Publications

October 1, 2009

Research was conducted to take advantage of the reduction in plant size and vigor often associated with induced polyploidy. The principle objectives were to induce polyploidy in seedlings from H. acetosella ‘Panama Red’ and to evaluate the effects on growth, morphology, and fecundity.

April 1, 2011

A report on Oregon State University affiliated research conducted with the purpose of documenting the chromosome number and genome size of Callicarpa species to add to the available information on the genus.

December 1, 2011

The purpose of this study was to investigate the influence of water stress (as induced by irrigation frequency) on growth and nitrogen (N) uptake of one deciduous and two evergreen cultivars of Rhododendron grown with different rates of N fertilizer in containers.

Boxwood blight, Cylindrocladium buxicola, a fungal plant disease relatively new to North America, has been detected in an Oregon nursery.

October 1, 2012

A discussion about cold hardiness and effective plant protection strategies to minimize cold damage. The Oregon State University affiliated author addresses how plants become cold hardy, stages of hardiness, and effective protection.

September 1, 2010

Phytophthora species are some of the most problematic plant pathogens in nursery production systems. The Oregon State University affiliated author provides these top 10 tips which will help prevent this group of pathogens from taking hold.

June 1, 2012

A recent report described a simple technique to double Cryptomeria japonica chromosomes. The objectives of this research was to evaluate the effectiveness of the technique and determine optimal treatment duration for doubling chromosome numbers in oriental arborvitae, american arborvitae, and western red cedar.

April 1, 2011

No matter how small, slugs and snails can cause huge headaches for growers. Fortunately, there are many ways these pests can be managed and eliminated. The author discusses the importance of and the different factors involved in a good integrated pest management plan.

October 1, 2007

The intent of the study was to expand current knowledge of nitrogen (N) uptake and allocation by container-grown Rhododendron by characterizing the plant growth, the extent of N uptake, and the changes in N storage that occur during the autumn and winter.

September 1, 1974

Cylindrocladium scoparium, a wilt disease of azaleas was a major problem for the azalea industry across the country in the mid 1960's. Studies were conducted to determine the cause of the wilt and identify control measures, observations and results are discussed.

November 1, 2012

An initial report on research conducted on two intelligent, or precision, sprayers designed for use in the ornamental horticultural industry. The goal of this research is to develop efficient and affordable sprayers that use technology to respond to crop size and presence.

February 1, 2011

Pests and pathogens are a threat for growers that produce containerized nursery stock. The authors discuss how to reduce these threats by considering the type of containers and growing media they use, where they are sourced, how they are handled, and how they are stored.

June 1, 2012

This study on interspecific hybridization in Tecoma Juss. was conducted to develop novel forms for the nursery industry. The selection of species used in the study included T. garrocha, T. stans, T. guarume, and T. capensis.

July 1, 2011

Researchers at Oregon State University have been studying how soilless substrates can be used together with moisture monitoring equipment to get the best results while reducing the need to irrigate. Topics specifically addressed include soilless substrate and water management.

January 1, 2012

Researchers evaluate selections from this sometimes underappreciated genus of landscape shrubs. Specific topics discussed in the article include landscape performance, disease resistance, and developing sterile cultivars.

December 1, 2012

Researchers evaluated regionally available alternative substrates for ornamental crop production in the Pacific Northwest. The objective was to investigate the physiochemical properties of the substrate and ensure no biomass is phytotoxic to ornamental crops.

April 1, 2006

A comprehensive guide for forest managers, Christmas tree growers, and forest-tree nursery operators in Oregon and Washington on sudden oak death, the disease caused by the recently introduced Phytophthora ramorum.

September 1, 2011

Plant pathologists track where Phytophthora ramorum came from and how it has managed to spread. The author specifically discusses Phytophthora ramorum clones and mating types and tracking the migration of the pathogen.

February 1, 2012

Growers can minimize their risk of exposure to plant diseases and reduce pesticide use by ensuring that their irrigation water is free of Pythium and Phytophthora species. The authors discuss several different disinfestation methods for nursery and greenhouse operations.

September 1, 2012

A review of the different means by which the potential for invasiveness in woody ornamentals can be reduced using genetic methods. Progress is reviewed in conventional breeding and transgenic biotechnology approaches to producing sterile forms of ornamental woody plants.

August 1, 2011

The Oregon State University affiliated authors strive to answer the question of whether plant physiology and breeding research can work collectively to develop more water-efficient and drought tolerant plants that will benefit the green industry.

A hearing is scheduled to discuss proposed changes to the quarantine area and allow use of an oak from disease free area.

March 1, 2012

A guide to help growers develop an effective weed management plan. Different strategies are presented on how to deal with annual and perennial weeds along with strategies for the growing issue of herbicide resistance in weeds.

December 1, 2008

Oregon State University affiliated author discusses the top 10 tips for preventing disease in nurseries. Specific topics addressed include site selection and drainage, sanitation practices, disease free plant sources, plants in container, and irrigation.

October 1, 2011

Correctly diagnosing a plant problem for nursery growers can be challenging. However, the right diagnostic resources coupled with an early and appropriate diagnosis can prevent pests or pathogens from spreading, saving time and money.

April 1, 2012

A comprehensive discussion about the issues concerning pre-packaged fungicide mixes, which can elevate the risk of developing pathogens that are resistant to treatment. Strategies for avoiding resistance are included in the discussion.

September 1, 2009

An experiment was performed to determine a more effective protocol for germinating C. americana seeds. It was hypothesized that scarification with sulfuric acid would aid in breaking seedcoat dormancy, thereby resulting in more rapid and uniform germination.

January 1, 2011

A comprehensive guide on P. ramorum. Topics discussed include; morphology, genetics, growth, distinguishing characteristics for identification, disease history, impacts in the forest, forest and wildland hosts and symptoms, and management and educational materials.

November 1, 2011

Pest management researcher discusses the Interregional Research Project No. 4, commonly known as IR-4, a federally funded program that assists growers of ornamental horticulture crops in obtaining safe and effective pest management tools.

July 1, 2012

Researchers at Oregon State University evaluated the potential of a remote soil-moisture-sensing technology in ornamental container production systems. The authors discuss the system they used, implications of the study, and their conclusions.

February 1, 2010

Japanese-cedar (Crytomeria japonica) performs well under a range of soil and environmental conditions but has been underused in landscapes, in part, due to winter browning. In previous studies, chance seedlings that did not exhibit winter browning were identified as tetraploids. This study was conducted to induce polyploidy in Crytomeria japonica.

January 1, 2012

A systems approach for the production of healthy nursery stock. The manual, published by the Oregon Association of Nurseries, is divided into 3 main parts. A systems approach introduction, voluntary best practices for your nursery, and the next step: systems approach certification.

December 1, 2011

Oregon State University researchers discuss their investigation of a new microscopic pest, eriophyid mites, which causes damage to linden trees. Identification and detection, distribution and behavior, and damage and control strategies are specifically discussed.

This new quarantine could impact ornamental growers shipping to Washington state.

August 1, 2012

A look into the world of plant breeding and the tools ornamental plant breeders have at their disposal to expedite breeding for specific traits. Topics addressed in the article include flow cytometry and molecular genetics.

Presentation from OSU researcher Jim Owen, discussing research conducted using common container media components.
April 1, 2011
A report on Oregon State University affiliated research, which was conducted with the purpose of documenting chromosome number and genome size of Callicarpa species to add to the available information on the genus.
June 1, 2007
The objectives of this study were 1) to elucidate the progenitor species of Rhododendron cultivars ‘Fragrans’, ‘Fragrans Affinity’, and ‘Fragrant Affinity’; and 2) to determine whether these cultivars are all distinct clones or possibly synonyms.
February 1, 2007
This study was conducted to evaluate the fertility of diploid and allotetraploid forms of Rhododendron L. 'Fragrant Affinity' and to determine if induced polyploidy is an effective method for restoring fertility in hybrids of distantly related rhododendrons.
August 1, 2010
Research was conducted at Oregon State University North Willamette Research and Extension Center with the objective of determining whether the addition of foliar fertilization would benefit a Christmas tree plantation or container-grown conifer operation.
July 1, 2010
Comprehensive guide on how to control spider mites in the nursery biologically by using predatory mites. Predatory mites are tiny little animals whose appetite for spider mites makes them a great tool for suppressing and managing mite outbreaks.
December 6, 2011
Researchers evaluated the toxicity of glucolimnathin 1 and its degradation products on several important soilborne pathogens of high-value crops. Pests targeted in the studies included plant-parasitic nematode Meloidogyne hapla, fungus Verticillium dahliae, and oomycete Pythium irregulare.
March 10, 2009
These studies were conducted to determine the compatibility of M. anisopliae (F52) with a wide range of fungicides commonly applied to container-grown ornamentals for the management of soil-borne plant pathogens. In addition, the impact of fungicide application to M. anisopliae population in soilless potting media (bulk and rhizosphere soil) was also determined.
February 3, 2007
Research was conducted to determine the persistence of Metarhizium anisopliae (F52), measured as infectivity against black vine weevil larvae, in a soilless potting medium at six wholesale nursery locations across the Willamette Valley, Oregon.
June 1, 2005
The objective of these studies was to determine the pathogenicity of entomopathogenic fungi against the cabbage maggot, Delia radicum (L.). The use of Metarhizium anisopliae isolate F52 in an integrated management program is discussed.
September 1, 2007
The objectives of this study were to determine the efficacy of a curative drench application of M. anisopliae for controlling black vine weevil (BVW) larval infestations in container-grown nursery plants and the effect of temperature on the rate of fungal growth and speed of kill.
January 1, 2008
Researchers recently developed a mass rearing system for the black vine weevil (Otiorhynchus sulcatus) and strawberry root weevil (Otiorhynchus ovatus) and now are able to conduct controlled experiments to study their biology and to develop chemical and biological management systems.
December 1, 2005
Studies were conducted to determine the efficacy of three species of entomopathogenic nematodes (Heterorhabditis marelatus, Heterorhabditis bacteriophora, and Steinernema riobrave) applied in infected host cadavers or as aqueous applications for black vine weevil larval control.
January 1, 2004
The black vine weevil Otiorhynchus sulcatus (F.) is the primary insect pest of field and container-grown woody ornamentals in the Pacifc Northwest (PNW). These studies were conducted to determine the natural occurrence of soil-borne entomopathogens in PNW nursery soils and determine their virulence to black vine weevil.
January 1, 2006
The purpose of this study was to characterize the behavior of black vine weevil larvae, Otiorhynchus sulcatus (F.), in the presence of two possible control options: the synthetic pyrethroid bifenthrin and the entomopathogenic fungus Metarhizium anisopliae (Metch.) Sorokin.

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