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
129
iii
On-farm irrigation system design and operation
David Bryla
USDA-ARS Horticultural Crops Research Unit
Irrigation water requirements
Blueberries require irrigation from early April (eastern Oregon and Washington) or early May
(western Oregon) to the end of September. In the Willamette Valley, a field of blueberries use
anywhere from 0.5 to 2 inches of water per week (from rain or irrigation). One inch of water
equals 27,000 gallons per acre. Therefore, a 10-acre field of blueberries requires 270,387 gallons
of water for each acre-inch of water. An irrigation system should be designed to meet the
maximum irrigation requirements that might be needed during the growing season, and not the
average irrigation requirements. Usually, the highest requirements are in late July, but peaks may
vary from year to year, depending on the weather conditions, the location of the field, the
cultivar, and the stage of fruit development (see ‘Irrigation Scheduling’ in the proceedings).
Irrigation system options and configurations
Most commercial blueberry fields are irrigated by overhead sprinklers or drip. Water is typically
applied one to two times per week as needed with sprinklers, and every one to three days with drip.
Sprinkler systems are relatively simple to install and maintain, and when designed properly,
obtain reasonable uniformity of water application. Some major advantages of sprinklers include
the ability to: run them for frost protect in the spring and for fruit cooling in the summer;
establish and maintain a cover crop between the rows; and apply the water with little to no
filtration. Drip systems, on the other hand, are somewhat more expensive to install and often
more difficult to maintain than sprinklers, but they offer: superior water control and distribution
uniformity; lower energy costs; improved application of fertilizer and other chemicals; improved
cultural practices, including the ability to irrigate during harvest; fewer weed and disease problems;
and reduced food safety concerns, especially when using surface water to irrigate. A few growers
are also using misters or microsprinklers for blueberry, primarily for cooling and chemigation in
conjunction with a drip system.
Drip irrigation often produces larger plants than sprinklers during establishment and results in
similar or higher yields than sprinklers when fertilizers are injected through the drip system.
These benefits are a result of higher soil water content and greater soil nutrient availability in the
vicinity of the roots with drip. However, drip can also increase the potential for Phytophthora
root rot, especially in highly susceptible cultivars such as Duke and Draper. Root rot does not
usually result in plant death in blueberry, but it will reduce growth and fruit production. Options
for preventing root rot include raised planting beds, suspended drip lines, wider drip line
placement, the use mefenoxam, fosetyl-Al, and phosphite/phosphonate/ phosphonic acid
fungicides (conventional only), and high pre-plant applications of gypsum (an option for organic
systems).
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Drip line placement
On most soil types, only one line of drip per row is needed for adequate irrigation of blueberry,
but two lines per row is often used to encourage a larger root system and increase plant access to
soil nutrients. The lines are often located near the base of the plants during the first year or two
after planting and later repositioned 6–12 inches on each side of the plants as the root system
develops. Installing the drip lines under weed mat or burying them under sawdust mulch helps to
secure the lines in place, prevents any damage during winter pruning, and reduces water runoff
on raised beds. Usually, the best option for blueberry is drip tubing (over drip tape) with in-line
pressure-compensating drip emitters. Depending on the soil type and plant spacing, the emitters
should be spaced 12-24 inches apart and have a flow of 0.25 to 1 gph. Sandy soils require a
closer emitter spacing than silty and clay loam soils. Lower emitter flow rates are generally
preferable for blueberry (greater lateral movement of water and nutrients and less below the root
zone), but higher flow rates might be necessary at sites with poor water quality (e.g., iron
bacteria).
Special needs
Frost protection. Sprinkler systems can be used to protect blueberry flowers from spring freezes.
However, they do not protect below 23-24 oF and can even increase damage when used
incorrectly or at the wrong time. When water freezes, it releases heat and protects the flowers.
Therefore, sprinklers need to run constantly during a frost event to ensure that ice is constantly
forming on the flowers. If the ice is allowed to melt, it will lower the temperature and damage
the plants more so than doing nothing at all. See additional resources for more information.
Acidification. Injection of sulfuric acid (H2SO4) into the drip system has also become a popular
practice in regions with high soil pH and/or a high percentage of carbonates and bicarbonates
(CO3 and HCO3) in the irrigation water such as California and eastern Oregon and Washington.
Because acid materials are hazardous and highly corrosive, a number of growers now use sulfur
dioxide (SO2) generators, often referred to as “sulfur burners”, in place of acid injectors for
acidifying the irrigation water and reducing soil pH. Elemental sulfur is burned in the generators
to convert it to sulfurous acid (H2SO3) and mix it with the irrigation water to lower the pH.
Sulfur burners are also certified for organic production. Other options for acidifying the water in
organic systems include injection of acetic or citric acid.
Evaporative cooling. Overhead sprinklers are effective at reducing berry temperature and heatrelated fruit damage in highbush blueberry. However, cooling at lower temperatures (e.g., each
time the temperature reaches 90 oF) could have an adverse effect on yield. Recently, we showed
that a threshold of 95 oF was adequate for cooling and resulted in higher yield than cooling at 90
o
F. We also found that microsprinklers were effective for fruit cooling in fields irrigated by drip.
If properly designed, microsprinklers are also very useful for applying certain pesticides
(chemigation).
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Additional resources
Drip Irrigation: An Introduction. C.C. Shock. 2013. Ore. St. Univ. Ext. Serv. Publ. EM8782.
Strategies for Efficient Irrigation Water Use. C.C. Shock, B.M. Shock, and T. Welch. 2013. Ore.
St. Univ. Ext. Serv. Publ. EM8783.
Using Sprinklers to Protect Blueberries from Spring Freezes. M. Longstroth. Mich. St. Univ.
Ext.
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