OSU BLUEBERRY SCHOOL
March 16-17, 2015
held at
Oregon State University, Corvallis, Oregon
This two-day blueberry “school” was organized for new and experienced blueberry growers,
farm managers, crew leaders, advisors, packers/shippers, and consultants. Experts from Oregon
State University, USDA Agricultural Research Service, Washington State University, and the
blueberry industry were asked to address key issues of where the blueberry market is going; how
you might be more successful in tight labor or volume markets; which cultivars are easiest to
grow and are in most demand; how to establish new acreage using cutting-edge methods;
projected costs and the resources available to growers for selecting new planting sites; how to
best manage existing acreage to maximize returns of high-quality fruit; provide basic information
on blueberry plant physiology to help growers minimize environmental stresses and improve
yield potential; nutrient management programs for optimal growth and quality; irrigation and
fertigation practices for higher quality and better efficiency; use of organic amendments and
mulches; planning for and improving machine harvest efficiency; pruning for hand or machine
harvest (where can you cut corners….or not), maximizing pollination for good fruit and seed set;
overviews of the most important blueberry viruses, diseases, insects, weeds, and vertebrate pests;
and tools for good pest management. Information throughout the program addresses the needs of
conventional, transitional, and organic growers. Simultaneous interpretation to Spanish has been
provided. This proceedings book contains information provided on these topics by each speaker
and co-authors. The thumb drive provided in the registration packet for each attendee includes a
copy of each presentation. Thank you for attending. It is our sincere wish that this will be a very
useful meeting and that you find the accompanying materials a valuable reference! –
Bernadine Strik, Professor and Extension Berry Crops Specialist, OSU and the members of the
organizing committee
Organizing Committee
Bernadine Strik, Chair, Oregon State University (OSU)
Wei Yang, OSU. Co-chair (sponsorship coordinator), OSU
Donna Williams, Rachel Williams & team at OSU Conference Services
Dave Bryla, USDA-ARS HCRU
Chad Finn, USDA-ARS HCRU
Vaughn Walton - OSU
Steve Castagnoli - OSU
Steve Renquist - OSU
Bryan Ostlund – Oregon Blueberry Commission
Eric Pond - industry
Jon Umble – industry
Derek Peacock - industry
Steve Erickson - industry
Nancy Jensen - industry
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Table of Contents
OSU Blueberry School
Title
Authors
Characteristics of production regions in the Pacific
Northwest
Lisa DeVetter, Pat Jones, Bernadine
Strik, Kathie Dello
1
Markets - what's the future for fresh, processed, and
organic markets? Things you MUST think about before
starting or expanding production
Rod Cook, Derek Peacock, Jeff
Malensky, David Granatstein
9
Cultivar choices- Tried and true to brand new
Chad Finn and Bernadine Strik
15
Economics of production – resources
Bernadine Strik and David Granatstein
29
Resources available for selecting a good blueberry site
Wei Q. Yang
37
Site selection and establishment of a blueberry field
Wei Q. Yang and Bernadine Strik
41
Organic soil amendments and mulches for blueberry:
the good, the bad and the ugly
Dan Sullivan (OSU)
47
On-farm irrigation system design and operation
David Bryla
53
Blueberry plant physiology - why it's important to
understand the plant to manage it well
Bernadine Strik
57
Irrigation scheduling: when, where, and how much?
David Bryla
63
Pruning - impact of plant age, cultivar, and harvest
method
Bernadine Strik
69
Harvesting - hand vs. machine
Bernadine Strik (moderator); Paul
Norris (Norris Farms); Frank Brown
(Littau Harvesters (Inc.); Doug
Krahmer (Berries Northwest)
75
Nutrient management of blueberry -- assessing plant
nutrient needs and designing good fertilizer programs
Bernadine Strik and David Bryla
79
Maximizing pollination in blueberry
Ramesh Sagili, Carolyn Breece, John
Borden
95
Blueberry viruses present in the Pacific Northwest and
suggestions for their management
Robert Martin
99
Blueberry bacterial and fungal diseases
Jay Pscheidt and Jerry Weiland
107
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Page
Title
Authors
Page
Weed management for blueberry fields in the Pacific
Northwest
Tim Miller
115
Getting hit high and low: Options for managing bird
and vole damage
Dana Sanchez (OSU
125
Management of arthropods, insect, and plant-parasitic
nematodes in blueberries
Vaughn Walton,Nik Wiman, Inga
Zasada, Joe DeFrancesco, Daniel
Dalton, Amy Dreves, Jana Lee, Lynell
Tanigoshi, Wei Yang
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Getting hit high and low: Options for managing bird and vole damage
Dana Sanchez
Asst. Professor and Extension Wildlife Specialist
Department of Fisheries and Wildlife
Oregon State University
Blueberry growers must manage several vertebrate pests that pose risks for fruit yield, fruit
quality, and plant survival. Many concerns derive from damage by deer, birds, and voles. Basic
tactics to manage wildlife conflicts fall into three main categories: block access, deter feeding, or
remove animals. Some conflict situations require management via combining tactics or varying
approaches over time to yield the best results.
Adequate fencing is the only way to achieve high rates of protection from deer damage.
Although implementation of that option can require significant initial investment, depending on
the size of the area to be protected and the value of the potential crop losses, the long-lasting
control provided by fencing could be the best long-term solution. Each grower will need to
consider the cost-benefit ratio and feasibility of such an investment. To achieve long-term
effectiveness, a fence must be regularly patrolled and checked for damage or compromise.
Despite their large body size, determined deer can take advantage of relatively small openings
created by other animals’ under digging at the base of fences or nimbly jump through gaps
between panels of welded wire. Fences to prevent deer entry should be built of strong and longlasting materials. The absolute minimum height recommended for the Willamette Valley is 6 ½
feet tall, but 8-foot fences are preferred. When building the fence, one must keep an eye on
topography. A fence sited adjacent to a significant rise outside of the fence can be compromised
by deer using topography as a ramp to reduce the necessary in-bound jump height. Where
habitual travel corridors or areas of frequent breach attempts are identified, addition of an
electric top strand and/or outrigger can be helpful. Regular upkeep and powering the fence at
night will be necessary to maintain the effectiveness of those assets as well, because deer are
notorious for “testing” fences of all types for weaknesses. Battery-powered, AC, and solarpowered options are available and offer some flexibility to suit different situations, but growers
should first assess the need to augment their fence with these tools before investing in these
additions. Deterrence of deer via area deterrents (e.g., “predator scents”) or taste deterrents
(several commercially-available options) can be used to achieve short- to medium-term
reductions in damage. However, any surface-applied deterrent will need to be renewed
frequently, and deer tend to habituate to smells and flavors after a period of time, making it
necessary to use multiple products in rotation. Hazing, such as startling deer with noise-making
devices is a temporary means of scaring deer, at best. Because deer habituate to stimuli that do
not actually result in harm, using hazing as a damage prevention tool would require constant
vigilance and varied application to achieve results. Use of incendiary hazing equipment requires
local and state permitting and is only viable in rural areas. In some cases, reduction of local
population might be a management option if a landowner or group of landowners can work with
the Oregon Department of Fish and Wildlife (ODFW) to secure depredation hunt permits or to
provide hunter access to private property during regular hunting seasons. At the very least,
landowners should contact their ODFW District Biologist to gain technical assistance and to
explore options for potential cost-share financing of fencing or other options. Call the ODFW
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headquarters (800-720-6339) with your property’s address or specific location information to
identify your District Biologist and their contact information.
Management of bird damage in fruit crops is a common concern. Scouting in the early morning
and early evening can help determine which species of birds are affecting the crop across the
growing season. Monitoring throughout the season(s) of damage is also important in determining
the effectiveness of management approaches (See tips in Burrows et. al. below). Although highly
effective, netting and frames or guide wire systems for anything but the smallest, most compact
plantings will initially be expensive. Deployment and subsequent storage of the nets each season
also require a seasonal investment of labor, and bird damage can vary from year to year
dependent on many external factors, leading some growers to question the long-term value.
Ground-feeding, seed-eating birds, such as house finches, may forage between netted rows.
Habitat management via tillage and vegetation management can be an additional tool to use in
combination with the netted rows. Beyond netting to exclude birds, growers can use one or more
alternative tools to manage bird damage. Trapping and lethal removal of birds is feasible for only
a few non-native, invasive species: pigeons, house sparrows, and starlings. In these cases,
contacting the regional U.S.D.A. Animal Plant Health Inspection Service (APHIS) representative
will be an important first step to gaining technical assistance and accessing registered avicide
product. Depredation permits for some native bird species can sometimes be obtained, but will
generally require working in concert with both the U.S. Fish and Wildlife Service and APHIS to
obtain necessary permits. Permitting for removals of native bird species is complex (See for
example, www.fws.gov/forms/3-200-13.pdf), so consultation with agency staff is vital. Similar
to deer, hazing birds with propane cannons or incendiary tools is only feasible in rural areas and
is subject to the same permitting rules. Better approaches to hazing yield the advantages of
predator-avoidance behaviors while sidestepping the always-present tendency of animals to
habituate to disturbances that are predictable, yet non-lethal. Especially on larger plantings or
across several adjoining plantings, seasonal employment of falconers is being used in multiple
states for protection of multiple bird-vulnerable, high-value crops. This tool is one for which
cost-benefit ratios need to be calculated early, as falconry companies are still relatively rare, so
seasonal contracts should be secured as early as possible. Others have developed predator-prey
audio systems that can be easily moved and which have good flexibility in the calls they
transmit. These systems can be programmed to deliver the calls of multiple predator (avian)
species, multiple distressed prey species, can add variable pitch to each of those calls (i.e.,
sounds like multiple different individual “voices”) and can be programmed to deliver sounds at
random or highly mixed (i.e., unpredictable to the birds) frequencies. Another advantage of these
tools is that they tend to attract little if any attention from human neighbors, allowing their use in
a broader range of sites. Still under development in the U.S. and abroad are drones, robo-falcons,
and other small, maneuverable devices that could be preprogrammed to deliver audio, visual, and
“behavioral” threats to feeding or hiding birds.
Voles can damage blueberry plantings through creation of their extensive aboveground runs, or
paths, through creation of their extensive underground tunnel systems, and through gnawing and
girdling plants. At least 9 species of vole (Microtus species) inhabit western Oregon. Because of
species-specific habitat requirements however, only two (gray-tailed and Townsend’s) provide
the majority of conflicts with production agriculture in the Willamette Valley of Oregon. One of
those species, the gray-tailed vole, is endemic to the valley, meaning that it evolved here. This is
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significant because across the country, many vole species can be vulnerable to tunnel flooding as
a means of population control. Our endemic gray-tailed vole however, evolved in an ecosystem
that flooded very regularly, thus it evolved behaviors and tolerances that make it invulnerable to
that approach.
The life history and ecology of the majority of vole species makes them a textbook example of
species capable of nearly achieving exponential growth, at least over short “boom” seasons. In
fact, Townsend’s voles hold some of the North American records for high population densities
during those population highs. Individual voles have short life spans ranging from 2-16 months,
but females have very high reproductive potential. Females are capable of breeding at 3-4 weeks
of age as they are still attaining their adult size, but some females delay for several months.
Individual females are capable of producing multiple litters between March and into November.
Gestation for litters of 4-8 pups lasts approximately 23 days. In part because of their “fast” life
cycle, voles are especially well suited to respond quickly to good environmental conditions. Asyet undiscovered combinations of priming factors allow vole populations to skyrocket in some
years, while in other years the population density will be so low as to escape significant notice or
need for investment of management effort. These characteristics make establishment of regular
monitoring plans (see Burrows et. al. for suggestions) vital, along with a stepped plan for
implementing varying levels of intervention.
Because at all population densities voles use their above- and below-ground pathways to provide
access to food and safety from predators, light tillage between rows to interrupt burrows and to
manage between-row food subsidies (i.e., grass and forbs) is a good baseline management
strategy. Encouragement or non-harassment of natural predators (e.g., foxes, weasels, hawks,
owls) is also a good and low-input strategy. However when vole populations are in a “boom”
phase, they overwhelm natural predators’ ability to eat the excess. Again, monitoring early in the
season to gauge how much intervention is needed will be greatly helpful. There is currently an
in-burrow Oregon SLN for registered zinc phosphide products, but this is not an option for
organic growers. A current cultural practice, laying fabric weed barriers beneath plants or highmounding mulch, actually creates safe vole refuges from predators, so both traditional and
organic producers should consider pulling the matting back during late winter/early breeding
season to allow those voles to be vulnerable to both the weather elements and predators. Finally,
some producers use taste-repellant products developed to reduce browsing by deer and rabbits.
As with any repellant, these would require frequent reapplication and rotation of different
products (flavors). Frequent maintenance of the repellency is especially important given the
constant entry of “new animals” into the vole population via reproduction.
See also:
Craven, S.R. & Hygnstrom, S.E. Deer. 1994. Prevention and Control of Wildlife Damage.
Extension, University of Nebraska.
Burrows, C.L., C.B. MacConnell, T.A. Murray, and K.K. Schlamp. 2015. Integrated pest
management for blueberries: A guide to sampling and decision making for key blueberry pests in
northwest Washington. Washington State University, Whatcom County Extension
http://whatcom.wsu.edu/ag/comhort/nooksack/ipmweb/blue/
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