Sudden Oak Death and Phytophthora ramorum

Disease

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.

The effects of Phytophthora ramorum infection on hydraulic conductivity and tylosis formation in tanoak sapwood

Disease
Researchers investigated the the mechanism by which P. ramorum causes disease symptoms and mortality in tanoak trees. This study sought to determine the spatial and temporal development of tyloses in tanoak infected with P. ramorum, and the relationship between abundance of tyloses and specific conductivity of the xylem.

Feeding Bare-root Trees

Fertilizer

Researchers, extension agents and growers affiliated with Oregon State University provide fertilizer recommendations for growing bare-root shade, flowering and fruit trees in Oregon's northern Willamette Valley.

Breaking it Down

Management

As interest in compost grows, so does the need to better understand what compost is, and to learn about the limitations and advantages of particular composts. Suggestions are provided for how to use compost testing as a tool to get greater value from compost use.

Reducing Phytophthora

Plant Disease

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.

Feeding Through the Leaves

Christmas Trees
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.

Into the Blue

Soil

A comparison of substrate amendments for the adjustment of hydrangea flower color based on data collected from studies conducted at Oregon State University North Willamette Research and Extension Center in Aurora, Oregon.

Activity of Meadowfoam (Limnathes alba) Seed Meal Glucolimnanthin Degradation Products Against Soilborne Pathogens

Disease
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.

The Effects of Methyl Bromide Alternatives on Soil and Seedling Pathogen Populations, Weeds, and Seedling Morphology in Oregon and Washington Forest Nurseries

Disease
Fumigation treatments (a conventional methyl bromide – chloropicrin application and reduced-rate alternative fumigant treatments) and a nonfumigated treatment were evaluated at forest nurseries in Oregon and Washington for their effects on soil pathogen populations, weeds, and seedling morphology.

Influence of Isolation Method on Recovery of Pythium Species From Forest Nursery Soils in Oregon and Washington

Disease
In an attempt to identify Pythium species (common dampening off pathogens) associated with forest nursery soils, field surveys were conducted at three forest nurseries (two in Oregon and one in Washington) in 2008 using three isolation methods.

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