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Expert Presentations

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Featured below are links and a brief description to WSU YouTube videos with educational content that includes invited seminars, presentations at meetings, “how to’s” in the field, lab visits, field day events, etc.  Items in the list are arranged chronologically with the newest video at the top.

  • “Weed Control in Orchards” (36:02). Speaker: Mr. David Granatstein, Sustainable Agriculture Specialist. Affiliation: WSU Center for Sustaining Agriculture and Natural Resources, Tree fruit Research and Extension Center, Wenatchee, WA 98801-1230. Synopsis: First, Mr. Granatstein notes several reasons to control weeds including limiting competition for young trees with nutrients and water, minimizing rodent (e.g., voles) habitat, eliminating hosts for pest and disease and to avoid blocking irrigation sprinklers. He describes the standard orchard system with herbicide strip and grass alley and noted that about 20 sq. ft. of weed free space is needed per tree during May-July.  He lists six different weed control options (noting pros and cons) including: residual and contact herbicides, mowing, tillage, flaming, inert mulches and living mulches.  Mr. Granatstein briefly discusses the issue of sub-lethal effects of glyphosate.  He described research supporting the benefits of using wood chip mulch for weed control.  He also discussed the concept of growing your own mulch. He notes that the use of living mulches in older trees has several benefits including excluding undesirable weeds while fixing nitrogen, improving soil quality and providing beneficial insect habitat.  He presents economic data for several alternative weed control strategies. He described a large-scale, 3-year organic trial looking at mulch, tillage, flaming or herbicides in Gala apple and Anjou pears. Over the three year period for Gala apple, they noted significant positive return on investment using mulch verse herbicide/flaming or tillage. He suggests several options for the future. Keywords: perennial weeds, annual weeds, herbicide strip, grass alley, dwarfing rootstock, competition, habitat, nutrient, irrigation, rodent, voles, root density, erosion, mowing, flaming, inert mulch, living mulch, organic, resistance, sub-lethal effect, glyphosate, mechanical tillage, wonder weeder, wood chips, paper mulch, weed fabric, oriental mustard, winter rye, Gala apple, Anjou pear, mow and blow, moisture stress
  • “Powdery Mildew Infection of Sweet Cherries: Expect the Unexpected” (19:52). Speaker: Dr. Claudia Probst, Postdoctoral Research Fellow in Plant Pathology. Coauthor: Dr. Gary Grove, Professor of Plant Pathology and Director. Affiliation: Washington State University Irrigated Agriculture Research and Extension Center, Prosser WA, 99350. Synopsis: Dr. Probst provides some taxonomic background on plant pathogenic fungi and notes that it is just one species that causes powdery mildew on cherry, Podosphaera clandestina. She explains the disease triangle and notes how this fungus needs a living, susceptible host and the right environmental conditions to cause disease.  She defined ontogenic resistance as the ability of plants or plant parts to resist or tolerate disease as they age and mature.  Dr. Probst noted that leaves are the biggest reservoir for season long inoculum production.  In their research program, they posed several questions: Which developmental stage of cherry is most susceptible to infection? How many spores are needed to cause infection? Is there a relationship between blossom and fruit infection? What role does the environment play?  From their laboratory and orchard inoculation experiments they learned that it doesn’t take many spores to cause significant disease at harvest. They also found that sweet cherry fruit had a reverse ontogenic resistance where immature fruit was more resistant to infection than mature fruit. Fruit were highly susceptible to infection near harvest.  They also found that spores could remain viable (latent) on the surface of the fruit for nearly two months (56 days).  They noted that bloom probably does not play an important role in the disease cycle and that the fungus may actually overwinter on the fruit. Keywords:  sweet cherry, powdery mildew, Podosphaera clandestina, spore, ontogenic resistance, leaf age, fruit age, phenology, orchard environment, Sweetheart, Bing, susceptibility, bloom, disease triangle, disease cycle
  • Apple Varieties of the Future from WSU’s Apple Breeding Program” (14:56). Speaker: Dr. Kate Evans, Assoc. Professor and Apple Breeder.  Affiliation: Washington State University Tree Fruit Research and Extension Center, Wenatchee, WA 98801-1230. Synopsis: Dr. Kate Evans emphasizes the fact that for any new cultivar to be successful in the industry, it needs to provide consistently good quality at harvest, it should be able to be handled in a commercial packinghouse and it needs the ability to be long-term stored and come out of storage with good eating quality.  Other important considerations that she noted include how amenable it is to different training systems, how easy it is to thin, the specific harvest window, whether it can be one-time harvested (or not) and what the commercial packout is.  Dr. Evans described the use of precision breeding techniques including four steps: 1. DNA-informed choice of parents; 2. DNA-informed selection of seedlings; 3. Extension evaluation of fruit; and 4. Extensive evaluation of selections.  Dr. Evans noted that now there are DNA tools to identify the following traits (fruit skin color, fruit acidity, fruit sugar, harvest date, fruit texture, fruit ethylene production, bitter pit susceptibility, fire blight susceptibility, scab susceptibility, and mildew susceptibility).  The use of these DNA tools can help to ensure that the correct parents are chosen for crossing and that seedlings lacking the desired traits can be discarded before they go to the field.  This allows for the reallocation of resources to other parts of the breeding program to improve overall efficiency.  She describes briefly the fruit evaluation in the lab and selection evaluation at grower sites and consumer testing.  Dr. Evans shares some details about the newest selection, WA 38, that will be marketed as Cosmic Crisp TM brand.  She describes consumer testing comparing WA 38 very favorably with Honeycrisp.  Two related videos include: Fruit Testing at the WSU Apple Breeding Program  and Cosmic CrispTM WA 38 Field Days. Keywords: apple, breeding, storage, fruit quality, packinghouse, training system, thinning, harvest, packout, precision techniques, genotype, phenotype, DNA-informed breeding, fingerprinting, seedling selection, fruit evaluation, sensory analysis, DA meter, digitest, texture, fruit maturity,  WA 2, WA 38, Cosmic CrispTM brand, systems trial, consumer testing, taste panel
  • Utilizing the WSU-DAS Version of the Spray Guide” (21:20). Speaker: Dr. Ute Chambers, DAS Manager and Educator. Affiliation: Washington State University Tree Fruit Research and Extension Center, Wenatchee, WA 98801-1230. Synopsis: Dr. Chambers explains how the WSU Decision Aid System ( can be used as a tool for making decisions for managing pests in your orchard. She noted that various inputs into the system include current and historic weather data from WSU’s AgWeatherNet, weather forecast data from NOAA, recommendations from the WSU Crop Protection Guide for Tree Fruits and the MRL database of the Northwest Horticultural Council.  These inputs provide data that is used for specific pest and disease models to provide both management and pesticide recommendations.  As part of the DAS spray guide, information is provided to the site visitor related to both pesticide efficacy and the effects of pesticides on natural enemies.  Dr. Chambers noted that natural enemies are also affected by pesticides aimed at pests.  This may occur because of acute toxicity or adverse sublethal effects.  She noted the effect of seven different common pesticides on natural enemies in the orchard and how this information is accessible in an online database (  Dr. Chambers noted that new models are being developed for green lacewings, syrphid fly and the pear psylla predator (Deraeocoris).  By knowing pesticide effects on natural enemies, the pest manager can be more careful on his pesticide choices and timing of their use for controlling pests while at the same time preserving natural enemies that provide biocontrol for free.  She spoke about the DAS historic weather data center to compare the date of pesticide application with the model predictions for the proper timing and how this might impact the efficacy of your control.  She also spoke about some new features including e-mail alerts/notifications for specific pesticide model events and pest monitoring through a new mobile web application for your smart phone or tablet.
  • The Evolution of Tree Fruit Pest Management Practices” (33:09). Speaker: Dr. Jay Brunner, Professor of Entomology and Director. Affiliation: Washington State University Tree Fruit Research and Extension Center, Wenatchee, WA 98801-1230. Synopsis: Dr. Brunner provides a historical perspective on pest management practices for apple in the Pacific Northwest.  He reviewed historical crises and the value of biological control.  Dr. Brunner reviews the discovery and adoption of pheromone use for pest trapping and mating disruption.  He reviews the development and use of predictive models that are driven by environment for the timing of pest sampling and the application of pesticides.  Dr. Brunner shares some history of the Food Quality Protection Act (1996) and how new regulations affected pest management.  He discusses the introduction of exotic pests and how this may impact future IPM practices.  Finally, Dr. Brunner discusses the impact of tree nutrition, netting, and genetic improvement of apple on pest management.
  • Pruning Bartlett Pear to Optimize Fruit Quality” (42:04). Speaker: Dr. Stefano Musacchi, Associate Professor & Endowed Chair, Tree Fruit Physiology and Management. Affiliation: Washington State University Tree Fruit Research and Extension Center, Wenatchee, WA 98801-1230. Synopsis: Dr. Musacchi introduces the concept of organ competition as it relates to both vegetative growth and fruit production and how pruning influences these responses. He introduces three new terms including brindilla (one year old shoot with terminal flower bud), Tira savia (pruning technique to induce a strong response in the apical part of the branch and minimize suckering and production of blind wood), and chicken paw or zampe di gallo (an old spur formation that produces small fruit when they become too weak).  He emphasizes the fact that small-sized flower buds result in small-sized fruits. He also introduces the five different tree growth habits of fruit bud production for pear cultivars.  Bartlett is Type 1 which is comprised primarily of 2-year-old branches with brindilla and spurs.  Dr. Musacchi speaks about pruning spindle trees and the importance of bending branches to a maximum of  a 45-50 degree angle from the vertical axis to avoid weak branches and the production of blind wood. He also introduces the concept of dynamic or renewal pruning and a three-year cycle. This involves a rotational strategy to produce new wood, develop 1-year-old wood and produce fruit on 2-year-old wood.  He emphasizes the importance of using primarily 2 or 3-year-old wood that is fairly close to the central axis of the tree for production of large, high-quality fruit.  Dr. Musacchi demonstrates using both girdling and notching to remove apical dominance and stimulate lateral branching in 2-year-old wood to avoid the production of blind wood.  Dr. Musacchi introduces the practice of using growth regulators to influence tree response to girdling and notching (e.g., combination of gibberellin plus cytokinin).  Dr. Musacchi speaks about the 30 percent rule (remove branches attached to main axis when their diameter exceeds 30 percent of the diameter of the main axis).  He notes that the tip of the branch should be higher than its insertion in the main axis. Dr. Musacchi demonstrates how to prune young spindle trees and also how to manage the top of the tree.  He also demonstrates how to manage trees that are different heights going down the tree row.  Dr. Musacchi also demonstrates spindle pruning of mature trees and the need to make the three-year cycle of renewal pruning.  Finally, he introduces the bi-axis (or Bibaum) training system to reduce excess vigor and to double the number of axes in the row without doubling the number of the trees.
  • Integrated Management of Postharvest Diseases of Pome Fruit” (31:29).  Speaker: Dr. David Sugar, Professor Emeritus of Plant Pathology, Affiliation: Oregon State University, Southern Oregon Research and Extension Center, Medford, OR 97502. Synopsis: This presentation emphasizes the management of postharvest diseases caused by fungi that enter pears through wounds (particularly during the harvest process).  Dr. Sugar notes that post harvest applications of fungicides and biocontrols are often applied too late.  He also notes four important elements of cultural control: i. Nitrogen management (reduce N in fruit); ii. Calcium enhancement (increase Ca in fruit); iii. Harvest maturity (harvest early in the maturity window); and iv. Sanitation (reduce disease inoculum sources in the orchard). Regarding fungicide control, Dr. Sugar discusses five different options: i. Preharvest applications (1 week before harvest); ii. Post harvest truck drenches (recirculating); iii. Post harvest bin drenching (non-recirculating); iv. Post harvest line-sprays; and v. Storage room thermofogging.  Dr. Sugar also notes that pre harvest calcium applications in the orchard plus a pre harvest fungicide treatment (1 week before harvest) resulted in excellent post harvest decay control.  Finally, he notes that post harvest applications of either fungicide or biocontrol products should ideally occur within 1 week of harvest.
  • Speaker Panel Question and Answer Session” (20:58 min).  Panel Speakers: Dr. Lee Kalcsits, WSU-TFREC (Wenatchee, WA), Dr. Gennaro Fazio, USDA-ARS (Geneva, NY), and Dr. Mark Mazzola, USDA-ARS (Wenatchee, WA), as part of the program “Roots: Foundation of Your Orchard’s Success” at the 2014 WSHA Annual Meeting, Kennewick, WA, December 3, 2014. Keywords:  third year cropping, compost, drip irrigation, phytophthora, seed meal, fumigation, functional roots, biochar, root branching, verticillium wilt, methyl bromide, telone, chloropicrin, fertigation, ammonium, nitrate, mycorrhizae, phosphorus, organic matter, sustainability, acidification, mow and blow, mulching
  • Roots and Soil Biology:  Managing the “Microherd” for Maximum Tree Performance” (33:24 min).  Speaker #4: Dr. Mark Mazzola, USDA-ARS (Wenatchee, WA), as part of the program “Roots: Foundation of Your Orchard’s Success” at the 2014 WSHA Annual Meeting, Kennewick, WA, December 3, 2014.  Keywords: nematodes, protozoa, actinomycetes, bacteria, fungi, oomycetes, root development, nutrient cycling, plant pathogen suppression, lesion nematode, Phytophthora, Pythium, Pseudomonas, Rhizoctonia, Agrobacterium, soil health, bulk soil, rhizosphere microbial diversity, organic matter, Bacillus, tillage, compost, urea, canola meal, mustard seed meal, green manures, bio-based waste products, replant disease complex, fumigation, Telone C-17, chloropicrin, Gala/M9, Arthrobotrys, Aporcelaimellus, Dactylella, Oidiodendron
  • Characteristics of Tree Root Systems” (57:54 min). Speaker #3: Dr. David Eissenstat, Penn State Univ. (University Park, PA), as part of the program “Roots: Foundation of Your Orchard’s Success” at the 2014 WSHA Annual Meeting, Kennewick, WA, December 3, 2014.  Keywords:  Gala, Golden Delicious/M9, minirhizotron, seasonal root production, root distribution, mulch, soil temperature, irrigation, branching order, root diameter, root anatomy, passage cells, cortex, fibrous absorptive roots, pioneer transport roots, root framework, root lifespan, apple, peach, blueberry, grape, citrus, poplar, woody root, mycorrhizal fungi, nonmycorrhizal fungi, colonization, hyphae, pathogen defense, arbuscules, N:C ratio, nitrogen, carbon, carbon footprint, respiration, specific root length, root box, cropping vs. non-cropping, carbohydrate availability, root foraging, urea, organic N, root pruning, fumigation, replant disorder, phosphorus fertilization, tillage, tree vigor
  • Optimal Tree Nutrition and Fruit Production Begins Underground – The Apple Rootstock Story” (46:43 min).  Speaker #2: Dr. Gennaro Fazio, USDA-ARS (Geneva, NY), as part of the program “Roots: Foundation of Your Orchard’s Success” at the 2014 WSHA Annual Meeting, Kennewick, WA, December 3, 2014. Keywords: apple rootstock, fireblight, soil health, scion performance, tree architecture, nutrient uptake, microbial interaction, apple replant disorder, G.935, M.9, G.41, G.214, G.969, root exploration index, nutrient bioavailability, absorbance, conductance, chaperones, interstem, soil pH, soil type, phosphorus, molybdenum, calcium, fruit and leaf nutrient concentration, calcium transport, brix, puncture pressure, trunk diameter, Honeycrisp, Fuji, Gala, Delicious, low temperature stress
  • Root Physiology and Function in the Orchard” (22:18 min).  Speaker #1: Dr. Lee Kalcsits, WSU-TFREC (Wenatchee, WA), as part of the program “Roots: Foundation of Your Orchard’s Success” at the 2014 WSHA Annual Meeting, Kennewick, WA, December 3, 2014.  Keywords: water and nutrient uptake, energy and nutrient storage, anchorage, soil ecology, phytohormones, tap root, fibrous roots, irrigation, water table, soil texture, soil patchiness, xylem transport, root hairs, symplastic pathway, apoplastic pathway, endodermis, casparian strip, transporters, channels, proton pump, rhizosphere, nutrient mobility, phosphorus, nitrate, soil pH, mycorrhizae, fungal associations, water logging, oxygen starvation, soil health, shovel.
  • Fruit Testing at the WSU Apple Breeding Program” (5:25 min). Synopsis: Dr. Kate Evans and her apple breeding team take us on a tour during a typical day in her Fruit Quality Evaluation Laboratory. Specifically, Kate will speak about the broader goals of the apple breeding program, the use of traditional tests to assess fruit quality of selections (maturity, firmness, crispness, acidity, soluble solids concentration, juiciness, sweetness, fruitiness) and the use of genetic markers to screen seedling materials for specific traits. The overall goal of the program is to create new high quality cultivars that have excellent fruit quality and storability and will be suitable for the growing conditions of central Washington. November 6, 2014.
  • The Hows and Whys of Soil Testing” (1h 4min). Invited Speaker: Dr. Joan Davenport, WSU Crop and Soil Sciences Dept. (IAREC-Prosser, WA). Seminar Series: Crop & Soils Dept. Seminar, WSU-TFREC, Wenatchee, WA. October 29, 2014.  Synopsis: This seminar focuses on four main topics: i. Defining what a soil test is; ii. Identifying what a soil test does and does not tell you; iii. Explaining how soil sample collection method influences results; and iv. Integrating the soil-plant-water environment.
  • Cosmic Crisp™ WA 38 Field Days” (4:38 min). Synopsis: This video was recorded at two commercial grower field days on September 17 and 30, 2014. It provides the viewer with a look at the Cosmic Crisp™ WA 38 apple both at Washington State University research trial sites (WSU-IAREC, Roza Research Farm, Prosser, WA and WSU-TFREC, Sunrise Research Farm, Rock Island, WA) and commercial grower trial sites (Allan Brothers, Inc., Prosser, WA and Stemilt Growers LLC, Quincy, WA). Various aspects of the trial research and cultivar attributes are discussed by Dr. Kate Evans (WSU Apple Breeder), Dr. Stefano Musacchi (WSU Tree Fruit Physiologist), Tom Auvil (Research Horticulturist, WA Tree Fruit Research Commission) and Dave Allan (grower cooperator, Allan Brothers, Inc., Naches, WA).
  • The Potential for Precision Soil Management in Orchards” (1h 17min). Invited Speaker: Dr. Dave Brown, WSU Crop and Soil Sciences Dept. (Pullman, WA), Seminar Series: Crop & Soils Dept. Seminar, WSU-TFREC, Wenatchee, WA.  August 13, 2014. Synopsis: This seminar presents the concepts of precision management and site specific characterization (e.g., electromagnetic induction, VisNIR penetrometer, remote sensing, rapid eye satellite imagery, drones, LiDAR, terrain modeling, soil water monitoring and spatial interpolation).
  • Tree Fruit Research and Extension at WSU” (4:23 min). Synopsis: This video presents an overview of the range and types of research Washington State University scientists do in support of the Washington tree fruit industry.
  • WSU’s Sunrise Research Orchard” (2:27 min). Synopsis: Washington State University, in collaboration with the state’s tree fruit growers, has established a state-of-the-art research orchard near Wenatchee, Wash. This short video provides a brief overview of the types of research being conducted at the orchard.


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