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 Page

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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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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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 heat-related 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 oF. 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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