities. The last illustration is usually the simple swing labeled "what the customer wanted". The one in which the swing passes through the cut-through trunk of the tree—the upper part of the tree being propped up by sticks under the branches—is usually attributed to engineers. Many of Pratchett's fans work in engineering and science.)

In addition to the inside of the house being larger than the outside, there are doors that reach a height of several yards and at the same time are only a few feet tall. He has a bathroom which he never uses, with a bar of bone-white, rock-hard soap and a towel rack with hard towels attached to the rack. The only usable items in the bathroom are a small bar of regular soap and one normal towel, both brought there by his manservant Albert.

The plumbing of his house has greatly confused him, and in "Death's Domain" it is explained that the pipes are completely solid, as is the u-bend for the floral-decorated toilet. The towels he originally constructed are also useless; he didn't realize that they had to bend, fold and be soft. In his 'bedroom' (which he never actually sleeps in), he has a violin, which he attempts to play. As with everything in his domain, he cannot create, only mimic, so he creates a racket, instead of music. This is said to greatly frustrate him.

Furthermore, Death's house is full of cats, roaming around. Moreover, he is also responsible for sending cats to heaven as mentioned in "The Amazing Maurice and his Educated Rodents" where Maurice encounters Death himself.

The initial books did not pronounce themselves about the sex of Death, although Ysabell called him 'Daddy', using the pronoun "it". In "Mort" Death's pronoun is given as "he" and "his" without the special capital as in the earlier books. In "Reaper Man", Death is unambiguously identified as a male, and in "Soul Music" and "Hogfather" Susan calls him her grandfather or "Granddad". When asked to describe Death, in the second Discworld computer game, the protagonist Rincewind hazards a guess, "Well, I suppose he's a man. You have to look at the pelvis, don't you?" In the comic strip adaptation of "Mort", Death is seen in mirrors as a black-bearded human wearing a black cloak, a look he takes when he needs to be seen by the living.

Many languages must provide a grammatical gender to each object, and death is often a feminine noun. As such, translations of early novels sometimes refer to Death as a woman. This is generally changed, by the time of "Reaper Man". Also, the personification of Death varies from country to country leading to further confusion, for example the Russian personification is that of an old woman, the Czech version uses a (normally non-existent) male variant of the usually female word for death for his name. Explanations are given in footnotes, often with a pun.

Death is both the servant and a part of The Old High One known as Azrael, the Death of Universes and ruler of all deaths.

In the earlier books and in "Thief of Time" Death works with War, Pestilence, and Famine, three other Horsemen of the Apocralypse. Like him they have become more human than their roles require. Death himself explains this in "Thief of Time" by saying that "form defines function." In "Thief of Time" they are reunited with Kaos, the Fifth Horseman, who had previously left before the group became famous and now works as a milkman under the name Ronnie Soak. With the exception of "Thief of Time", the other Horsemen do not generally appear in the books focused on Death.

""Mort"", short for Mortimer, but which also means 'death' in Quirmian (and also in French), is the title character in "Mort". He is first seen as the overly-thoughtful son of a farmer in the Octarine Grass Country, near the Ramtops. Having proved himself unworthy as a scarecrow he is chosen by Death to be his apprentice. Mort's father gave his consent, mistaking Death for an undertaker. Mort is described as being very tall and skinny, with muscles like knots in string. He has a shock of bright red hair, and walks as if he is made entirely of knees.

Mort starts off at the bottom, learning to accept his position while mucking out the stables, and trying to ignore Ysabell, Death's adopted daughter. When Death feels in need of a break, Mort takes over "The Duty". Unfortunately for Mort, his feelings for a teenage princess of Sto Lat get in the way of his job and he starts off a chain reaction of events by impulsively preventing her assassination. Reluctant to tell his master about his gaffe, Mort tries various unsuccessful methods to fix the situation. After fighting and losing to Death, Mort is given an extra lease on life when the Grim Reaper chooses to turn over his Lifetimer, allowing Mort to stay in the world of the living.

After the events of "Mort", Mort leaves Death's service and marries Ysabell. The couple are given the title of Duke and Duchess of Sto Helit, and they later become the parents of Susan Sto Helit. They subsequently meet their end after a freak accident sends their carriage plunging into a ravine, as revealed in "Soul Music". They had discussed this with Death and had turned down his offer to extend the duration of their existence, by letting them stay in his domain, on the grounds that it wouldn't be the same as actually lengthening their lives.

In "The Light Fantastic", Rincewind overhears Twoflower teaching the Four Horsemen of the Apocalypse, (Death, Famine, Pestilence and War) how to play bridge. At one point, War calls out Death with ""Mort"" but we later learn that the only people in the room (other than Twoflower) were Death, Famine, Pestilence and War. The name might be a possible reason as to why Death chose Mort as his apprentice especially as, when Mort first introduces himself to Death by name, Death's reply is.

In the Cosgrove Hall Films animation of "Soul Music", Mort is voiced by Neil Morrissey. In 2004 BBC Radio 4 adapted "Mort", with the title character voiced by Carl Prekopp and Ysabell being voiced by Clare Corbett. Mort is included in Wayne Barlowe's "Barlowe's Guide to Fantasy".

Ysabell is the adopted daughter of Death, who saved her as a baby when her parents were killed in the Great Nef desert (no explanation has been given as to why he did this; Ysabell said that "He didn't feel sorry for me, he never feels anything... He probably "thought" sorry for me."). When first encountered she is a sixteen-year-old girl with silver hair and silver eyes who, it transpires, has been sixteen for thirty-five Discworld 'years' (no time passes in Death's Domain). During her encounter with Rincewind (see below), her behaviour is sufficiently flamboyant as to cause him to believe she is "bonkers". When Mort first encountered Ysabell, he was given the impression of "too many chocolates" (though Pratchett notes that he would have described her as "Pre-Raphaelite" if he had ever heard the word). She also has a fixation for the colour pink.

Ysabell first appeared in "The Light Fantastic", where she met Rincewind, and was surprised to learn that he was not actually dead. This state of affairs might not have continued long if the Luggage had not intervened. During the events of "Mort" it became clear that Ysabell was competent in carrying out the work of her father including The Duty and 'doing the nodes'. This mainly involves figuring out which deaths needed to be attended to personally, an important aspect of all reality. Before Mort arrived she shared her home with Albert, Death's manservant.

Susan Sto Helit is Mort and Ysabell's daughter and only child. When she first appears as a schoolgirl in "Soul Music", Susan has just inherited the duchy on the death of her parents. From the time she was a small child until the start of the book, when she is sixteen, her parents have hidden her background from her and brought her up to be logical, and it comes as a shock when the Death of Rats and Quoth the raven come looking for her. She has to act as a stand-in for Death when he disappears, but subsequently returns to her education. Despite the fact that she has inherited all of her grandfather's abilities, she longs to be normal, and gets human jobs, first as a governess (in "Hogfather"), and then as a schoolteacher (in "Thief of Time"). Death is constantly dragging her back into the world of the occult. At the end of "Thief of Time", she begins a relationship with Lobsang Ludd, the anthropomorphic personification of Time.

Albert (originally known as Alberto Malich) is Death's manservant, butler, and cook. Once a wizard and founder of the Unseen University, he attempted to gain immortality by reciting the Rite of AshkEnte (a ritual to summon Death) backwards, believing this would force Death to stay away from him. Instead it brought him directly to Death's Domain. Since time in Death's Domain does not flow in the same way as it does on the Discworld, Albert succeeded, in a way, at gaining immortality. Before returning to the world during "Mort", "Albert" had 91 days, three hours and five minutes of Time left on the Disc, most of which he spent shopping and using the soap and baths at the ""Young Men's Reformed Cultist of the Ichor-God-Bel-Shamharoth's Association"" (Death is not very good at making plumbing). As of "Hogfather", he has only a few seconds left, and can no longer leave Death's side. Albert is a highly idiosyncratic cook, believing everything needs to be fried to get rid of the germs, including porridge.

Albert's childhood was touched upon lightly in "Hogfather", revealing that he comes from a very poor family (even by Ankh-Morpork standards). This novel also suggests that he is fond of pork pies with mustard and adores drinking sherry.

There was a statue of Alberto in the hallway of Unseen University, inscribed (apart from the usual student scribbles) with ""We Shall Not See His Like Again"." This, of course, turns out to be entirely wrong. After the destruction of the statue in "Mort", and the wizards' belief that the returned Albert was the statue, it is suggested that a new one be built in a very secure place—such as the dungeon (allegedly to prevent it being defiled by students). Alberto Malich was a powerful wizard, perhaps the most powerful a wizard can be (though not likely a Sourcerer). This is reflected in how easily Albert devised a spell to slow the passage of time (a near-impossible feat with Discworld magic) indefinitely around a small area.

When Death goes missing in "Soul Music", Albert tries to find him on the Disc, but gets robbed and his life-timer (hourglass of life) is broken. After this incident, Albert has approximately 34 seconds left, and thus cannot return to the world of the living anymore, as Death cannot make his life longer. The remaining sand is now kept in a bottle in Albert's bedroom. Albert is able to temporarily return to the Discworld during the events of "Hogfather", although in this instance he merely inhabits the pseudo-reality created for the Hogfather to allow him to travel around the entire world in a single night, and hence is not actually "in" the world, strictly-speaking.

While Death and Albert seem to get on rather well, it is a fragile relationship. In "Mort", Albert returns to the world to help Death, but seems ready to attack him when it looks like he has his former job as Archchancellor back. He also seems not to trust Death with his life-timer, which is why he takes it with him in "Soul Music", despite Death later reflecting that such an action was pointless as he would never have done anything to it. Frequently, Albert finds himself trying to keep Death ""on course"" when his master becomes too human. He and Susan do not get on very well.

Binky is Death's steed, named so by Death because it is "a nice name". He is a living horse; Death tried a skeletal steed, but kept having to "stop and wire bits back on". Death also tried a fiery steed, but it repeatedly set his barn and his robe on fire.

Binky is rather more intelligent than most horses and is pure, milky and white (it is noted in some novels that Binky is an exception to the biological rule of "grey" equines). He can fly by just creating his own ground-level, as well as travel through time and across dimensions, sometimes leaving glowing hoofprints in his wake, but is in all other respects a perfectly ordinary horse. He is well-treated, and loyal to his master and Susan. His shoeing is done by Jason Ogg, the Lancrastian blacksmith of mythical skill. Binky is not immortal, but while in Death's service does not age. Binky gains part of his powers by sharing one of Death's qualities: he's so much "realer" than ordinary things such as walls, great distances, or time that he can simply ignore them.

Death gave Susan a "My Little Binky" gift set for her third birthday. It was returned by her parents, fearing that it would make her a less "normal" child.

The Death of Rats, also known as the Grim Squeaker, is not, strictly speaking, a personification in his own right but rather an aspect of Death allowed an independent existence. His purpose is to usher on the souls of dead rodents, as well as assisting Death in other ways. His jurisdiction also seems to cover certain kinds of "ratty" humans, such as Mr. Clete in "Soul Music", Mr. Pin in "The Truth", and Mr. Pounder in "Maskerade".

He was one of a disparate multitude of death-personifications created during Death's absence in "Reaper Man". The Death of Rats refused to be reabsorbed into Death himself upon the latter's resumption of his duties; therefore Death kept him around for company. The Death of Fleas also escaped resorption, but has not been seen since "Reaper Man". The Death of Rats resembles a rodentine skeleton walking on its hind legs, wearing a black robe, and carrying a tiny scythe, his form having taken shape from the latent form of Death himself in "Reaper Man", as he came into existence in the vicinity of Bill Door.

The Death of Rats more easily finds ways around the Rules than Death does, and has assisted Susan in "Soul Music", "Hogfather", and "Thief of Time". He sometimes travels with a talking raven named Quoth who also acts as his translator.

The Death of Rats, like Death, speaks in, but has a vocabulary consisting of words such as'and ', the last used when it laughs, although its speech can be interpreted from context much like the Librarian's.

In the mythology of the Changeling Clan in "The Amazing Maurice and his Educated Rodents" the Death of Rats is known as the Bone Rat.

A talking raven. He hangs around with the Death of Rats. He was named Quoth by his previous owner, a wizard with no sense of humour who was attempting to make a joke by referencing the famous line in "The Raven" by Edgar Allan Poe. Quoth refuses to give in to this stereotype by saying "the N word" ("Nevermore"). At times he acts as steed and interpreter for the Death of Rats. He has a constant craving for eyeballs (a reference to ravens pecking the eyes out of corpses) and frequently mistakes various other objects for eyeballs, such as olives and walnuts. He was originally one of the ravens from the Tower of Art, the magical properties of which gave him his ability to speak.

He was first seen in "Soul Music", and since then has made appearances in all novels involving Susan Sto Helit. Neil Pearson voices him in the Sky One adaptation of "Hogfather".

The New Death appears in "Reaper Man" when he comes to collect the old Death, then known as "Bill Door". The New Death is the old Death's replacement as a result of the plot by the Auditors to rid the world of sloppy thinking.

The New Death comes from human belief, but is quite different from the original, having been formed from modern Discworlders who think of death as being a malevolent force rather than the simple cessation of life. Though he has the usual black robe, he is larger and has only smoke underneath his robe, rather than bones, and wears a crown, to the disgust of the original Death. He rides the classic skeletal steed, in contrast to the special, but nevertheless very real, Binky. Instead of a scythe he wields a weapon "which may, at some point in its evolution, have incorporated aspects of a scythe, in the same way a scalpel incorporated aspects of a stick". In place of a face or skull, the new Death wears a crown, and is prideful, dramatic, cold, and cruel; the literal embodiment of humanity's fear of death. He chooses to arrive exactly at midnight and appears in a flash of lightning purely for the dramatic effect, something the old Death finds demeaning and rather excessive. When he corners Bill Door, he mocks him and beats him instead of finishing the job.

The new Death is destroyed by Bill Door, using the scythe he used on the farm; a humble garden tool, not the infinitely sharp implement of Death, but sharpened by his rage and the harvest. Bill Door was disgusted and horrified by New Death's callous attitude toward humanity, and his victory is the triumph of the compassionate "reaper man" over the tyrant who has no care for the harvest.

The Rite of AshkEnte (also Ashk'Ente or Ash'Kente) is the ancient magic ritual that summons and binds Death into a circle and prevents him from leaving until invited to do so by the summoning wizard. This may be wishful thinking on the part of the wizards as, in "Eric", Death appears outside the circle, behind the wizards, and in "Reaper Man" a wizard comments that he believes Death only stays in the circle for the look of the thing. The Rite is not tuned to Death himself, but rather whoever happened to be doing the job; Mort (then Death's apprentice) was almost forced to respond to the summons, and Susan Sto Helit (his granddaughter) was summoned and subsequently bound. This does not appear to apply to Death himself, although he may do so out of politeness.

Since Death is professionally involved in almost everything that is going on everywhere, the Rite is usually performed so that he can be questioned on otherwise inexplicable phenomena. This is usually done only when all other avenues have been exhausted as most powerful wizards are quite old and therefore unwilling to attract the attention of Death. Death hates being summoned because he is always summoned at the worst possible time, such as when he is at a party.

The Rite is also the reason for Albert's affiliation with Death; while he was still Archancellor of Unseen University, Albert attempted to become immortal by performing the Rite backwards, reasoning that this would banish Death away from him, but instead it transferred Albert to Death's realm, where he decided to remain on the grounds that time didn't pass in Death's realm and he is thus essentially immortal.

There are twelve ways of performing the Rite, but eight of them cause instant death, and so might just be considered to summon Death in the "usual" manner, and the ninth is very hard to remember. This leaves three ways to safely summon death: Although the Rite can be performed by a couple of people with three small sticks and 4 cc of mouse blood or even with a fresh egg and two small sticks, the wizards (Ridcully excepted) prefer to do it the old fashioned way, with heavy equipment consisting of numerous drippy candles, octograms written on the floor, thuribles, and similar paraphernalia. They feel it's not "proper" wizardry if it's not showy enough.

In the "Discworld" books, the Rite has been used several times:

In the 1997 animated adaptations of "Soul Music" and "Wyrd Sisters", Death was voiced by Christopher Lee.

In the 2006 Sky One adaptation of "Hogfather" he was voiced by Ian Richardson. The actor who played the physical Death in Hogfather was Marnix van den Broeke, a 6-foot 7 inch tall Dutchman.

In the 2008 adaptation of "The Colour of Magic", van den Broeke reprises the physical role, with Lee returning to the voice after the death of Richardson.

Death has been voiced in all five BBC Radio adaptations of Discworld novels. Geoffrey Whitehead played the part in the adaptation of "Mort", John Rowe played him in "The Amazing Maurice and His Educated Rodents", and Michael Kilgarriff voiced Death in Episode 4 of "Small Gods". In both "Guards! Guards!" and "Wyrd Sisters" Death is credited as being played by himself (In "Guards! Guards!" he is actually voiced by Stephen Thorne who also played Sergeant Colon).

Death has appeared in various other media: in the Discworld Game Series he is voiced firstly by Rob Brydon and later by Nigel Planer.

Death has also been played by numerous actors in amateur stage productions of "Wyrd Sisters", "Mort", "Soul Music", and "Hogfather", as well as various other plays based upon the novels.

After his death in March 2015, Pratchett's daughter Rhianna wrote in three tweets from her father's Twitter account:

Fans launched a tongue-in-cheek petition on Change.org, requesting for Death to return Pratchett to life because "Terry Pratchett turned Death from a figure of hate into a much loved and sometimes welcomed character. No-one else cared about you Death. You owe him!"

The Death of Rats has appeared in the animated "Soul Music" and in the radio play of "The Amazing Maurice and His Educated Rodents", but has not been given a voice credit for either. In the "Hogfather" TV series the voice was credited to Dorckey Hellmice (an anagram of Michelle Dockery who played Susan Sto Helit in the same TV series), while in the "Discworld 2" game, the voice is credited as Katherine the Crocodile. The Death of Rats also appears in Discworld Noir.

In Cosgrove Hall's 1996 animated "Soul Music", Albert was voiced by Bryan Pringle. In BBC Radio 4's 2004 adaptation of "Mort", he was voiced by Philip Jackson.

In Sky One's live-action version of "Hogfather", Albert was played by David Jason.

Albert also makes an appearance in the computer game "", voiced by Nigel Planer.

Death has appeared in every Discworld novel, with the exception of "The Wee Free Men" and "Snuff", and had a possible cameo at the end of "Johnny and the Dead" (the character was not identified, but spoke in unquoted small caps). The Discworld books with Death as a leading character, starting with "Mort" in 1987, are:

Death (Discworld)

Death is a fictional character in Terry Pratchett's "Discworld" series and a parody of several other personifications of death. Like most Grim Reapers, he is a black-robed skeleton usually carrying a scythe. His jurisdiction is specifically the Discworld itself; he is only a part, or minion, of Azrael, the universal Death. He has been generally used by Pratchett to explore the problems of human existence, and has become more sympathetic throughout the series.

He is fond of cats, who can see him at all times, and curry, the consumption of which he describes as like biting a red-hot ice cube.

In addition to the inside of the house being larger than the outside, there are doors that reach a height of several yards and at the same time are only a few feet tall. He has a bathroom which he never uses, with a bar of bone-white, rock-hard soap and a towel rack with hard towels attached to the rack. The only usable items in the bathroom are a small bar of regular soap and one normal towel, both brought there by his manservant Albert.

Furthermore, Death's house is full of cats, roaming around. Moreover, he is also responsible for sending cats to heaven as mentioned in "The Amazing Maurice and his Educated Rodents" where Maurice encounters Death himself.

Death is both the servant and a part of The Old High One known as Azrael, the Death of Universes and ruler of all deaths.

In the Cosgrove Hall Films animation of "Soul Music", Mort is voiced by Neil Morrissey. In 2004 BBC Radio 4 adapted "Mort", with the title character voiced by Carl Prekopp and Ysabell being voiced by Clare Corbett. Mort is included in Wayne Barlowe's "Barlowe's Guide to Fantasy".

Albert's childhood was touched upon lightly in "Hogfather", revealing that he comes from a very poor family (even by Ankh-Morpork standards). This novel also suggests that he is fond of pork pies with mustard and adores drinking sherry.

Binky is Death's steed, named so by Death because it is "a nice name". He is a living horse; Death tried a skeletal steed, but kept having to "stop and wire bits back on". Death also tried a fiery steed, but it repeatedly set his barn and his robe on fire.

Death gave Susan a "My Little Binky" gift set for her third birthday. It was returned by her parents, fearing that it would make her a less "normal" child.

The Death of Rats, also known as the Grim Squeaker, is not, strictly speaking, a personification in his own right but rather an aspect of Death allowed an independent existence. His purpose is to usher on the souls of dead rodents, as well as assisting Death in other ways. His jurisdiction also seems to cover certain kinds of "ratty" humans, such as Mr. Clete in "Soul Music", Mr. Pin in "The Truth", and Mr. Pounder in "Maskerade".

The Death of Rats more easily finds ways around the Rules than Death does, and has assisted Susan in "Soul Music", "Hogfather", and "Thief of Time". He sometimes travels with a talking raven named Quoth who also acts as his translator.

The Death of Rats, like Death, speaks in, but has a vocabulary consisting of words such as'and ', the last used when it laughs, although its speech can be interpreted from context much like the Librarian's.

In the mythology of the Changeling Clan in "The Amazing Maurice and his Educated Rodents" the Death of Rats is known as the Bone Rat.

He was first seen in "Soul Music", and since then has made appearances in all novels involving Susan Sto Helit. Neil Pearson voices him in the Sky One adaptation of "Hogfather".

The New Death appears in "Reaper Man" when he comes to collect the old Death, then known as "Bill Door". The New Death is the old Death's replacement as a result of the plot by the Auditors to rid the world of sloppy thinking.

The new Death is destroyed by Bill Door, using the scythe he used on the farm; a humble garden tool, not the infinitely sharp implement of Death, but sharpened by his rage and the harvest. Bill Door was disgusted and horrified by New Death's callous attitude toward humanity, and his victory is the triumph of the compassionate "reaper man" over the tyrant who has no care for the harvest.

The Rite is also the reason for Albert's affiliation with Death; while he was still Archancellor of Unseen University, Albert attempted to become immortal by performing the Rite backwards, reasoning that this would banish Death away from him, but instead it transferred Albert to Death's realm, where he decided to remain on the grounds that time didn't pass in Death's realm and he is thus essentially immortal.

In the "Discworld" books, the Rite has been used several times:

In the 1997 animated adaptations of "Soul Music" and "Wyrd Sisters", Death was voiced by Christopher Lee.

In the 2006 Sky One adaptation of "Hogfather" he was voiced by Ian Richardson. The actor who played the physical Death in Hogfather was Marnix van den Broeke, a 6-foot 7 inch tall Dutchman.

In the 2008 adaptation of "The Colour of Magic", van den Broeke reprises the physical role, with Lee returning to the voice after the death of Richardson.

Death has been voiced in all five BBC Radio adaptations of Discworld novels. Geoffrey Whitehead played the part in the adaptation of "Mort", John Rowe played him in "The Amazing Maurice and His Educated Rodents", and Michael Kilgarriff voiced Death in Episode 4 of "Small Gods". In both "Guards! Guards!" and "Wyrd Sisters" Death is credited as being played by himself (In "Guards! Guards!" he is actually voiced by Stephen Thorne who also played Sergeant Colon).

Death has appeared in various other media: in the Discworld Game Series he is voiced firstly by Rob Brydon and later by Nigel Planer.

Death has also been played by numerous actors in amateur stage productions of "Wyrd Sisters", "Mort", "Soul Music", and "Hogfather", as well as various other plays based upon the novels.

After his death in March 2015, Pratchett's daughter Rhianna wrote in three tweets from her father's Twitter account:

Fans launched a tongue-in-cheek petition on Change.org, requesting for Death to return Pratchett to life because "Terry Pratchett turned Death from a figure of hate into a much loved and sometimes welcomed character. No-one else cared about you Death. You owe him!"

In Cosgrove Hall's 1996 animated "Soul Music", Albert was voiced by Bryan Pringle. In BBC Radio 4's 2004 adaptation of "Mort", he was voiced by Philip Jackson.

In Sky One's live-action version of "Hogfather", Albert was played by David Jason.

Albert also makes an appearance in the computer game "", voiced by Nigel Planer.


Who is head of the District of Columbia Fire and Emergency Medical Services Department?

In June 2015, Jullette M. Saussy was named the medical director of DC Fire and EMS. On January 29, 2016, she announced her resignation from that position in a letter to Mayor Muriel Bowser. In her letter, she called the department's culture "highly toxic to the delivery of any semblance of quality pre-hospital medical care."

The District of Columbia Fire and Emergency Medical Services Department, (also known as DC FEMS, FEMS, DCFD, DC Fire, or Fire & EMS), established July 1, 1884, provides fire protection and emergency medical service for the District of Columbia, in the United States. An organ of the devolved district government, Fire & EMS is responsible for providing fire suppression, ambulance service and hazardous materials containment for the federal district.

On January 13, 1803, District of Columbia passed its first law about fire control, requiring the owner of each building in the district to provide at least one leather firefighting bucket per story or pay a $1 fine per missing bucket.

The first firefighting organizations in the district were private volunteer companies. To end the problems created by rivalries between these companies, District of Columbia approved in 1864 an act to consolidate them and organize a paid fire department. Seven years passed before it was implemented on September 23, 1871, creating the all-professional District of Columbia Fire Department with a combination of paid and volunteer staff. The department had seven paid firefighters and 13 call men to answer alarms, manning three engines and two ladders.

By 1900, the DCFD had grown to 14 engine, four ladder, and two chemical companies.

In 1968, the entire DCFD was mobilized during the riots that followed the assassination of Martin Luther King, Jr. The four days of disorder saw widespread civil unrest, looting and arson, which ultimately required help with 70 outside companies to battle over 500 fires and perform 120 rescues.

In the 1970s and 1980s, the department was riven by racial tension as the nearly all-white department became much more racially integrated and African American firefighters sought upper-level supervisory and management positions.

In January 2010, "The Washington Examiner" reported that, in a major management failure, the agency failed to budget for seniority pay in its fiscal 2010 budget, causing a $2 million shortfall. After a hiring freeze left 130 positions unfilled, the department was projected to spend $15.4 million in fiscal 2010 (2.5 times the budgeted amount). More than 75 percent of the agency's budget goes to salaries and fringe benefits.

Problems with vehicle maintenance also worsened after 2010. The department lost track of the location of reserve vehicles, and sometimes listed fire engines as available for duty when they had been stripped for parts and sent to the junkyard. In 2012, the agency hired a consultant at a cost of $182,000 to create an accurate database of vehicle status and location. Both the D.C. Council and the District of Columbia's inspector general have strongly criticized the department's record. The District of Columbia Firefighters Association, Local 36, IAFF, argues that the problem lies with poor management, while DCFEMS has said the problems either cannot be accounted for or are the result of rank-and-file incompetence or neglect.

In July 2013, more than 60 DCFEMS ambulances were out of commission due to maintenance issues, and the department was forced to hire a private ambulance service to provide staffing at a Major League Baseball game. On August 8, 2013, a DCFEMS ambulance ran out of fuel while part of President Barack Obama's motorcade, and ended up stranded on the South Lawn of the White House. (EMS personnel said they reported a broken fuel gauge months ago, while DCFEMS said workers failed to fill the vehicle with gasoline.) On August 13, 2013, two DCFEMS ambulances caught fire—one while delivering a patient to MedStar Washington Hospital Center, the other while responding to an emergency call at an apartment building on Benning Road SE. (Another ambulance was dispatched to take the patient to the hospital.)

, these are the DCFD's stations and equipment.