Farewell-to-spring (Clarkia amoena) is native to the Pacific Northwest and commonly found in gardens, due to its aesthetic value and purported benefits to pollinators. Oregon and Washington are home to five subspecies of C. amoena, yet commercially available seed is limited to C. amoena ssp. lindleyi and C. amoena cultivars....
Managed honey bees (Apis mellifera) play a vital role in pollinating cultivated crops worldwide. Honey bee colony declines reported in the past two decades have been associated with stressors such as pests and diseases, pesticide exposure, and poor nutrition. In the wake of these colony declines, beekeepers have strived to...
Daikon, mizuna, mizspoona, and komatsuna are novel Asian vegetables for which a market exists in Oregon, especially in the organic sector. However, these crops are currently not grown widely in the area, despite the favorable growing environment of Oregon’s Willamette Valley. Little is known about the appropriate application level of...
Escalating demand for organic blueberries has driven a significant expansion of northern highbush blueberry (NHB; Vaccinium corymbosum L.) production area. This expansion is particularly pronounced in regions of the Pacific Northwest where native soil conditions are sub-optimal for NHB, notably east of the Cascade Mountain Range of Oregon and Washington,...
Honey bees are vital for our food production and ecosystem due to their critical pollination services. The beekeepers in the United States and worldwide have reported significant colony losses for over fifteen years. Several stressors are implicated in these colony declines, including parasites, diseases, poor nutrition, and pesticide exposure. There...
One of the most economically important genes in squash (Cucurbita spp.) is the B gene which conditions precocious depletion of chlorophyll in preanthesis fruit. The B genes are found naturally occurring in at least three of the five domesticated species of Cucurbita, including C. pepo, C. maxima and, most recently...
Oregon State University campus grounds have long been admired for their beauty and the diversity of over 65,000 individual woody plants that grace the 570 acres of campus. The woody plant collection has provided a living learning laboratory for the university and surrounding community for decades. The campus grounds include...
Cannabis sativa L. is emerging as an economically important crop, particularly for its high levels of cannabinoid production. One of these cannabinoids, cannabigerolic acid (CBGA), is the precursor to many well-researched cannabinoids such as the psychotropic delta-9-trans-tetrahydrocannabinolic acid (Δ9-THCA i.e., THCA) and the medically relevant cannabidiolic acid (CBDA). CBGA has...
Cabbage maggot, Delia radicum (Diptera: Anthomyiidae) impacts the production of Brassicaceae crops worldwide. The larva feed on the roots of crops causing reductions in yields due to impaired root function and unmarketability of crops. Chemical and cultural management programs are commonly used to control cabbage maggot with varying rates of...
Hemp is a dioecious, annual, flowering plant in the Cannabaceae family. It has been used for thousands of years to produce textiles, essential oils, and medicines. The overall purpose of these experiments was to propagate the cannabinoid-free cultivar, ‘I3’, and follow up by inducing polyploidy in the ‘I3’ hemp via...
The Pacific Northwest region of the United States is known for quality production of blueberries, blackberries, and red raspberries. However, as the climate shifts to warmer, drier, and more extreme summers, growing these water intensive berry crops is becoming increasingly difficult. Furthermore, water regulations within agriculture are becoming more prevalent...
Cannabis production has gained popularity over the last 10 years. There is a growing demand for true-to-type grain, fiber, and resin crops. Breeding for homozygous trait development with traditional methods can take as long as 8 years. With dihaploid breeding, homozygosity can be achieved in 2 generations saving breeders time...
Vineyards in Oregon’s Willamette Valley are predominately planted to perennial grass cover in the alleyways of vineyards. This grass cover is grown to increase worker and equipment traction, as well as reduce erosion and manage vine vegetative vigor. However, with increasing frequencies of drought and warming temperatures, the use of...
Common bean (Phaseolus vulgaris L.) comes in a huge assortment of fresh and dried varieties, including snap beans, kidney beans, and pinto beans. Together, these and other market classes provide a third of the daily dietary protein in some cultures, particularly in Africa, Asia, and developing nations in the Americas....
Buddleja davidii (butterfly bush) is a highly adaptable landscape plant known for pollinator attraction. Unfortunately, it is also regarded as an invasive plant in highly disturbed environments across the globe. It is an invasive species in Oregon, officially classified as a class B noxious weed in 2004. Currently the state...
The certified organic blueberry (Vaccinium sp.) market has continued to expand in the last two decades, including in Oregon. The development of an industry-public research coalition has fostered expansion. In 2015, a survey consisting of on-site, in-person interviews with certified and transitional organic growers in Oregon found the majority of...
The European hazelnut (Corylus avellana L.) is a tree nut crop that is important in Oregon, which produces 99% of the United States’ hazelnuts but only 5% of the world’s supply. In order to maintain this market share, farmers in Oregon need cultivars that produce high quality nuts, mature early,...
Organically certified Northern Highbush Blueberry (NHB; Vaccinium corymbosum L.) production in the Columbia Basin region of Oregon and Washington is expanding. Soils in the region are typically calcareous and highly alkaline, often requiring pH adjustment to an ideal range of 4.5–5.5 to support the establishment of the acid-loving, ericaceous crop....
Chrysobothris mali Horn and C. femorata Olivier (Coleoptera : Buprestidae) are two flatheaded wood boring beetle species that have become economically impactful pests in North American high value tree cropping systems. Both species are native to North America, with C. femorata occurring across the continent (Wellso and Manley 2007), whereas...
Improving crop cultivars for use on organic farms is pertinent, as current elite germplasm is less resilient within the more variable context of organic farm environments. Although a growing number of studies have focused on organic plant breeding in cereal crops, very few have focused on vegetable crops, especially those...
Biochar is a highly porous, carbon-rich residue produced by thermochemical conversion (pyrolysis) of plant biomass and carbonaceous organic materials under oxygen-controlled conditions. Chars produced by this process tend to have high ion-exchange capacities and, when added to soil, increase retention of water and nutrients and improve soil aggregation, porosity, and...
Black raspberry (Rubus occidentalis L.) is a US Pacific Northwest specialty crop prized for its unique flavor profile and nutritional attributes. A major obstacle for the raspberry industry is Black raspberry necrosis virus vectored by the large raspberry aphid (Amphorophora agathonica). Market expansion depends on production, which is currently hindered...
Due to a growing body of literature documenting declines in pollinator populations, there has been increased public interest in pollinator conservation. In urban and suburban landscapes, many gardeners and urban land managers are interested in gardening for pollinators, particularly bees. Simultaneously, many homeowners and municipalities are interested in other aspects...
With confirmation of non-nutritive sugar, erythritol, having insecticidal properties to Dipterans, this thesis research focuses on use of erythritol as a human-safe management tool for small berry and cherry pest, Drosophila suzukii, commonly referred to as spotted-wing drosophila. Drosophila suzukii is a destructive invasive fruit fly from Asia with an...
Previous studies indicated that fertigating with nitrogen (N) was more effective than using granular N fertilizers in production of northern highbush blueberry (Vaccinium corymbosum L.). To build on these findings, four studies were conducted in western Oregon to determine whether fertigation was also an effective method for applying other nutrients,...
The choice of what to eat is political, and food systems shape and are shaped by political and economic power. During the last several hundred years, agricultural and food power has been consolidated to an unprecedented degree, and this consolidation continues today. This paper will describe this process as “Governing...
The recently emerged Grapevine Red Botch Virus (GRBV) impedes proper berry ripening primarily by reducing sugar accumulation and color development in red-fruited Vitis vinifera L. cultivars. To date, there is no recommended management strategy for virus spread or the impacts of the disease beyond removal and replacement of infected vines....
Pacific flatheaded borer (PFB), Chrysobothris mali Horn (Coleoptera: Buprestidae), has recently become a serious pest in newly planted European hazelnut, Corylus avellana L. (Betulaceae) in Oregon. Larvae feeding on the inner bark can lead to girdling, loss of transpiration, and ultimately can cause dieback or death of the tree. Although...
Annual bluegrass (Poa annua L.) is a prolific annual grassy weed that can be found worldwide in most landscapes. Known for its ability to produce seedhead at low heights (0.32 cm), thrive in over-maintained areas, and germinate anywhere, annual bluegrass is a highly invasive weed. Due to annual bluegrass’ persistence,...
Italian ryegrass [Lolium perenne L. ssp. multiflorum (Lam.) Husnot] resistant to multiple herbicide sites of action continues to limit winter wheat production in western Oregon. In addition to impacting wheat production, multiple resistant Italian ryegrass may threaten the market for annual ryegrass seed for cover crops if wheat fields with...
Nitrogen (N) is the most important nutrient to manage in the overall wine production system, since N has a large influence on vine productivity and fruit quality in the vineyard and also on fermentation kinetics and fermentation-derived aromas in the winery. Previous studies investigated the influence of either vineyard N...
Drosophila suzukii (Diptera: Drosophilidae) is an insect of global concern that causes serious damage to soft-skinned fruits. D. suzukii is widespread in North America, South America, Europe, and Asia and is listed as an invasive pest with strict quarantine protocols governing import and export. Given the damage caused by D....
European hazelnut (Corylus avellana L.) is a diploid with 11 pairs of chromosomes (2n = 2x = 22), monoecious, dichogamous and wind-pollinated. Eastern filbert blight (EFB) caused by Anisogramma anomala is a serious disease of European hazelnut (Corylus avellana) in North America, and infection leads to cankers that girdle branches...
Drosophila suzukii (Diptera: Drosophilidae), is a serious pest in soft and stone fruit industries worldwide. The unique serrated ovipositor of female Drosophila suzukii allowed the species to reproduce in intact, ripening fruit before the harvest. Current control methods rely heavily on insecticide application, only becoming less profitable due to the...
Betalains are a group of compounds that are major natural food colorants used by the food processing industry. These secondary compounds are found in only a few orders of plants with the Caryophyllales being the source of several domesticated crops. In particular, the family Chenopodiaceae in general and table beets...
Grapevine red blotch disease (GRBD) is caused by Grapevine Red Blotch Virus, a virus in the Geminiviridae family. Observable symptoms can manifest in red cultivars, such as leaf blades that are partially to fully red, red veins, and different combinations of the two. Previous research has shown evidence of reduced...
Grapevine red blotch virus (GRBV), the causal agent of red blotch disease (RBD) in grapevine, Vitis vinifera L., is an emerging pathogen of significance to the wine grape industry of Oregon, USA. To address knowledge gaps of GRBV epidemiology, spread of GRBV was evaluated in Oregon vineyards over four years....
The azalea lace bug (Stephanitis pyrioides Scott) is a global pest of rhododendrons and azaleas (Rhododendron spp.). It is originally from Asia, has been established in the eastern U.S. for the past century, and was recently detected in the Pacific Northwest in 2008-2009. Stephanitis pyrioides feeds on the underside of...
Landscape plants are highly diverse and nursery producers often grow thousands of taxa to satisfy the varied needs and aesthetic tastes of consumers. Related to this diversity, ornamental plant breeders must be nimble and diverse in their approach. Two seemingly disparate studies were conducted to investigate improving ornamental shrubs –...
The European hazelnut (Corylus avellana L.) is a diploid (2n = 2x = 22) tree crop important to the economy of Oregon’s Willamette Valley, where 99% of hazelnut production in the United States is located. Corylus avellana exhibits sporophytic self-incompatibility (SSI), controlled by a single S-locus with at least 33...
The persistent color (pc) trait in snap bean (Phaseolus vulgaris L.) belongs to a member of the cosmetic stay-green gene family. It is considered very desirable by snap bean breeders for its impacts on pod quality. Persistent color imparts a uniform dark-green color to pods and expresses in seeds as...
Managing Microdochium patch on intensively manicured annual bluegrass putting greens is a challenge for turfgrass professionals in cool-humid climates similar to the Pacific Northwest. Fungicides are the predominant means to mitigate damage caused by this fungal pathogen, however pesticide restrictions are making it even more challenging to suppress Microdochium patch....
Hazelnuts (Corylus avellana) produce a prolific growth in the base of the trunk and roots, known as suckers, which are often removed in order to promote the development of a single trunk tree. Sucker removal facilitates cultural practices and mechanized operations, such as weed management and harvest. Sucker presence can...
European Hazelnut (Corylus avellana L.) is an important crop in the Pacific Northwest where around 5% of the world's hazelnuts are produced. Hazelnut production in the Pacific Northwest is threatened by eastern filbert blight (EFB) caused by the pyrenomycete Anisogramma anomala. Host resistance is a useful strategy to control disease,...
Bacterial blight (Xanthomonas arboricola pv. corylina) (Xac) of hazelnut (Corylus avellana L.) was described first in Oregon in 1915 and is now recognized as a damaging disease of young hazelnut trees worldwide. Stressed hazelnut trees in conditions such as planting on marginal sites, and trees between 1 and 4-years-old are...
The goal of the work in this dissertation was to identify alternative soil amendments to improve plant growth and yield during establishment of highbush blueberry (Vaccinium hybrid). Woody materials, such as sawdust and wood chips, have a high carbon to nitrogen (C:N) ratio and low water holding capacity, which can...
Although the concept of breeding crops for organic agricultural systems has been around for decades, few studies have been reported for vegetable crops to quantify and compare how conventional and organic systems differ in their selection pressures on genotypes advancing through the breeding cycle; especially research utilizing modern sequencing capabilities....
Cover crop establishment in late-season crops, like sweet corn, may be difficult due to the relatively short operational window following crop harvest. In regions like western Oregon, where fall-precipitation can occur when the crop is still in the field, cover crops may not be able to be planted, due to...
The majority of grapes grown in Oregon are produced in Western Oregon’s Willamette Valley, where two-thirds of the acreage is planted to Pinot noir. The production of Pinot noir in the Willamette Valley comes at a high cost, and growers are seeking ways to increase profits while maintaining quality fruit...
Urban landscape water use is increasingly a focus of water conservation efforts. This is especially true in the arid and semi-arid regions of the western United States where increased demand, environmental concerns, and extended periods of drought have created chronic water shortages. However, until recently, little attention has been paid...
Hybridization, polyploidy, and apomixis have made phylogenetic estimation in Rubus challenging. I used target capture to sequence approximately 1000 low copy nuclear loci and the chloroplast genome for 94 accessions representing the genus Rubus and distributed worldwide. Species phylogenies were estimated using two coalescent based methods, ASTRAL-II and SVDQuartets, and...
Hibiscus and lilacs (Syringa spp.) are economically important nursery crops in the US that accounted for 4.5 million units ($30 million) and 2 million units ($20 million), respectively (USDA, 2016). To maintain and expand the market share of ornamental plants such as lilacs and Hibiscus, novel performance, floral ornamental value,...
Prunus laurocerasus, commonly known as cherrylaurel, is a woody shrub grown in temperate climates for its durability and landscape appeal. Due to its abundance of drupes that are spread by birds, cherrylaurel is a litter nuisance in cultivation and also has escaped cultivation such that it has naturalized. Furthermore, it...
Winter squash is an important late winter vegetable crop for local and regional markets; however, farmers in western Oregon report that this crop is marginally profitable due to losses in storage and relatively low yields for the high culinary value kabocha and buttercup types. In order to increase the sales...
Great Lakes coastal wetland communities are threatened by the impacts of invasive plants on ecosystem function and biodiversity. What allows invasive plants to become dominant in invaded communities can be hard to define and context-dependent. Traits associated with invasion success in wetland systems – rapid vegetative growth, competitive superiority in...
Urban agriculture (UA) is defined as the production of food crops or livestock within urban areas. Despite its popularity in the United States, research into UA systems suffers from a general underrepresentation of commercial urban systems. As a result, urban growers often have unique technological needs that are unmet by...
Heat-related fruit damage is a common problem in the northern highbush blueberry (Vaccinium corymbosum L). This is particularly true in regions such as the northwestern United States, where summers are warm and dry, and daytime temperature regularly exceeds 32 oC. Millions of dollars of fruit damage are reported in blueberries...
This is a Ph.D. dissertation for a study conducted at OSU/Horticulture. The main objective of this study was dissecting the genetic background for white mold resistance in common (snap) bean. Tow main approaches were followed to achieve the goal. The first approach was using the classical quantitative trait loci (QTL)...
Green bean flavor has been studied since the 1960’s to better understand Blue Lake flavor in processed green beans in Oregon. Research by Stevens and colleagues showed that Blue Lake flavor could be reconstituted in a bland bean by adding 0.4ppm of 1-octen-3-ol and 1.6ppm of 3-hexen-1-ol. These two volatile...
Winegrapes are an important crop for Oregon agriculture, ranking amongst the top ten agricultural commodities based on farmgate value. The most widely planted winegrape cultivar in the state is ‘Pinot noir’ (Vitis vinifera L.), and the majority of acreage is produced in the Willamette Valley. Production of quality ‘Pinot noir’...
In recent years, many studies have focused on the molecular and biochemical mechanisms regulating the development of wine grapes. The course of grape berry development is directed by genetic design and is mediated by phytohormones, which regulate grape berry growth and development by orchestrating a complex network of interacting genes,...
Rising human populations and climate change are putting increasing demands on our already-limited freshwater sources. In response to these concerns, homeowners and municipalities have been encouraged to replace turfgrass – a plant with relatively high irrigation needs – with drought-tolerant plants that do not require frequent irrigation. However, the many...
Drosophila suzukii is a global and economically significant pest of berries and other soft fruits. This insect can survive and reproduce under a wide variety of environmental conditions and with a substantial number of cultivated and wild hosts. Management of D. suzukii is commonly done with chemical control strategies. However,...
As blueberry (Vaccinium sp.) production has increased in recent decades, a new interest has developed in the cultivation of blueberry in soilless substrate containers. Historically, blueberry has been propagated and grown in soilless substrate at nurseries, but nursery production is short in duration and plants are small relative to a...
Hereditary variation is a vital component in the development of new and improved cultivars of landscape plants. Sources of hereditary variation include naturally occurring variation, recombination due to controlled crosses, artificial mutagenesis, and genetic modification via biotechnology. Here I explore all methods with the exception of genetic modification via biotechnology....
Spotted wing drosophila (SWD), Drosophila suzukii, is an economically damaging pest on small fruits. The estimated economic impact is hundreds of millions of dollars annually in the U.S. alone, and increasing every year. Current control of SWD relies heavily on chemical insecticides which have many negative impacts on environmental and...
Lilacs are a group of ornamental trees and shrubs in the Oleaceae family consisting of 22 to 30 species. There are six series within genus Syringa: Pubescentes, Villosae, Ligustrae, Ligustrina, Pinnatifoliae, and Syringa. Fertility and cross-compatibility among cultivars, species, and series have yet to be formally investigated. Over three years,...
Ornamental landscapes require considerable amounts of inputs, including but not limited to irrigation, mowing or pruning, fertilization, and pest management. However, school systems have limited budgets, which reduce their access to resources and labor hours. Therefore, the objective of this project is to identify ground covers that can compete with...
Halyomorpha halys Stål, brown marmorated stink bug or BMSB, is now present in 43 US states. A native of eastern Asia, this pest can feed on ~200 different plant species damaging bark, leaves, buds, stems, and fruits. Many of these plant species include wild plants, ornamentals, and agricultural crops. BMSB...
The common cherrylaurel (Prunus laurocerasus) and Portuguese cherrylaurel (P. lusitanica) are economically important landscape shrubs across the United States. To gain a better understanding of physiology and morphology in these higher level polyploids (P. lusitanica, 2n = 8x; P. laurocerasus, 2n =22x), a variety of breeding experiments were performed. The...
The perception of a long-term cost advantage of synthetic infill turf systems relative to natural grass systems has contributed to a rise in their popularity in the USA. However, few comprehensive cost assessments of natural grass and synthetic infill systems exist. There are also no studies looking at interactions between...
Drought and mandatory water restrictions are limiting the availability of irrigation water in many important blueberry growing regions and new strategies are needed to maintain yield and fruit quality with less water. Three potential options for reducing water use, including deficit irrigation, irrigation cut-offs, and crop thinning, were evaluated for...
Drosophila suzukii (Diptera: Drosophilidae) is a devastating pest that attacks thin-skinned stone and small fruit in all major production regions of the United States and worldwide. D. suzukii first appeared in the United States in 2008 and is believed to be native to Southeast Asia. This vinegar fly has a...
Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is an invasive insect pest that has become established and problematic in the Pacific Northwest. Known colloquially as the brown marmorated stink bug (BMSB), H. halys causes direct damage through feeding activity on a wide range of agronomic and horticultural crops. The objectives of this...
Root rot diseases are a major constraint to bean (Phaseolus vulgaris L.)
production around the world. Both snap beans and dry beans are affected. Root rot diseases can be caused by a variety of pathogens; however, Fusarium solani is a common causal agent. Fusarium root rot is a primary yield...
The azalea lace bug (Stephanitis pyrioides Scott) is a recently detected invasive pest to the Pacific Northwest and has become a major concern in Oregon. It feeds on azaleas as well as rhododendrons causing stippling on the top side of leaves. The damage is aesthetically displeasing and affects plant vigor...
Hazelnut is one of the most important nuts in worldwide production and the European hazelnut (Corylus avellana L.) is the most economically important of the 11 recognized hazelnut species. Development of new cultivars is continuous, with emphasis on better nut quality, high yield and disease resistance. Hazelnuts are highly heterozygous,...
Honey bees (Apis mellifera) are responsible for approximately $17 billion in crop production per year in the United States, and are arguably the most important pollinators in the nation. The future of crop pollination and production is threatened by widespread national honey bee colony losses, which have averaged approximately 30%...
Stevia (Stevia rebaudiana) is a perennial herbaceous plant native to Paraguay and used traditionally by the native Guarani peoples for centuries to sweeten medicinal teas. Stevia has only been commercially cultivated over the past 50 years and cultural practice information suitable for implementation by growers is limited. Currently stevia’s commercial...
There is limited information available on production of trailing blackberry, particularly certified organic plantings, which are of interest to growers as there is increased consumer demand and a price premium over conventionally-produced fruit. Various production strategies were evaluated for their effect on yield, biomass production, carbon (C), and nutrient concentrations...
European hazelnut, an important nut crop in Oregon agriculture, is threatened by the fungal disease eastern filbert blight (EFB) caused by Anisogramma anomala (Peck) E. Müller. The hazelnut breeding program at OSU has been working on development of EFB-resistant cultivars. DNA markers allow mapping of traits using segregating progenies and...
Currently, fungicide applications are the predominant method of control for the cool weather pathogen Microdochium patch (Microdochium nivale). Increasing pesticide restrictions have generated concern regarding management of Microdochium patch. Three separate field trials exploring non-traditional fungicides were conducted between 2013 and 2015 on an annual bluegrass (Poa annua L.) sand-based...
Strawberry is economically the most important berry crop grown worldwide and breeders are continuously striving to develop improved cultivars. So far, marker assisted breeding (MAB) in strawberry has been limited to the private sector. However, loci controlling some traits of economic importance such as perpetual flowering (PF) and soluble solids...
Honey bees are important pollinators for many agricultural systems throughout the world. However, recent honey bee declines have caused great alarm, drawing attention to the vulnerability of worldwide agriculture to pollinator loss. These declines are often attributed to a combination of pests, pathogens, viruses, chemicals, and a lack of proper...
Northern highbush blueberry is a long-lived perennial crop that is well adapted to low soil pH conditions. The plants are often shallow rooted and absorb primarily the ammonium (NH₄) form of nitrogen (N) rather than nitrate-N (NO₃-N). Traditionally, commercial blueberry fields have been irrigated with overhead sprinklers and fertilized using...
Novel approaches to crop load management of pear orchards in the Pacific Northwest (PNW) are necessary, but will need to vary according to the unique vegetative and reproductive growth habits of the cultivar. 'D'Anjou' is vigorous and non-precocious; thus, strategies to limit vigor and induce early fruiting are required. In...
Vertically shoot positioned (VSP) training systems are common in Oregon's Willamette Valley, where deep fertile soils and high regional precipitation task growers with curbing vegetative vigor within this system. Management strategies, such as canopy hedging and cluster-zone leaf removal, are used to improve microclimate within the canopy and around the...
This thesis investigates the success of and challenges facing small farmers operating direct marketing farm businesses in Oregon's Willamette Valley. This qualitative study utilizes participatory methods to gain the unique perspectives of small farmers regarding their success and challenges. Small farms are important players in local food systems and ensuring...
Drosophila suzukii (Diptera: Drosophilidae), a pest of thin-skinned fruits, has been detected worldwide recently, with new locations of establishment determined annually since it first became a concern on continental North America in 2008. Drosophila suzukii females are different from most other drosophilids as being one of two known species capable...
Drosophila suzukii Matsumura (Diptera: Drosophilidae) are small invasive flies that in the past five years (2009-2014) invaded berry and stone fruit production regions in Europe and the Americas. Evolutionary adaptations, biological traits, and anthropogenic factors have contributed to its current status as a global pest. Females oviposit eggs into ripe...
Red raspberry, Rubus idaeus L., is a valuable crop for the U.S. Pacific Northwest and clonal propagation is required to produce disease-free plants and for germplasm preservation. One challenge of red raspberry micropropagation is the wide variation in growth response among the cultivars. The studies described in this dissertation were...
Snap beans are the vegetable form of dry bean (Phaseolus vulgaris L.) with low fiber, stringless and round, succulent pods that are eaten in the immature stage. Seed companies commit significant resources to maintaining purity and uniformity of snap bean cultivars. While some variability may be introduced through outcrossing (beans...
Managed honey bee (Apis mellifera L.) colonies are important pollinators of many cultivated crops. Honey bee colony declines averaging 30% annually in the United States for the past 7 years have caused significant concern and hence have been a topic of intensive investigation. These declines are reportedly due to multiple...
A major constraint to the production of self-rooted wine grapes (Vitis vinifera) in eastern Washington is plant-parasitic nematodes. Plant-parasitic nematodes can impact grape productivity by limiting water and nutrient uptake, educing physiological changes, and extracting plant nutrients from roots, thereby reducing root biomass, plant vigor, and yield. The most commonly...
The impact of fertilizer source and cultivar on growth, fruit quality, and yield was evaluated in organic blackberry (Rubus L. subgenus Rubus Watson) from 2011-2013 in three studies. In all studies, plants were drip irrigated, and weeds were managed using a woven polypropylene, permeable landscape fabric (weed mat). At a...
Halyomorpha halys (brown marmorated stink bug, Hemiptera: Pentatomidae), an invasive insect pest, has established populations in the Willamette Valley of Oregon. Halyomorpha halys is a potential pest of many specialty crops in the Willamette Valley, including hazelnuts (Corylus avellana L.). The objectives of this study were to 1) characterize the...
A project to restore and increase the native riparian habitat on a 1½ acre site along Oak Creek will begin in spring 2013. In order to carry out long-term monitoring and evaluation of the efficacy of the restoration effort, it is necessary to know what is growing there now. To...
The objectives of this study were to: 1) determine how organic matter (incorporated vs. surface mulch) and nitrogen fertilization rate impact northern highbush blueberry (Vaccinium corymbosum L.) plant biomass, carbon accumulation, plant losses and allocation, and mycorrhizal infection in mature plants, and 2) determine the magnitude of carbon fluxes (carbon...
Strawberry is one of four crops included in the USDA-NIFA Specialty Crop Research Initiative-funded RosBREED project along with apple, peach, and cherry. Phenotyping strawberry for specific horticultural and commercial traits is important to identify associations with genotypic marker(s). This process is the first step in translating genomic knowledge into enhanced...
The use of cover crops in young vineyards is not widely accepted in the Pacific Northwest due to concerns of water and nutrient competition between the cover crop and vines. The last 2 years of a 4-year study started in 2009 are reported here. The study evaluated the use of...