By Bryan Hed, Andy Muza, and Michela Centinari
For this week we would like to devote our blog to Jody Timer, our grape insect pest specialist at the Lake Erie Regional Grape Research and Extension Center in North East, PA, who retired at the end of February.
Jody came to work at the Penn State research center in August of 2004, filling a position long since vacated by her predecessor, Sudha Nagarkatti. With an M.S. degree in Biology and many years of experience monitoring water quality and chemistry for a company in the North East area, Jody was hired to work at the North East lab as a skilled technician for Dr. Michael Saunders of the Entomology Department at the University Park campus. From day one, Jody was a passionate researcher for grape growers in the Lake Erie Region and eventually the whole state for almost 15 years (how the time flies!). Her main research has always focused on control methods for the grape berry moth and how this knowledge can be applied to management programs. In that regard she and her technician, Mike Schultz, have spent countless hours each season monitoring berry moth populations on several local commercial farms in the Lake Erie region, and working closely with Andy Muza, Erie County extension, to provide real-time updates on pest pressure for local juice grape growers.
She has also played key roles in the study of a number of invasive pests like Japanese beetle, Multicolored Asian Lady Beetle, Brown Marmorated Stinkbug, Spotted Wing Drosophila, and most recently, Spotted Lanternfly. One of my most memorable moments in working with Jody was my involvement in one of her experiments to taste test stink bug tainted Concord grape juice; one of the reasons I shudder at the mere mention of ‘cilantro’.
Jody’s position was mostly devoted to conducting research but she often played the part of teacher through extension presentations of science-based recommendations for grape growers at regional meetings like the Mid-Atlantic Fruit and Vegetable Convention in Hershey, PA; statewide meetings like the spring grape disease and insect pest workshop; and local extension meetings such as coffee pot meetings and the mid-summer chicken BBQ in the Lake Erie region. Jody is also a world traveler and, having been to many exotic places across the world, she has a unique and heightened perspective that most people only experience through TV and books. I’m sure that she is looking forward to seeing many more places with her husband, Rich, after her retirement. For those of us who worked closely with Jody over the years, she will also be remembered for her hard work ethic, devotion to her family, and her great sense of humor. Jody’s retirement will leave a large hole in our grape team and our efforts to serve the grape growers of Pennsylvania. We wish her well in her retirement.
By Dr. Molly Kelly, Enology Extension Educator, Department of Food Science
As harvest comes to a close we have planned which wines will be going through malolactic fermentation (MLF). This article provides some information to assist you in dealing with a potentially difficult MLF.
Malolactic fermentation (MLF) is a process of chemical change in wine in which L-malic acid is converted to L-lactic acid and carbon dioxide. This process is normally conducted by lactic acid bacteria (LAB) including Oenococcus oeni, Lactobacillus spp. and Pediococcus spp. O.oeni is the organism typically used to conduct MLF due to its tolerance to low pH, high ethanol and SO2. Most commercial strains are designed to produce favorable flavor profiles.
Although inoculation with a commercial starter is recommended, MLF may occur spontaneously. The lag phase associated with spontaneous MLF may increase the risk of spoilage organisms as well as the production of volatile acidity. Inoculation with a LAB culture can help avoid these problems by providing the cell population needed to successfully conduct MLF (more than 2×106 cells/mL). The compatibility of yeast and LAB should be taken into account since failed MLF may be due to incompatibility between these two organisms.
The key to a successful MLF is to manage the process and to monitor the progress. Although there has been extensive research on the MLF process, it may still be difficult to initiate at times. The possible causes of difficult MLF have been studied less extensively than those of stuck/sluggish alcoholic fermentation. In this article, factors that may influence the start and successful completion of MLF will be discussed.
The main chemical properties that influence MLF are well known: pH, temperature, ethanol and SO2 concentration. A study by Vaillant et al (1995) investigating the effects of 11 physico-chemical parameters, identified ethanol, pH and SO2 as having the greatest inhibitory effect on the growth of LAB in wine.
Generally, LAB prefer increased pH’s and usually, minimal growth occurs at pH 3.0. Under winemaking conditions, pH’s above 3.2 are advised. The pH will determine the dominant species of LAB in the must or wine. At a low pH (3.2 to 3.4) O. oeni is the most abundant LAB species, while at higher pH (3.5 to 4.0), Lactobacillus and Pediococcus will out-number Oenococcus.
MLF is generally inhibited by low temperatures. Research demonstrates that MLF occurs faster at temperatures of 200 C (68˚F) and above versus 150C (59˚F) and below. In the absence of SO2 the optimum temperature range for MLF is 23-250C (73.4˚F-77˚F) with maximum malic acid conversion taking place at 20-250C (68˚F-77˚F). However, with increasing SO2 levels, these temperatures decrease and 200C (68˚F) may be more acceptable.
LAB are ethanol-sensitive with slow or no growth occurring at approximately 13.5%. Commercial O. oeni strains are preferred starter cultures due to tolerance to ethanol. The fatty acid composition of the cell membrane of LAB can be impacted by ethanol content.
LAB may be inhibited by the SO2 produced by yeast during alcoholic fermentation. A total SO2 concentration of more than 50 ppm generally limits LAB growth, especially at lower pH where a larger portion of SO2 is in the antimicrobial form. Generally, it is not recommended to add SO2 after alcoholic fermentation if MLF is desired.
Some of the lesser known factors impacting MLF are discussed below.
MLF can be inhibited by medium chain fatty acids (octanoic and decanoic acids) produced by yeast. It is difficult to finish MLF when octanoic acid content is over 25 mg/L and/or decanoic acid is over 5 mg/L. Bacterial strains that tolerate high concentrations of octanoic and decanoic acids may be important in successful MLF. It is important to check your supplier regarding strain specifications. Yeast hulls may be added before the bacteria are inoculated (0.2g/L) to bind fatty acids. Yeast hulls may also supply unsaturated fatty acids, amino acids and assist with CO2 release.
Some fungicide and pesticide residues may negatively impact malolactic bacteria. Residues of systemic pesticides used in humid years to control botrytis can be most detrimental. Care should be taken in harvest years with high incidence of botrytis. Winegrowers should be familiar with sprays used on incoming fruit and also adhere to pre-harvest intervals.
Lees found at the bottom of a tank can become compacted due to hydrostatic pressure, resulting in yeast, bacteria and nutrients being confined to the point that they cannot function properly. Larger tank sizes may contribute to increased delays in the start of MLF. This inhibition of the start of MLF can be remedied by pumping over either on the day of inoculation or on the second day after inoculation of the bacteria.
Alternatively, contact with yeast lees can have a stimulating effect on MLF. Yeast autolysis releases amino acids and vitamins which may serve as nutrients for LAB. Yeast polysaccharides may also detoxify the medium by adsorbing inhibitory compounds. A general recommendation is to stir lees at least weekly to keep LAB and nutrients in suspension.
Residual levels of lysozyme may impact MLF. Follow the supplier’s recommendations regarding the required time delay between lysozyme additions and the inoculation of the commercial MLF culture. Strains of O. oeni are more sensitive to the effects of lysozyme compared to strains of Lactobacillus or Pediococcus.
Malic acid concentration
Malic acid concentrations vary between grape cultivars and may also differ from year to year in the same grape cultivar. MLF becomes increasingly difficult in wines with levels of malic acid below 0.8g/L. In this case a ML starter culture with high malate permease activity or a short activation protocol is recommended. Check with your supplier to ensure that the chosen strain has these attributes if needed.
Wines with levels above 5 g/L malic acid may start MLF, but may not go to completion. This may be due to inhibition of the bacteria by increasing concentrations of L-lactic acid derived from the MLF itself.
Difficult MLF can result from insufficient nutrients necessary for LAB growth. Since yeast can reduce available nutrients for LAB, time of inoculation is important to avoid competition for nutrients. The addition of nutrients when inoculating for MLF is especially important if the must and wine has low nutrient status or if yeast strains with high nutritional requirements are used. The addition of bacterial nutrients can help ensure a rapid start and successful completion of MLF.
Research demonstrates that the longer it takes to initiate MLF, there is a greater risk for Brettanomyces growth. Some inoculate during alcoholic fermentation (AF) to avoid this problem. Co-inoculation involves adding malolactic starter 24 hours after AF starts. By controlling microbial populations, the growth of spoilage organisms such as Brettanomyces may be inhibited.
Note that inorganic nitrogen (diammonium phosphate) cannot be used by LAB. Check with your supplier for the optimum nutrient product for your particular MLF needs.
Malolactic bacteria are sensitive to excessive amounts of oxygen. The bacteria should not be exposed to large amounts of oxygen after AF is complete. Micro-oxygenation may have a positive impact on the completion of MLF. This impact may be due to the gentle stirring associated with micro-oxygenation that keeps LAB and nutrients in suspension rather than the exposure to oxygen itself.
Some red grape cultivars may have difficulty completing a successful MLF. Some varieties that may experience increased MLF problems include Merlot, Tannat and Zinfandel. This may be related to certain grape tannins negatively impacting the growth and survival of LAB.
Polyphenols can have either stimulatory or inhibitory effects on the growth of wine LAB. This effect depends on the type and concentration of polyphenols as well as on the LAB strain. The tannin fraction of wine tends to complex with other compounds, minimizing their inhibitory effects on MLF. However, in wines that contain a large amount of condensed tannins only, LAB are increasingly inhibited.
MLF nutrients containing polysaccharides have been shown to minimize this effect. This may be due to interactions between the polysaccharides and tannins.
MLF difficulties are usually due to a combination of factors. A stuck or sluggish MLF is usually not the result of one factor alone. It is important, therefore, to both understand and manage the MLF process at each step of the winemaking process. Proper measurement of the process is also vital to be aware when MLF is not proceeding as desired.
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Britz, T.J. & Tracey, R.P., 1990. The combination effect of pH, SO2, ethanol and temperature on the growth of Leuconostoc oenos. J. Appl. Bacteriol. 68, 23-3 1.
Costello, P.J., Morrison, R.H., Lee, R.H. & Fleet, G.H., 1983. Numbers and species of lactic acid bacteria in wines during vinification. Food Technol. Aust. 35, 14-18.
Davis, C.R., Wibowo, D., Eschenbruch, R., Lee, T.H. & Fleet, G.H., 1985. Practical implications of malolactic fermentation: a review. Am. J. Enol. Vitic. 36, 290-301.
Henick-Kling, T. & Park, Y.H., 1994. Considerations for the use of yeast and bacterial starter cultures: SO2 and timing of inoculation. Am. J. Enol. Vitic. 45, 464-469.
Henick-Kling, T., 1995. Control of malo-lactic fermentation in wine: energetics, flavour modification and methods of starter culture preparation. J. Appl. Bacteriol. Symp. (suppl) 79, 29S-37S.
Henschke, P.A., 1993. An overview of malolactic fermentation research. Wine Ind. J. 2, 69-79.
Ingram, L.O. & Butke, T.M., 1984. Effects of alcohols on micro-organisms. Adv. Microbiol. Physiol. 25, 254-290.
Krieger, 5., 1993. The use of active dry malolactic starter cultures. Austral. New Zealand Wine md. J. 8, 56-62.
Kreiger-Weber, S. and P. Loubser. 2010. Malolactic fermentation in wine. In Winemaking Problems Solved. C.E. Butzke (ed), pp. 88-89.Woodhead Publishing Limited, Cambridge, UK.
Kreiger-Weber, S., A. Silvano and P. Loubser. 2015. Environmental factors affecting malolactic fermentation. In Malolactic Fermentation-Importance of Wine Lactic Acid Bacteria. In Winemaking. R. Morenzoni and K. Specht (eds), pp.131-145. Lallemand Inc., Montreal, Canada.
Kunkee, R.E., 1967. Malo-lactic fermentation. Adv. Appl. Microbiol. 9, 235-279.
Lafon-Lafourcade, S., Carre, E. & Ribereau-Gayon, P., 1983. Occurrence of lactic acid bacteria during the different stages of vinification and conservation of wines. Appl. Environ. Microbiol. 46, 874-880.
Lonvaud-Funel, A. 2001. Interactions between lactic acid bacteria of wine and phenolic compounds. Nutritional aspects II, synergy between yeast and bacteria, Lallemand Technical Meeting, Perugia, Italy.
Loubser, P.A. 2004. Familiarise yourself with malolactic fermentation. Wynboer Technical Yearbook (a Wineland publication). 5:32-33.
Loubser, P., 2005. Bacterial nutrition – essential for successful malolactic fermentation. Wynboer technical yearbook 2005/2006, pp.95-96.
Malherbe, S., F.F. Bauer and M. du Toit. 2007. Understanding problem fermentations-a review. S. Afr. J. Enol. Vitic. 28(2):169-186. Nel, H.A., Moes, C.J. & Dicks, L.M.T., 2001. Sluggish/stuck malolactic fermentation in Chardonnay: possible causes. Wineland Magazine, Wynboer vol. 144, July, pp.1 13-115.
Nielsen, J.C., Pilatte, E. & Prahl, C., 1996. Maitrise de la fermentation malolactique par l’ensemencement direct du yin. Revue Francaise d’Oenologie 160, 12-15.
Nygaard, M. & Prahl, C., 1996. Compatibility between strains of Saccharomyces cerevisiae and Leuconostoc oenos as an important factor for successful malolactic fermentation. Proc. 4 0, Int. Symp. Cool Climate Vitic. Enol., Rochester, NY.
Renouf, V. and M.L. Murat. 2008. L’utilisation de levains malolactiques pour une meilleure maitrise du risqué Brettanomyces. Rev Enol. 126:11-15.
Renouf, V., S. La Guerche, V. Moine and M. Murat. 2009. Techniques for dealing with awkward malolactic fermentations. Wineland Magazine. pp. 82-85.
Vaillant, H., Formisyn, P. & Gerbaux, V., 1995. Malolactic fermentation of wine: study of the influence of some physico-chemical factors by experimental design assays. J. Appl. Bacteriol. 79, 640-650.
Wibowo, D., Eschenbruch, R., Davis, CR., Fleet, G.H. & Lee, T.H., 1985. Occurrence and growth of lactic acid bacteria in wine: a review. Am. J. Enol. Vitic. 36, 301-313.
Zoecklein, B. 2011. Fermentation considerations for the 2011 season. Enology Notes #159. As found on the Wine/Enology Grape Chemistry website
Bryan Hed, Department of Plant Pathology and Environmental Microbiology, Penn State Extension
With a new season underway, I’d like to talk about some of the recent grape disease research that’s being conducted at Penn State. For this blog, we revisit Grapevine leafroll disease and leaf removal for fruit rot control.
Grapevine leafroll disease or GLD is associated with the presence of phloem inhabiting plant viruses of the family Closteroviridae. These viruses generally cause a degeneration of the primary phloem in shoots, leaves, and cluster stems. There are currently five species of grapevine leafroll-associated viruses; GLRaV-1, 2, 3, 4, and 7, and these viruses, especially GLRaV-1 and 3 have been spread across long distances (worldwide) through the sale and distribution of infected nursery material. Short distance spread of GLRaV-1, 3, and 4, within the vineyard or between adjacent vineyards, can occur by phloem-feeding insect vectors, specifically species of mealybugs and scales. No vectors have yet been discovered for GLRaV-2 and 7, which don’t appear to be as commonly found in northeastern vineyards.
The most obvious symptoms of the disease are cupping and loss of chlorophyll in the leaves in late summer and fall, during the ripening period. On red-fruited varieties, like Vitis vinifera‘Cabernet Franc’, leaves of infected vines can display red coloration of the interveinal tissue, while veins remain green. On white-fruited varieties like Chardonnay, symptoms are less noticeable and leaves tend to look yellowish and cupped. These symptoms are not necessarily diagnostic of the disease and may be confused with symptoms of nutrient deficiencies, water stress, and even crown gall. Therefore confirmation of infection by GLRaVs can only be made in the laboratory through serological or molecular analysis of phloem tissues in leaf petiole or dormant cane samples of suspect vines. More significant, and perhaps less recognized effects of GLD are reduced yield and vegetative growth, and even lower cold hardiness–a factor of critical importance for varieties grown in the northeastern U.S. GLD can also lead to a delay in fruit maturity with negative effects on fruit chemistry at harvest (lower soluble solids, higher titratable acidity), and reduced color development in red grapes of V. vinifera grapevines; all factors that might adversely impact perceived wine quality. Vineyards can be scouted annually for GLD during the ripening period, and tissue samples from symptomatic vines can be sent to a laboratory for confirmation.
There is no curative treatment for GLD as infection by GLRaVs is permanent, and the disease is best managed through removal or roguing of infected vines and replanting with certified virus-free material. So if you’re planning to order vines soon for planting a new Vitis vinifera vineyard next spring, I would strongly suggest the use of certified material. Research has shown that local spread of GLRaV-1, 3, and 4 can be minimized by targeting mobile stages of the vectors (mealybug and soft scale crawlers) with well-timed insecticide applications. There are no known sources of resistance to GLRaVs among Vitis species and these viruses have been found in V. labrusca, to Vitis interspecific hybrids, and V. vinifera. Infections of V. labrusca appear to remain latent or dormant and have not been shown to result in visual symptoms of the disease or economic impact, though research on native varieties has been minimal. On the other hand, V. vinifera is severely affected, and GLD has been shown to result in substantial economic losses among those cultivars.
Grapevine leafroll disease is nothing new to most of the world and symptoms of the disease were noted in French vineyards 165 years ago. But it seems relatively new to the northeastern U.S. grape and wine industry partly because V. vinifera grapevines, the species most dramatically affected, are relatively new to this industry. Therefore, as the acreage of V. vinifera in the northeast continues to expand and become a larger part of the premium wine industry, our encounters and frustrations with GLD will likely increase.
Surveys conducted in New York, Virginia, Ohio, and more recently, Pennsylvania, have confirmed the presence of these viruses throughout the major grape growing regions of the northeast. In Pennsylvania, we began our efforts by conducting an online survey to collect information from grape growers. In July of 2017, a link to a brief online questionnaire was sent out to 105 Pennsylvania wine grape growers across the Commonwealth to collect information about what varieties they grow, whether or not they have seen symptoms of leafroll virus in their vineyards, and if they would be willing to cooperate in the confidential collection of tissue samples from their vineyards blocks for determining the presence of these viruses.
In this initial phase of the project, sample collection focused on four cultivars of Vitis vinifera (Cabernet franc, Pinot noir, Chardonnay, and Riesling) and one French hybrid cultivar, Chambourcin, that were deemed among the most important cultivars in the PA industry. Twenty-eight cooperators were growing these cultivars and were selected for tissue collection. Growers were individually contacted via email and arrangements were made to collect leaf petiole samples from their vineyard blocks. Of these 28 growers, 22 reported they had seen leafroll-like symptoms in their vineyards. In late summer/early fall of 2017, samples were collected from 42 vineyard blocks from 16 locations. Samples were collected from symptomatic and non-symptomatic vines, in a randomized manner, and transported back to the laboratory and stored at 4°C until serological analysis by enzyme-linked immunosorbent assay or ELISA.
Overall, about 36% of the 42 blocks were positive for leafroll virus in 2017. Fourteen percent of the Chambourcin blocks sampled contained vines that tested positive for leafroll virus 1 and/or 3. Amongst the V. vinifera blocks sampled, 39% contained vines that tested positive for leafroll virus 1 and/or 3. Specifically, 29, 38, 42, and 50% of the Riesling, Pinot noir, Chardonnay, and Cabernet franc blocks were positive for leafroll virus, respectively. At one location where we were able to collect data on all four V. vinifera cultivars and where there were many vines positive for leafroll virus among all cultivars, there was a good correlation among red varieties between vines that showed symptoms (red, curled leaves) and vines that tested positive. However, among white varieties (Riesling and Chardonnay) the correlation was poor. This may indicate that it is harder to visually identify suspicious vines among white cultivars than it is among reds.
It appears that grapevine leafroll viruses are widespread and can be found in many grape growing areas of Pennsylvania. Among the varieties sampled in 2017, Cabernet franc was the most heavily infected by the viruses. However, this could change as we plan to expand the survey into more vineyards in 2018 which we were not able to reach in 2017. We also have identified healthy and infected grapevines within the same vineyard. These vineyards can be revisited in subsequent seasons to test disease spread to healthy vines. Furthermore, studies will be performed to test the impact of grapevine leafroll disease on grape quality and productivity in Pennsylvania, with the ultimate goal to mitigate the economic impact of the disease on the PA wine industry.
These surveys are an important and necessary first step toward determining the impact of GLRaVs and their associated disease. These viruses can have a significant impact on vineyard health and fruit quality, especially for those operations invested in the culture of premium V. vinifera. It is therefore essential for academic institutions to continue to develop research programs around this important group of pathogens and create a growing body of information that will help vineyard managers reduce their spread and impact. Below are some references that I drew from for this bit on leafroll viruses and GLD. The last reference is available free, online, and is a great review of GLD by some of the leading experts from New York, California, and Washington.
Bahder, B., Alabi, O., Poojari, S., Walsh, D., and Naidu, R. 2013. A Survey for Grapevine Viruses in Washington State ‘Concord’ (Vitis x labruscana L.) Vineyards. Plant Health Progress, August 5, 2013. American Phytopathological Society (online).
Compendium of Grape Diseases, Disorders, and Pests. 2nd edition, 2015. Editors Wayne F. Wilcox, Walter D. Gubler, and Jerry K. Uyemoto. The American Phytopathological Society. Pp. 118-119.
Naidu RA, Rowhani A, Fuchs M, Golino D, Martelli GP. 2014. Grapevine leafroll: a complex viral disease affecting a high-value fruit crop. Plant Dis. 98: 1172–85. https://www.researchgate.net/publication/270339365_Grapevine_Leafroll_A_Complex_Viral_Disease_Affecting_a_High-Value_Fruit_Crop
More on Botrytis bunch rot/sour rot control from the church of fruit-zone leaf removal
The practice of leaf removal for bunch rot control is based on concepts developed many years ago by lots of research that examined its effects on fruit-zone microclimate, source limitation, and fruit set, among other things. In short, removal of leaves from nodes in the fruit-zone increases sunlight exposure, air circulation, and pesticide penetration to developing fruit. This creates a fruit zone environment that is much less conducive to the development of Botrytis and other harvest-rot-inducing microorganisms that prefer to do their dirty work in darkness, still air and high humidity. Indeed, the most consistently successful bunch rot control programs will not simply rely on Botrytis specific fungicides but will integrate cultural methods like fruit-zone leaf removal
Fruit-zone leaf removal has generally been applied between fruit set and veraison. But there is a growing body of information being developed around early fruit zone leaf removal(ELR) and its effects on the development of Botrytis bunch rot and sour rot. ELR is the removal of leaves in the fruit zone before, or at the beginning of, bloom, and interest in this area of research has increased in several areas of the world in recent years. For example, recent research in Italy by Stefano Poni and his colleagues details the effects of ELR on crop load management, fruit and wine quality, and disease control, especially for late season bunch rots. Here in the U.S., research to study the effects of ELR is being conducted in places like Michigan, Pennsylvania, and New York, among other areas. But why is there added interest in ELR for bunch rot control?
In addition to fruit zone environment, cluster compactness plays a large role in harvest rot development. A three-year study we conducted with Vignoles over 15 years ago clearly showed that the more compact the cluster (measured as the number of berries per length of the cluster), the more rot we observed developing in that cluster. It’s no accident that many of the most bunch rot susceptible varieties typically produce clusters of tight or compact architecture (Chardonnay, Pinot gris, Pinot noir, Riesling, Vignoles). The removal of the most mature, photosynthetically active leaves (those in the fruit zone) before or during bloom, starves the inflorescences for sugars and reduces the number of flowers that set fruit. Fewer berries per cluster generally result in looser clusters that develop less bunch rot. Taken together, ELR combines the benefits of an improved fruit zone environment with less susceptible clusters and generally greater reductions in bunch rot development than what would be achieved with post fruit set leaf removal (which would not, theoretically, reduce cluster compactness). When we examined ELR for six consecutive seasons in our experimental Chardonnay vineyard, we found that we could eliminate two Botrytis-specific fungicide sprays and achieve harvest rot control that was equivalent to, or better than, a full Botrytis spray program (four sprays). This adds to the appeal of ELR as Botrytis fungicides are often the most expensive fungicide inputs in rot control programs, and reducing chemical pesticide inputs is a significant response to the growing public interest in agricultural products with a healthier profile (though some may debate how relevant a healthier profile is to the consumption of wine!).
But there are potential drawbacks to ELR (it’s always something). For example, the reduction in berry number per cluster generally results in a reduction in cluster weight that can result in a reduction in yield. This can be a downside to ELR in operations where yield reduction is unacceptable to production goals. However, over the course of the six years in our Chardonnay experiment, we were able to minimize or eliminate yield reduction by ELR, while maintaining bunch rot reductions. So reductions in yield by ELR can be managed to some extent. Also, in our experience, ELR seemed more effective on some varieties (Chardonnay and Vignoles) than others (Pinots?) in terms of reducing compactness and bunch rot. There were also seasonal variations from year to year. So there is some level of inconsistency with this method; sometimes the rot reductions are statistically significant and sometimes they aren’t.
More recently, research with ELR has been taken a step further to examine the mechanization of this practice; manual leaf removal is expensive and time-consuming, and timing can be critical. Experiments over the past several years in Europe and the U.S. have shown that the use of air pulse leaf removal technology can remove enough fruit zone leaf area (about 35-50% of that which would be achieved by hand removal (100%)) to mimic the effects of manual leaf removal. As we expected, this technology appears to work most efficiently (removes the most leaf tissue in the fruit-zone) on more upright, two-dimensional training systems like vertical shoot position (VSP) or four-arm kniffen systems, when compared to more three-dimensional training systems like single, high-wire, no-tie systems. Mechanization is often the key to greater adoption of a practice, but only if it improves economic sustainability. An air pulse leaf removal system can represent an investment of tens of thousands of dollars. This would hardly be cost-effective for operations with just a few acres to treat per season. However, large farms that have lots of acres to treat may benefit through mechanization of ELR. Also, in regions where there is a concentration of wine grape acreage (ie, the Lake Erie region, Finger Lakes, etc), this machinery could be shared, or the work contracted, to ease the capital investment necessary on a per farm basis.
So ELR is not a silver bullet. I would instead consider it some buckshot in a silver shotgun shell that is still under development; it can be an important component of an effective, integrated bunch rot control program. If you have bunch rot susceptible varieties such as those mentioned above, and would like to apply this practice in your vineyard, I would recommend you test it out on a few vines first and compare the results to the rest of your vineyard (all other things being equal) to see if this is something that will work for you. As I mentioned above, the results may vary somewhat from one variety to the next and from one season to the next.
And one last thing for wine grape growers with sour rot susceptible varieties: please review Wayne Wilcox’ newsletter from last year (June 2017) regarding the Cornell research on sour rot control. Wayne’s graduate student, Dr. Megan Hall, completed some groundbreaking work on the biology of grape sour rot and the development of effective ways to minimize it by targeting fruit flies in the vineyard.
Updated dates and locations: Upcoming regional meetings with winemakers to meet Molly Kelly, Penn State Enology Extension Educator
The dates and locations for the state-wide meetings with the new enology extension educator, Molly Kelly, have been finalized:
- Northeast: April 5, 2018 Nimble Hill Winery, 219 Windswept Lane, Mehoopany, PA 18629 (Updated address)
- Southwest: April 25, 2018, Glades Pike Winery, 2208 Glades Pike (Rt. 31), Somerset, PA 15501
- South Central: April 26, 2018, Penn State Fruit Research and Extension Center, 290 University Dr., Biglerville, PA 17307
- Northwest: May 3, 2018, **Change in location: South Shore Winery, 1120 Freeport Rd. Rt. 89, Northeast, PA 16428
- Southeast: May 9th, 2018, Clover Hill Vineyards and Winery, 9850 Newtown Road, Breinigsville, PA 18031
All sessions will be from 1:00 pm-4:00 pm.
Please contact Molly at email@example.com if you have any questions.
Please register by clicking on the link. https://extension.psu.edu/wine-faults-sensory-training-meetings (if link does not open, copy and paste into your browser’s address bar).
These sessions will include wine faults sensory training, a question and answer period and a tour of the host winery (if applicable). Attendees are also invited to bring one bottle of cellared wine to be assessed blindly by the group.
Sessions in Biglerville and Erie will include an additional optional sensory session with researchers from Penn State. They will be running a short sensory exercise after the meet and greet. They are studying the sensory characteristics of white wines in Pennsylvania and hope to survey wine professionals in order to compare responses with wine consumers. Your input will assist with important research that will directly impact the Pennsylvania wine industry.
These meetings are FREE!
We hope that you can join us and I look forward to meeting all of you!
By: Denise M. Gardner
While I know this has reached many of you, I would like to announce that my last day with Penn State Extension will be on September 1, 2017. After 6 and half years with Penn State Extension, I have decided to start a new venture and open ‘Denise Gardner Winemaking,’ a wine consulting business for wine producers and consumers.
While I had the opportunity to speak briefly about this decision at the 2017 PWA Annual Conference, I wanted to take some time to reflect upon my time at Penn State and my perspective on what I’ve seen change since I joined the Extension team in 2011.
Most of my interest in wine grapes and enology is affiliated with the mentorship provided by Mark Chien, Penn State’s previous Extension Viticulturist, and Joanne Levengood from Manatawny Creek Winery. The two of them worked a lot with me as a young high school student interested in the wine industry. Eventually, they helped me execute a research project pertaining to red wine color stability, and my success affiliated with that project provided me with an opportunity to work for Lallemand as a student intern in Toulouse, France the summer before I started college. Mark wrote about this story in one of his many newsletters in 2003. However, I will never forget the shock and disbelief I felt when I opened up a letter from Mark with an attached check containing a list of the Pennsylvania wineries that had financially contributed to support my travel costs associated with the internship. This act of kindness and support from so many local wineries that did not know me made an everlasting impression on me, and it had been my goal from that day forward to return to the Pennsylvania wine industry.
I share this story now to remind everyone how impressionable young adults are and the impact we can make on shaping their careers and futures. As I leave Penn State, I recognize that one of the greatest awards affiliated with this position was the opportunity to work alongside so many talented young adults while they were students at the University. Their involvement with Extension not only helped me manage the five year NE-1020 variety trial research project, but it also gave me an opportunity to expose many students to this industry. While many of them may not know their final career destination, I truly believe they have all been worth the grant funds, the introductions, the internships and co-ops, and the time that many of us have allocated towards developing their professional careers. Mentorship will definitely help shape our industry if we take the time to make it a priority, and I am excited to see where these young minds eventually lead us if they continue to integrate back into the wine industry. I hope many of them stay in the field, as I truly believe that in order for the industry to grow, stay competitive and progress, we will need their education, experience and application.
I am also proud of the educational workshops that have been developed since 2011 to address wine production and quality issues. While wine quality starts in the vineyard, its quality ends in the winery, and I am overjoyed to have been a part of the educational process that has assisted several winery operations within the state. The Wine Quality Improvement (WQI) Short Course, originally started by Dr. Stephen Menke and managed in interim by Mario Mazza, has reached almost half of the wineries in Pennsylvania through its attendance. It has always been a pleasure to hear about how this program has influenced those that have participated, and I would like to publically thank all of the previous students, both undergraduate and graduate, that have contributed to the success of the short course, as well as my industry volunteers: Mario Mazza, Jamie Williams, and Virginia Mitchell. Without their contributing time and patience, the success of the WQI would not be where it is today.
Finally, there is undeniably a wonderful team of individuals here at Penn State that works very hard to address industry questions and needs. Dr. Michela Centinari, Dr. Ryan Elias, Bryan Hed, Dr. Helene Hopfer, Dr. Kathy Kelley, Andy Muza, and Jody Timer, as well as Dr. Rob Crassweller, Mike Masiuk, and Dr. Michael Saunders are all committed to the success of making the wine industry and Penn State a lifelong collaboration. It was not an easy decision to leave this stellar group of people. I hope that you, as industry members, will continue to support them as the program should only evolve and grow from here. As the enologist in the group, I was fortunate enough to have a supportive and thought-provoking advisory committee. I hope that many of you will consider supporting the next enologist by serving on their own advisory committee in an effort to keep this growing program a part of Pennsylvania’s industry and academic communities.
Between the growth of our academic team and the involvement of students in industry-related research, Pennsylvania has shown well within the research spectrum. I have been very proud of all of the Penn State students that have taken their research and presented at state-wide, regional, and national conferences. Additionally, the research executed by our faculty is top notch. While the benefits of research may not always be immediately apparent, the caliber of research and outreach associated with students and faculty has helped make Pennsylvania’s industry recognizable at a national scale. Sometimes that recognition is small and other times it is monumental. With the financial support of the PA Wine Marketing and Research Board, I hope that we will continue to see the collaboration between industry and academia continue, as well as witness the growth and seriousness of the state’s industry and academic programs. After all, no great wine region has ever succeeded without the arms of science, education, and research coming together.
I have learned that research helps us grow and get better as an industry. It can be slow, yes, but it shows us that we do not know it all after all, and it allows us to adapt to changing conditions like new pest integration in the vineyard or high pH winemaking practices. I hope I see many of you at the American Society of Enology and Viticulture – Eastern Section (ASEV-ES) Conference in Pennsylvania next year. This conference is a forum for regional research, but it also creates networking opportunities, highlights the wine quality affiliated with the hosting state, and includes a focused workshop on an industry relevant topic. For the 2018 conference, we believe the focused workshop will be related to high pH in the vineyard and cellar and how to address those problems. For the number of Pennsylvania wineries that contribute financially to support ASEV-ES scholarships, I thank you for supporting so many of our students, especially those at Penn State that I have seen benefit from these awards. No contribution – large or small – goes unnoticed.
For those that are concerned about the nature of the position, Penn State Extension is committed to the position, and the current job opening it is already posted on the Penn State jobs website. Please support the next hire! I know the team will find an amazing individual to fulfill this role, and I’m looking forward to all that they accomplish with the position.
My last day with Penn State Extension will be on September 1, 2017, but I hope I will not lose touch with many of you through the transition. I will continue to run this message through the next few V&E News email distributions, but you can also find the generation of Denise Gardner Winemaking on Facebook (www.facebook.com/GardnerDeniseM/) until the website’s (www.denisegardnerwinemaking.com) launch in September and reach my by email: firstname.lastname@example.org. This new venture will definitely be unique, and I hope many of you will consider exploring it in the coming months ahead as I am staying focused on Eastern, Southern and Midwestern production practices. Despite this transition, I will continue to work out of Pennsylvania and am hopeful that this new venture will be applicable for many of the local and regional wineries.
Again, it has been a pleasure working alongside many of you and I thank you for making me a valuable part of this industry. I wish you all a fruitful growing season and a successful 2017 harvest. I can’t wait to taste the vintage!
By: Jody Timer, Entomology & Lake Erie Regional Grape Research and Extension Center
Over the last ten years there have been an inpouring of newcomers to the insect community of Pennsylvania’s grape vineyards. These pest, combined with the numerous indigenous pest, have created an ever evolving challenge for the area’s grape growers. In this blog, I will briefly review the grape pest which I feel are becoming ever increasingly problematic for grape growers to control.
The Spotted wing drosophila has become a progressively severe problem in blueberries raspberries, and grapes. Recent research has shown that they are attracted to all cultivars of grapes that we tested. Spotted wing Drosophila, Drosophila suzukii, Matsumura (Diptera: Drosophilae) (SWD) is an invasive vinegar fly of East Asian origin, that was recently introduced into the United States. It was first found in California in 2008 and is now found in all major fruit-growing regions of the country including Pennsylvania. It was first discovered in Pennsylvania’s Lake Erie grape growing region in the late fall of 2011. The potential infestation rate of spotted wing Drosophila differs from other vinegar flies because the female possess a serrated ovipositor that cuts into healthy fruit to lay eggs. Consequently, spotted wing Drosophila (SWD) larvae can be found in fruit that is just ripening: https://youtu.be/dPr61VC2gyo
During egg-laying, it is believed that sour rot and fungal disease can also be introduced, further affecting the fruit quality. During peak temperatures, a female can lay more than 100 eggs a day. Such a high reproduction rate indicates the SWDs’ high potential for fruit infestation and their potential for spreading rapidly through a field or a vineyard. Because of this prolificity it has become increasing important to protect wine grapes starting at veraison. A good YouTube video on how to identify SWD damage is: https://youtu.be/DLNDnMMfWfs
In our research we have seen SWD showing up earlier in the spring each season and their numbers increasing yearly. SWD do attack injured grapes before non-injured, they tend to wait till veraison before attacking grapes, and they will reproduce in fallen berries. For this reason it is important to keep your vineyards as clean as possible and to maintain coverage of these wine grapes through harvest. Trapping and forecasting can lead to improvements in grower’s capability to optimally time pest management decisions which should reduce both the direct cost of pesticide treatments and the indirect cost to wineries. Information can also be found at:
The brown marmorated stink bug (BMSB) is currently a very serious pest in tree fruits and vegetables, and can be a nuisance when they overwinter in houses. Although BMSB prefer other fruits and vegetables to grapes, they do feed on grapes. Their damage can cause ugly scars on table grapes and grapes grown for sale at fruit stands. This type of damage is not important to wine grape and juice grape growers, however, the holes open pathways for fungal and bacteria late season infections. This season, in the Lake Erie region, we have begun to see a small number of BMSB damaged grapes. BMSB may also be easily harvest with the grapes. The insects tend to move to the interior of the cluster when disturbed and are hard to see. When they are killed they give off a foul odor – which is how they got their name. Our research has shown that this odor and resulting taste do survive the pasteurization of juice grapes, but disappears after being stored for longer periods of time. There is conflicting research on whether this taint transfers to wine, more research is ongoing. There are traps commercially available to trap these insect, but their efficacy is very low. BMSB have been found in both grape foliage and grape clusters; they seek the moisture, sugar, and warmth on the inside the clusters (especially overnight) and they often migrate to the cluster’s interior close to harvest. This makes the possibility of BMSB inside the cluster very likely when these grapes are mechanically harvested and transported to the processor.
With the yearly increase of numbers of BMSB in the Pennsylvania vineyards, it is very important for growers to scout for the adults and the presence of the eggs on the underside of grape leaves. There are one to two generations in Pennsylvania. A compilation of research can be accessed at www.STOPBMSB.org
The newest invasive poised to become a major problem to grape growers, the spotted lanternfly (SLF), Lycorma delicatula, (Hemiptera: Fulgoridae) is native to China, India, Japan, and Vietnam and has been detected for the first time in the United States in northeastern Berks County, Pennsylvania. This approximately one inch long insect with piercing-sucking mouthparts has the potential to impact the green industry, grape growers, tree fruit growers, and the forests and wood products industries in Pennsylvania as well as the United States. The host plants of the SLF in its native habitat include grapes, pines, stone fruits, and up to 50 other hosts. Early detection of the SLF is critical for effective control and protection of Pennsylvania’s agriculture and its related businesses. SLF group feeds on grapevines in numbers great enough to cause destruction of the entire grapevine. Grapes are listed as a primary host in its native regions. To date this insect has been confined to areas of Berks and Bucks counties in Pennsylvania. The PDA has issued a general order of quarantine for these areas over the past few years, however this insect is slowly increasing its range.
The following is a link to the PDA’s information on the SLF: www.pda.state.pa.us/spottedlanternfly. You may find a link to a pdf copy of the SLF Order of Quarantine, a PowerPoint on Lycorma Inspection Tips, and the SLF Pest Alert at this website.
What to do if you:
- See eggs: Scrape them off the tree or smooth surface and place the eggs in a tightly sealed container with 70% alcohol or hand sanitizer to kill them.
- Collect a specimen: Send the adult/nymph specimen or egg mass to the PDA Entomology Lab for verification. The mailing address for the lab is: PDA, Entomology Room-111, 2301 N. Cameron St., Harrisburg, PA 17110. First, place the sample collected in 70% rubbing alcohol or hand sanitizer in a leak proof container. Complete the PDA Entomology Program Sample Submission Form. This sample form can be found in the PDA SLF website www.pda.state.pa.us/spottedlanternfly.
- Report a site: Call the Bad Bug hotline at 1-866-253-7189 with details of the sighting and your contact information.
The most destructive insect pest in the Lake Erie region remains the native Grape Berry Moth (GBM), Paralobesia viteana. This insect is becoming increasingly harder to control as result of shorter residual time of insecticides, resistance to insecticides, and abandoned vineyards. GBM larval burrow into the grape berry soon after hatching, making precise timing of spray applications a critical component of control. This insect has four generations per year. Each generation increases in number exponentially if control measures are not applied to the early generations. Spray timings can be calculated by following the NEWA model recommendations (see earlier posts). Growing seasons with large populations of GBM, will require a second spray in July and/or August to control the populations, and to prevent them from moving farther into the vineyards. Scouting for GBM damage often during the season is a critical component of control, as the pheromone traps capture only the males and are not a good indicator of infestation after the first generation. More information can be found on extension pages and on the LERGP Podcasts on Youtube.
By Dr. Kathy Kelley
I have been fortunate over the past few years to co-lead groups of Penn State undergraduates on a two-week experience in Paris, France, with the goal of comparing U.S. and French agriculture and food systems. The students learn about U.S. systems from Penn State experts during the spring semester and then they learn about the French systems when abroad in mid-May. Grape and wine production happens to be one of the topics they study, and they get an opportunity to not only visit a vineyard and winery in Pennsylvania but a couple of operations in the Champagne region. On my time off I visit wine shops and look for wine-related “things” that may be of interest to you, our blog readers. What follows is a bit of what I have seen so far on my trip.
Learning about Wine in High School
One of the stops we took the Penn State students to in the Champagne region was an agricultural high school (Lycée Agroviticole – Crézancy; http://bit.ly/2qyL40l). The school was founded in 1870 and is just one of several schools that teach students about farm management. Some of the students who have an interest in becoming winemakers, along with high school graduates who seek viticulture and enology training, are responsible for the vineyards and grow the three main wine grapes used to make Champagne (Chardonnay, Pinot Noir, and Pinot Meunier).
In addition to learning about grape production, the students also learn the multi-step process of making Champagne and are involved in all steps of the process.
Under the direction of a cellar master, the students’ final product is labeled and available for purchase. Selections, with the price in U.S. dollars, include Brut Tradition ($15.00), Brut Blanc de Blanc ($16.30), Brut Rose ($16.75), Demi-Sec Tradition ($15.73), and Euphrasie Millesime 2008 ($21.35) (http://bit.ly/2rljEMQ). A product that is now available, but was not in 2015 when I last visited with a group, is Brut Terroir – their organic option ($19.11).
Champagne can be purchased online as well as from the cellar at the school. A building is currently being converted into a retail space that the students will operate. Students interested in Champagne production also attend conferences, participate in judging events, and co-host events for the industry.
A 20,000 Euro ($22,474.74) Bottle of Wine
I am drawn to retail establishments and really enjoy observing how products are displayed, how the space is used, and the overall “feel” of the store. While Paris has many wine shops and places to buy wine (even a wine shop where no French wine is sold/served (http://soifdailleurs.com), I enjoy visiting La Cava at the Lafayette Gourmet near the Opera Garnier in the 9th Arrondissement (http://bit.ly/2rkwriQ) because it is in the midst of a supermarket in the basement of a department store and it is staged as if it were a museum. It is roomy, security guards are staged at the entrances, and the lighting highlights certain pieces (wines).
There are approximately 2,500 labels, of which almost half are from Bordeaux. Each time I visit I look for the most expensive wine available for purchase. Though I found a few bottles that were priced over 2,000 euro (approx. $2,250 U.S.), I also found a few 750 mL bottles that were just a bit more: a 1945 Chateau Latour (Bordeaux), which Parker awarded a 90/100 and Wine Spectator a 100/100 (http://bit.ly/2rTOKs6), that sells for 12,900 euros (approx. $14,500 U.S.) and an 1899 Chateau d’Yquem (Bordeaux) for 20,000 euros (approx. $22,500), which Wine Spectator awarded a 91/100 (http://bit.ly/2qjseYs). However, if those prices seem a little steep, do not forget that you can request a VAT tax refund when you leave the country, which for the Chateau d’Yquem is 2,400 euros (approx. $26,900 U.S.).
Another shop that I visit when in Paris is Lavinia (located in the 1st Arrondissement, http://bit.ly/2qnVah7). The business was established in 1999, has over 6,500 labels (including selections from the U.S.), and is often referred to as the Europe’s largest wine store.
“La Cave” is in the basement level and houses rare and expensive wines. In order to access the wines in this section, you will need to ask a staff member to open the door with a code, after which they will accompany you while you make your selection, and then they will bring the bottle to the cashier. This is the one section of the store where it is forbidden to take photos of the bottles in an effort to minimize any exposure to excessive light from a camera’s flash.
After walking around both floors you may be interested in having a meal in the restaurant. If you are interested in learning what wines pair with items on the menu you need only look at the display outside the dining room, find the particular food item (e.g., salad, cheese, a specific entrée), and refer to what wines are positioned in the column under the photo. If you would like to taste a particular wine, ask for a card (deposit of 3 euros), load 10 euros or more onto the card, and insert it into one of four machines that will dispense a select number of reds, rose, or white wines, all for 1.10 euro to 9.60 euro per 3 cl (1 fluid ounce).
As you can imagine with a city the size of Paris – the number of options for getting a glass or bottle of wine is immense. If Paris is on your list of places to see, or if it is time for you to visit again, be sure to investigate what bars, restaurants, shops, and tastings you would like to experience. While many establishments are well known and marked there are also a number of speakeasies in the city that deserve a visit, one of which is Lavomatic (https://www.lavomatic.paris).
Lavomatic is a working laundry mat with a secret door hidden behind one of the dryers. After you push the “start” button on the dryer and pull the door to open it- you will find a dark staircase that leads up to a small bar with a few small seating areas including a few swings that hang from the ceiling.
Until next time…