Abstracts 2005

06-03-001      Jacobs, Jeff

Leadership Competencies

No abstract, seed grant only

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06-03-002 Reaves, Scott

The Role of Nutrients and C-Reactive Protein on Cardiovascular Disease

No abstract, seed grant only

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06-03-003 Goldenberg, Marni

Understanding Longitudinal Outcomes of Wilderness Participation Using Means-End Analysis

Typically, means-end theory is used to understand consumer decision-making behavior.  Means-end theory specifically examines the linkages between the means (the service) and the ends (the consequences and values important to the individual).  Means-end theory links attributes (the physical aspect or characteristics to describe a service or product), with consequences (desirable or undesirable results), with values (end states that consumers are trying to achieve).  Previous research has used means-end theory to examine outcomes associated with ropes course and Outward Bound participation.  Outward Bound is a nonprofit, educational organization that utilizes an outdoor/natural resources based environment to provide groups of participants a wilderness adventure expedition.  This previous research expanded the use of means-end theory to uncover the outcomes associated with a multi-day outdoor adventure experience versus the one-day ropes course experience.

Through this past research, it was apparent that more research needed to be developed.  This study will use means-end theory to examine long-term outcomes of outdoor adventure experiences.  There is a gap in the research on longitudinal studies related to outdoor adventures.  One of the results from the means-end research that examined Outward Bound experiences stated that participants experienced a value of transference.  This means that participants had a motivation to transfer the information they learned on the outdoor education course into their daily lives.

Means-end research can be collected through interviews or questionnaires.  It is the intention to collect data via one-on-one interviews.  Over the course of several years, the interviews will be conducted over the phone.

To complete this research, a group would be studied over a 5 to 10 year length of time.  Initial funding would start with this grant.  Additional funding would be generated after initial research findings would be disseminated at conferences and through publications.

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06-03-004 Beckett, Jon

Application of multiple marker, pre-implantation genetic testing of bovine embryos

In order to ensure a consistent supply of safe, affordable and high-quality animal based food products, producers of domestic livestock strive to improve genetic influences in their herds.  Increasing the genetic potential of sires has taken place for more than 50 years through artificial insemination.  With high-performing females, the collection of embryos gives producers the potential to increase selection pressure.  However, the most significant potential gains will be achieved through genetic testing.  Successful efforts to combine the reproductive biotechnologies with genomic techniques enable scientists to identify embryos carrying increased genetic potential for certain traits.  Recent advances in gene amplification enable investigators to use sex-specific probes to determine sex in only 1 cell removed from embryos.  The biopsy method has had increasing success in fresh and frozen embryos.  The limiting factor on performing multiple DNA tests on an embryo biopsy is the very limited amount of DNA available in each biopsy.  Recently, whole genome amplification has become a viable method of consistently and uniformly increasing the amount of DNA available from each biopsy.  The proposed research will validate the MDA method for more than 2 DNA tests, and develop a strategy for producing “designer” bulls for a California producer using a combination of embryo transfer and DNA testing.  Finally, a third single nucleotide polymorphism (SNP) has been discovered for -calpain (a tenderness gene).  Briefly, cows with desirable genetics will be purchased by a coastal rancher.  The cows will undergo embryo transfer at Cal Poly, the embryos will be biopsied, DNA from embryo biopsies will be amplified using polymerase chain reaction (PCR) and presence of alleles for the multiple traits will be identified.  Recipient cows will be implanted with genetically tested embryos determined to have the desirable traits, i.e. bull calf with desirable -calpain genotype.  The first objective of this study will be to develop laboratory protocols for the testing for more than one gene from a single biopsy.  The second objective will be to design primers for the 3rd SNP for -calpain, and the third objective will be to apply the preimplantation genetic testing technology to a California beef herd. 

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06-3-005 Brown, Wyatt

Investigations into the Modified Atmosphere Packaging of Pre-cut Artichokes

California accounts for nearly 100% of the total U.S. production of artichokes.  Marketing problems with fresh artichokes include the high respiration rate of the buds, the tendency of the buds to discolor easily and for the discoloration to be dark and very noticeable.  The goal of the proposed research is to develop a viable modified-atmosphere (MA) package for pre-cut artichokes, that will maximize shelf-life while minimizing or eliminating unwanted browning.  The study will initially explore the use of antioxidants and antibrowning agents to control or alleviate tissue discoloration due to trimming.  Compounds to be tested include but are not limited to:  ascorbic acid, citric acid, erythorbic acid, the pyrophosphates, the carrageenans, and ethylenediaminetetraacetate (EDTA).  Compounds will be tested alone or in combination.  The use of surfactants and/or wetting agents to promote the efficacy of the compounds will also be investigated.  Concomitantly, tests will be run to assess bud respiration as affected by age, variety and season of harvest.  Respiration data will be used in the development of a modified atmosphere (MA) package.  Additional factors to be evaluated in developing the MA package will include film type, bud temperature in storage and at retail, and antioxidant and/or antibrowning agents.  Data to be collected during storage studies will include in-package levels of carbon dioxide and oxygen, film permeability to carbon dioxide and oxygen as affected by temperature, and changes in color (including discoloration) and weight of the artichoke buds.  Tests also will be run to investigate the effect of 1-methylcyclopropene (1-MCP) in reducing the rate of discoloration and/or senescence of packaged artichokes.  Economically, the impact of this series of studies should be far-reaching.  The proposed research seeks to test the efficacy of standard antioxidants/antibrowning agents  as well as novel compounds such as kappa- and lambda-carrageenans in preventing the browning of artichoke buds.  As artichokes discolor rapidly when cut or bruised, success in the area of research will have immediate impact to the artichoke industry of California which is seeking a means to successfully market pre-cut, ready-to-microwave artichoke buds.  Additionally, this research will indicate additional methods to prevent the discoloration of commodities such as pre-cut lettuce and apples.  A unique aspect of the research is to investigate the potential for 1- MCP to extend the shelf-life of artichokes.  As very little research has been conducted with vegetables and 1-MCP, the work proposed will further indicate the possible value of this compound to the vegetable industry, both nationally and within California, and should be of use in having this chemical registered for different vegetable commodities.

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06-03-007 Delmore, Bob

Effects of implants on physiological growth and carcass attributes in Holstein Steers

Effects of implants on physiological growth and carcass attributes in Holstein Steers
Since 1950, performance enhancing products have been used to increase the productivity of beef production.  These products enhance growth and efficiency, resulting in lower costs for consumers.  In addition, food safety is improved by decreasing animal health problems, thereby decreasing antibiotic use.  The most common performance enhancing product is the class of growth promoting steroid hormones.  The use of growth-promoting implants in the US is widespread – an estimated 95% of fed cattle receive growth-promoting implants.  Although implants dramatically increase average daily gain (~10%) and improve feed efficiency (~15%), there is evidence that implants decrease quality grades (Prime, Choice, Select and Standard) and tenderness of the meat. This reduction in quality grade is caused by a decrease in marbling (fat cells--adipocytes--that contribute to the eating quality of meat).  Traditionally, it was thought that implants decreased the body’s capacity to deposit adipocytes within muscles.  However, recent evidence suggests that the use of implants changes the growth curve of the animal such that the weight of the animal at a given physiological endpoint has been increased.  In other words, if implanted cattle are carried to a heavier weight, they will not demonstrate suppression in quality grade.  The two previous studies concluding the implant effects on physiological endpoint, were conducted in cattle of traditional beef genetics. While the vast majority of cattle fed in the US are of traditional beef cattle background, there is a large number of steers that enter feedlots as byproducts of the dairy industry.  Indeed, California places approximately 750,000 Holstein steers in feedlots annually.  These cattle offer much greater genetic consistency than cattle of traditional beef breeds.  Therefore, treatment effects will be more evident.  The objective of the proposed research is (a) to determine the changes in body composition of Holstein steers over time with and with-out implants, (b) determine the effect of implants on the growth curve of Holstein steers, (c) determine the effect of implants on tenderness and quality grade, and (d) calculate the cost of production to achieve a given physiological endpoint.

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06-03-009 Green, David

Evaluation of pesticide efficacy as influenced by adjuvant and nozzle type

Pest control is a significant issue for turfgrass managers, requiring a well developed program to safely and effectively control the various pests which infest turfgrass. Pesticides are one of several methods used in these pest control programs.  Unfortunately past misuse of pesticides has led to severe damage to humankind and the environment.  To protect humankind and the environment government agencies such as the Environmental Protection Agency and the California Department of Pesticide Regulation have developed strict regulations restricting the use of existing pesticides and development of new pesticides.  This regulation has led to fewer and less potent pesticides available for pest control, especially in low volume markets like turfgrass.  Adjuvants have been marketed as pesticide additives to improve efficacy and reduce drift potential.  Studies have shown that these adjuvants can significantly improve pesticide efficacy and reduce drift, but they also may have negative effects such as pesticide incompatibility and increased phytotoxicity (Curran, 1999; Hager et al, 2000).  Additionally, adjuvants have been shown to influence spray nozzle performance.   Adjuvant density and influence on water surface tension impact the atomization and pattern produced by different spray nozzles (Sprayer Systems Co, 2004).  Ferrell et al (2003) showed that adjuvants influenced the performance of different spray nozzles, impacting the tendency of the pesticide to cause phytotoxicity in cotton.  This study demonstrates the need for more research into understanding how pesticide/adjuvant mixtures influence nozzle performance.  No research of this type has been conducted in turfgrass, although there is significant interest in this field by the California turfgrass industry.  Funding for this research will be used to evaluate pesticide efficacy in turfgrass, specifically examining the effect of adjuvants on pesticide and nozzle performance as they influence pesticide efficacy, drift potential, and phytotoxicity.  Objectives of this research will emphasize the control of white clover (Trifolium repens) and English daisy (Bellis perennis) in perennial ryegrass (Lolium perenne) turf as influenced by adjuvant/post-emergent herbicide mixtures applied through different nozzle types.  Results from this research will increase knowledge of pest control techniques in turfgrass, developing improved application techniques which increase pesticide efficacy and minimize environmental contamination from drift.

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06-03-010 Hall, Mike

Assessing high-intensity short-duration grazing as a wildlife management tool in coastal California

Livestock grazing and wildlife management are sometimes in conflict.  For example, in northwestern California, large flocks of migratory geese graze intensively on short grass pastures and put a tremendous economic burden on local dairymen.  In central coastal California, where rangelands are much drier, overgrazing has been implicated as a cause for the decline of numerous wildlife species.  To meet the needs of society, farmers, and the environment, agriculturists and natural resource managers in coastal counties of California must work creatively to integrate livestock grazing with wildlife management.  In this project, we aim to assess the capacity for an innovative rotational grazing practice to meet ranchers’ needs while maintaining biodiversity and wildlife resources in two coastal regions of California.  Working closely with a team of graduate and undergraduate students from both Cal Poly and Humboldt State Universities, we will monitor grass conditions and wildlife responses to controlled grazing experiments.  We propose a series of experiments in Humboldt County to assess the capacity for grazing to create grass conditions on public land that will attract geese away from private pastures and ease the economic burden on the dairy industry.  In San Luis Obispo County, we propose studies to assess the potential benefits of rotational grazing on range condition while assessing impacts on wildlife, especially birds and small mammals.  The work is collaborative and interdisciplinary.  The project will be led by experts on rotation grazing (Mike Hall), wildlife-habitat-relationships (Matt Johnson), and goose management (Jeff Black) in cooperation with numerous industry partners, such as the Humboldt County Farm Bureau, the U.S. Fish and Wildlife Service, and the California Department of Fish and Game.  Thus, students involved in the project will not only learn state-of-the-art approaches for assessing effects of grazing on range condition and wildlife, they will also learn the value of agriculture and natural resource managers working together to identify mutually beneficial land use practices, and that lesson may be the most lasting of all.

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06-03-012 Hawk, Susan

Fatty Acid Modulation of Vitamin A and Breast Cancer

Fatty acids, particularly the omega-3 fatty acids present in fish oils, have been shown to optimize health by decreasing the risk of breast and other cancers.  In animal models, omega-3 fatty acids can decrease the incidence, growth and metastasis of mammary tumors, and in vitro, these fatty acids have been shown to exert growth regulatory effects against breast cancer cells; effects that are very similar to that observed with retinoids. At the cellular level, studies by ourselves and others have provided evidence that alterations in retinoid metabolism may be linked to aberrant signaling and cellular responsiveness in breast cancer cells.  In spite of this link to metabolism, little is known with respect to how normal mammary epithelial cells take-up and metabolize retinoids. Interestingly, my preliminary studies show that select fatty acids are associated with alterations in retinol uptake and retinoid metabolism in both normal and carcinoma mammary cells.  Evidence indicates that some fatty acids may enhance cellular retinoid metabolism and function.  However, the mechanism(s) underlying the anticancer effects of fatty acids is unknown. At present, there is a paucity of data concerning the effects of specific cancer preventative fatty acids (omega-3’s) on retinoid metabolism.  Furthermore, the effects of these and other fatty acids on retinoid metabolism in mammary carcinoma cells is completely unknown.  
I hypothesize that omega-3 fatty acids augment retinoid uptake and metabolism, and that these specific fatty acids exert these effects to a greater extent than other fatty acids.  This enhanced metabolism may in turn serve to optimize or maintain levels of active retinoids thereby potentiating the differentiative and growth regulatory properties of endogenous retinoids and slowing cancer progression.

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06-03-013 Headrick, David

Field Management Plan and Biocontrol Rearing System for Citrus Peelminer

Peelminer, Marmara gulosa Guillen & Davis (Lepidoptera: Gracillariidae), is a recent (1999) and persistent pest of citrus fruit in the San Joaquin Valley.  Peelminer larval stages create serpentine mines, scarring the rinds of citrus fruit and rendering it unacceptable for fresh market sale.  Growers of susceptible varieties initially experienced up to 80% infested fruit and insecticides have failed to provide control.  After three years of intensive study we plan to bring the current information together to build a management program for peelminer in the San Joaquin Valley that provides growers the necessary tools and information to effectively deal with this pest.  Citrus peelminer pest management requires an ecological approach using techniques such as pheromone traps, a degree-day model, and augmentative releases of natural enemies for successful control. The information gained from this research proposal will also directly benefit management of the citrus leafminer, Phyllocnistus citrella as it shares many of the same parasites.

Matching funds from ARI will be used to develop and investigate two additional aspects to the work funded by the California Citrus Research Board.  The first aspect is to continue studies of peelminer populations in Mexico, working with two colleagues to define the problem there and potentially move parasitoids from California into Mexico.  Current studies funded by ARI and Buy California have shown that Mexico may be an area of origin for peelminer.  A better understanding of the pest there will aid our efforts at managing it in the Central Valley.  The second aspect is to devote resources toward the development of an augmentation program for peelminer control in the San Joaquin Valley using a newly discovered parasitoid Hadrotrichodes wauhkeon LaSalle.  This parasitoid is currently being studied by a graduate student who was previously funded with an ARI grant.  The parasitoid shows promise as a control agent for both peelminer and the up and coming pest, citrus leafminer.  The Citrus Research Board is unable to fund these ancillary projects, thus without ARI money, these two aspects of the overall program will be lost and jeopardize the eventual outcome of the entire project.


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06-03-015 Jaster, Ed

Enhanced Growth in Jersey Dairy Calves

Nutrition and health of the young calf is crucial to maximize calf survival and growth rates. Traditionally, newborn calves after receiving colostrum were fed only limited amounts of milk replacer (MR) in an effort to get them to consume dry feed, and potentially reduce the cost of feeding milk replacer.  However, like most mammals, during the first 2 to 3 weeks of life, the calf’s digestive system is immature and is only designed to digest milk-based nutrients efficiently and for these infants, milk or milk replacer must be the major source of nutrition.  Several recent studies have indicated that calves fed on accelerated growth diets enriched in at least one of the three major components: protein, fat, and carbohydrates, had higher growth rates with increases in frame and lean tissue without fattening than controls.  The potential advantage to such changes in feed regimen are reduction in age at first calving, increase in feed efficiency by lowering the cost per pound of weight gain, and improved overall health of the animal and reduced veterinary costs.  However, these studies were done on beef cattle.

This study will be conducted with newborn to 10 week-old Jersey dairy calves at the Cal Poly University Dairy Farm.  Newborn calves will receive colostrum until day 3 of the study at which time they will be divided into three study groups; group 1 will receive the standard industry amount of milk replacer and groups 2 and 3 will receive two different levels of “accelerated or enhanced” replacer.  The calves will be fed the same regimen through week 6, half the amount on week 7 and then weaned.  Calves will be weighed each week and blood tests done every other week.

Results from this study should allow dairy herdsman to optimize the feeding of their newborn calves to fit the intended purpose of the individual animal – health and early maturity for the females and possibly frame and mass for the males.  California’s dairy industry is one of the largest and healthiest in the world and this project will help it stay there.

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06-03-017 Khalil, Hany

Mechanisms of Protection and Intestine Colonization of Probiotic Bacteria Offered by Milk Fat Globule Membrane in Yogurt as Determined by Laser Tweezers

Food acceptance, and consequently consumer’s choices, strongly correlates with its perceived role in human health. Consumption of probiotic lactic acid bacteria has a very positive impact on human health. Probiotic bacteria can be incorporated in many food products to enhance their health benefits. However, in order to express their benefits, probiotic bacteria must first survive food processing and second colonize the intestine. The influence of processing conditions on their survival and the mechanism of their intestinal colonization are not well elucidated, and published data lack accurate and practical physical evidence. Hence, the objective of this project is to fully understand the survival of probiotic bacteria in a fermented food system, and the impact that the food and processing have on its binding properties. This data is essential in order to develop an ingredient with active probiotic cultures.
Yoghurt offers a readily compatible food system which can function as probiotic carrier. Moreover freeze drying is a process known to minimally impact bacterial viability. Lyophilization (freeze drying) is the removal of water from frozen material. It is an excellent method for preserving microbes and heat-sensitive materials. In commercial practices bacteria are suspended in a suitable protective medium, frozen and exposed to a vacuum. The bacteria maintain their viability in a dehydrated state for a long time if packaged properly. However, the bacteria have to be suspended in a protective medium, De Valdez, G.F et. al.1983. Most common protective medium are skim milk, honey, raffinose, glutamate and lactose. Some hydrocolloids have shown to exhibit some protective effect during freeze drying, Champagne, C.P. et.al. 1996. In this project yoghurt with special formulations will be used as protective medium.
Therefore the experimental approach is to study yoghurt formulations and freeze drying parameters on the survival of probiotic bacteria and the effect that this has on the bacteria’s ability to bind to intestinal tissue. The freeze-dried yoghurt ingredient can then be incorporated in many cereal, fruit, vegetables, meat and dairy food products
The advent of new technologies based on laser traps and ‘tweezers’ allow for accurate measurement of the interactions among molecules and particles. Laser tweezers technology uses laser light and electronic controls to measure forces between microscopic particles. It has been applied successfully to some model as well as biological systems. Laser tweezers technology will be utilized to characterize membrane physical binding between the bacteria, food components, and intestinal tissue. Surface binding is responsible for the protective effect of milk fat globule membrane (MFGM) on probiotic culture during processing as well as their attachment to the intestine.

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06-03-020 Peterson, Dan

Examination of endogenous and exogenous phytase in domesticated birds

Phosphorus (P) is one of the major environmental pollutants excreted by poultry and swine, and excess environmental P is directly related to eutrophication and loss of biodiversity in water systems.  High levels of excreted P from animal production systems are related to the low digestibility of P from plant sources, since it is bound in the phytate molecule which vertebrates cannot break down.  While plant-based ingredients that are fed to commercial poultry and swine actually contain adequate levels of P to meet the animals’ nutrient requirements, this P is not available to the animal.  As a result, inorganic P is supplemented in poultry and swine diets, resulting in P excretion from unabsorbed inorganic sources as well as undigested phytate-bound P.

Phytase is a microbial-derived enzyme that breaks down the phytate molecule, liberating phytate-bound P and rendering it digestible.  To minimize high P excretion levels, exogenous phytase enzyme is often added to diets.  Additionally, transgenic technologies have been used to generate pigs which produce phytase enzyme in the digestive tract. These strategies increase P availability, reduce the need for supplemental dietary P, and subsequently reduce P excretion.  The PI and Co-PI have made substantial progress in generating transgenic quail at Cal Poly which secrete phytase in the digestive tract.      

In addition to the need for reduced P in excreta to prevent environmental effects, recent data gathered by the Co-PI indicate that the phytate molecule alters intestinal physiology, such that inflammation is significantly increased in animals fed high dietary phytate levels.  Addition of exogenous phytase enzyme into diets of animals fed high phytate significantly reduced markers of inflammation, indicating that increasing the hydrolysis of the phytate molecule may improve animal performance and well-being, which ultimately will lead to reduced costs of production.

The purpose of the proposed research is to extend current efforts to produce and characterize phytase-transgenic Japanese quail, and to further examine the role of exogenous phytase on intestinal physiology.  These efforts will facilitate the appropriate application of phytase, exogenous or endogenous, to ensure environmental friendliness and maintain animal performance, health and well-being.

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06-03-022 Pettey, Allen

Development of nutrient excretion models in pigs and poultry

Environmental impacts of animal production systems have long been a concern throughout the world.  The issue of excess nitrogen and phosphorus, two primary nutrients implicated in environmental contamination, will become a driving influence in the development of regulations concerning the feed ingredients used in animal rations, limits on sizes of operations, locations of animal production facilities, and measures used to apply animal waste effluent back onto agricultural land.  Due to the concentrated nature in which pigs and poultry are raised in the United States, these two species have become a primary target for regulation of nutrient output.

One method to estimate the amount of phosphorus being excreted by pigs and poultry is to quantify the true requirement for this nutrient.  This is done by estimating the maintenance needs of the animal, the animal’s influence on digestibility of phosphorus from feed ingredients, and the retention of phosphorus into body tissues.  In the current NRC for swine (1998), this type of modeling approach is used for amino acids, yet a scarcity of data exists allowing for the same methodology to be applied to mineral requirements.  Recent work (Pettey et al., 2004) indicates that a modeling approach is applicable to swine mineral requirements, however, multiple factors influencing these requirements have yet to be studied.  Very little data exist concerning the whole body retention of phosphorus in broilers, thus prohibiting the development of any model approach to estimate requirements and excretion levels at this time.

The proposed studies look to further investigate the factors influencing maintenance requirements for phosphorus in growing pigs and poultry, and the retention rates of phosphorus in whole body tissues.  Four experiments will be conducted using growing-finishing pigs placed in metabolism crates to estimate the effect of body weight, feed intake, phosphorus intake levels, and phytase inclusion on endogenous phosphorus excretion.  A similar study will be conducted in broilers to provide novel information regarding endogenous phosphorus losses in birds.  Coinciding with the estimation of maintenance phosphorus requirements, the retention of phosphorus on a mass basis, and in proportion to nitrogen retention, will be studied in pigs and poultry.  Nitrogen balance has been extensively studied in pigs and poultry, thus correlating phosphorus balance to nitrogen balance in a factorial fashion will allow for greater strength in utilizing derived models from this data into practical industry applications.

The basis of any model used to predict nutrient excretion is an understanding of the true requirement of nitrogen and phosphorus throughout the growing life of the pig and broiler.  The first step in the development of a nutrient excretion model will be to quantify all routes of nutrient utilization in pigs and poultry, and utilize the data collected to develop a set of prediction equations which will estimate nutrient excretion when dietary levels are in excess.

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06-01-017 Mark, Walter

Spatial Modeling of a Biological Invasion: Landscape-level establishment and spread of Phytophthora ramorum in California

Biological invasions cause dramatic ecological changes around the globe.  Invasive species alter ecosystem processes, undermine biodiversity at multiple scales, and negatively influence 49% of all imperiled species in the United States.  One type of invasion that is occurring with growing regularity is the spread of non-native plant pathogens.  By killing host species that play key roles in forest ecosystems, invasive plant pathogens can dramatically alter forest community structure and genetic diversity of host populations. 
The emergence of the invasive pathogen, Phytophthora ramorum, has caused epidemic levels of a forest disease called “Sudden Oak Death” in coastal regions of California and southwest Oregon.  Phytophthora is a large genus of widely distributed water molds that cause many economic and ecological problems in agriculture and forestry.  More than 60 plant species are potential hosts, enabling P. ramorum to inhabit a variety of widespread forest types.  Among its host species, P. ramorum causes two forms of disease: lethal branch or stem infections, and non-lethal foliar and twig infections.  The lethal form of the disease kills several important trees, including tanoak (Lithocarpus densiflorus), coast live oak (Quercus agrifolia), black oak (Quercus kelloggii), canyon live oak (Quercus chrysolepis), and Shreve’s oak (Quercus parvula var. shrevei).  Except for tanoak, the pathogen does not seem to spread from these species.  In contrast, widely abundant foliar hosts such as bay laurel (Umbellularia californica) and tanoak can support the production of numerous dispersal spores on their leaves, which can be spread via rainsplash and wind, as well as on nursery stock, in stream water, and soil transported by vertebrates.  Establishment of this non-lethal form of the disease may play a key part in transmitting the pathogen and enabling it to develop persistent populations.
It is critical that we gain an understanding and ability to predict disease spread in order to develop effective strategies for detection, management, and prevention.  Spatial modeling of disease dynamics is an approach that is critically needed for developing a predictive understanding of factors that influence plant pathogen dispersal and infection processes.  Modeling enables integration of multidisciplinary information and provides a framework for repeatable, nondestructive experiments at broad spatial scales.  Spatial modeling can also be used to reconstruct past events and forecast future trends.  A variety of ecological simulation models (e.g. land cover change, forest succession and wildfire) have been successfully applied to facilitate a predictive understanding of a system’s behavior and structure under heterogeneous landscapes and environments.  However, few studies have developed spatial models of plant disease spread in natural systems because a multidisciplinary framework is needed to incorporate fine-scale processes of pathogen dispersal and survival into landscape-level models.
Spatial modeling of disease dynamics is also direly needed to assist in the selection of threatened sites for early-detection monitoring efforts.  It is essential to understand where and when P. ramorum will spread in order to effectively monitor the disease and manage threatened forests.  The regulatory process for P. ramorum will also benefit from such research.  Regulation of Phytophthora ramorum is taking place within California by the California Department of Food and Agriculture (CDFA), nationally by the Animal Plant Health Inspection Service of the US Department of Agriculture and internationally by several controls, which have imposed quarantines on California plant products.  The regulatory and quarantine efforts depend upon accurate mapping of the areas infested by P. ramorum.  Lacking accurate distribution information, quarantines tend to be broad scale to protect receiver sites and have a very negative impact on the California plant industry.


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