Reducing Phytophthora

Authors: Parke, Jennifer (OSU) Date: 2010

Phytophthora species are some of the most problematic plant pathogens in nursery production systems. The quarantine pathogen Phytophthora ramorum has received the most notoriety, but many Phytophthora species pose a challenge for nursery growers.

These pathogens cause trouble because of their persistence and spread in infested soil and water, and their ability to attack a wide variety of plants. Some species cause root rot, whereas others cause foliar blight and shoot dieback. Several species can infect plant parts both above and below the ground.

In collaboration with Niklaus Grünwald and Val Fieland of the USDA-ARS Horticultural Crops Research Laboratory, Carrie Lewis and I (Oregon State University) recently completed a three-year project to determine the most common sources of Phytophthora contamination in nurseries. We applied a systems approach to identify three critical control points in nursery production systems: contaminated soil/gravel beds, contaminated irrigation water, and used pots. Another potential source of Phytophthora spp., not included in our study, is nursery stock brought in from off site.

So what is the take home message for growers? Here are the top 10 practical tips for nursery growers:

Download (PDF): Reducing Phytophthora (2MB)

The Woody Plant Seed Manual

Authors: Bonner, F.T. and Karrfalt R.P. (eds.) Date: 2008

The major audience for this book, as for its two predecessors, is those who are involved in the growing and planting of trees and shrubs. Their involvement can be collection and sale of seeds, production of nursery stock (both bare- root and container), or planting itself. Planting for commercial forest production is the traditional mainstay of tree planting, but planting for wildlife food, watershed protection, urban environmental improvement, ornamental enhancement, wetland mitigation, and carbon sequestration are all on the increase. Ecosystem management, now commonly used in the management of many federal and other governmental forest lands, has decreased the use of planting to regenerate the forests and has increased the role of natural regeneration. Those who apply these practices will find this book useful also in the data on flowering and seed production. Although the book is not intended to be a detailed textbook on seed ecology and physiology, there is sufficient scope and depth to the material included to make it useful to anyone who studies seeds.

Download (PDF): The Woody Plant Seed Manual (21MB)

Use of Mycorrhizae for Native Plant Production

Author: St. John, T.

The mycorrhizal symbiosis is well known, but not yet in widespread use in the com- mercial nursery trade. The often-cited mycorrhizal growth response is in not the most signi cant mycorrhizal effect. Instead, the important effects are performance in the eld and improved nutrition and disease resistance in the nursery. These bene ts may be of use in meeting regulatory requirements related to fertilizer runoff and pesticide use. A nursery mycorrhiza program requires modi cation of some current practices and careful choice of appropriate fungi.

Download (PDF): Use of Mycorrhizae for Native Plant Production (120KB)

Salvaging Plants for Propagation and Revegetation

Author: Buis, S.

Salvaging native plants is the act of rescuing plants from a construction or disturbance site before they are destroyed. We have not found salvage to be a cost effective method for obtaining most of the plants we sell in our nursery or use in our own projects. However, we do sometimes salvage plants, either to obtain plants that are dif cult to propagate, to increase the genetic diversity of plants in our nursery, because they are unusual species that we don’t have access to otherwise, or to preserve plant genetics on a disturbance site for future replanting. Factors important to consider in salvaging plants include species, size, site access and soil type, whether to use hand or mechanical techniques, time of year, available crew, etc.

Download (PDF): Salvaging Plants for Propagation and Revegetation (275KB)

Native Plant Propagation and Restoration Strategies

Author: Haase, D. and Rose, R. (OSU) Date: 2001

Abstract: Propagation and planting of native plants for habitat restoration is a multi-faceted process. There are many issues over which there is general agreement among restorationists, but there are a number of subjects that cause disagreement. For example, restorationists often agree that native plants should be emphasized, but disagree over where seeds or transplants should come from. In this paper, I examine four areas of controversy: the use single or multiple sources of a species at a given restoration site (the SOMS debate), source distance of plant materials, the use of native plant selections, and the importance of one’s definition of “native plant.” I conclude that some of these issues may be resolved through careful research, while others will remain a matter of personal opinion, and can only be resolved through a clear statement and scope of objectives of each restoration project.

Download (PDF): Native Plant Propagation and Restoration Strategies (3MB)

Nursery Manual for Native Plants: a Guide for Tribal Nurseries

Authors: Dumeroese, Luna & Landis (eds.) Date: 2009

This handbook covers all aspects of managing a native plant nursery, from initial planning through crop production to establishing trials to improving nursery productivity into the future. It was written to assist Native Americans in growing native plants and draws extensively on tribal activities for the many photos and specific examples in the text.

Download (PDF): Nursery Manual for Native Plants: a Guide for Tribal Nurseries (3.7MB)