Viticulture and Enology Extension News Washington State University

SPRING 2011 CONTENTS Spring Greetings from WSU- and Enology Extension Washington State University’s Viti- sessment, new and emerging VITICULTURE culture and Enology Extension News pests, graduate student research in clonal identification, irrigation sensors Cold Hardiness Program...... Page 2 (VEEN) is back! With a slightly new look and different publication fre- for , and more. There is also an Assessing Cold Damage...... Page 3 quency (twice a year, Spring and article on dealing with high acid wines. Fall), we hope this will be a useful Pest Updates: SWD, BMSB....Page 4 resource and guide to the informa- Don’t forget: more information is tion available to you through WSU. just a click away at: www.wine.wsu. Disease Updates: BBR, PM....Page 5 edu, including event information, Ex- This issue focuses on viticulture, with tension Publications, and Articles Nutrient Assessment...... Page 6 articles ranging from cold damage as- regarding current issues in V&E. Of course, we always welcome sugges- Clonal Identification ...... Page 6 tions, comments and questions as we work to help build on the extension and Native Covercrops in WA ...... Page 7 outreach resources available from the V&E Program at WSU. Happy reading! Irrigation Sensors...... Page 8

AgWeatherNet...... Page 9 Dr. Michelle Moyer Viticulture Specialist

Dr. Jim Harbertson ENOLOGY Enology Specialist As we eagerly await spring, this issue of Dealing with High Acid...... Page 10 VEEN will review 2010 and provide some insight to potential issues in 2011.

People Profiles...... Page 11 Find us on the web: WSU International Trip...... Page 12 www.wine.wsu.edu/research-extension Calendar of Events ...... Page 13 Information, when you need it. That is the power of the internet! Visit the WSU Viticulture and Enology Research and Extension website for valuable information regarding research programs at WSU, timely news releases on topics that are important to your business, as well as information regarding EDITORS upcoming workshops and meetings. Dr. Michelle Moyer It is also a valuable site for downloading our most recent Extension Dr. Jim Harbertson publications, as well as finding archived articles and newsletters you can print on demand. Find quick links to AgWeatherNet, the Viticulture and Enology Certificate and Degree programs, as well as to other Viticulture and Enology related resources.

WSU Extension programs and employment And don’t forget, you can also find us on Facebook! are available to all without discrimination. Evidence of noncompliance may be reported Go to: www.facebook.com/WSU.Vit.Enol.Ext and “Like” the page! through your local WSU Extension office.

1 WSU Grape Cold Hardiness Program By Markus Keller, WSU-Prosser Follow the cold hardiness

The ‘Thanksgiving freeze’ on posts these results weekly on the levels of selected grape November 24, 2010, caused damage WSU Viticulture and Enology website. varietes at: to buds and vines that varied widely By clicking on a variety name located among varieties and vineyard in the center cold-hardiness table locations. Despite a general warming (about 20 varieties are available), you trend in winters seen in the last 30 can access a seasonal cold hardiness years, this freeze event demonstrated graph specific to that variety, along once again that cold injury remains a with the seasonal temperature www.wine.wsu.edu major concern for Washington’s wine pattern. Growers may use these and juice grape industries. graphs (Fig. 1) to follow seasonal trends and forecast approximate The viticulture team at WSU continues hardiness levels based on current to provide critical temperatures for temperatures. cold hardiness on the viticulture and developing a mathematical model [6] enology website at: http://wine.wsu. that will eventually be able to fill in the This information is important, since gaps. edu/research-extension/weather/ the temperatures at which the buds, cold-hardiness. This service began bark (phloem), and wood (xylem) are This model will run on AgWeatherNet over 20 years ago and is conducted killed fluctuate throughout the winter. (AWN) at: http://weather.wsu.edu. primarily as a service to Washington’s Using this information is crucial for AWN is a large network of more than grape growers in collaboration with growers to make informed decisions 130 weather monitoring stations Ste. Michelle Wine Estates, Thurston concerning freeze protection, as well distributed throughout the state, and Wolfe Winery, and Hogue Ranches. as post-freeze sampling and pruning is hosted and supported by WSU for Our work is sponsored by WSU, the strategies [2-5]. the benefit of Washington State’s Washington Association of Wine various agricultural industries. Grape Growers, and the Washington Due to equipment and labor State Concord Grape Research limitations, the WSU team cannot Council. test every variety, every week, at every location. Fortunately, thanks For further reading on cold hardiness, The program regularly tests the cold to a grant from the USDA Viticulture see the following: tolerance of buds and canes [1] and Consortium-West, we are currently [1] Mills L.J., Ferguson, J.C., and Keller, M. 2006. Cold hardiness evaluation of grapevine buds and cane tissues. AJEV 57:194-200. [2] Davenport, J.R., Keller, M. and Mills, L.J. 2008. How cold can you go? Frost and winter protection for grape. HortScience 43:1966-1969. [3] Keller, M. 2010: The Science of Grapevines – Anatomy and Physiology. Elsevier: Academic Press, Burlington, MA. [4] Keller, M. and Mills, L.J. 2007. Effect of pruning on recovery and productivity of cold-injured Merlot grapevines. AJEV 58:351-357. [5] Wolfe, W. 2000. Vine and vineyard management following low temperature injury. Proceedings of the ASEV 50th Anniversary Annual Meeting, Seattle, Washington, June 19-23, 2000. pp. 101-110. [6] Ferguson, J.C., Tarara, J.M., Mills, L.J., Grove, G.G., and Keller, M. 2011. Dynamic thermal time model of cold hardiness for dormant grapevine buds. Annals of Botany 107:389-396.

Fig. 1: As a part of the Cold Hardiness Program at WSU, graphs showing winter tem- perature trends and bud, xylem and phloem cold hardiness levels are readily available for viewing.

2 Cold Damage in Vineyards By Michelle Moyer, WSU-Prosser

Spring is quickly approaching, making it easy to forget the long, cold winter. For many grape growers across the state, however, the evidence of just how cold it really was has become painfully ob- vious. The ‘Thanksgiving Freeze’ of 2010 not only announced the early ar- Fig. 2: Compound bugs of grapevines contain 3 smaller buds, the primary (center), secondary (left), riva of winter, it led to damage in grape- and tertiary bud (right). Live buds are green (Left image), dead buds are brown (right image). Photos vine buds, canes, and trunks; damage by Lynn Mills which we may have not yet fully real- what to do in those situations where ized. you are faced with 75-100% damage, at all nodes. Generally, a “wait and On October 31, 2002, a similar cold see” approach is suggested: hedge, snap led to substantial vine inner bark then wait until budbreak to assess (phloem) damage. As a result, WSU damage. Shoot numbers can then be was frequently asked the question adjusted or the decision to retrain can of “what to do next?” The resulting be made. work demonstrated that if there was substantial phloem damage, but rela- So how do you know the extent of cold tively little bud damage (67% versus damage in your vineyard? Sample! 25%, respectively), vines could fully More information on sampling tech- recover [1]. This occurred regardless niques can be found at: www.wine.wsu. Fig. 3: In many cases, you can see dead bark edu/research-extension . When sam- (phloem), but still have live, healthy green wood of pruning severity (ranging from mini- (xylem). Photo by Michelle Moyer mal pruning to complete bud removal). pling, select individual vines randomly, However, minimal pruning may help in but cover areas that are representative to reduce the likelihood that additional yield compensation. It is also important of sectional differences in your block, damage will not go unnoticed. to consider overall vine health and de- including those in areas that are prone velopment in the years following dam- to cold/frost damage. This will provide What can we learn from all of this? In age, i.e. recovery years are not the information on whether particular sec- order to deal and adjust for cold dam- best time to implement severe stress tions of your vineyard sustained more age, you need to know the extent of it. practices. damage than others. Assessing damage by looking at buds, canes and trunks before pruning is criti- What do you do if you have substan- After collecting canes from these se- cal. While we are seeing damage as tial bud damage in addition to phloem lected vines, the assessment process a result of the ‘Thanksgiving Freeze’ damage? The first thing to consider is can begin. Specifics on assessment of 2010, there are some pruning tricks where that bud damage is seen. If in- can be downloaded from our website. that can be done to either ensure jury is closer to the cordon (i.e. nodes We determine the viability of tissues by survival, a crop, or both. 1-5), but bud further out are alive, then their color [3]: green is good, healthy it is advisable to hedge. If the damage tissue; brown is dead tissue. There For detailed information on the topics is only seen on distal buds, then normal can also be an array of damage (and discussed, see the following: spur or cane pruning is acceptable [2]. therefore, colors), so it is good to have The challenge, however, is determining reference tissue. In trunk wood (xy- http://wine.wsu.edu/research-extension/ lem), milky-white to light brown is also files/2011/03/Cold-Damage-Assessment21.pdf an indication of damage (Fig. 1). [1] Keller, M, and Mills, L.J. 2007. Ef- For buds (Fig. 2), record the location fect of Pruning on Recovery and pro- on the cane where you see damage, as ductivity of Cold-Injured Merlot Grape- mentioned above. The same is true vines. AJEV 58:351-357. for cane sampling (Fig 3). To assess trunks look at both slightly above the [2] Wolfe, W. 2000. Vine and Vineyard soil line, and near the head. Pay par- Management Following Low Tempera- ticular attention to the south side of the ture Injury. Proc. Of the ASEV 50th An- vine, as it can be prone to cold dam- niversary Annual Meeting. Seattle, WA. age due to daytime deacclimation as a June 19-23, 2000. result of reflected heat from the snow. [3] Mills, L., J. Ferguson, and M. Keller. Trunk sample with caution: DO NOT 2006. Cold-hardiness evaluation of Fig. 1: Damage to the wood (xylem) in the trunk GIRDLE. Sampling for cold damage isn’t always brown: sometimes damaged wood grapevine buds and cane tissues. Am. should be done shortly before pruning, will appear milky-white. Photo by Michelle Moyer J. Enol. Vitic. 57:194-200. 3 Pest Alerts for 2011 Spotted Wing Drosophila (SWD)

Spotted Wing Drosophila (SWD) is a new pest in Washington orchards and vineyards. First introduced to the continental USA in 2008, it has slowly made its way north from California to most growing regions in WA. Related to other vinegar flies, SWD is a cause for concern due to the female’s ability to pierce the skin of, and lay eggs in, rip- ening fruit as opposed to over-ripened and decaying fruit. While preliminary studies at WSU indi- cate that grapes may not be a preferred fruit source for SWD, it is a suitable food Fig. 1: The male SWD has the characteristic Fig. 2: The female SWD is distinguished choice, and the fly is still capable of black spots near the tips of its wings. It will by its large, saw-like ovipositor that has also have 2 sex combs (black), on its front characteristic darker “teeth”. Photo by M. causing damage to grapes. In addition legs. Photo by A. Arakelian Hauser to the direct physical damage cause by egg-laying, the piercing activity of the able at: http://extension.wsu.edu/swd. have the characteristic wing spots. fly can also lead to the introduction of However, they do have a prominent bacteria, yeasts and other fungi which Properly identifying SWD is critical to ovipositor that is saw-like and used to can lead to rot or a reduction in wine control, as there are many types of na- pierce fruit skin (Fig. 2) in order to lay quality. tive fruit flies that can resemble SWD. eggs in ripening fruit. Flies will be less than 1/8” in size, and Monitoring your vineyard for the pres- will have red eyes. Male fruit flies are An extensive handout on SWD is avail- ence of SWD before starting a spray identified by the presence of a black able for download at: http://ipm.wsu. program is advised. This can be done spot near the tips of their wings (Fig.1), edu click on “Small Fruits” then find the using apple-cider vinegar traps. Infor- and they have 2 sex combs. Female paragraph on SWD. Click on the “bul- mation on how to build traps is avail- flies are harder to ID, as they do not letin...” link within the paragraph text. Brown Marmorated Stink Bug (BMSB) The Brown Marmorated Stink Bug (BMSB) was first found in the Allen- town, PA area in the 1990s. Since then, it has established itself as both a residential and agricultural pest. In addition to congregating in houses, it feeds on a number of crops, causing a range of damage and disfigurement of fruit and vegetables, including but not limited to, tree fruit, grapes, berries, vegetables, corn, soybeans, and orna- mental . It is distinguished from other Stink Bugs by its stripped antennae, black and white banding on the abdomen, and smooth shoulders. More informa- tion on BMSB can be downloaded at: http://pmtp.wsu.edu/downloads/bms- bIDsheet.pdf The challenge with BMSB is that it trav- els quickly, usually as a result of hitch- hiking on vehicles and storage units. It The Brown Marmorated Stink Bug adult is distin- The Brown Marmorated Stink Bug likes to con- has been collected in Vancouver, WA, guished from other stink bugs by its banded at- gregate in mass, especially in its overwintering but has not been found in eastern WA. tenae and legs, banded coloring on the abdomen locations. These overwintering locations often If you suspect you have BMSB, notify edge, and smooth shoulders. Photo by E. LaGasa include building structures and poten- your local WSU Extension agent. Cap- tially wineries. Photo by P. Shearer ture a bug for identification, and keep it in your freezer until you can take it in for examination. 4 Botrytis Bunch Rot and Powdery Mildew: 2010 Review By Michelle Moyer and Gary Grove, WSU-Prosser

“ is what we expect, weather is Table 1: Timing and type of fungicides for the control of Botrytis Bunch Rot what we get.” Mark Twain (BBR), or for dual control of BBR and Powdery Mildew on clusters. Uncharacteristic cool and wet weather Powdery Botrytis in 2010 resulted in many challenges, Timing Compound Mildew Bunch Rot Notes from delayed ripening to high juice acidity. A very noticable challenge was Trifloxystrobin Yes Yes the widespread occurrence of Botrytis (Flint) Apply at highest Bunch Rot (BBR), and the economic Pyracostrobin + labeled rates for consequences of this epidemic are not Bloom boscalid Yes Yes dual control. entirely clear. Preliminary information to (Pristine) from WA indicates that the disease af- Fruit Set fected about 8,000 and 3,000 acres of Difenconazole + Read label for ap- white and red grape varieties, respec- cyprodinil Yes Yes propriate rates. tively. While most affected vineyards (Inspire Super) had some healthy clusters, this would Trifloxystrobin equate to losses of $25,056,000 and (Flint) Yes Yes $15,132,000, respectively. (Assump- Apply at highest tions based on 4 ton/acre crop loads Pyracostrobin + labeled rates for for ‘Chardonnay’ and ‘Cabernet Sauvi- Bunch boscalid Yes Yes dual control. gnon, using prices listed in the January Closure (Pristine) 2007 USDA-NASS Grape Release). To Difenconazole + prevent the harvest of diseased bunch- Yes Yes Read label for ap- es, hand-harvest was used in some cyprodinil propriate rates. vineyards that are normally machine- (Inspire Super) harvested, at an estimated additional Fenhexamid No Yes cost of $375 per ton (‘Chardonnay’). (Elevate) Late season such as those in western WA Pyramethanail No Yes sprays may only are prone to annual outbreaks of BBR Veraison (Scala) be necessary if due to the favorable moist, cool condi- to conditions are Harvest Iprodione tions, particularly near bloom. Due to (Rovral) No Yes right for BBR eastern WA’s normally arid summer development. climate, BBR occurence tends to be Cyprodinal No Yes sporadic. However, the unseasonably (Vangard) moist weather between the months pattern in 2011, there is the possibility at véraison and preharvest (Table 1). of May and June, then again in Sep- of over-spraying for BBR as a compen- In eastern WA, years with “normal” pre- tember of 2010, set the year up for the sation for last year. To avoid this, WSU cipitation (e.g. DRY between fruit set wide-spread outbreak. in collaboration with WAWGG, held a and harvest), late season BBR fungi- BBR can infect fruit at two different workshop in January to help develop cide sprays may be unnecessary. a rational strategy for managing BBR stages: from bloom to bunch closure, The role of leaf removal in manag- and again during véraison to harvest. in 2011. Drs. Doug Gubler (UC-Davis) and Wayne Wilcox (Cornell University) ing PM and BBR cannot be overem- During the first stage, BBR infects clus- phasized. Both Gubler and Wilcox ters through the cap scars and dying shared their extensive experiences with BBR management in California stressed the incorporation of this cul- stamens, and can also survive on floral tural practice into the overall vineyard and other debris that gets stuck inside and New York, respectively. Wash- ington growers recognize the bloom to disease management system. Gubler the cluster during closure. These infec- presented data indicating that leaf re- tions remain latent (inactive) until vérai- pea-sized berry period as the keystone for managing powdery mildew (PM) on moval is equally or more important son, where they can then express the than fungicide applications for manag- classic BBR symptoms. fruit, and typically make 2-3 PM fungi- cide applications during this period to ing BBR. Leaf removal also improved At the end of the season, BBR can in- control it. Like PM, the bloom period management of PM. Much of this is fect ripening fruit through wounds, of- is critical for BBR control. The use of through better spray penetration into ten caused by insect feeding, powdery fungicides that offer control of both is the fruit-zone, and increased air circu- mildew damage, or berry splitting as recommended at the highest labeled lation and sunlight penetration, which a result of compact cluster architec- rates during bloom to control PM and to reduces the environmental favorability ture. BBR infects fruit in this manner prevent BBR infection of flower parts. for BBR and PM fruit infection. because it is a relatively weak fungal Last year also presented challenges pathogen. It prefers readily acces- Gubler and Wilcox also recommended taking notes on prevailing and predict- in controlling PM, though not to the sible or weakened food sources. A same extent as BBR. As mentioned, major issue in 2010 was the need for ed weather conditions when devising BBR management strategies. If the targeting PM fungicides from bloom to increased hang time to bring fruit to pea-size is the key to controlling dis- desired sugar and acid levels. Longer 2011 season has above-average pre- cipitation, additional dual-purpose fun- ease development on fruit. What many hang-time means more chances for in- people don’t realize is that control of fection and BBR development. gicide applications should be consid- ered at pre-bunch closure, while BBR PM is also a key component of control- If we have our normal summer weather specific compounds should be applied continued on Page 7

5 PNW 622: Nutrient Sampling in Irrigated Vineyards By Joan Davenport, WSU-Prosser

We all know that the inland Pacific be recycled for next year. Northwest is not California. We grow wine and juice grapes in a climate with Another difference is that we recom- hot summers and cold winters where mend sampling at veraison rather than irrigation is a must. But for years, the bloom. The bulletin provides values only standards for tissue nutrient test- for both, but plant nutrient transport is ing came from other areas – in particu- more stable at veraison and this data lar California for wine grapes and New can be used for planning next year’s York for juice grapes. Here’s the good fertilizer strategies as well as any late news – we have our own standards season fine tuning. now! The bulletin provides the optimal nutri- Over the past 12 years the soils pro- ent level numbers in whole grape leaf gram at WSU-Prosser has lead a tissues samples when the samples are number of projects in plant mineral collected at bloom and veraison. In ad- nutrition in wine and juice grapes – of- dition, there is guidance for how many ten collaboratively with former WSU- leaves to collect and what leaf position Viticulturist Dr. Bob Wample, and more to use. recently with current WSU-Viticulturist Dr. Markus Keller, and emeritus WSU- What’s different with the new bulletin? We developed this bulletin for you Soil Scientist Dr. Bob Stevens. The First and foremost, we are recom- and hope it will be truly useful. But work has been funded by an array of mending using whole blades for evalu- as the old Italian proverb reminds us agencies and particular thanks need to ating tissue nutrient status. Our results “The best fertilizer for the vineyard is go to the Washington State Concord showed that leaf petioles overestimat- the footsteps of the vineyardist” – and Grape Research Council, the Wash- ed the need for plant nitrogen fertiliz- no numbers can substitute for know- ington Wine Advisory Board, and the er over 85% of the time. Why? If we ing your vineyard block and keeping a NW Center for Small Fruits Research. think about a petiole, it really is a straw watchful eye. From all of these efforts, research and that plant sap flows through. In an arid survey projects have given us the data environment, that flow varies greatly. Here is the web address and the bulle- we needed on grapevine nutritional However, the leaf blade integrates tin is free – just download or print: status. Dr. Don Horneck of Oregon what the vine experiences throughout http://cru.cahe.wsu.edu/CEPublica- State University (Hermiston) helped the season and reflects what is stored tions/PNW622/PNW622.pdf co-author the bulletin. for this year’s crop as well as what will The Value of Clonal Variation in Washington Grapes By Kathie Nicholson, Graduate Student, WSU-Pullman Compared to other fruit crops, there choices which may be better suited to Is there a need for a resource that is very little focus on developing new a particular region or may exhibit fruit could genetically confirm clonal identity wine grape varieties, uutside of breed- qualities that better fit the winemaking within wine grape varieties? Addition- ing for disease resistance, shorter rip- styles of the area. ally, how important are clonal variations ening time, drought resistance, or other to the Washington wine industry, and to similar characteristics. The existence Clones result from genetic mutations what extent are consumers interested of grapevine clones, i.e. the specific that can occur during vine develop- in this facet of the wine they purchase? selection of grape varieties with desir- ment, and this variation is then main- able characteristics compared to the tained with vegetative propagation. In These questions arose as a research standard, such as looser clusters or addition to looser clusters or cold hardi- project that began here at WSU looking increased cold hardiness (Fig. 1), pro- ness, changes in chemical components at various methods to identify genetic vides viticulturists with plant material of the fruit may occur that can influence differences among wine grape clones. wine characteris- We felt it was important to know the tics, such as fruit viewpoints of the population that could aroma, wine tex- benefit from this research, thus, two ture, and aging abil- surveys were conducted. The first was ity. However, these directed to the wine industry to deter- clonal differences mine their perceived value of clones, are not visible, mak- and the extent they believe consum- ing traditional plant ers would be influenced by identifying identification using clones on a wine label. ampelography dif- ficult. Currently, The second survey was directed to clonal verification is consumers regarding their general based on the faith knowledge and interest in wine grape that the vine used clones, and the extent their purchases for propagation was would be influenced if labels included Fig. 1: Comparison of cluster density of two Syrah clones . correctly identified. clonal information. Both surveys asked (W. Farquhar 2006. http://ucanr.org/sites/ intvit/files/24458.pdf.) continued on Page 7

6 Beneficial Insect Conservation in Washington Vineyards By David James, WSU-Prosser

The concept of ‘Farmscaping’ Wash- ficials. For example, mite-eat- ington vineyards by restoring native ing ladybeetles were strongly shrub-steppe plants and habitats has attracted to Rock Buckwheat been mooted for a few years now. Re- and Columbia Basin Prickly search on the feasibility and potential Pear, while minute pirate bugs of ‘beauty with benefits’, a program that were most attracted to Yel- envisioned developing habitat for pred- low Sweetclover, Gray Rab- ators and parasitoids of grape pests, bitbrush, Tall Buckwheat and has commenced at WSU-Prosser with Showy Milkweed. Predatory funding from the Western Sustainable thrips were most common on Agriculture Research and Education Oregon Sunshine and Yellow (WSARE), the Northwest Center for Sweetclover while ladybeetles Small Fruits Research (NCSFR) and and parasitic wasps were fa- the WA Wine Advisory Committee. vored by Lewis’ Mock Orange and Clematis. Initial studies looked at the potential of Re-introducing native habitats within and around vineyards xeric, flowering native perennial plants Fineleaf Hymenopappus, will provide refugia for beneficial insects needed in biological for attracting natural enemies of grape Golden Currant, Showy control for pest management of grape. Photo by David James. pests. In 2010, 43 species of flowering Milkweed, Coyote Mint and perennials in Yakima Valley were eval- Wood’s Rose attracted ich- uated for beneficial insect attraction. neumonid and braconid wasps while ver appear to be well-suited as sus- Attraction of 9 groups (families, gen- Munro’s Globemallow attracted tainable, IPM-enhancing ground covers era) of beneficial insects was assessed Anagrus wasps. Gray Rabbitbrush at- because of their hardiness, drought tol- using yellow sticky cards placed on, or tracted almost twice as many parasitic erance and likely mowing tolerance. adjacent to, plants. The top 10 species wasps from other families than any oth- for attraction of beneficial insects were er plant. At least 23 plants emerged as We will shortly establish a website ded- Showy Milkweed, Yellow Sweetclover, having potential for attracting beneficial icated to our vineyard habitat restora- Wood’s Rose, Western Clematis, Gray insects; all are native except one (Yel- tion project. This site will provide prac- Rabbitbrush, Yarrow, Green Rabbit- low Sweetclover). tical information on how to optimally brush, Ocean Spray, Hoary Aster, and restore native habitats in your vineyard Lewis’ Mock Orange. These data are preliminary and will be to provide the greatest benefits to pest expanded in 2011. Plants like the buck- management and conservation of na- Different plants attracted different bene- wheats, Yarrow and Yellow Sweetclo- tive plants, bees and butterflies.

Clonal Variation BBR and PM Management continued from Page 6 continued from Page 5 if the wine industry in Washington State were not previously aware of clonal ling BBR. Severe PM infections can would benefit from a resource that variation, after a brief description, 81% result in fruit cracking, a clear entryway could genetically confirm clonal iden- indicated that their purchase would for BBR. However, light PM infections tity. likely be influenced by identification of (“diffuse infections”), on fruit can en- the clone on the label (assuming they hance BBR. Diffuse infections cause From the wine industry, 72 responses knew the characteristics of that clone), microscopic damage to the berry skin. were received (21%). When buying and 71.2% indicated they would possi- These are also direct avenues for BBR vineyard stock, 88% of wine industry bly pay more for a bottle if they knew infection. respondents believed clonal varieties the clone used exhibited desired char- were an important consideration; 47% acteristics. Both the wine industry and Last year highlighted the role of weath- responded that it is an important con- consumers indicated that there is a er in disease development. Knowing sideration when purchasing grapes for need for a resource that could geneti- this influence is important in determin- the winery. When it came to what they cally confirm clonal identity, with posi- ing the timing and type of fungicide ap- felt would be important to consumers, tive responses of 79% in both cases. plication. In 2011, keep that in mind, only 26% of the wine industry respon- and be prepared to adjust if conditions dents felt that having confirmed identity In summary, the survey results indicat- change. More information on spray of grape variety clones would be impor- ed that clonal variation is important to programs is available in the 2011 WA tant to the consumer and consequently the wine industry, is potentially impor- State Grape Pest Management Guide, enhance sales, and 33.3% responded tant to consumers, and that there is a downloadable at www.wine.wsu.edu/ that it would not be important to the need for a resource in Washington that research-extension. consumer. could genetically confirm clonal iden- tity. Additionally, results indicated that Use with care. Apply them only to The consumer survey was a random consumers are possibly more interest- plants, animals, or sites listed on the labels. sampling from consumers at a Pull- When mixing and applying pesticides, follow all ed in clonal variation than the industry label precautions to protect yourself and others man, WA, wine shop, and requests believes they are. Realization of this around you. It is a violation of the law to disregard for participation were posted on two consumer interest could provide moti- label directions. If pesticides are spilled on skin WSU websites related to viticulture vation for novel marketing strategies in or clothing, remove clothing and wash skin thor- and enology, resulting in 52 responses. oughly. Store pesticides in their original contain- the Washington wine industry. ers and keep them out of the reach of children, Although 56% of consumers polled pets, and livestock.

7 Irrigation Sensors for Washington Vineyards By Troy Peters, WSU-Prosser Good irrigation water management will increase yields, improve crop quality, conserve water, save energy, decrease fertilizer requirements, and reduce non-point source pollution. Using soil moisture measurements is one of the best and simplest ways to get feed- back to help make water management decisions. However, the installation, calibration, and interpretation of the data from these instruments is often overwhelming. Here’s an attempt to provide practical recommendations for using these sensors to improve your operation. Soil Water Content-based soil mois- ture sensors: (Capacitance, Neutron Probe, Gravimetric) Soil water content measurements are more meaningful for irrigation sched- uling when they are compared to the maximum amount of water that the soil can hold long term (field capacity). The simplest way to determine your soil’s Fig. 1: Measuring soil moisture is a good practice to help improve crop quality and water-use ef- field capacity is to use the sensor to ficiency. take a soil water content measurement at a time when you are confident that the soil is full of water, yet free water irrigate before the soil water content or shallow soil areas), and irrigate be- has had time to drain. Good times to reaches 6.3 inches (10.5 – 4.2) if man- fore this point in the future. Also, take make these measurements are in the ageing for no stress. To impose water readings right after an irrigation; if the spring as soon as soil thaws (assum- stress, then irrigate to keep soil water bottom sensor goes to zero, then it’s ing adequate soil moisture recharge content above 2.1 (10-8.4), but below possible you over-irrigated. If it shows over the winter), or 12 to 24 hours after 6.3 inches. Wilting point is at 2.1 inch- no movement, apply more water next a heavy irrigation. The water content es. time. A word of caution when using measurement must be multiplied by the tension-based soil moisture sensors depth of soil in the root zone that it rep- Use plant and soil observations over when the soil is dry: Many growers resents, to give the total water content time to refine these estimates. For ex- find their use frustrating as the sensors in that soil depth. ample if the first observable signs of tend to lose suction, or contact, with the plant water stress is at 7.0 inches in- soil under this condition. It also helps to have an estimate of the stead of 6.3, then the 6.3 inch estimate soil water content at which the plants of the water stress line should be re-set Additional Recommendations: begin to experience water stress. This to 7.0. With this method, the absolute can be estimated from the previously accuracy of the sensor is less impor- •Avoid preferential flow of water from measured field capacity and the soil’s tant, because it is just being compared the surface to the sensor due to instal- available water capacity (AWC). See to itself. lation process. http://websoilsurvey.nrcs.usda.gov for •Flag the sensor so it can be easily soil survey information on your soil’s Tension-based sensors: (watermark found. AWC. This AWC number is then multi- sensors, tensiometers) plied by 42 inches (3.5 ft) root depth for When using tension-based soil mois- •Graphical representation of the data most vines, to get the inches of water ture sensors, the soil’s field capacity, greatly helps with data interpretation. that is held between field capacity and wilting point, and the maximum deple- •Use soil water measurements with ir- wilting point. It may be necessary to tion point are mostly irrelevant. A soil rigation scheduling tools such as Kan- use a different root depth if the soil is that is full of water will have a mea- sched and daily water use data from shallow. sured soil water tension near zero. For AgWeatherNet or AgriMet for better maximum growth, vines should be irri- water management. To manage vines for no stress, it is a gated before the soil tension reaches good idea to limit the soil water deple- 40-50 centibars (Note: centibar is a unit •Keep records. Correlate readings tion to only 50% of the AWC in the root for tension. The higher the number, the with observations. zone. For example the soil AWC from greater the water stress). For regulat- •Stay away from both the field capac- websoilsurvey is 0.20 cm/cm (same ed deficit irrigation (RDI), this could be ity, and water stress points if possible. as in/in). Multiply this by 42 inches to increased to 80 centibars. Again, since these measurements can be inaccu- •Realize that soil and sensors have get a total AWC in the root zone of 8.4 variability. inches. To manage for no stress the rate and soil specific, refine your limits maximum depletion should be half of using crop observations over time. For •Be patient and stick with it. It may that, or 4.2 inches. If the field capac- example, note the measured soil water take a year or two before you are good ity, measured early in the spring (Mar. tension at the earliest indications of wa- at interpreting your sensor readings. 1), is 10.5 inches in the root zone, then ter stress (this will appear first in sandy, 8 AgWeatherNet Update By Gerrit Hoogenboom, WSU-Prosser

The Washington Agricultural Weather message will be sent to Network (AgWeatherNet, AWN) is one your mobile or regular e- of the largest automated agricultural mail address when this weather station networks in the USA. temperature has been Formerly known as PAWS, AWN was reached. You can delete upgraded in 2008 to state-of-the-art your alert under “Run data logging equipment and weather Favorites/Alerts.” monitoring sensors, along with a new communication system using cell data Another temperature telemetry. feature of interest, es- pecially during winter, is AWN currently encompasses 135 sta- the Grape Cold Damage tions with many stations located in the Decision Aid that can Columbia Basin as shown on the wel- be accessed from the come screen of the AWN website (Fig. “Grape Cold Damage” 1). Each station monitors air tempera- option. The critical tem- ture, relative humidity, rainfall, solar peratures on this web- Fig. 1: AWN has weather stations located throughout Washington radiation, wind speed and wind direc- page are provided by State. Interactive maps on the AWN website allow you to select tion, leaf wetness and soil temperature WSU’s Viticulture team. specific stations you are interested in. (Fig. 2). The observations are taken at The output tells you a 5-second frequency and summarized when a critical temperature that results Please feel free to explore the Ag- every 15 minutes. AWN has two data in tissue death has occured. The cat- WeatherNet website at: www.weather. computer servers, one at the Wash- egories of BUD10, BUD50 and BUD90 wsu.edu. For questions or suggestions ington Tree Fruit Research Center in correspond to the temperatures at for improvement, please contact Gerrit Wenatchee and one at the Irrigated which 10%, 50% and 90% of the pri- Hoogenboom at: gerrit.hoogenboom@ Agriculture Research and Extension mary buds will be killed. PHL10 refer wsu.edu. In future issues of VEEN, we Center (IAREC) in Prosser. Both com- to the temperature at which 10% of will discuss other features of the Ag- puters communicate with each weather the phloem is damaged or when cane WeatherNet website, and how to use station through the internet and the cell damage starts, and XYL10 refers the additional alerts to aid in production data telemetry system. the temperature when phloem damage decisions. is complete and xylem damage starts. Users of AWN can access all weather data and related information from the website at: www.weather.wsu.edu. Ac- cess is free; however, you have to cre- ate a login name and password. The “Current Observations” option provides the current air temperature, dewpoint temperature, wind speed and other in- formation for all stations. This informa- tion is updated every 15 minutes. If you are interested in receiving a warn- ing when the temperature has dropped below a critical threshold value, such as for frost and freeze protection, you can set up an alert message under “Ad Low Temperature Alert” (Fig. 3). Af- ter you have defined your alert, a text

Fig. 3: Signing up for alerts is easy at AWN. A low temperature alert for Walla Walla, WA is pictured Fig. 2: Each AWN site is equiped with standard above in a screen capture, where the alert name, a temperature threshold vale of 32F, and site have weather monitoring stations. been selected.

9 Dealing with High Acidity in Must and Wine By Thomas Henick-Kling, WSU-TriCities, and Jim Harbertson, WSU-Prosser The following is a compilation of mini- works well in most white wines, espe- Yeast and bacteria compete for many articles released by Enology Extension cially Chardonnay, Sauvignon Blanc, of the same nutrients. Special nutrient during the 2010 harvest season. The and Pinot Gris. It also can be used in mixes for ML bacteria also can be help- scope of the articles revolved around Riesling. Blending of MLF and non-MLF ful when inducing MLF soon after com- management of must and wine in chal- wine should also be considered (note: pletion of alcoholic fermentation. Many lenging production years, such as that sterile filter the blended wine to avoid of these nutrients are depleted during seen in 2010. unwanted MLF in the bottle!). In order alcoholic fermentation. The autolyzing to avoid buttery ML odors, it is best to yeast relase some nutrients back into Monitor pH and Titratable Acidity use a co-inoculation of yeast and ML the wine. Mistakes with acidity can be made in bacteria. Alternatively, inoculate wine cool years. High titratable acidity is at the end of alcoholic fermentation and Deacidification with 2K CO3, CaCO3 more acceptable in white wines but it keep the wine on yeast lees. The yeast Potassium (K) and calcium (Ca) will is disrupting in red wines. Excessive will remove excess diacetyl and other react with the grape acids (malic and acidity can cause wine imbalance, and ML flavors and help enhance fruity fla- tartaric) to form insoluble salts, and accentuate astringency in red wines. vors in the wine. Alternatively, a yeast carbon dioxide will be given off as a There are several factors, including fining can be done after completion of result. As a natural occurence in wine- acidity, that affect astringency (tannin MLF, to remove excess buttery flavors. making, K will form several types of concentration, alcohol concentration). salts with tartartic acid and malic acid

To make a balanced wine, you must A large number of ML starter cultures (K2TA, KHTA, K2MA, KHMA). Calcium, keep these in mind. As a guideline, try are available for direct inoculation. as a contrast, will only form a couple to have must titratable acidity (TA) for However, all lactic acid bacteria are of salts (CaTA, CaMA). However, Ca red wines near 6 g/L. In some cases, strongly inhibited at pH values below can form a salt with malic and tartaric such as Pinot Noir, a TA of 7 g/L might 3.2. The ideal starting pH for MLF is acid simultaneously (MAHCaHTA) and be acceptable. Finished wine pH can between 3.2 and 3.4, in the presence the treatment has been dubbed the be between 3.3 and 3.8, depending on of some alcohol (5% and more). In this “double-salt” technique as a result. The the tannin content. Low tannin wines condition, Oenococcus oeni will domi- formation of the double-salt is actually typically have lower pH. If the must TA nate all other lactic acid bacteria. Spe- rare, but the name persists. is higher than the goal of 7 g/L then you cial adaptation procedures will have to should consider deacidification. be used to induce MLF in wines below Which Carbonate Salt a pH of 3.1. Should I Use? Acid adjustments in wine can be made If the TA needs to be lowered by only up until bottling. In addition, you can For low pH wine, deacidify a small 2-3 g/L, simply use potassium bi- warm wine before bottling to improve amount to raise the pH to about 3.4, carbonate or potassium carbonate mouthfeel and reduce vegetative fla- inoculate it with a starter culture, and (KHCO3 or K2CO3). If more acid needs vors. This can be done by heating wine after ~2/3 of the malic acid has been to be removed, it is better to use the to 104°F for ~2 days. metabolized, use it to inoculate another double-salt deacidification with calcium part of wine which can be of lower pH. carbonate (CaCO3). It is important to Bench trials are generally a best-prac- When inoculating wine with a wine ML note that the double-salt technique fa- tice for wine adjustments. Bench-trials starter culture, the starter culture must vors the removal of tartaric acid rather allow you to see if the adjustments have be 10% by volume. Another possibil- than malic acid, unless the initial con- the desired effects before these adjust- ity is to start with a wine/water/juice centrations of malic acid are double ments are made on a larger scale. ML starter culture. If you use a liquid the concentration of tartaric acid. This starter culture, check it under the mi- technique should only be carried out on Deacidification croscope to be sure it is Oenococcus a portion of the juice (~25%) because Potassium or calcium carbonate and does not contain spoilage yeast or it would otherwise destabilize the wine

(K2CO3, CaCO3) can be used to re- unwanted bacteria. by leaving primarily malic acid behind, move wine acids. Pre-fermentation ad- continued on Page 11 dition is done for two reasons. First, with pre-fermentation addition, there is less danger of losing aroma com- pounds that are primarily in non-vola- tile precursor forms. These precursors are less susceptible to loss due to this type of addition. Second, wine yeast and lactic acid bacteria are sensitive to high acidity and low pH. Wine yeast can tolerate pH values below 3, but are stressed. Fermentation of very low pH musts should be done at moderate temperatures around 68°F. Biological Deacidification – Malolactic Fermentation Malolactic fermentation (MLF) is an excellent tool to lower wine acidity, improve mouthfeel, and remove some unripe, green flavor characteristics. It Fig. 1: High acidity can be dealt with in the winery, when longer hang-time isn’t an option. Photo by is used in (almost) all red wines and it Jim Harbertson

10 New Faculty and Visiting Scientists in V&E

Gerrit Hoogenboom Michelle Moyer Pascual Ramero Director Assistant Professor Visiting Scientist AgWeatherNet Viticulture Extension

Dr. Hoogenboom In February, Dr. The V&E Program joined WSU in Au- Moyer joined the welcomed a visit- gust 2010 as the Di- facutly at WSU- ing scientist this rector of AgWeath- Prosser. She is a January. Hosted erNet and Prof. of graduate of Cornell by Dr. Markus Agrometeorology. University (New Keller, Dr. Romero He is originally from York) with a PhD will be working on the Netherlands, in plant pathology, grapevine water where his parents focused on grape stress and deficit owned two acres powdery mildew irrigation; specifi- of greenhouses for and decision aids cally, he will be in- fresh vegetable production, including for disease management. She also vestigating thresholds and indicators table grapes. He graduated from Wa- spent time in the Riverland region of for stress levels. Romero is a scientist geningen University with a dual MS in South Australia. Moyer is originally at Instituto Murciano de Investigación Horticulture and Theoretical Produc- from Wisconsin, where her family owns y Desarrollo Agrario y Alimentario in tion Ecology. His PhD is from Auburn a wholesale and retail horticultural southeastern Spain, where he also University in Agronomy and Soils. nursery and landscape company. She works on irrigation and grapevine wa- Prior to WSU, Hoogenboom managed joined the V&E team with a 70% exten- ter stress. Romero recently won the the Georgia Automated Environmental sion and 30% research appointment, 2010 “Best Viticulture Paper” from the Monitoring Network for the Univeristy and will be focusing on canopy man- American Journal for Enology and Viti- of Georgia. His goal is to make AWN agement, vineyard site selection, and culture, for his work on regulated defi- one of the best automated weather vineyard mechanization. She will also ciet irrigation and impacts it has on vine station networks in the USA, providing be working closely with the Certificate and fruit quality parameters. It is avail- high quality weather data and practical Program and mentoring graduate stu- able for free at: http://www.ajevonline. decision aids in support of the grape, dents. org/misc/best_papers.dtl enology and other local industries. or after malolactic fermentation, and fractions. Mix well. Wait several hours Dealing with High Acid even just before bottling. When de- and check the TA and pH. acidifying the wine before malolactic continued from Page 10 fermentation is important to be care- Calculations: CaCO : 0.67 g/L reduces TA by 1 g/L which is easily metabolized by yeast ful that the pH does not increase too 3 and bacteria. Only add the amount of (i) (vol.) L x present TA (g/L) – a = desired TA much. To avoid growth of spoilage (ii) CaCO needed = a x 0.67 calcium carbonate for the entire lot to bacteria, the pH before MLF should be 3 a small portion of the juice. Because below 3.4. Use KHCO3 to remove ex- KHCO3: 0.673 g/L removes 1 g/L tartrate such a large concentration of CaCO3 is cess acidity before bottling. K CO : 0.62 g/L removes 1 g/L used, the treated juice can reach a pH 2 3 between 4.5-6.5. You will need to add White wine TAs are typically higher LEAVE O.5 g/L of tartrate the treated juice back to the original lot, than in red wines. At target value for (i) 230 g KHCO3/500 mL %TA x vol (mL) = and then re-adjust the juice using tar- white grape must is TA 8 to 11 g/L. mL of solution added taric acid to your targeted pH. Late harvest, botrytized, and ice wines have higher TAs to balanced with the Excess Ca in the wine can cause Ca- tartrate instabilities and there is no way During CaCO3 addition, juice is agitated high residual sugar. to help the precipitation process. The to test for this instability. With 0.67 g reaction time is short: only 30 min in a How much should I add? of CaCO3 you are really only adding 0.268 g of Ca. Wine typically contains large tank. Settling takes ~60 minutes. The limit to CaCO3 and KHCO3 addition is the avalaible tartaric acid, so deter- 40 to 140 mg/L of Ca; the majority of Ca

When doing the CaCO3 addition, it is mine this in the must. Plan your CaCO added to wine will be removed with the 3 precipitate as tartrate and malate salts. counter productive to chill the juice. or KHCO3 addition to remove excess Calcium-tartrate solubility is unaffected tartaric acid. However, it is important to by cold temperatures and carbon di- leave 0.5 g/L of tartaric acid, otherwise Calculating Wine Additions oxide is actually more soluble. Also, the treated wine will oxidize rapidly at Calculating wine additions under du- a simple indicator that the reaction is an alkaline pH. ress can be stressful and tricky. We finished is that bubbles have stopped recommend using computers with evolving. Because the reaction gener- With the double salt method, you take spreadsheet applications to streamline ates carbon dioxide there is a danger of 20 to 40% of the must to be treated the mathematics and archive the in- asphyxiation, and it is better to do the and add all the calculated necessary formation. There are several wine-ad- dition websites available that can help treatment either in an outdoor tank or in CaCO3. The high pH produced in this a very well ventilated room. fraction of must will also facilitate pre- calculate particular additions. Example URLs: http://wineadds.com/, http:// cipitation of malic acid. After CaCO3, Small acid corrections (around 1 g/L) agitate well, let settle and rack. Re- vinoenology.com/, http://www.iwine- can be done in the wine after alcoholic combine the treated and non-treated maker.com/. 11 WSU Winery and Vineyard Tour: Chile and Argentina 2012

Are you interested in tasting Malbec while sitting in a vineyard in Mendoza, Argentina? Or how about discussing winemaking preferences with other industry professionals while sipping a Chilean Cabernet Sauvignon Gran Reserva?

If your answer was yes to either of these questions, then you may be in- terested in the 2nd International WSU Winery and Vineyard tour. This tour, will be visiting key viticulture regions in Chile and Argentina, drinking wine with the winemakers, and kicking the dirt with resident viticulturists.

The tour will be from January 15-28, 2012 and is designed especially for Washington State winemakers and grape growers. While in Chile, the tour will visit the most renowned wine regions surrounding Santiago; Maipo Valley, Colchagua Valley, Aconcagua Valley and Casablanca Valley. Then, after a quick flight over the Andes Mountains, the tour will continue in the Enjoy the beautiful scenery while touring vineyards in Chile. Photo courtesy of www. famous Argentinian Mendoza Valley down2earth-prowein.com. wine region. • Daily breakfast at hotel; There will be a website for you Of course, all work and no play is not • Assistance of a bilingual local guide to sign up for the trip with a the way to spend a winter vacation. (who happens to be a Sommelier); 25% deposit due by May 15, Built into the program is free time • Transportation via deluxe bus to all 2011. to allow you to explore the cities of group activities; Santiago and Mendoza, the beach at • Lunches and dinners as listed in the Payments via credit card will incur a Valparaiso, and a resort in the Andes itinerary; Mountains. 5% surcharge and all payments via US • Tours of Santiago and Valparaiso; dollar check will incur a $25 surcharge • 12 wine tastings at vineyards; per check. Space is limited, and the cost of the • Two-day excursion on the Pacific trip is determined by the number of Coastline. Sound like something you may be in- participants. The 2nd International terested in? If so, contact Theresa WSU Winey and Vineyard tour costs Not included in price quote: Beaver ([email protected]) for a more are estimated below: • Airfare from US to Santiago; detailed daily itinerary and information • Entry reciprocity fee for entry into on registration. Cost per participant, based on Chile for US citizens ($140); single occupancy rooms: • Entry reciprocity fee for entry into • 30 participants: $3,584 each; Argentina for US citizens ($140); • 34 participants: $3,506 each; • Internal Airfare from Santiago to • Cost reduction for second person Mendoza: $250 per participant. (Air within a couple is $824. taxes are subject to change prior to complete purchase of airfare. This Items included in price quote: reservation is released every 10 • Organization of all educational ac- days and needs to be requoted). tivities with vineyard specialists;

Ever thought about going back to school? Consider the WSU Viticulture and Enology Certificate programs! These 23 month-long programs (one for Viticulture, one for Enology) are offered online, and include 3 weekend, hands-on camps for participants. Space is limited, so reserve your spot today:

http://wine.wsu.edu/education/certificate

12 Viticulture and Enology Extension News Washington State University

Calendar of Events

Date Description

7 April Grape Fieldmen’s Mtg: Barn Inn, Prosser, WA 15 April LIVE Annual Meeting, NW Vit. Center, Salem, OR 19 April 2010 Vintage Review Workshop, WSU-Prosser 27 April Tasting Room Staff Training, Woodinville, WA 5 May Grape Fieldmen’s Mtg: Barn Inn, Prosser, WA

2 June Grape Fieldmen’s Mtg: Barn Inn, Prosser, WA

American Society for Enology and Viticulture Meeting: 20-24 June Monterrey, CA

7 July Grape Fieldmen’s Mtg: Barn Inn, Prosser, WA 4 August Grape Fieldmen’s Mtg: Barn Inn, Prosser, WA 10 August Introduction to Wine Chemistry Workshop: WSU-TC

12 August Viticulture and Enology Field Day: WSU-Prosser

17 August Advanced Wine Chemistry Workshop: WSU-TC 24 August Wine Sensory Workshop: WSU-TC

25 August Advanced Wine Sensory Workshop: WSU-TC

Check the website for changes and updates to the Calendar of Events. Have events you want publicized? The next VEEN will be in late August/Sep- tember and is accepting events between September 2011-March 2012. Let Jim ([email protected]) or Michelle ([email protected]) know by 1 August 2011.

www.wine.wsu.edu

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