PROCEEDINGS OHIO ••WI SHOR

1985

OHIO AGRICULTURAL RESEARCH AND DEVELOPMENT CENTER WOOSTER, OHIO This page intentionally blank. CONTENTS

CLEANING AND SANITIZING OF WINERY EQUIPMENT Dan Robinson & Susan Read ...... •....•..•...•...... •..••..•.. 1 BREEDING GRAPES FOR COLD HARDINESS AND QUALITY James N. Moore ...... • . . • ...... • . • • . . . • . . • . • . • . . • . . . • 3 AN OVERVIEW OF ENOLOGICAL RESEARCH IN CALIFORNIA Ra 1 ph Kunkee ...... ••.•.•....•...••.•.•••.•...••.•...... •• 7 GRAPE PHYLLOXERA: AN OVERVIEW OF NEW CONCERN WORLDWIDE Roger N. Williams & Daniel M. Pavuk ...... ••••.•...•..•••... 11 STEPS TO PRODUCING HIGH QUALITY LABRUSCA WINES Daniel Robinson ...... •...•.....••...•.•.....•..•.•.... 16 PRINCIPLES OF SULFUR DIOXIDE ADDITION Jim-Wen R. Liu &James F. Gallander ..•.•.•.••...... •.•••...•. 21 VINEYARD MECHANIZATION - IT'S EFFECT ON YIELD AND QUALITY Justin R. Morris ...... •.•...•..••.•...... •...... 26 AN UPDATE ON FEDERAL RULES AND REGULATIONS PERTAINING TO·WINES Renee Romberger Breen ...... •...... ••...•.••• 36 EVALUATION OF AN ELECTRONIC BLACK ROT DISEASE PREDICTOR IN COMMERCIAL GRAPE VINEYARDS M.A. Ellis, L.V. Madden, & L.L. Wilson ...... 41 WHITE WINE QUALITY AS INFLUENCED BY MUST CLARIFICATION James F. Gallander ...... ••...•..•.....•..••••••.•. 45 SOURCE-SINK RELATIONSHIPS IN THE GRAPEVINE Marti n L . Ka p s ...... •..••...••••••.••.•...•...•.•• 48 RESULTS OF PRESERVING FRESHLY PRESSED GRAPE JUICE R.R. Breen, K.L. Wilker, J.F. Gallander & J.F. Stetson .•...•• 55 NEW APPROACHES TO WHITE TABLE WINE PRODUCTION Ra 1ph Kunkee .....•....•...... •....•.••••••..••.....••.•.••..• 64 OVERVIEW OF VITICULTURE AND GRAPE UTILIZATION RESEARCH AT THE UNIVERSITY OF ARKANSAS Justin R. Morris ...... •...... •...... •.•...... •...... •• 67 AN OVERVIEW OF WINERY SANITATION Susan Read .....•.••.....•...... •...•.•.•....•••...... •.• 84 THE DEVELOPMENT OF AN INTEGRATED PEST t~NAGEMENT PROGRAM FOR OHIO VINEYARDS Daniel M. Pavuk & Roger N. Williams •.•..•...... •...... •...• 92 GRAPE CULTIVAR RESEARCH G. A. Cahoon ...... •...••...... •. 94 PREFACE Approximately 150 persons attended the 1985 Ohio Grape-Wine Short Course, which was held at the Fawcett Center for Tomorrow, The Ohio State University, Columbus, Ohio, on February 18-20. Those attending were from 10 states not including Ohio and represented many areas of the grape and wine industry. This course was sponsored by the Department of Horticulture, The Ohio State University in cooperation with Ohio Agricultural Research and Development Center, Ohio Cooperative Extension Service, Ohio Wine Producers Association, and Ohio Grape Industries Committee.

All publications of the Ohio Agricultural Research and Development Center are available to all on a nondiscrimdnatory basis without regard to race, color, national origin, sex, or religious affiliation. 10/85-lM CLEANING AND SANITIZING OF WINERY 1:!12UIPMENT Dan Robinson & Susan Read Widrrer 's Wine Cellars, Naples, NY Canandaigua Wine Co., Canandaigua, NY

No matter the size of a winery, good manufacturing practices pertain to all. The following areas are a must for everyone in order to have an effective sanita­ tion program.

Harvesting Equiprrent should be cleaned with high pressure fresh water. Mechanical harvesters should be hosed down at the end of each day's picking. Bins should be hosed dc:Mn at the crushing station irmrediately after being dumped. Where fruit is to remain in the bins for an extended period of time, a dilute chlorine (15 ppn) rinse is also a good idea. Crushers and presses should be washed free of all visible debris at the end of each day. All stems and pomace should be removed from the processing area to avoid build-up of fruit flies. If switching from high color reds to whites, the press cloths and working surfaces should be bleached out with strong chlorine solutions--about .5% chlorine.

Pumps should be flushed and drained after each use. Sanitation is incor­ porated with the lines and hoses.

Lines, Hoses, and Non-Wood Tanks should be cleaned with 3% caustic soda solu­ tions and rinsed with dilute chlorine. Circulation through the lines is suffi­ cient, but high pressure tank washers are useful for tanks too large to scrub. The caustic solution can generally be re-used until it loses its slippery feel. A precautionary filter to eliminate grit from damaging tank washers should be instal­ led between the Pl.lf!P and the washer.

Floors should be swept to remove large debris and then can be kept clean with immediate flushing with fresh water and scrubbing with dilute chlorine solutions. Where heavy stains persist, high pressure spray of caustic/chlorine mixtures is ef­ fective in cleaning concrete. HTH is not an abrasive cleanser and is very expen­ sive if used as such. It should be dissolved and the solution used. Direct sprin­ kling of the product and hosing can cause particles to cling to stainless steel and corrode it severely. Avoid puddles by using a squeegee or wet/dry vacuum cleaner.

Heat Changers for chilling juices or fermenting wines are rapidly scaled with tartrates. A 3% caustic wash at the end of each shift, or whenever operating pres­ sures rise, will rapidly remove the tartrates. This is inportant because they act at insulation and decrease the efficiency of the chilling.

Centrifuges can be ignored because no one presently owns one.

Diatomaceous Earth Filters with polypropolene cloths can be cleaned and sterilized without being removed from the plates, a laborious task, by circulating 3% caustic soda through them, then sterilizing with so2;citric acid solution. We generally use five pounds of citric acid per 1,000 gallons and 200 ppm so2• The outside of the cloths do not get cleaned arrl can be rooldy and acetic. They can be washed with fresh water and sprayed with chlorine solutions.

1 Wooden Storage Tanks can be cleaned with tank washers using "the winery special", a solution of 20% concentration of 90% sodium carbonate (soda ash) and 10% sodium hydroxide (caustic soda). After cleaning low pH so2 solutions at 200 ppm S02 will preserve the tank if it is kept completely full. The low pH is in­ sured oy either adding liquid so2 to the wat~r or a rrdxture of citric acid and potassium metabisulfite. Chlorine, as a strong oxidizing agent, is not recommended for wood. On tank exteriors it can be used for killing molds and can be followed with a spray of Quaternary Amine sanitizers on the exterior only for a residual fungicidal effect. The "O'Sullivan" preparations do work, rut it is irrportant that the surface be very clean before application. Linseed oil is great mold food, don't use it. Small barrels can be stored by burning sulfur strips inside until all oxygen is consumed. Be careful to have a cup under the hanger to catch drips.

Bottling Sheet Filters should be kept clean and free of deposits that may har­ bor microorganisms. When packed with pads, the filters may be maintained overnight with a strong citric acid (50 lb/100 gal) and 200 ppm so2 solution inside the fil­ ter and lines. This can be flushed out with fresh water and saved for the next night. The water can then be pushed out with the wine. When the pads are blocked, a 3% caustic solution is circulated through the lines for about 20 minutes. This solution can also be saved and re-used. It breaks down the pads, rut they are to be thrown out anyhow. It loosens soil on the plates so that when the filter is opened the soil can be removed with light scrubbing and washed down with fresh water.

Bottling Tanks rarely need high pressure soil removal because they contain only clean wine. They should be washed with spray balls using warm water im­ mediately after emptying. They can then be rinsed with a dilute solution (15 ppm chlorine) of sodium hypochlorite, drained and left open.

Membrane Filters and Fillers can be kept clean by hot water only if it is used for sterilization before starting operations and flushed clean at the end of each day. We use 190 degree water for about 25 minutes each morning to sterilize and for about 5 minutes to clean up at the end of each day. If these filters are to be stored for a period, a "packing solution" of approximately two pounds citric acid and five ounces sorbic acid to 50 gallons water can be used. During each break, we spray the filler spigots with a 25 ppm Iodophore spray from a squirt bottle. This is allowed to drop off during the break and not washed before beginning bottling again. We find no residues in even the first bottle filled after the break because the amount used is so small.

All Processing Buildings should be kept clean and free of debris or standing water. If fruit flies develop, they can be controlled with fogging using pyreth­ rins, a food-grade insecticide.

Keep in mind the safety of the worker. Some of the chemicals used can be dan­ gerous if rrdsused. Proper instruction on making and disposal of cleaning solutions is a must. Provide proper equipment such as gloves, boots and goggles. And by all means, reinforce your program with regular inspections and positive attitudes.

2 BREEDING GR\PES FOR COLD HARDINESS AND QUALITY

James N. Moore Department of Horticulture & Forestry University of Arkansas Fayetteville, Arkansas

The rr:ost important grape sp:cies in the world, Vi tis vinifera L., is believed to have originated in the region between the Black and Caspian Seas. In its early evolution in this region, and later around the Mediterranean region, it experienced 1i ttle selection pressure for cold tolerance. Most rrodern culti vars of V. vinifera will be injuroo by tercperatures lower than -20°C, even for a short period"-of tiJ:IE. 'I'hi s cola sensi ti vi ty of derivatives of V. vini fer a offers a great challenge to breeders attempting to develop grape cultivars for-colder regions of the world, since V. vinifera is the standard of quality for both fresh fruit and wine.

While cultivar:s of V. vinifera proved to be well adapted to areas of California, atten:pts by early colonists to grow vinifera grapes in eastern North .A.rrerica failed. These repeated failures can be attriooted to a combination of la-:::k of resistance to diseases and insects and to susceptibility to low winter tempera­ tures. The use of modern pesticides has at least partially overcome the pest bar­ rier, allov1ing the production of vinifera grapes in sorre areas in eastern U.s., b..1t the limitation imposed by winter cold still remains.

~en it becorres obvious to the early settlers of North AJ:Ierica that insurmoun­ table obstacles existed fer the cultivation of the Old World grapes, they slowly began to consider the native i'\.rrerican species, which abounded everywhere. While these native species could be grown very easily, their quality left something to be dc:£ired. In most species, the skms were thick and tough, separating readily from the flesh but leaving a pulpy flesh from which t..'1e seeds did not readily separate. Generally, the sugar content was low, and acidity, especially around the set."'<'ls, was high. Many had strong objectionable flavors, in contrast to the rich vinous flavor of the vinifera. It was apparent that arrelioration of these objectionable charac­ ters by hybridizing with the high qmlity cult.ivars of v. vir:ifera was nee::ied.

One of the first grape breeders to practice intersr;ecific hybridization be­ cween V. vinifera and AJ:Ierican grapes species was Edward S. Rogers of Massachusetts, who was active in grape breeding in the mid-1800's. Rogers hybrids \~!ere primarily from v. labruxca x V. vinifera. t·1any of his hybrids were widely planted for a time arrl· one 'Agawam""'; still remains. The major contribution of Rogers was not so much the varieties he de\~loped, bJt that v. vinifera could be valuable in hybridization to contrioote fruit quality. A contercporary of Roger:s, George w. Canpbell of Ohio, also hybridized v. labrusca with v. vinifera. His 'CaiP'pbell Early' is still an important cultivated variety as well as a g-ood parent in grape breL~ing. Many other private breeders, too nUJ:Ierous to mention here, con­ tril:ute::i to native grap:; irnproverrent during the 19th Century. Two, hO'Never, deserve rrention because of their efforts to breed cold hardy cultivars. Charles .Arnold of Canada and Louis Suelter of Minnesota indeperrlently demonstrated the value of the riverbank grape, V. riparia Michx. (V. vulpina L.) for contributing resistance to extreme winter temperatures. The latter developed 'Beta', a v. riparia x 'Concord' hybrid, which was subsequently used extensively in further breeding. More recent breeders who made improvements in developing cold-hardy grapes through the use of v. riparia are M.J. Dorsey, A. N. Wilcox, and E.P. Swenson of Minnesota and N:E. Hansen and R.M. Peterson of South Dakota. These 20th

3 Century breeders have built on the foundation laid by their predecessors by combining cold hardiness with higher fruit quality. Among noteworthy cold-hardy cultivars recently released from these programs are 'Edelweiss' and 'Swenson Red' from Minnesota and 'Valiant' from South Dakota. While v. riparia is of value in contributing genes for resistance to very low temperature~ it generally transmits low fruit quality to its offspring. Some of the negative characters contributed by this species are small fruit size, small cluster size, highly acid fruit, low soluble solids, and undesirable flavor co~ ponents. In breeding for cultivars adapted to more moderate cold climates in the midwestern and northeastern regions of the u.s., a better donor for cold hardiness is v. labrusca. This species, and many of its derivatives, will withstand -32°C. It also transmits large berry size and a strong distinctive flavor, although the flavor can be readily ameliorated by hybridizing with V. vinifera. Hybridization between V. labrusca and v. vinifera has been the basis of the success of the grape breeding program conducted at the New York State Agricultural Experiment Station. From this long-standing program, over 40 cultivars have been released. Some are first generation hybrids of American grapes and v. vinifera while others are from advanced generations. Some are more cold hardy-than others and they differ in quality factors, depending on the relative proportion of v. vinifera and V. labrusca genes contained. Some, such as the recently released 1Canadice', eXhib1t a n1ce balance of cold hardiness and fruit quality. The new 'Reliance' seedless grape from Arkansas, hardy to -34°C, is a hybrid of two New York releases, 'Ontario' and 'Suffolk Red', and demonstrates that hardiness and fruit quality can be derived from this genetic background. Genes for high quality and moderate cold tolerance may be obtained from some cultivars of wine grapes of vinifera, or predominately vinifera, origin. The French hybrid, 'DeChaunac', is reported to have some cold hardiness and the v. vinifera wine cultivars 'White Riesling' and Gewurtztraminer' are more tolerant to cold than most viniferas. By using such cultivars as sources of quality in crosses with more hardy, but lower quality, labrusca-derived clones, breeding progress might be accelerated. Breeding Approach

The major objective outlined for the New York Experiment Station grape breed­ ing program at its initiation in 1888, combining vinifera fruit quality with the cold hardiness, productivity, and disease resistance of American species, is still a valid approach today.. Present day breeders not only have germplasm developed by · our predecessors on which to build, but also have a wealth of information on grape breeding behavior gleaned over the past 100 years to more effectively plan our breeding strategies.

Results of the past clearly show that we cannot expect to capture all the desirable quality genes and adaptive genes in one or a few generations of inter­ specific hybridization. Gene segregation in Vitis is complex, with many unfor­ tunate genetic linkages. Only in well-planned, long-term breeding programs will it be possible to obtain the ideal mix of desirable genes from the donor species. Due to the detrimental effects of inbreeding in Vitis, selfing and backcross­ ing approaches for combining genes have limited usefulness. The best breeding approach seems to be the combining of unrelated interspecific hybrids, which allows

4 a naximum of gene recombination. In this approach, each generation of seedlings must be carefully evaluated for combinations of desired characters, an:l only the best as parents in additional rounds of hybridization and selection. ~1ost evalua­ tions in the past were based on field observations. While filed testing is still important, especially in tl1e latter stages of cultivar development, breeding progress can be accelerated by the use of laboratory testing, especially for such important characters as cold hardiness (freeze chamber evaluation) and disease resistance (mass seeding screening under. controlled coooitions}. Recently, a great deal of interest has been expressed in the scientific com­ munity concerning the potential of using modern biotechnology to genetically ffi1- gineer higher crops plants. Some even claim that traditional plant breeding rr.ethods, such as hybridization aoo selection, will soon become obsolete in plant ~rovement. Genes for cold hardiness or disease resistance could, for instance, be inserted into the genome of high quality grapes in a laboratory, without carry­ ing along undesirable genes, creating instantly a genotype that has eluded conven­ tional grape bre8ders for a hundred years. While I have respect for the potential of genetic engineering, and believe that it will become a strong and positive tool for plant improvement in the future, I do not perceive it as a panacea for curing all problems in higher plant improvement. At present, there are several important technical limitations to the use of genetic enqineering in improving grapes. We do not yet have genetic maps sha.~ing the locations of specific genes in the genome. Thus, we have no basis for iden­ tifying genes that code for useful traits. Secondly, genetic engineering usually requires that a functional plant be generated from a single transformed cell. we do not yet ha\~ this technology for grape. Thirdly, and perhaps most importantly, most important traits of grapes and other higher plants are of a quantitative genetic nature in that they are coded by, not one, but many genes, or are affected by modifer genes. Thus, transfer of a trait from a donor to receptor species would require the simultaneous transfer of DNA from several sites throughout the genome. In the absence of gene maps, this would be highly unlikely to achieve. Cold hard.i..ness in grapes is a complex phenomenon, no doubt conditioned by many genes, and influenced by environmental and physiological factors, most of which are poorly uooerstood. We know that the resistance or susceptibility to cold injury varies with the time of year that the cold is experienced and with the levels of temperatures preceeding the minimum temperatures. Often, severe injury may occur from sudden freezing temperatures in the fall, before plants are sufficiently hardened-off. This type of injury is common to v. vinifera cultivars. Most American grape species begin to harden in late summer, apparently in response to shortening day-length. Terminal growth ceases and wood becomes brown and hard well in advance of the first fall freeze. In v. vinifera, ha.~ever, vegetative qrO"Nth continues as long as there is adequate water and nutrients and the prevailing tem­ perature is sufficient. Thus, much of the wood may be still green and tender when the first freeze occurs, and extensive damage may result. This characteristic of v. vinifera should be strongly selected against when evaluating hybrids involving vinifera. An important obstacle to improving the cold hardiness of grapes is that the response of plants to cold is affected by many cultural and physiological factors. It is well known that a grape culti var may show very different levels of cold har­ diness depending on the levels of stored carbohydrates in the wood during the winter. Thus, anything resulting in failure to store adequate carbohydrates in the

5 summer and fall, such as overcropping, insect or disease damage to leaves, early defoliation by frost, drought damage, or poor soil fertility will decrease the vine's tolerance to cold. In short growing season areas, plants that ripen early may appear more hardy, since they have more time after harvest to replenish their carbohydrate supplies. This relationship between vine health and cold hardiness dictates that field evaluations must be made under uniform and optimum conditions. Future Prospects

The foundation laid during the past 100 years in combining cold hardiness with high fruit quality in grapes will be the basis for rapid improvement in the future. To achieve this goal will require well-supported, long-term breeding programs directed by persons with skill and patience. Past experiences clearly indicate that success will not be achieved in one or a few seedling generations, but that the deliberate recombination of desirable genes, a few in each of a series of generations, will be required for ultimate success. Modern technology of screening and identifying desirable genotypes will accelerate breeding programs. It seems appropriate at this time that grape breeders in eastern North America re-evaluate their ultimate objective. Do we want to develop grape cultivars that are identical to v. vinifera but with added cold hardiness and disease resistance? Will we settle for-no less than this? Adrndttedly, v. vinifera is the world stan­ dard for quality in grapes. But will some of the hybr1ds of American and vinifera we develop have unique qualities that are as acceptable in fresh fruit or wine as those of vinifera? Is it not possible that some combinations of quality factors from two or more species may even be superior to those of a single species? The finding in Ohio consumer preference studies that 87% of the consumers interviewed preferred 'Reliance', a hybrid of labrusca and vinifera, to 'Thompson Seedless' is thought-provoking. We must not compromise our goals of high quality, but we should not set such narrow standards that we might overlook a jewel of different glitter.

6 AN OVERVIEW OF ENOLOGICAL RESEARCH IN CALIFORNIA Ralph Kunkee Department of Viticulture & Enology University of California Davis, CA Although the title of this report would seem to have to do with enological research in the "State" of California, in fact, the discussion will be lirni ted mostly to that at the University of California at Davis. However, some important resea.cch on the detection of mold on freshly harvested grapes has recently cone out of the State University at Fresno. This has to do with the problem of estimating the amount of rot on grapes which have been harvested mechanically. California normally has long, dry summers, and thus with the proper viticultural practices, molds and mildews should not be a big problem. However, from tima to tima, an ear­ ly (in August) warm rain has a devastating effect on the ripe crop. It has been worked out by the Fresno people that the best detection would be to measure the amount of acetic acid (from premature alcoholic fermentation) and also to measure the a.rrount of gluconic acid corning from the rrold itself. These two measurercents, then, would be a good index of the extent of rot--but would also require the use of sane sophisticated equipmant at the "sugar shack". Other non-University research in California would include: 1) that being done at the very large wineries, and which is generally kept from the competition for several years; and 2) that being done on a rrodest scale at all wineries. The lat­ ter generally involves the "fine tuning" of techniques which are used in the set­ ting of style(s) of wines of the particular winery. In all of the enological (and viticultural) research, one can see the impor­ tant of raising the efficiency of production. It is quite evident in California that the corrpeti tion from the inexpensive imported wines can be countered in only one way, decreased costs of our grape and wine productions. While this kind of threat is probably not of obvious importance for the Ohio wine producers at the mo­ ment, since you have clientele which are very interested in local wines, as this clientele continues to expand their tastes, it is only a matter of time when the imported wines will make substantial inroads into the Ohio wine market, also. So let us now speak about the research that is currently of importance at the University. One of the things that is not being looked at very rruch anymore is the idea of · the selection of microorganisms for either the primary fermentation or the malolac­ tic ferm:mtation. In a way, we could say that that problem has been solved, but this is not to say this is a closed subject. We must keep open eyes and an open mind, but at the moment this is a very pressing part of research either at Davis or in the individual wineries. One of the pressing problems, at least recently, has been that of "sluggish" fermentations. The problem of "sluggish" fermentations seems to involve two kinds of situa­ tions: 1) it is perhaps a general nutritional lack in the grape juice; a low amount of nitrogen so that the yeasts are not vigorous enough to carry on to the end of fernentation where the alcohol concentration becomes high; and 2) it seems to have to do with the lack of certain specific nutrients, perhaps a certain amino acid in musts from some vineyards. Again, the yeasts are not vigorous enough to carry on

7 the alcoholic fermentation. These problems seemed to be more exaggerated after our drought of 1976-77, especially with Chardonnay. I am not saying that it was the drought that brought this about, but it seems like the problem is disappearing. However, we must not fool ourselves because this whole idea could come back again. Our vineyards in California, and yours too, are getting older and older compared to what they were when there were plenty of nutrients in the grape juice. With European colleagues this is becoming a big problem, too. A lot of the problems you hear about in European wine operations, the idea of needing to aerate the must or to add yeast "ghosts" (or cell walls) to continue fermentations, or the problems of volatile acidity coming from malolactic fermentation taking place along with the alcoholic fermentation probably have to do with nutrition. These problems in European vineyards will eventually become our problems. We have mentioned a research topic that is not being actively pursued, aoo one that is. To cover some of the other areas, perhaps the best way is by "personality"-that is to mention each of the active professors in our Department, and give a quick discussion of what I believe is their most important or most in­ teresting current research. As many of you know, we have lost several people late­ ly due to retirements, and sadly, to death. However, we have been very fortunate in our recruiting efforts and now have four new people to whom we are looking with great expectations. Of course, their research is only commencing, but so much of it is especially exciting, because each of them is very interested in the physiol­ ogy, morphology, nutrition, water relations of the grapevine; vis-a-vis, the ripe berry, its juice and the resulting wine. Let us begin with viticulture and Professor Kliewer. He continues to collect a tremendous amount of data. I think what he is doing in the long run will be very, very important for the enologist-putting together a big picture of nutrients in the grape juice. To me the biggest problem the viticulturist faces is that one must precisely specify the variety of grape, the location, the soil type, the trel­ lising, the kind of fertilizer application, the kind of irrigation regime, etc. What you have is a real checkerboard of all kinds of information, rather than a unified series of things. Kliewer is gathering this information to give us even­ tually a unified idea of grape physiology.

An important new aspect of viticulture involves biotechnology. Professor Meredith is working on the development of a grape plant from a single callus grape cell. The potential here is enormous, if it can be done; and it has been done to other plants--namely carrot and tobacco. The idea would be to subject the in­ dividual cells to some sort of inhibitory pressure, say Pierce's Disease, cold tem­ peratures, salinity and so forth, and with mutagen treatments select a mutant that survives this pressure. Presumably she could transfer this new cell back to the full plant state and it would carry over this resistance. This is asking a lot, and it has not happened yet, but the potential and the possibility is there. Let us go on to the enologists. We can begin with Cornelius Ough, who is Department Chair. He is a very productive person doing research mainly on analysis of wine and detection and effects of additives and stabilizers. He has just published a very extensive review on bioamines found in grapes and wine; compounds much as histamines and other biological active amines, and their importance. Most of these are not flavor compounds; some of them are supposed to have health hazards and that is part of the reason that he has published that review. In fact, he has found no health hazards, even the amount of histamine actually found is very low.

8 Professor Singleton works on the aging of wine in barrels and in bottles~ For the developrrent of bottle bouquet, he has put forward a scheme tha;: involve~ a slo;J change in redox potential in the herrretically sea1erl (corked) bottle of wine with time. He is also very much involved in barrels and in the phenols that are extrac­ ted into the wine. But, one of the rrost exciting things he is doing has to do with must handling. He discovered that during crushing, if not done under controlled conditions a lot of things happen very qdckly and long before the fermentation regins. One of these things is the uptake of tartaric acid in a complex, such as caftaric acid. The only way you can danonstrate this is by keeping the must un.Jer very non-oxidative conditions; use a lot of so2 , ascorbic acid, and co2 • YO'l then get corrpounds that are in the grape juice you cannot find for a few seconds after crushing unless you do this. This has led to same speculations. There may be a lot of other complexes that we do not know about. Amino acids, such as sorre of the arorr:atic amino acids, or the sulfur containing amino acids which we do not fjnd in grape juk"'e might, in fact, be there, but in a complexed form. The yeast know they are there, but it is only we who do not know that they are. I'm looking fon-Ja;:d to more of this research am seeing what other kinds of things are there at the very beginning that are rrore-or-less mass.

I am going to move along to Professor Noble, ~17ho works on the flavor com­ ponents of grapes and wine, trying to relate the chemistry with the var:ious flavors. One of the flavors she is working on, as well as the people around thf:: world, is that of pyrizine corrpound that is supposed to give the Cabernet a bell pepper-like character y Arrl, indeed that chemical certainly does have all those characteristics. She is also interested in the same kind of thing with Chardonnay .. But, I think the biggest contribution that she is making now is this kind of fine­ tuning sensoz:y evaluation of wine; what she calls "descriptive analysis". The W:J.Y this works is to set aside the teaching tool, the Oavis 20-point scale, which c2r­ tainly does have its place, and instead of doing a blind tasting at first, what she ~~as a panel do is taste wine together with labels and discuss them and corre up with various kinds cf descriptors, about a dozen or so, that they can agree on. After that, then the wines undergo blind tasting. The various elerrents they corre up with are rated on how strong they are in each of these wines. Then some sort of statis­ tical evaluation is done to corre with a fingerprint of the \>line. Then, only then~ do you get into the idea of evaluating than for preference. Once you get the fin­ gerprints of the wine, then you decide are they the qualities you want in that type of wine or not. This is really far more informative than anything we have had in the past. Professor Boulton is very active in the study of the interrelationship between nutrients in the grape juice and the subsequent fermentation. This involves a general nutritional deficiency or a specific nutritional deficiency, say the ab-­ sence of cysteine. Another important result is the idea that the transport of the sugar: htc the yeast is the rate limiting step; and this then can be governed by thP. yeast strain itself, as well as by the temperature, the concentration of the sugar, and the enthanol concentration. So we have the idea of ethanol being irnpor­ tant very early in the fermentation. This can be good for typing yeast strains, which is sorely needed, but also for predicting the extent of the fermentation: ,,.,ill it go to dryness or not, and how fast will it go? He is devising automatic rrethods for: detection of this very early in the ferrrentation. These results are important. The winemaker wants to know when the fermentation is going to be finished (you need labor and energy to move that wine out of the tank to clean the tank, etc.). 'I'hus, an adjustment of temperature of the fermentation or inoculation

9 size can be made in order to control the timing of the refrigeration and labor neerls. One more person to mention is Professor Ryu, the Amerine Chair. He is a biotechnologist, but he is interested in looking at the genetic make-up of various wine yeast strains. He is also interested in applying the new technologies that are being used in the pharmaceutical imustry am in other food industries for ex­ ample, the idea of using the immobilized cells or enzymes, to wine. Whether the results will be acceptable now or not is not the thing. I would like to present some of my interests. At the moment, I am especially interested in the topic of ethanol tolerance. Many of the things we were talking about, what Boulton was doing, for example, and perhaps Singleton, too, have to do ultimately with ethanol tolerance. The questions are: why on the one hand are wine yeast cells so much more tolerant to ethanol than other kinds of yeasts? On the other hand, why can •t they be made more tolerant? We need to know the mechanisms. If some of those involve single genes, then they could be manipulated so that we could em up with yeasts that are more tolerant to alcohol. Would we want that? I think all of you would like it to a certain extent; for example, for cold tolerance. A lot of you, depending on the style of wine you are making, want cold fermentation to bring about formation of fermentation bouquet which can overcome some lack of varietal material or to overcome other material that might be too strong. Cold fermentations are very slow. Presumably if yeasts were more alcohol tolerant, they should be able to ferment faster at a cold temperature. But, the use of these yeasts goes beyond that. Think of gasohol, for example. Several of the proposerl mechanisms for ethanol tolerance seem to involve the structure of the cell membranes. Other mechanisms of ethanol tolerance have to do with the glycolytic enzyme itself. No matter how many enzymes there are, one of those has to be more intolerant or easily denatured than all of the others. What enzyme is that? The possibility that one of the mechanisms by which tolerance can be increaserl is to select for strains in which the enzyme is not so easily denaturerl. I wish to come back to the idea of genetic engineering. Of course we should not get too carried away with the promise at the moment. However, we have used the technique to produce some new and interesting nutants of wine yeast. We have made a leucine-less mutant of Montrachet. This is more difficult than you might think. Montrachet is what we call diploid and homothalic and it is not easily manipulated genetically. But, we are able to get a mutant which ferments just as well as the parent strain. This mutant lacks the ability to make both leucine and isoamyl al­ cohol, the latter is the most important contributor to the fuse! oil fraction. For brandy production, costly methods of distillation are used to remove the isoamyl alcohol. So use of this mutant for the fermentation should make brandy production, or indeed any other alcoholic beverage, a lot simpler and less expensive. Another aspect of genetic engineering might be to clone the gene for malolactic fermenta­ tion am transfer it from lactic acid bacteria into wine yeast. Well, we have done that, too. Not as successfully, I should say. We now have r-t>ntrachet yeast that will carry out the malolactic fermentation, but not very well. As often happens in biotechnology, we obtained the nutant, rut only a weak one. More work is needed before it could be considered as a viable organism for vinification. Of course, then there is the question of whether the winemakers would really want to use such an organism. We have to fim out more about bacteriological stabilization after its use and about the flavors formed by that yeast.

10 GRAPE PHYLLOXERA: AN OVERVIEW OF NEW CONCERN V\ORLD\\TIDE

Roger N. Williams an:l Daniel M. Pavuk Ohio Agricultural Research and Development Centet, The Ohio State University Wooster, OH 44691 Edmund Niemczyk Research Institute of Pomology & Floriculture 96-100 Skierniewice, Poland

The grape phylloxera, Daktulosphaira vitifoliae (Fitch) is widespread, being found in most grape producing regions of the world. The phylloxera is a tiny aphid-like insect which in its native habitat is found on roots and foliage of wild grapes. The original home of the phylloxera is eastern North America. It remained confinoo in eastr>rn North America until the middle of the 19th century, when it was inadvertently introduced into viticultural areas of Europe and began its inf3100us role as spoiler. The phylloxera reached France about 1860. Somewhat earlier, ~~rican vines had been taken to France in connection with studies to control pow­ dery mildew or as museum specimens. With these plants, unknown to the importersr came phylloxera. In France, the environment was as favorable to this organism as its native habitat---or more so--and it ran rarrpant in the vineyards. About 75 per-· cent of the vines of France were destroyed within thirty years {Winkler et al. 1974). Since that time the pest is known and dreaded wherever grapes are grown. Initially, concerns were prir~rily for root infestations of the European vines, Vitis vinifera {L.), which were so vulnerable to the phylloxera. However, more recently there are repeated reports that this aphid-like insect is changing its be­ havior aoo posing new concern worldwide. The purpose of this article is to point out several repoz:ts in the literature and contacts with other grape researchers which seem to substantiate our concern over biological changes observed in the northeast over the past several years. BIOLOGICAL NOTES

The grape phylloxera is a very hardy insect which is able to flourish in diverse envirorments ranging from hot deserts to bitter cold winter weather in northern latitudes. It has a complex life cycle, existing below tne soil surface on the roots of susceptible vines, and above ground we have the aerial form, which attacks the foliage. There are two ways which the phylloxera survives the winter in cold, humid environments. First, and perhaps most importantly, the phylloxera overwinters as a 1st instar nymph (crawler) under the bark on the roots. In the spring, these nymphs mature and begin to lay eggs on the roots, and the below ground cycle is started anew. Above ground the grape louse survives in the form of an egg deposited in a protected place on a fruiting cane. In the spring these spe­ cial eggs begin to hatch about the time of bud burst. This starts the summer cycle which is continuous on grape foliage until the fall. A sudden cold snap in the fall may partially destroy eggs remaining inside leaf galls. HCMevBr, a portion of the crawlers from the leaves are usually able to move to the roots and become es­ tablished. Since eastern grapes are most commonly on their own roots, varying in susceptibility, the phylloxera is often able to survive and even multiply-­ guaranteeing future phylloxera in the area.

11 During the active expansion phase of the phylloxera, populations grow rapidly, fostering local dispersal of both the root form and the leaf form. Dissemination of the insect over long distances is most common through movement of infested planting material. However, in Ohio we have additional problems with local move­ ment from adjacent wild vines. Many areas in western North America and elsewhere in the world do not have problems with native grapes as a source of phylloxera. EARLY PROBLEMS WITH V. VINIFERA IN U.S.A.

The phylloxera was first described in 1855 by A. Fitch according to Russell (1975). Before that time it was an unknown quantity; however, we suspect it was a major factor in eliminating European vines on their own roots. Early settlers in North America, particularly the French, brought V. vinifera vines with them and tried to establish vineyards of the selections whic~were most successful in Europe. They were always disappointed. If the growers were lucky, the plantations might last a few years, but sooner or later they would slowly sic­ ken and die (Ordish 1972).

European vines were planted in Florida as early as 1564. The English planted vineyards in Virginia in 1630. William Penn tried in Pennsylvania in 1635. In 1690 a Swiss colony started a vineyard in Jessamin Co., Kentucky. All of these vineyards of European grapes failed (Ordish 1972). There seems to be little doubt that one of the contributing factors to these failures was the tiny aphid-like North American insect better known later as the grape phylloxera. BEHAVIORAL DIFFERENCES IN PHYLLOXERA

Since the phylloxera wiped out the French wine industry in the nineteenth cen­ tury, it has spread to every grape producing region of the world. It is the most important insect pest of grapes worldwide. The phylloxera is the reason for utilizing resistant rootstocks in most parts of the world, especially where European grapes, Vitis vinifera, are grown.

Over the past few years we have suspected the presence of more than one biotype of the foliar phylloxera in the Buckeye State. What is meant by the term "biotype"? Generally, insect biotypes morphologically resembly one another so closely that they can only be distinguished on the basis of subtle biological traits such as preference for or the ability to survive on different hosts. Such differences may be due to a wide range of causes.

We have begun to find phylloxera galls on 'Concord' grapes which account for 85% of Ohio's production. This concerns us because from previous experience we know that foliar phylloxera reduce photosynthesis and severe populations cause premature leaf abscission in late summer or early fall. Since 'Concord' is not considered a normal host for the leaf form of the phylloxera, it was surmised that we were possibly dealing with a new biotype. In reviewing the literature and talking to other grape entomologists, several other instances were encountered which also indicated that more than one biotype of the phylloxera exists. Table 1 is a resume of information by other researchers who

12 have found evidence of differing behavior between "strains" or biotypes of this insect. With renewed interest for table grapes, vinifera grapes and French hybrids in this region, we need to be aware of the possible liffiftations of resistant foliage and rootstocks to the phylloxera. New phylloxera biotypes are something that we may have to deal with in any grape planting. It is now known that vines \IThich were previously resistant to phylloxera are now susceptible due to new phylloxera biotypes. LITERATURE CITED

1. Borner, C. 1914. On the susceptibility and immunity of vines to the attacks ot the vine louse. Biol. Centralblatt. Leipzig 34(1):1-8. 2. Borner, c. 1924. The problem of species of Phylloxera. Verh. Deutsch. Ges. agnew nt., 4 Mitgliederversauml. Frankfut a.M 10:13-33. 3. Helm, K.F. 1984. Phylloxera biotypes. Pgs. 11-13 IN G.O. Buchanan anc G. Amos, eds. The biology, quarantine and control of grape phylloxera in Australia and New Zealand. Victoria Dept. of Agric. Agric. Note Ser. No. 145. 4. Ordish, G. 1972. The great wine blight. J.M. Dent and Sons, Ltd., London, 233 p. 5. Russell, L.M. 1974. (Issued Feb. 14, 1975). Daktulosphaira vitifoliae (Fitch), the correct name of the grape phylloxera (Hemiptera: Homoptera: Phylloxeridae). J. Wash. Acad. Sci. 64:303-308. 6. Schilder, F.A. 1947. The length of the proboscis of the races of the vine aphid. Preliminary Comnunication. Festschr. Appel. 1947. 53-54. 7. Stevenson, A.B. 1970. Strains of the grape phylloxera in Ontario with dif-­ ferent effects on the foliage of certain grape cultivars. J. Econ. Entomol. 63 (1) :135-138. 8. Strapazzon, A. and v. Girolami. 1983. Foliar infestation of the grape phyl­ loxera (Viteus vitifoliae (Fitch), completing holocyclic reproduction on grafted European v1nes (Vitis vinifera (L.) (in Italian). Redia 66:179-194. 9. Williams, R.N. 1979. Foliar and subsurface insecticidal applications to con­ trol aerial form of the graph phylloxera. J. Econ. Entomol. 72(3):407-410.

10. Winkler, A.J., J.A. Cook, W.M. Kliewer, L.A. Lider. 1974. General viticul­ ture. Univ. Calif. Press, Berkeley. 710 pp.

13 Fig. 1. Leaf gall cut open Fig. 2. Tip growth of young grape to show female grare shoot with newly formed phylloxera and eggs galls of the grape (magnified). phylloxera.

Fig. 3. Root form of grape phylloxera on Clinton grapes causing abnormal swelling at root tips.

14 TABLE 1. Behavioral differences of grape phylloxera around the world.

Date & Observations on Changing Location author (s) Phylloxera Behav~_o_r______, ______Australia 1984 Possible existence of 2 biotypes through behavioral Helm and enzyma.tic differences. (1) Sydney type highly virulent to Schwarzmann & 3309, much less virulent to ARGl, 106.8 & Cabernet Sauvignon. (2) NE Victorian type seems to be virulent to Cabernet Sauvignon but less so to AGRl.

Brazil Ca. 1974 For years the leaf fonn of the phylloxera had been Sao Paulo present on foliage of rootstocks in commercial plantings and rootstock gardens. Little by little phylloxera galls have begun to attack 'Niagara' foliage. This new problem has expanded to the point that they are now using chemical control.

Canada 1970 Two strains; (1) causes necrosis but not galls Stevenson on 'Marechal Foch'; (2) caused galls without necrosis on 'Marechal Foch'. All isolates tested caused galls on 'Chelois', 'Verdelet', 'Chancellor•, 'Clinton', and v. riparia. Italy 1983 For 2 years (1981-82) it was demonstrated that Strapazzon spring leaf galls were formed by females hatched & from winter eggs. Based on bibliographical Girolami information holocyc1ic reproduction on v. vinifera vines is a new event. It SeemS therefore that a new "race" is forming.

Germany 1914 Concluded there were 2 species of vine louse; Borner (1) the northern species, w/long snout, from 1924 the Alleghanies; adapted to European vines and Borner some American vines. (2) the southern species, 1947 w/short snout, from the Mississippi Valley region; Schilder adapted to resistant American vines. (3) Differing grape cultivars seems to verify biotypes.

U.S.A.. 1984 Ganzin 1 (AXR #1) rootstock has been used (Western) Granett successfully in california for over 40 years. (Personal comn.) Recently it has been attacked by phylloxera suggesting a new/different biotype present.

15 STEPS TO PRODUCING HIGH QUALITY LABRUSCA W!NFS Daniel Robinson Widmer's Wine Cellars, Inc. Naples, NY Production of high quality Labrusca table wines differs from the production of vinifera in only one important consideration. It is the recognition and acceptance that the intense fruit characters of these wines require a degree of sweetness in order to obtain a harmonious balance between aroma and flavor. This does not mean that all Labrusca table wines need to be as sweet as, for example, Manischewitz Cream Concords, nerely that they not be bone dry. Having accepted this, our steps in production are directed towards capturing and preserving the maximum fruit flavors and using blending and sweetening techniques to produce fruity, uncompli­ cated, well balanced table wines. Dessert wines, both sherries and ports, are produced by exactly the same tech­ niques no matter what the variety. We make our dessert wines from both Labrusca and hybrid varieties and they are recognized as being among the best in the world. Regardless of the grape variety, it is the long, oxidative aging in small oak casks which produces the desired "rancio" flavors of premium dessert wines. I will be happy to discuss these techniques in a question and answer period, but I will con­ fine this paper to the production of Labrusca table wines. Harvesting The first step in production of table wines is the securing of clean, sound, unoxidized, ri~ grapes at the crushing station. By ripe, I do not nean having enough natural sugar to produce the desired alcohol content, but rather having the most desirable flavor profile independent of the sugar level. For example, we feel that the optimum maturity for Niagara grapes is between 13 and 14° Brix. The use of mechanical harvesters has enabled us to schedule our harvest so that we receive most of our grapes at these optimum levels. Oxidation of the fruit can cause flavor loss and premature aging. We add 80 oz. of potassium metabisulfite to each one ton picking bin to reduce the oxidation of the mechanically harvested fruit. We also try to do our harvesting in the early morning hours between midnight and 10 a.m. to keep the temperature of the fruit at a m1n1mum. We then require delivery to the winery within 8 hours of harvesting. Hand picking of the grapes can eliminate sone of the bruising, but because it must be done in daylight, it is a trade-off with higher tenperature. Crushing and Pressing Exposure of fruit to oxygen is greatest during crushing and pressing. It would be nice to do these operations in an inert gas environment but the expense of this procedure makes it impractical. Whatever the system used to transform the grapes into juice, it is essential to minimize oxidation and aeration wherever pos­ sible. To the extent that it is not possible, so2 must be used to inhibit oxida­ tive browning and subsequent loss of flavor. We Iike 50 to 60 ppm of free SO in the juice after pressing. We make our adjustments using PMS at the crusher w~en­ ever we can, but also adjust the juice after pressing if necessary. Labrusca grapes, because of their high pectin content, require treatment with

16 both pectinase: enzynes and cellulose fiber to achieve maximum yields of high quality juice. Although rice hulls are effective in pressing arrl chea~r than cel­ lulose fibers, they cause excessive suspended solids and off-flavors in the juice. \qe use any one of the available pectinase preparations, looking for the lowest dol­ lar amount of enzyme which gives us a dry press cake. Although enzyme activity is increased at ele,mted temperatures, we prefer to press as cold as possible to rGduoe oxidation. If necessary, we increase the enzyme level or the holding tine rather than heating the mu~~t.

The ideal pressing system would incorporate static draining tanks as enz}~ reaction vessels dumping directly into membrane or bladder batch presses sized for the quantity of drained grape skins. The press aid and enzymes would be adderl. directly at the crusher to minimize the need for agitation which causes aeration and generates sus:t:enderl solids. Our system used non-draining reaction tanks being pumped to Willmes bladder presses which drain as they are being filled. Bladder and membrane r;.·resses, although slow and labor intensive, are preferable to con­ tinuous screw presses or piston presses because the thin press cake allows maximum juice yield at low pressure. The high pressures used in screw or basket presses extract excessive tannins, causing bitterness in the juice and wine. If these presses are used, the press juice should be separated from tha free run and processed in a manner designed to quickly reduce the tannins. Clarification

The next step after pressing is clarification of the juice. It is important that the suspended solids be reduced to the 1% range. Excessive sol1ds during fer­ mentation cause unreliable fermentations with off odors, foaming, poor tempera~ure control, color problems, bad flavors and wine clarification problems. Our pressing system yields between 190 and 200 gallons per ton of juice with between 3 and 8% suspended solids6 The ideal system would eliminate most of these solids, but sorre clari ticati.on would still be necessary. Although many wineries use both disk and decanter type centrifuges for this job, we do not believe that they are a wise investment. They are very expensive and ill suited for this task. Given that our harvest temperatures are relatively cool, we prefer to settle the juice overnight arrl rack off the clarified juice the foll

17 We use several different yeasts, but we use Ra:l Star Champagne yeast for our Labrusca varieties. Although it does not have the fermentation bouquet of Epernay, its low sulfite production makes it attractive to us for reasons I will get to shortly. We purchase small quantities of active dry yeast and use them to breed up our starter cultures. We generally add 2 to 5% of a rapidly fermenting wine to a pre-fermentation blend to initiate the fermentation.

We usually leave the new fermentation at ambient temperature until we observe ferrrentation activity. We t.~en cool the fermentation to 50°F and maintain the fer­ rrentation between 50 and 60°F. Cool fermentation is essential in the production of wines with the~ maxiiii.lm fruit flavor. Because it gets quite cold in our cellars in November, we allow the fermentation temperature to rise up to 65°F once the Brix is down below 5. We do this to make sure that the fermentation does not stop prema­ turely. Where we employ sto~ fenrentation to retain unfermented sugar in the wiue, we chill the wine to 30 F when the sugar level reaches the desired point. At this time we adjust the level of free so2 to roughly 50 ppm. Post Fermentation Clarification After fermentation is complete, or has been halted, it is desirable to remove the yeast to avoid the off odors that they may produce under highly reducing condi­ tions. This is an area where high speed disk centrifuges are very useful. Unfortunately, few wineries, including ourselves, can afford to spend $200,000 on a machine that is used only a few weeks each year. As a consequence, it may be many months before the yeast lees are removed from contact with the new wines. It is here that the champagne yeast strain proves valuable. It does not easily break down and release the sulfide residues of its amdno acids. Neither does it produce them directly as long as the fermentation was begun with lo~ solids juice. This yeast gives us the ability to clean up our wines at an economical rate without risk of spoilage. Labrusca wines possess a colloidal haze after fermentation which is not seen in vinifera or hybrid wines. We suspect that it is a polysaccaride-pectin complex, but we have not clearly identified it. It makes D.E. filtration difficult b¥ slim­ ing over the D.E. rapidly. We do know that agar-agar preparations will remove this haze, but we have had no luck with any other treatment. We almost always find that 2 lbs/1000 of 11sparkolloid" or a similar preparation will remove the haze. Stabilization Labrusca wines, depending on the ripening conditions, may have heat liable proteins. It is our practice to begin heat stability tests on our wines as soon as fermentation is complete. This is done with trial finings of bentonite. Once the necessary level of bentonite is determined, we treat the wines with both bentonite and sparkolloid and top them up corrpletely. We allow them to settle unti 1 the necessary clarity for filtration is achieved. This typically takes only a week or so, but because of our limited filtration speed, it may be April before a wine is filtered from its yeast lees and finit~gs. Where our capacity for cold storage allows, we combine clarification and heat stabilization with cold stabilization, the removal of excess potassium bitartrate. This allows us to get brilliantly clear, heat and cold stable wines with a single filtration. We are not able to do this with all our wines. We begin D.E. filtering as soon as possible and continue until all wines are off fermentation

18 lees~ If they are cold stable, it is a bonus, but our goal is the earliest possible yeast re~val. When we filter cold unstable wines off fermentation lees, we then transfer the wine to cold storage for tartrate precipitation. Our standard for cold stability is that a brilliantly clear sample not deposit tartrates after 3 hours freezing at 0°F. When the wines are cold stable, we again D.E. filter them to remove the tartrates. Storage The fresh fruit flavors which we have captured in these new wines are best preserved by immediate bottling. Even the residual C02 from fermentation is an as­ set to the finished product because it brings out the aroma. It is not economical­ ly practical for a winery our size to bottle all its wines at once, early in the new year. It may, however, be a reasonable thing for srrall wineries with limited ability to store small quantities of wine. One consequence of this is that the wines will differ from one year to the next. Whether or not this is an advantage, depends on how you market your wines. Because we are a mass marketing company, we do not vintage date mo3t of our wines and do our best to insure uniformity from bottling to bottling and year to year. Our blending and storage practices are ac­ cordingly different than those of a smaller company. We bottle our wines in response to sales and try to keep a minimum of finished goods inventory. We also generally maintain 18 months inventory of bulk wine. This is both an insurance policy against a disastrous harvest and a means of insur­ ing uniformity of taste. We store the bulk Labrusca wines as cold as possible, usually between 28 and 30°F in full stainless steel or glass wine tanks. We nBin­ tain the free so2 in the 30 to 50 ppn range. The full tanks minimize oxygen pick up and the combination of free so2 and cold slow down the oxidative processes which reduce fruit flavor. We employ different processes for wine types which require more complex, aged flavors, but with our Labrusca table wines we go to great care to prevent aging. Blending As we prepare our bottling blends, we are conscious not only of the chemical analysis of the wines and their relative varietal percentages, but also the ages of the wines in particular blends. Late in the fall of 1984, for example, our Niagara was almost 100% 1983 wine. By late December, we had blended in 10 to 20% of the 1984 wine. By April, it may be more like 40% 1984 and 60% 1983. By June it is a 50/50 blend and by August more like 70% 1984 and 30% 1983. This practice, com­ bined with our standard winemaking processes, insure such a uniformity of flavor that the consumer perceives no change from year to year. Another key factor in this perception is the chemical profile of our finished wines. The alcohol, sugar, acid, so2, and color vary only slightly from blend to blend. The sweetness level is the main factor adjusted just prior to bottling. We do this with a variety of techniques. We do use arrested fermentation on some wines, add sugar or sweet wines to dry wines, or add unfermented juice to dry wines. Many of our finished blends involve all of these techniques.

19 Bottlii!S_ our final concern in the production of slightly sweet, fruity table wines is the preservation of the favor and quality in the bottle. Although sorbates can be used to prevent fermentation, we prefer to employ sterile bottling and ~ane filtration. We do sterile filtrations with filter sheets of cellulose fiber and D.E. We filter into sterilized bottling tanks. 0Jr bottling lines are sterilized with hot water from the membranes to the fillers every morning. After bottle, our QC department cultures samples of every bottling run which must be free of yeast and bacteria ~fore the wine is cleared for shipment. Shelf-Life The final factor in maintaining wine quality is insuring proper storage before sale and quick rotation of the retailers shelf stock. This requires close coopera­ tion between producer, wholesaler, and retailer. It is the most difficult to con­ trol. In spite of all our precautions, we know that we occasionally have old, oxidized product in same small stores far from our main distribution channels. Fortunately, it does not happen often. Although I have been addressing the production of Labrusca table wines, these same procedures are the ones that would be used with fruity, off dry wines made from vinifera, such as Riesling, Gewurtztraminer, or Muscat Ottenel, or hybrids like Seyval or Ravat. Vinifera and hybrids are somewhat easier to press and clarify, but the same steps should be followed.

20 PRINCIPLES OF SULFUR DIOXIDE ~ITION 1 Jim-Wen R. L1u and James F. Gallander Departrrent of Horticulture Ohio Agricultural Research & Development Center, The Ohio State University Wooster, OH 44691

The use of sulfur dioxide in making wines has been known for many centuries. In solution, sulfur diox1de 1s rather unique, because 1t has both antimicrobial and antioxidative activity. In qeneral, 100 ppm sulfur d1ox1de is adda3 at the tine of crushing, and 20 to 30 ppn ttee sulfur dioxide t s maintained during wine produc­ tion. This level of sulfur \·hoxide will inhibit: the growth of spoilage microor­ ganisms and prevent discolorat1on 1n the wines. Therefore, it is important that both the total and free sulfur dioxide be analyzed after fernentation, periodically throughout the aging penod, and prior to bottling. Th1s 1s basic to a good winery quality control program.

It is also important to avoid an excessive am:>unt rJf sulfur dioxide in wines. If too much sulfur dioxide is added to a rrust, fernentat: 1on may be delayed, and the resulting wine will ~ave a high bout~ sulfur dioxide content. In wine, excessive amounts of sulfur dioxide may bleach the color and cause an objectionable, pungent odor. In addition, the maximum amount of total sulfur d1ox1de permissible in wines in the United States is 350 ppm. Chemistry of Sulfur Dioxide

Sulfur dioxide n-ay be adderl to a rust or wine as a gas, salt, or aqueous solu·­ tionw For the small winery, the preferred method 1s usually adding salts of sulfur dioxide, such as potassium metab1sulfite. This salt 1s awroximately 57.6% sulfur dioxide and is easy to handle by a small-scale operation. When sulfur dioxide is added to water, the general reactions that occur are as follows:

so2 (g) ~ so2 {aq) (Molecular so2) so2 (aq) + H2o ~ H2so3 (sulfurous acid) H2so3 :L::!::' HS0 3- + H+ (bisulfite) + H+ (sulfite)

From the above, it is seen that several ioni~ spec1es are formed and their con­ centrations are influenced by the level of H ions (pH).

1Adapted from a previous article '~intaining Correct Levels of Free Sulfur Dioxide in Wines". Proceedings, Ohio Grape-Wine Short Course, 1980.

21 PERCENT DISTRIBUTION OF FREE S02 IN AQUEOUS SOLUTION AT VARIOUS pH's Molecular Bisulfite pH 002 {HS03 -)

3.0 5.56 94.43 0.006 3.5 1.83 98.15 0.019 4.0 0.59 99.35 0.063

The effectiveness of sulfur dioxide deperrls primarily on the concentrations of these ionic spec]es. The portion of these ionic species that are not bound to other corrpouoos in musts aoo wines is known as free sulfur dioxide. It is this form that contributes most to the activity of sulfur dioxide in preventing spoilage and discoloration. For the other form, fixe:l or bound, the ability of sulfur dioxide, mainly the bisulfite ion, to combine with acetaldehyde, pyruvic acid, glucose, and other corrpourrls is known to decrease the action of sulfur dioxide.

Aldehyde-bisulfite [ Ketone-bisulfite complexes Sugar-bisulfite Anthocyanin-bisulfite

Therefore, the effectiveness of sulfur dioxide is related to those factors which influence the fornetion of sulfur dioxide binding compounds. Same of the most important factors include: yeast strain, temperature, aeration, and must com­ position. Another prime factor is pH, which not only affects the formation of binding compoutns such as pyr..1vic acid, but also the ionic form of sulfur dioxide. Since these factors are not the same for all wines, it is essential to routinely measm::e the free sulfur dioxide. This will aid in determining the correct amount of sulfur dioxide to ad3 and when to treat the wines. Experiment and Discussion To illustrate the fact that each wine binds sulfur dioxide in different proportions of free to bound, five varietal musts were treated with 100 ppm of sul­ fur dioxide at the time of crushing. Each wine was fermented by a standard proce­ dure using the wine yeast, Montrachet #522. About five days after dryness (-1.5° Brix), each wine was analyzed for free and total sulfur dioxide by the Ripper procedure (1). The amounts of free sulfur dioxide covered a range of 11 to 15 ppm

22 with the variety Aurore having the lowest content (Table 1). These results indicate that the must composition has a significant effect upon the proportion of sulfur dioxide which is free. Even though 100 ppm of sulfur dioxide was added, the total was found to vary between 62 to 115 Wtl· It is well known that sulfur dioxide may be produced during yeast formation. This would account for the high total sulfur dioxide contents in some of the wines. For the other wines, volatilization and oxidation of sulfur dioxide may have been the cause for the loss of sulfur dioxide. TABLE 1. Free and Total Sulfur Dioxide of Five Varietal Wines Immediately After Fermentation. Sulfur Dioxide, ppm Variety Free Total

Aurore 11 84 Villard Blanc 13 115 Vidal 12 61 Seyval 15 114 Catawba 14 86

The next step in treating wines with sulfur dioxide is to bring the free sul­ fur dioxide content to 20 to 30 ppm. To obtain this level by calculation is rather difficult, because the ratio of free to total varies widely from one wine to another. The common method is to add various levels of sulfur dioxide to a series of wine samples and determine their free sulfur dioxide content. For the five varietal wines in this study, various amounts of sulfur dioxide were added to a series of samples. These samples were treated with an additional 20, 40, 60, and 80 ppm sulfur dioxide. After the samples were sealed and stored for five days, each sample was analyzed for its free sulfur dioxide content. The data were plotted on graph paper, ppm of sulfur dioxide added versus ppm of free sulfur dioxide found. After drawing a line between the points, the amount of sul­ fur dioxide to be added to obtain 20 ppm free sulfur dioxide was determined for each wine. This is illustrated in Fig. 1 by using the data of Vidal wine samples.

23 40

Q) I -o X .,....0 Cl

~ ~ 20

25 porn

0 20 40 60 80 Sulfur Dioxide (ppm) Added

Fig. l. Effect of adding sulfur dioxide on the free sulfur dioxide content in Vidal wine.

It is estimated that approximately 25 RJffi of sulfur dioxide must be added to the Vidal wines to obtain an additional 8 ppm free sulfur dioxide. The resulting Vidal wine will then contain about 20 Pfm free sulfur dioxide. The results for the other varietal wines including the Vidal wine are summarized in Table 2. The~e results indicate that when a subsequent addition of sulfur dioxide was made the amount of free depended upon the variety. An additional 35 ppm sulfur dioxide was required for Aurore, but Villard Blanc required only 22 ppm to obtain 20 ppm free sulfur dioxide.

TABLE 2. Aroount of sulfur dioxide to be addoo to several wines for the pur­ pose of obtaining 20 ppm free sulfur dioxide.

0 ng1na. . 11 00 Free so2 to & ~ree so2 Content added 1ncrease yarlely (ppn) (ppm) (Pin)

Aurore 11 35 9 Villard Blanc 13 22 7 Vidal 12 25 8 Seyval 15 30 5 Catawba 14 30 6

1Approximately 5 days after dryness.

24 SUM-1ARY

Since the ratio of free to total sulfur dioxide depends upon so many factors, it is important to analyze each wine on a regular basis. This will aid in deter­ rrdning the correct amount of sulfur dioxide necessary to produce the required free sulfur dioxide in a particular wine. In general, the free sulfur dioxide content of a wine should be kept within 20 to 30 ppm. ~tis range is usually sufficient to prevent spoilage by oxidation and growth of microorganisms. LITERATURE CITED

1. Amerine, M.A. aoo c.s. Ough.. Wine aoo Must Analysis, John Wiley am Sons, NY I 1974.

25 VINEYARD MECHANIZATION ·- IT'S EFFOCT ON YIELD AND QUALI'l'Y

Justin R. Morris University of Arkansas Fayetteville, AR 72701 Grapevines have traditionally been trained and modified to provide a support system for production, but these systems have not necessarily been well-suited to mechanization. Currently, there is a m~jor research effort throughout the world to modify grapevines so that viticultural practices can be economically mechanized while maintaining or irnprovinq yield and guali ty. Trellis systems must be devised and shoot positioned to accommodate precise mechanical movement, to use machines successfully for pruning, harvesting, and otl1er grape production operations.

Trellising Systems for Mechanization

Many of the single curtain training systems (Fo~r-Arm Kniffin, Umbrella Kniffin, Keuka High Renewal, arrl various other long cane pruning systems) are ef­ fective for mechanical harvesting, but mechanical pruning obviously is impossible with those systems. With the need to improve vineyard management efficiency, there is a need for trellising systems that can be totally mechanized, therefore, the trellising system must be designed to all~N maximum accessibility of the fruit to the harvester's shaking mechanism and allow effective mechanical pruning. A properly trained vine should allow efficient machine operations without excessive damage to the vines or reductions in yield and/or quality. One of the first training systems that accomplished these objectives was the Geneva Double Curtain Training System (GDC), developed by Shaulis et al. {30) in New York. The GDC trellising system doubles the length of the cordon per vine, and with shoot positioning, there is an increase in the number of shoots on vigorous vines that can have their basal nodes adequately exposed to sunlight. Most vigorous vines of large-leafed Vitis vinifera cultivars with a drooping-shoot growth habit and annual cane prunings of 1.35 kg (3 lbs) or more at 240 em {8 ft) in-the-row spacing may be expected to give the greatest response to the GDC system {10).

The cordon-support wires should be 180 em (6 ft) above the ground and 120 em (4 ft) apart. The vines are cordon trained and short cane pruned {i.e., 4 to 6 nodes). In contrast to Vitis vinifera, the fruiting canes of Vitis labrusca ·cordon-trained vines are selected from nodes of very short vert1cal arms onoinat­ ing within the lower 180° of the horizontal cordon. The cordon must be in c~n­ tinuous contact with the support wire in order to obtain maximum efficiency from mect-.anical harvesting and pruning.

Bilateral cordon 03C) trained Vitis labrusca vines also can be effectively harvested and pruned by machine (18;19;20). The BC trellising system for eastern grown Vitis labrusca consists of establishing bilateral cordons on Basic Brite lt8 wire at approximately 180 em above the vineyard floor. The fruiting canes are selected as described for the GDC system. Research in Arkansas (18) that compared the 3 major trellising systems has shown the BC system to be as productive and to produce comparable fruit quality to the Umbrella Kniffin system; however, the en::: system was more productive than either of the other 2 systems with no reduction in

26 fruit quality. The BC and GOC system can be effective with rrechanized harvesting and pruning, hence these systems are recormrended for vigorous Vitis labrusca cultivars in Arkansas. There are still problems, with all of the advantages of the cordon systems (GDC and BC), such as cordons that sag or break loose completely from the wire. Also, the action of the rrechanical harvester, may cause damage if t!1e vines slide along the cordon. This type of damage might increase the amount of Eutypa infec­ tions. Since it is known that a large number of cut surfaces, which result with spur pruning, the cordon system increases the chance of infection by Eutypa. Also, harvester damage might contribute to winter injury on tender cultivars in areas ~1ere winter injury is a major problem. Bilateral cordon (BC) training with spur pruning is currently the most common training system in California vineyards (3). However, the fruiting spurs are selected from the upper 180° of the cordon, since Vitis vinifera cultivars grow up­ right. A common OC trellis used for California wine grapes consists of a two-wire vertical trellis. A 210 em (7 ft) stake is driven into the ground to a depth of 50 em (20 in) at each vine. A 12-gauge high tensile strength (HTS) cordon wire is lo­ cated approxinately 05 em (42 in) above the vineyard floor. A foliage support wire (13-gauge HTS) is usually attachErl 30 em (12 in) above the cordon wire. This wire is usually moved upward for better foliage support as the spur positions move up­ ward with age. Some growers install a third wire at the top of the stake for addi­ tional support and some growers install a cross-arm on top of the stake to spread two top wires 72 em (24 in) to 90 em (36 in) for extremely vigorous vines. The width of the cross arm is determined by vine vigor. and by the choice of the rrechanical harvester that is to be used. The distance between the fruiting wire and the cross arm is a compromise between maximum foliage support, accessibility of harvester rods, and the anticipated increase in spur height (19). Studer et al. (36) proposed a new system that uses a coiled wire that produces uniformly trained vines. In their study they used a wire in the form of a long­ lead helix to &lpport and automatically shape the vine cordons. Either growing shoots or mature one-year-old canes were wrapf€(1 into the spiral, thereby providing support for the cordon at intervals equal to the lead of the helix. The cane's diametral growth in future years is subject to a spiral girdle. The cane may grow arourrl the wire and as a result from some injury the cambium layers may touch on each side and grow together. This system has not yet been fully tested on a com­ rrercial basis, but the results indicate that a mechanical harvester or mechanical pruner performs roore effectively and efficiently with straight trunks and a uniform, straight cordon system. These conditions are necessary even if the cor­ dons are trained to a conventional straight wire that may require some retying of cordons each year. Shoot Positioning Effective rrechanical pruning can be accorrpl.ished with the Vitis labrusca species produced on the GDC or BC system, only when the vines are shoot pos1tioned, which placesthe canes in proper position for mechanical pruning. Also, shoot positioning is an effective method of improving fruit quality (22) and of exposing the lower nodes on the bearing units to sunlight to make the basal nodes more productive than under shaded conditions (22,30). Shoot positioning is particularly effective with large vigorous vines of Vitis labrusca cultivars, which have large

27 leaves and a drooping-shoot growth habit. Shoot positioning can be accomplished either by hand, or, more efficiently, with a mechanical shoot positioner. As soon as the tendrils touch the wire or another cane they fasten very quick­ ly, therefore, vines are usually first shoot positioned just before bloom. A good job of shoot positioning will usually require a second and sometimes a third pass with a mechanical shoot positioner. Mechanical Pruning In the late 1960's grape producers indicated that once mechanical harvesting was totally implemented, the most time-consuming hand labor operations in the vineyard were the pruning and tying operations. Grape producers complained of decreasing availability of qualified labor for pruning and tying and indicated that these should be the next operations mechanized (21,31}. A mechanical pruning aid for 'Concord' grapes was developed in New York by Pollock et al. (29} for use on cordon trained vines. A triangular arrangement of reciprocating cutter bars es­ tablished the length of cane and cane position. This New York pruning system was supglernented by a mechanized bcushing technique to remove the top shoots (upper 180 of the cordon) early in the spring. With these techniques, vines were suc­ cessfully mechanically pruned with no manual selection of canes for one season. Research was initiated in 1969 in Arkansas, and by 1971, preliminary results indicated mechanical pruning of grape vines could be accomplished and would reduce pruning labor by as much as 50% (21). TWo viticultural concerns were pointed out in this early research. One was the impossibility of treating each vine in­ dividually (balance pruning according to vine size}, which might result in the overcropping or undercropping of individual vines. The other concern was the in­ ability to select and leave only the best fruiting canes, since the best canes may be removed by the mechanical pruner. Shoot positioning has helped eliminate this second concern.

An additional detailed study was established in Arkansas to examine the ef­ fects of mechanical pruning on yield, vine size and juice quality of shoot posi­ tioned 'Concord' grapevines on GDC or BC training systems (18,20). The vines were mechanically or balanced pruned to a 30 + 10 severity. The mechanically pruned vines were left untouched, or were adjusted to 60 or 90 nodes per vine. After 6 consecutive years, follow-up pruning by hand to limit the number of nodes per vine to 60 following mechanical pruning maintained vine size, and produced fruit yield and juice quality comparable to vines balance pruned to a 30 + 10 schedule. Both the no-touch-up treatment and retaining 90 nodes per vine following mechanical pruning treatments reduced per vine and per node fruit yields after the 6th year and resulted in unacceptable objective and sensory juice quality. Also, these two treatments resulted in uneven ripening of Concord grapes, which contributed to the problem of low soluble solids and poor juice color. Therefore, continuous mechani­ cal pruning of Concord grapes as an aid is recommended only in shoot positioned vineyards where pruning can be followed by cane selection and adequate node limita­ tion. It was also suggested that grape producers consider a pruning cycle consist­ ing of one year of completely mechanized pruning followed by a year of balanced pruning. Same commercial operations in California use mechanical pruners mounted to the inside chassis portion of a grape harvester. One such commercially available unit is composed of a shredder, four side cutters and two top cutters. The shredder

28 eliminates the major portion of the canes on the sides of the vine so that thio~ side cutters can cut the canes on the sides and lower portion of the cordon. These side cutters are automatically centered on the vine row and cordon by the guidance skis. The top cutting saws can be hydraulically adjusted by the rear operator of the pruning unit in order t0 maintain the desired vertical length of spurs above the cordon. It is extremely critical to have well nanaged, uniformly trained cordon in order for this unit to operate at maximum efficiency.

Freeman and Cullis (6} studied rrechanical hedge pruning of 1Cabernet Sauvignon • and 'Do:radi llo 1 vines in Australia that were trained to a BC system. The yield and capacity of hedged vines were equal to or greater than the manually ptuned vines, except in 1976 when the hedged 1 Doradillo 1 vines had lower yields, Ni th the 'Cabernet Sauvignon 1 , a triangular hErlge initially had lower yields but in later years yielded more than the sqtmre and offset hedges. This increase in Cabernet yield with the triangular hedge was a result of increased berry number corrpared to the other. hedge shapes.

Freeman and Cullis (6) concluded vine hedging was a viable alternative to detail~~ manual pruning for these vinifera grapes in Australia. In another study, Freeman (Personal comuunication. Viticultural Res. Sta., Griffith, New South Wales) reports that the major quality characteristics affected by total rcechanical pruning are smaller berries and clusters. .Also, he indicated that the mechanically pruned hedge presents no problems during the mechanical harvesting operation. Mechanical hedging of Vitis vinifera vines on a commercial scale is now being adopted rapidly in Australia (5, 7~, where· pruning cost reductions of up to 75% have been recorde.1 (7) •

Intrieri and Marangoni (8) reported alternate "up-

29 Today, many of the comnercial harvesters in all grape growing regions errploy "pivotal strikers", which consist of a double bank of flexible horizontal rods that strike and shake the vine to remove fruit. The "trunk shaker" or pulsator harvest­ ing concept is another method commonly used in California. This method incor­ porates 2 parallel rails to impart horizontal vibration to the upper trunk and/or cordon. The trunk shaker is effective in removing only fruit in contact with a rigid trunk or cordon, and much less material other than grapes (MOG) is harvested. Some of the newer machines have combined the 2 principles and reduced the number of horizontal rods. One comnercial company refers to its unit as a "pivotal pul­ sator". This unit results in less leaf removal and vine damage, since it operates at a lower speed. A harvester with "pivotal striker" head has a little more tolerance for handling stakes that may be out of line than does the "pulsator" head. Machine-harvested grapes may contain a rather high percentage of MOG such as bark, canes, leaves and petioles (12,13,28), and poor trellising and training of the vines can be major contributors to this problem. All of this MOG may not be removed and eventually may cause off-flavors in the processed products. Cultivars that are more difficult to harvest usually contain more MOG than do easily harvest­ ed cultivars (28). It is also imperative in mechanically harvested vineyards trel­ lised on wooden stakes that a magnet be installed on the machine's discharge convey or to collect staples and other iron-containing objects. A mechanical harvesting crew will deliver about the same amount of fruit to the processing unit as do hand-harvesting crews with certain cultivars that are readily suited for mechanical harvesting (3) (e.g., 'Concord', 'Niagara•, 'Flora', 'Thompson Seedless', 'Gewurztraminer', and 'Cabernet Sauvignon'}. Much less fruit may be delivered to the processor with hard-to-harvest cultivars (e.g., 'Emerald Riesling', 'Grenache', 'Zinfandel', and 'Muscat Canelli') than do hand-harvesting crews. Structure of the cluster framework and its adherence to the vine and to the berries are the main factors that determine how easily and in what condition the fruit is removed. Fruit of most cultivars are removed primarily as single berries. This is particularly true of berries with fairly loose attachment. Cultivars with a firm berry attachment and a tough or wiry cluster framework are the most dif­ ficult to harvest mechanically. 'Emerald Riesling' has berries that are held securely by the internal vascular system ("brush") of the pedicels. The harvester must "juice" the fruit off the vine, leaving the cluster framework and the large, wet brushes behind. The soft, juicy berry texture of 'Semillon', 'Muscat Canelli', and 'Burger' presents harvesting problems because of juice loss during fruit han- . dling. Conversely, the very firm berries of easily harvested 'Tokay' and 'White Malaga' undergo almost no juicing during machine removal (3). Larger fruit and those harvested later in the season are more susceptible to mechanical damage (13,23). The ease or difficulty of mechanical harvest also depends upon training system, type and condition of the trellising system and wire, and vine vigor. Many cultivars of muscadine grape (Vitis rotundifolia, Mich.) do not ripen uniformly, thus once-over harvesting removes immature as well as mature berries. The presence of imnature fruit is undesirable since it lowers the quality of the processed product. A system for sorting machine-harvested muscadine grapes into maturity classes has been developed at the University of Arkansas (11). This

30 system utilizes brine solutions of different strengths to separate the grapes according to specific gravity. Thus, ripe berries with good quality can be separated rapidly and inexpensively from immature berries with poor quality. Muscadine grapes are also unique in that an abscission layer forms as the ber­ ries mature. This layer is so complete within some cultivars that fully ripe fruit will drop in advance of the nechanical harvester's collecting machanism. The University of Arkansas designed an extended collecting unit, which is adaptable to the front of any conventional commercial harvester, that prevents the loss of those over-mature fruit.

A considerable time delay between mechanical harvesting and delivery to the processing plant can result in increased enzymatic activity and browning, oxidation (ie., loss of color), and development of off-flavors and microbial growth (1,3,13,14,26,34). Temperature from the time of harvest to the time of processing probably influences the quality of machine-harvested grapes more than any other factor (3,14,15,16,17,25,26). Grapes placed in peat boxes after harvest do not in­ crease in temperature for 72 hr (15). The initial temperature of the grapes at harvest governs the storage temperature, regardless of the external air tempera­ ture. High temperature at harvest in combination with a delay in processing leads to rapid deterioration of grag: juice quality (15,17). Grapes harvested when fruit temperature is high (about 35 C) produce high levels of alcohol and acetic acid, both of which are signs of microbial spoilage, and have poor color (17). The al­ cohol and acetic acid contents of mechanically harvested grapes begin to accumulate 12 hr from the tine of harvest, if grape temperature at harvest is as high as 29°C and increase rapidly after 18 hr of holding at 29° or 24 hr at 24°. Decreases in soluble solids, flavor, and color quality parallel the increases in alcohol and acetic acid (15). Off-flavors in the processed juice product can be expected when alcohol levels reach 0.25%. High temperatures (above 25°C) of grapes at harvest usually are not a problem in cool areas (1,13,23), but grapes in hot areas, such as the San Joaquin Valley of California and in the southern United States, should be harvested during cool periods of the day or at night to minimize quality loss (15).

Addition of SO to machine-harvested grapes decreases quality loss during holding (1,3,15,16,f7,25). Addition of 80 to 160 ppm sulfur dioxide immediately after harvest slowed postharvest deterioration of machine-harvested grapes by delaying alcohol accumulation and loss of soluble solids for 24 hr when held at 35°C (15). Also, so2 discourages bacterial spoilage that might be expected at high fruit temperatures over a long period; it also serves as an antioxidant to prevent · juice browning. Higher rates of so2 applied to machine-harvested grapes at a low temperature (24°) delayed alcohol production for 42 hr (15). The type of containers used for hauling the grapes to the processing unit can influence product quality. Initially, 0.91 - MI' (1-ton) capacity wooden bins with food-grade plastic liners were used to accommodate the fruit; however, many opera­ tions on the West Coast have shifted to a 3.6-4.5-MT (4- to 5-ton) capacity hydraulic, self-dumping vineyard gondola that dumps the harvested grapes from the vineyard into bulk tank trucks which are hydraulically dumped at the processing plant. These bulk collection units have not reduced the quality of the processed product (1~ 1 14,25).

31 Guidelines for Operators of Commercial Harvesters

The following guidelines were developed by our grape research group at the University of Arkansas in cooperation with the commercial grape processing industry to maintain or improve the quality of machine-harvested grapes: 1) select the proper rpm of the shaking mechanisms or strikers and the proper ground speed for the harvester for each cultivar and crop load situation (the importance of proper machine adjustments and operations cannot be overercphasized) ; and 2) establish a time limitation from harvesting to processing plant delivery. The time limitation will depend on cultivar (2 to 4 hr for grapes used for premium white wines and 8 to 14 hr for grapes used for red wine and grape juice.)

Other factors to be considered are fruit temperature, so2 usage, and quality standards required for. the final product: 1) apply so2 when harvesting under high­ temperature conditions,at the rate of 100 ppm as the grapes pass over the final delivery conveyor; 2) prepare vineyard to eliminate MDG problems. This may require mechanically trirondng low-hanging canes that interfere with harvest, removing bird nests, removing tall weeds, preparing a smooth surface to the vineyard floor, and stopping all cultivation in sufficient time prior to harvest to minimize dusty con­ ditions during harvesting; 3) inspect the vineyard for foliar-feeding insects, and if necessary, apply required special sprays sufficiently ahead of harvest; 4) provide a bin or conveyer inspector as part of the harvesting crew. This in­ dividual would remove MOG, watch for plugging of cleaning fans, hydraulic leaks, and mechanical failures, and monitor the application of so2; 5) keep harvested grapes covered at all times and require a complete washing of delivery bins or con­ tainers after the grapes are dumped at the processing plant or winery; and 6) wash and clean mechanical harvesters thoroughly with an approved detergent-sanitizer at the end of each 8- to 10-hr operating shift (under some conditions a complete high­ pressure water rinse may be required during the operating shift). Sumnary The most success in vineyard and harvest mechanization has occurred using to­ tally integrated systems that include proper cultivars, cultural programs, harvest­ ing principles, postharvest handling, and product utilization. Research efforts must continue to refine and improve the weak areas of each of these systems. Literature Cited

1. Bourne, M.C., D.F. Splittstoesser, L.R. Mattick, W.B. Robinson, J.C. Moyer, N.J. Shaulis, and E.S •• Shepardson. 1963. Product quality and mechanical grape harvesting. Proc. New York St. Hort. Soc., Geneva. 2. cargnello, G. 1980. Research on new training systems and on total mechaniza­ tion of viticultural operations. p. 274-283. IN: UCD Grape and Wine Centennial Symposium Proc. Univ. CA, Davis. 3. Christensen, L.P., A.N. Kasimatis, J.J. Kissler, F. Jenson, and o.A. Luisi. 1973. Mechanical harvesting of grapes for the winery. CA Agr. Ext. Bul. AXT-403.

4. Cargnello, G. and L. Lisa. 1980. Mechanical winter pruning of GDC trained vineyards. p. 270-273. IN: UDC Grape and Wine Centennial Symposium Proc. Univ. of CA, Davis.

32 5~ Freeman, B.M. 1980. Experiments on vine hedging for mechanical pruning. p. 261-263. IN: UCD Grape am Wine Centennial Symposium Proc. Univ. of CA, Davis. 6. Freeman, B.M. and B.R. CUllis. 1981. Effect of hedge shape for mechanical pruning of vinifera vines. Amer. J. Enol. Vitic. 32:21-25. 7. Hollick, R.R. 1980. Mechanical pruning of vines in Australia. p. 264-265. IN: UCl> Grape am Wine Centennial Syrcposium Proc. Univ. CA, Davis.

8. Intrieri, c. and B. Marangoni. 1980. The alternate "up-down" mechanical pruning system: Experiments on vines GDC trained (V. vinifera cv. Montuni). p. 266-269. IN: UOJ Grape am Wine Centennial Synpo..c:;iurn Proc. Univ. CA, Davis. 9. Johnson, s.s.. 1977. Mechanical harvesting of wine grapes. USDA, Economic Research Service, Agr. Econ. Rept. 385.

10. Jordan, T.D., R.M. Pool, T.J. Zabadal, and J.P. Tomkins. 1981. Cultural practices for cOll'llercial vineyards. New York State College of Agriculture a.nd Life Science, Cornell Univ., Ithaca. Misc. Bul. 111, p. 29-30. 11. Lanier, M.R. am J.R. Morris. 1979. Evaluation of density separation for defining fruit maturities and maturation rates of once-over harvested mus­ cadine grapes. J. Amer. Soc. Hort. Sci. 104:249-252. 12. Marshall, D.E. 1977. The cluster buster. Agr. Res June, p. 14. 13. Marshall, D.E., J.H. Levin, and B.F. Cargill. 1971. Properties of 'Concord' grapes related to mechanical harvesting and handling. Trans. Amer. Soc. Agr. Eng. 14:373-376.

14. Marshall, D.E., J.H. Levin, B.F. Cargill, and R.T. Wittenberger. 1972. Quality of bulk handled 'Concord' grapes. Paper presented 1972 Ann. Mtg. Amer. Soc. Enol. , Uni v. CA, Davis. 15. Morris, J.R., D.L. Cawthon, and J.W. Fleming. 1979. Effects of temperature and so2 addition on quality and postharvest ~1avior of mechanically-harvested juice grapes in Arkansas. J. Amer. Soc. Hort. Sci. 104:166-169.

16. Morris, J.R., J.W. Fleming, R.H. Benedict, and D.R •• McCaskill. 1972. Effects of sulfur dioxide on postharvest quality of mechanically harvested grapes. Ark. Farm Res. 21(2):5.

17. Morris, J.R., J.W. Fleming, R.H. Benedict, and D.R. McCaskill. 1973. Maintaining juice quality of 'Concord' grapes harvested mechanically. Ark. Farm Res. 22(1):3. 18. Morris, J.R. and D.L. Cawthon. 1980. Mechanical trimming and node adjustment of cordon-trained 'Concord' grapevines. J. Amer. Soc. Hort. Sci. 105:310-313.

19. Morris, J .R. and D.L. Cawthon. 1980. Yield and quality response of 'Concord' grapes to training systems and pruning severity in Arkansas. J. Amer. Soc. Hort. Sci. 105:307-310.

33 20~ Morris, J.R. and D.L. Cawthon. 198. Yield and quality response of 'Concord' grapes (Vi tis labrusca L.) to rrechanized vine pruning. Amer. J. Enol. Vi tic. 32:280-282. 21. Morris, J.R., D.L. Cawthon, and J.W. Fleming. 1975. Effect of mechanical pruning on yield am quality of 'Concord' grapes. Ark. Farm Res. 24(3):12.

22. Morris, J .R., D.L. Cawthon, and C.A. Sims. 1984. Long-term effects of prun­ ing severity, nodes per bearing unit, training system and shoot positioning on yield and quality of 'Concord' grapes. J. Amer. Soc. Hort. Sci. 109:676-683. 23. Moyer, J.C., N.J. Shaulis, am E.S. Shepardson. 1961. Grape harvesting research at Cornell. Proc. 1961 NY St. Hort. Soc. 250-255.

24. Olrno, H.P. 1980. Mechanical harvest of grapes~ p. 187-190. IN: UCD Grape and Wine Centennial Symposium Proc. Univ. of CA, Davis. 25. O'Brien, M. and H.E. Studer. 1977. Closed and open transport and sampling of wine grapes. Trans. Amer. Soc. Agr. Eng. 20:631-634.

26. Peterson, R. 1979. Most important machine picker feature may be nighttime use. Calif. & Western States Grape Grower. Dec., p. 14. 27. Petrucci, V.E., C.D. Clary and M.O'Brien. 1983. Grape harvesting systems. pp. 525-574. IN: M. O'Brien, B.F. Cargill and R.B. Fridley (eds.) Principles and practices for harvesting and handling fruits and nuts. AVI Publishing Company, Inc. , Westport, CT. 28. Petrucci, V.E. and R. Siegfried. 1976. Research Note: The extraneous matter in mechanically harvested wine grapes. Amer. J. Enol. Vitic. 27:40-41. 29. Pollock, J.G., E.S. Shepardson, N.J. Shaulis, and D.E. Crowe. 1977. Mechanical pruning of American hybrid grapevines. Trans. Amer. Soc. Agr. Eng. 20:817-821. 30. Shaulis, N.J., H. Amberg, and D. Crowe. 1966. Response of Concord' grapes to light, exposure and Geneva Double Curtain training. Proc. Amer. Soc. Hort. Sci. 89:268-280. 31. Shaulis, N.J., J. Pollock, D. Crowe, and E.S. Shepardson. 1973. Mechanical pruning of grapevines; progress 1968-1972. Proc. New York State Hort. Soc. 118:61-69. 32. Shepardson, E.S. and W.F. Miller. 1962. Progress report, 1962, Mechanical grape harvester research. Rep. Res. NY St. Agr. Exp. Sta., Geneva. 33. Shepardson, E.S., N. Shaulis, and J .c. Moyers. 1969. Mechanical harvesting of grape varieties grown in New York state. pp. 571-579. IN: B.F. Cargill and G.E. Rossmiller (eds.) Fruit and Vegetable Harvest Mechanization: Technological Implications. RMC Rep. 16 Rural Manpower Center, Michigan State Univ., East Lansing.

34. Splittstoesser, D.F., D.L. Downing, N.F. Roger, and D.I. Murdock. 1974. Influence of the harvest method on contamination of fruit by Byssochlamys ascospores. J. Milk & Food Tech. 37:445-447. 34 35~ Studer, H.E. and H.P. Olmo. 1969. Mechanical harvesting of grapes in California: cultural practices and machines. p. 611-621. IN: B.F. Cargill and G.E. Rossrrdller (eds.) Fruit and vegetable harvest mechanization: tech­ nological implications. RMC Rep. No. 16, Rural Manpower Center, Michigan St. Univ., East Lansing. 36. Studer, H.E., A. Porras Piedra, and M. Bovio. 1984. Grapevine response to coiled wire training. Proc. Internat 1 1 Symp. Fruit, Nut and Vegetable Harvesting Mechanization. Amer. Soc. Agr. Eng. Publ. 5-84, p. 349-356. 37. Whittenberger, R.T., D.E. Marshall, J.H. Levin, and B.F. Cargill. 1971. Bulk handling of 'Concord' grapes for processing: quality evaluation. (Paper presented at the Ann. Meet. Amer. Soc. Agr. Eng. )

35 AN UPDATE ON f,EDERAL RULES AND ROOULATIONS PERTAINING TO WINES Renee Romberger Breen Department of Horticulture The Ohio State University Ohio Agricultural Research & Development Center Wooster, OH 44691

On September 24, 1984, the Federal Register published some changes and proposed changes for wine vinification. The Bureau of Alcohol, Tobacco, and Firearms sent copies of this document to all bonded wineries in the state to inform them of the changes. Although some regulations became effective on October 24, 1984, all amendments were finalized on March 25, 1985. This article will summarize the changes being made by the regulations and highlight some of the most important issues.

Following is a summary of the important changes in wine production made by these new regulations. 1) BATF deleted materials which are no longer in use in the production and cellar treatment of standard wines. A summary of the materials deleted for this reason is given in Table 1.

TABLE 1. Materials which have been deleted because they are no longer used.

1. Actiferm (Roviferm) 7. Mineral oil (White) 2. Aferrin 8. Prornine - D 3. Clari/Prare 9. Protovac PV-7916 4. Combustion Product Gas 10. Ridex - High 5. Ferrix 11. Wine Clarifier 6. Fulgur 12. Yeastex

2) Treating materials used solely in formula wines were also deleted from the list. Since these wines require the submission and subsequent ap­ proval by BATF of a formula listing the materials being used, there is no need to list them in the regulations. Table 2 lists sorre of the compounds which were deleted.

TABLE 2. Materials which have been deleted because they are used in formula wines.

1. Acetic acid 2. Diammoniurn rnonohydrogen phosphate 3. Egg yolk 4. Oak chips charred

36 3) In addition to the other deletions, all sodium compounds were removed from the list of approved materials. The use of sodium treating materials is no longer deemed to be an acceptable commercial practice among winemakers be­ cause of health considerations. Table 3 lists the compounds which are no longer to be used in wine and suggests possible replacements for them.

TABLE 3. Sodium treating materials which must be replaced by other compounds.

Material Replacement ------~------1. Sodium benzoate Potassium benzoate 2. Sodium bisulfite Potassium bisulfite 3. Sodium carbonate Potassium carbonate, Potassiurrt bicarbonate, or calcium carbonate 4. Sodium caseinate Casein or potassium salt of casein 5. Sodium citrate Potassium citrate or citric acid 6. Sodium iso-ascorbate Ascorbic acid or iso-ascorbic acid 7. Sodium metabisulfite Potassium metabisulfite 8. Sodium sorbate Potassium sorbate or sorbic acid

4) With all the deletions, there have also been some new materials and processes authorized for wine treatment. These materials are listed in Table 4, including a brief summary of their uses.

37 TABLE 4. Materials and processes which are now authorized treatments.

Material Use ~~~~------1. Malo-lactic bacteria To stabilize grape wine

2. Potassium bicarbonate (KIC03) To reduce excess natural acidity in wine.

3. Thiamine hydrochloride Yeast nutrient to facilitate fermentation (Vitamin B1) of wine. 4. Enzymes A. carbohydrase To convert starches to fernentable (alpha-Amylase) carbohydrates B. carbohydrase To convert starches to fernentable (beta-Amylase) carbohydrates c. carbohydrase To convert starches to fernentable (Gluc~lase, carbohydrates Amyloglucosidase) D. Catalase To clarify and to stabilize wine E. Glucose oxidase To clarify and to stabilize wine F. Cellulase To clarify and stabilize wine and to facilitate se.r;aration of juice from the fruit. G. Pectinase To clarify and stabilize wine and to facilitate separation of juice from the fruit. H. Protease (general) To reduce or to remove heat labile proteins I. Protease (Bronelin) To reduce or to remove heat labile proteins J. Protease (Ficin) To reduce or to remove heat labile proteins K. Protease (Pa.r;ain) To reduce or to remove heat labile proteins L. Protease (Pepsin) To reduce or to remove heat labile proteins M. Protease (Trypsin) To reduce or to remove heat labile proteins

5) All references to brand nanes have been deleted in the regulations. The treating materials are now listed b¥ component ingredients under generic terms. The trade nanes of the materials affected b¥ this change and the new listings are described in Table 5.

38 TABLE 5~ Treating naterials listed under generic designations.

M~a~te=r=l=·a=l=-~(T~r~a~d~e~n~ame~~) ______N_ew __ r_._is_t_l_·n~g~------1. Acidex Calcium carbonate (with or without calcium salts of tartaric & malic acids) 2. AMA Special Gelatin Solution Gelatin (food grade) 3. Alnl:Er ByF and/or Alnl:Erex 1003 Yeast nutrient

4. Anti foam A; Antifoam AF enulsion; Defoaming agents Antifoam C 5. Atmos 300 Defoaming agents

6. Cold Mix Sparkolloid Inert filtering aid

7. Cufex Ferrocyanide compounds (sequestered complexes) 8. Fermcozyme Vin; Fermcozyme Vin XX Pectolytic enzyme 9. Klerzyme H.T. Pectolytic enzyme

10. Koldone Fining agent

11. Metafine Ferrocyanide compounds (sequestered complexes) 12. Sparkolloid No. 1 Inert filtering aid

13. Sparkolloid No. 2 Inert filtering aid 14. Sulfex Ferryocyanide compounds (sequestered complexes) 15. Takamine cellulase 4000 Precipitating agents

16. Uni-Loid Type 43B Precipitating agents

17. Veltol Maltol 18. Veltol Plus Ethy 1 mal tol

19. Yeastex 61 Yeast nutrient

6) The usage levels of the treating material will be prescribed in both American and metric units of measure. Since our winemakers work in American units rather than metric units, the American units of measure will be the primary citation in the literature. The metric measure will be given paren­ thetically as an aid for scientific research and to facilitate an internation­ al understanding of u.s. requirements.

39 7) Revised limitations were prescribed for the use of some treating rraterials. The most important compounds are listed in Table 6.

TABLE 6. Revised usage limitations on treating materials.

Material ------Lirrdtation 1. Potassium bitartrate The amount used shall not exceed 35 lbs/ 1000 gal. of grape wine. 2. Sorbic acid and potassium salt of The finished wine shall contain not more sorbic acid than 300 milligrams of sorbic acid per liter of wine 3. Water for yeast rehydration Not more than 15 L of water for each kg of yeast. The increase in volume of the juice shall not exceed 0.5% by volume

8) New procedures were established for experimentation with new treat­ ments by wineries, and the procedure for obtaining authorization to use new treabrents on a comnercial scale was revised. Specific provisions have been made in the regulations to allow the use of a material on an experimental basis. This will allow the winemaker to obtain sufficient data to justify submitting an application for using the material on a commercial scale. BATF is providing for an experimental authorization in a new regulation section en­ titled "Experimentation with new treating material or process". For a copy of the Federal Register which details the changes discussed in this article or for further information contact:

Michael J. Breen FAA, Wine and Beer Branch Bureau of Alcohol, Tobacco, and Firearm:; 1200 Pennsylvania Ave., NW Washington, D.C. 20226

LITERATURE CITED 1. Office of the Federal Register. Code of Federal Regulations: Title 27, Parts 4 and 240. u.s. Government Printing Office, Washington, D.C. (September 24, 1984).

40 E.VALUATION OF AN ELEcrRONIC BLACK Rar DISEASE PREDicrOR IN (X)MMERCIAL GRAPE VINEYARDS M.A. Ellis, L.V. Madden, and L.L. Wilson Department of Plant Pathology Ohio Agricultural Research & Development Center The Ohio State University Wooster, OH 44691

A microcomputer-based electronic unit for predicting grape black rot infection periods has been developed and tested on an experimental scale at the Ohio Agricultural Research and Development Center (OAROC:, see 1984 Ohio Grape-Wine Short Course Proceedings). In experimental tests, the unit accurately predicted black rot infection periods in the vineyard. When the unit was used to time after­ infection sprays with a curative fungicide (Bayleton 50WP), three to five sprays were saved compared to a standard protectant spray program in 3 years of testing.

All experiments conducted to date indicate that the black rot predictor is ac­ curate and should be useful in timing curative spray applications of fungicide for black rot control. Our data suggests, especially in dry growing season, that use of the predictor in an after-infection or curative spray program could result in significant reductions in the number of fungicide sprays used to proved adequate black rot control. During the 1984 growing season, we evaluated the black rot predictor on a com­ mercial scale at four locations in Ohio. The four locations were selected to represent north, central and southern Ohio. The grower, location, number of acres treated, and variety at each location were:

1. Kenneth Joe Schuchter 3. Tony Debevc Valley Vineyards Farms Chalet Debonne Vineyards Morrow, Ohio Madison, Ohio Southern Ohio ( 4 acres) Northeast Ohio (2 acres) Variety - Aurore Variety - Aurore

2. OAROC 4. Bill Mayton Wooster, Ohio Avon, Ohio Central Ohio (1/2 acre) North Central Ohio (2 acres) Variety - Aurore Variety - Concord

The selection of these growers and locations was based on the concentration of grape acreage and location in the state. Prior to the growing season in 1984, black rot predictor units were leased from Reuter-Stokes, Inc., Cleveland, Ohio, and placed in each respective vineyard. The units electronically monitor tempera­ ture, relative humidity, leaf wetness, and rainfall and then determine whether con­ ditions are favorable for infection.

The fungicide spray program used to evaluate the predictor is described in Table 1. The first three sprays of the season are protectant sprays. The first two sprays are specifically for control of Phomopsis cane and leaf spot. The third application is a protectant spray of mancozeb. At 10 days after the third spray, the after infection or curative program is initiated. The fungicides used in the

41 curative program are Bayleton 50% wettable powder and mancozeb 80% wettable powder in combination. The Bayleton produces 3 to 4 days of curative activity against the black rot fungus and is the essential element to a curative spray program. The rnancozeb gives good protection against black rot and also controls downy mildew. Because Bayleton is not effective against downy mildew, the combination with man­ cozeb is essential. Once the curative program is initiated, growers spray within 3 days after the initiation of an infection period. We assume that there is good protectant ac­ tivity from the mancozeb in the spray cornbinatio~; therefore, we disregard any in­ fection periods that occur within 10 days after application, unless 1.6 inches of rain falls. After the 10-day period or if 1 1/2 inches of rain, the grower responds to the next infection period. This spray program is continued until the berries reach 5% sugar, at which point they are no longer susceptible to black rot. All growers maintained a conventional protectant spray program on the remaining portion of the vineyard for comparison.

The results from the commercial evaluation of the black rot predictor were very prorrus1ng. With the exception of the predictor at Chalet Debonne in Madison, all units perfo:rm:d well. The unit at Chalet Debonne was hit by lightning and the trial was terrrdnated.

Results from the remcunmg three locations are presented in Table 2. The curative spray program based on predicted infection periods by the black rot predictor resulted in four less spray applications than the conventional spray program at a\.RDC. At Valley Vineyards, Ken Schuchter saved three sprays using the curative program as compared to his conventional protectant program. Bill Mayton at Avon did not reduce the number of sprays by using the predictive unit. In fact, he made one more spray in the curative program (eight sprays) than in his conven­ tional protectant program (seven sprays). This was because the Concords were sprayed with protectants much less frequently than the other varieties. Excellent disease control was obtained at all three locations in both the conventional and curative programs.

We feel that the commercial evaluation of the black rot predictor was success­ ful. Especially in dry growing seasons or locations, the use of a curative spray program based on the black rot predictor could result in significant reductions in the number of fungicide spray applications and, therefore, result in a significant financial savings to the grower. In wet growing season or in specific locations, the predictor may not result in a reduced number of sprays, but may be useful in improving the timing of spray applications. The predictor determines whether or not infection could have occurred. In some locations or seasons, it is possible that the standard protective schedule is not sufficient for optimal control of black rot. In these cases, additional sprays will be needed. In these cases, however, better disease control is likely to occur.

42 TABLE 1. Spray program for corrmercial evaluation of the grape black rot predictor.

1. 1/2 inch green New shoots 1/2 inch to 2 inches long

Captan 50% wettable powder 3 lbs/acre 2. 4 inches green New shoots 4 to 6 inches long Captan 50% wettable powder 3 lbs/acre

3. 10 inch green New shoots 10 to 12 inches long Mancozeb 80% wettable powder 3 lbs/acre

At 10 days after the 10 inch shoot spray, we will initiate the After Infection, Curative Program

After Infection, Curative Program l. All after infection, curative program sprays will be:

Bayleton 50% wettable powder 4 oz/acre PLUS Mancozeb 80% wettable powder 3 lb/acre Maneb plus zinc (at 2 lbs per acre) will be used instead of mancozeb within 66 days of harvest.

2. Sprays will be applied within 3 days after the initiation of an infection period. Get the spray on as soon as possible after the infection period ends. It must go on within 3 days. 3. Once an after infection, curative program spray has been made, we will ignore any infection period that occurs within 10 days, unless 1 1/2 inches of rain occurs. After the 10 day period, we will respond to the next infection period.

4. Use a spreader-sticker at the recommended label rate.

5. The after infection, curative program will be terminated when berries reach 5% sugar content, or when the maximum amount of Bayleton (18 oz per acre per season) is used. Additional sprays of maneb plus zinc alone may have to be made for downy mildew control, depending upon the weather. 6. A print-out of ''History of Infection Periods" must be made each week and kept with your records. Each date of application and the material and rate sprayed must be recorded. These records are critical to the successful completion of this program.

43 TABLE 2. Performance of the grape black rot predictor in commercial vineyards in Ohio - 1984

Number of fungicide sprays Conventional Eradicant protectant program based Location Acreage Variety program on predictor

Wooster .5 Aurore 11 7

Morrow 4 Am::or.e 11 8

Avon 2 Concord 7 8

Geneva* 2 Niagara, Catawba

*The predictive unit at Geneva was hit b¥ lightning and the curative program was terminated.

44 WHITE WINE QUALITY AS INFLUENCED BY MUST CLARIFICATION James F. Gallander Department of Horticulture The Ohio State University Ohio Agricultural Research & Development Center Wooster, OH 44691

Juice clarification prior to fermentation has become a widely accepted prac­ tice for white table wine production. Recently, Cooke and Berg (2) in California reported that 16 of the 17 wineries surveyed in 1982 used some method to clarify juice before fermentation. In contrast, an earlier survey by Cooke and Berg (1) reported only 2 of the 8 wineries clarified juice prior to fermentation. This il­ lustrates that most wineries now recognize the importance of juice clarification in making high quality white table wines. In general, low levels of solids in juice prior to fermentation improves the quality of white wines. Studies of juice clarification on wine quality by Singleton et al. (7), Williams et al. (10), and Van W>rk (8) indicated that wines prepared from clarified juice were higher in wine quality. Singleton et al. (7) described the wines from clarified juice as being fresh, clean, delicate, and fruity. In addition, these wines lacked off-odors, particularly hydrogen sulfide. In the same study, wines from turbid juice were considered as being harsh which was relatej to their higher bitterness and astringency ratings. Solids content during fermentation also influence the level of higher al­ cohols, fuse! oil, and volatile esters in wines. Wines from clarified juice often contain low levels of fuse! oil and higher ester concentrations. Crowell and Guymon (3) and Groat and Ough (5) indicated that an increase in juice solids cause a higher formation of higher alcohols. Wagener and Wagener (9) found that high values of fusel oil in white wines were detrimental to wine quality. These resear­ chers also investigated the effect of juice clarification on ester formation in wines. They reported that the total ester content in the wines was a good indica­ tion of the aroma ratings. Wines with high concentrations generally received the best aroma ratings by the taste panel.

Clarification Methods

Freshly pressed juice usually contains a relatively high amount of insoluble solids which consists of skin and seed particles, and pulpy material. As indicated earlier in this paper, these fragments of grape tissue have an adverse effect upon the quality of white table wines.

In order to obtain clarified JUices prior to fermentation, several methods may be used to remove the grape solids. The most common practice, especially among small wineries, is the settling method. After processing the grapes with an addi­ tion of 50 to 75 ppm sulfur dioxide, the juice is usually held at 55° to 65°F for a period of 12 hours. During this time, the juice solids settle to the bottom of a holding tank yielding an upper layer of relatively clear juice. To permit settling without spontaneous fermentation, cool temperatures and adequate levels of sulfur dioxide are important factors for this clarification method.

Also, the addition of pectic enzymes to freshly pressed juices is often employed to facilitate settling and improve juice clarity. Several commercial

45 pectic enzymes are available for the clarification of juices. Since pectins are present in grape juices and provide a protective colloidal action, solids are often prevented from settling from juices. The hydrolytic action of pectic enzymes results in a loss in the stabilizing properties of the pectins. This action allows the suspended particles to settle, thus clarifying the juices. Commercial pectic enzymes may be added and mixed directly to the juices. Bentonite is another agent used to help juice clarification. Bentonite is a clay material which has a tremendous ability to swell in the presence of water. This material in juice carries a strong negative charge and is attracted to the positively charged substances. When neutralization occurs, flocculating particles are formed which then clarifies the juice upon settling.

Also, juice clarification can be achieved by centrifugation or filtration. Both methods are relatively expensive and the cost of clarifying JUice by these practices can be prohibitive to the winernaker. The major advantage of these methods is the additional juice recovery from the sediment.

Factors Affecting Sediment

With respect to the settling method, the relative high percentage of sediment is a major disadvantage of this practice. DuPlessis {4) reported that sediment percentages in settled juices were influenced by several factors. These included: variety, fruit maturity and temperature, and equipment used in processing the grapes. He mentioned that over-ripe grapes with high sugar contents tended to give high sediment levels. Warm grapes arriving at the winery and certain types of juice separators also yielded juices with high sediment percentages. In addition, the variety of grape was found to influence the solids content of the JUice. For the varieties studied, the sediment percentages ranged between 6 and 40% {percent by volume). An overall average of the percentage of sediment was near 20%. Slightly higher values were obtained by Ough and Crowell {6) and Vanwyk (8).

Ohio Study The following portion of this report will summarize a study that was conducted in Ohio to determine the effect of juice clarification on the wine quality of two white French hybrids. In 1983, grapes from the varieties Seyval and Vidal blanc were harvested from a commercial vineyard in northern Ohio. At the same location, the grapes were im­ mediately transported to the winery for processing. After the grapes were destem­ med and crushed, the musts were treated with 75 ppm sulfur dioxide and transferred to a horizontal wine press. The free run, light pressed {including free run), and heavy pressed (including free run plus light pressed) juices were obtained from each of the two grape varieties. During each pressing treatment, two juice lots {agproximately 20 liters each) were collected and ameliorated with sucrose to 20 Brix. One lot without clarification was inoculated immediately with Montrachet #522. The other lot with clarification was inoculated after settling for 12 hours. Each treatment was tested in triplicate. All wines were fermented in glass carboys and placed in 18°c storage. The wines were fermented to dryness, racked, bottled, and analyzed after five months storage. · Within each variety, differences in JUice composition were slight among the clarification treatments. Wines produced from the clarified juices were slightly

46 higher in pH and volatile acidity than those without clarification. However, results of the sensory tests indicated that wines made from clarified juices were ranked best in aroma and taste. In fact, these wines were usually preferred by the taste panel at the l% sigr1ificance level for each pressing treatment.

Literature Cited 1. Cooke, G.M. and HeW. Berg. 1969. Varietal table wine processing practices in California. I. Varieties, grape, and juice haooling and fermentation. Am. J. Enol. Vitic. 20:1-6.

2. Cooke, G.M. and H.W. Berg. 1983. A re-examination of varietal table wine processing practices in California. I. Grape standards, grape and juice treatment, fermentation. Am. J. Enol. Vitic. 34: 249-256.

3. Crowell, E.A. and J.F. Guymon. 1963. Influence of aeration and suspended material on higher alcohols, acetoin and diacetyl during fermentation. Am. J. Enol. Vitic. 14:214-222. 4. DuPlessis, c.s. 1977. Grape components in relationship to white wine quality. Int. Symp. Qual. Vintage. 117-128. 5. Groat, M. and c.s. Ough. 1978. Effects of insoluble solids added to clarified musts on fertnentation rate, wine composition, and wine quality. Am. J. Enol. Vitic. 29:112-119. 6. OUgh, c.s. and E.A. Crowell. 1979. Pectic-enzyme treatment of white grapes: temperature, variety, aoo skin-contact time factors. Am. J. Enol. Vitic. 30:22-27.

7. Singleton, V.L., H.A. Sieberhagen, P. de wet and C.J. van wyk. 1975. Composition and sensory qualities of wines prepared from white grapes by fer­ mentation with and without grape solids. Am. J. Enol. Vitic. 26:62-64.

8. Van Wyk, C.Je 1978. The influence of juice clarification on composition and quality of wines. Proc. Int. Enol. Syrnp. Auckland, New Zealand. 33-45.

9. Wagener, W.W.D. and G.W.W. Wagener. 1968. The influence of ester and fuse! oil alcohol content upon quality of dry white wine. s. Afr. J. Agric. Sci. 11:469-476.

10. Williams, J.T.,C.S. Ough and H.W. Berg. 1978. White wine composition and quality as influenced by method of must clarification. Am. J. Enol. Vitic. 29:92-96.

47 SOURCE~Sil~ RET~TIONSHIPS IN THE GRAPEVINE

Martin L. Kaps Dep3.rtr£Ent of HorticrJltm:e Ohio Agricultural Research & Dew~lopment Center 'rhe Ohio State University Wooster, OH 44691

'l'he source-sink relationship in grape and otbe:r fruit crops involves leaves (source of photosynthesis products) and fruit (sink for photnsynthesis products) and the transport (moverrent of: these products) between them. 'I'he author: 's research deals vii th transport between source sink. Tabulated data on two exp3riments con-­ ducte::: in 1984 are presented in tables l, 2, 3, and 4. One experirrent involved ad­ justing leaf position in relation to a basal fruit cluster on a grapevine grO'~<'Tl to a single shoot (Figure 1). 'rhe second experirrent involved shading lower leaves and aJ.lowing upper leaves to be exposed to light, and comparing this to exposed leaves in lower or up!:_)er positions on a grapevine grown to a single shoot (Figure 2).

Before di8cussing the results of these experirrents 1 some pY~eliminary information on leaf photosynthesis and factors that influence it will be presented. 'I'hese factors include plant characteristics, cultural practices, and envirorunental changes.

Following bud break in grape, leaf photosynthesis increases, reaching a peak at full leaf expansion ( 30 to 40 days after unfolding) with a graduate decline oc­ curring through the remainder of the season (10). The 2ate of photosynthesis in grape is reported to be 20 to 30 rng- CO absorbed per dm of leaf area p3r hour (9) • Cultivar and rootstock differences in Photosynthetic rate are reported for grape and apple, although differences are small (3). Fruiting has a positive influence on leaf photosynthesis. Conversely, the removal of fruit brings about a rapid decline in photosynthesis (8). Cultural practices can prevent a premature decline in photosynthesis. Adeqt~te nitrogen nutrition is important in maintaining leaf photosynthesis. Phosphorus and potassium deficiencies have less effect on leaf photosynthesis than when nitrogen is deficient (2).

Maintaining good pest control is important since loss of leaf area reduces the plants photosynthetic potential. On apple, some loss of leaf area can occur without effecting leaf photosynthesis. Loss of leaf area from many holes is more detriiTEnta1 than an equivalent area in a few larger holes (6). In addition, reduc­ tion in photosynthesis due to sucking insect damage occurs before visible syrrptoms become noticeable (5)e Spray materials used to control these insects can have a detrimental effect on photosynthesis. Manipulation of the grape canopy through cordon division (Geneva Double Curtain) and net positioning exposes a greater leaf area to direct light which in­ Ci'eases a grapevine's photosynthetic potential (13, 14). Shoot topping as a cul­ tural practice decreases leaf photosynthesis (ll).

Environmental changes in light, temperature, and water availability influence l_eaf photosynthesis. Increasing light leads to an increase in photosynthesis. The photo~ynthesis m~chanism in apple is saturated at a light intensity of 590 watts per m · which is well below potential solar radiation of 1000 watts per rn or greater (12). Urrler cloudy conditions, leaf photosynthetic response to changing

48 light is rapid. On overcast days, diffuse light is important in maintaining photosynthesis. Optimum temperature for photosynthesis in grape is 20 to 30°C at saturating light intensities (9). Water supply effects photosynthesis. Reports in apple indicate that photosynthesis is maintained even at a low soil moisture con­ tent (1). In a field situation, all these environmental factors can act to control photosynthesis. Transport of photosynthesis products from the leaves to fruit changes with plant development (4). As grape shoots first develop, movement of photosynthate occurs toward the growing point. Within a few days, a bi-directional movement oc­ curs. Later only basal movement to the parent vine occurs. A change in the direc­ tion of photosynthate movement occurs again after fruit set with the leaves below the fruit transporting photosynthate upwards.

One question that the author's research addresses on photosynthate transport is if leaf position relative to the fruiting cluster is important. Reports in ap­ ple indicate that leaves a distance away can support fruit growth (7). In grape, leaves a distance away from the fruit can also support fruit and vegetative growth as well as leaves close to the fruit (Tables 1 and 2). Leaves on plants that were in an upper position in relation to a basal cluster had the capability to increase in size to a greater extent than lower position leaves (Table 1). This likely is due to more favorable nutrition and envirormental conditions when the leaves are first developing. Regrowth as an added 'sink' did not affect yield. Fruit maturity as measured by soluble solids and pH, and vegetative growth were improved by regrowth (Table 1 and 2). This indicates that regrowth is self-sufficient and does not draw on other parts of the vine for photosynthate.

The first experiment shows that transport of photosynthesis products can oc~~r over long distances in the grapevine and support fruit growth as well as leaves close to the fruit. Regrowth adds photosynthetic products to the vine rather than compete with the fruit for them.

The second experiment addresses the question of whether shaded lower leaves contribute to fruit development in grape. It is apparent from the data that shaded lower leaves do not improve fruit yield or maturity (Table 3). However, there is a positive contribution of shaded lower leaves to plant dry weight, particularly root growth (Table 4).

Leaf shading and defoliation occur in field grown vines. The present research shows that leaves further removed on the shoot have the capability to support the fruiting clusters. In addition, potentially some contribution of shaded leaves to vegetative growth of the grapevine occurs.

49 LITERA'rtJRE CITED 1. Allmendinger, D.F., A.L. Kenworthy, and E.L. Overholser. 1943. The carbon dioxide intake of apple leaves as affected by reducing the available soil water to different levels. Proc. Arner. Soc. Hort. Sci. 42:133-140.

2. Childers, N.F. and F.F. Cowart. 1935. The photosynthesis, transpiration, and stomata of apple leaves as affected by certain nutrient deficiencies. Proc. Amer. Soc.Hort. Sci. 33:160-163. 3. Ferree, M.E. and J.A. Barden. 1971. The influence of strains and rootstocks on photosynthesis, respiration, and morphology of 'Delicious' apple trees. J. Amer. Soc. Hort. Sci. 96:453-457.

4. Hale, C.R. and R.J. Weaver. 1962. The effect of developmental stage on direction of translocation of photosynthate in Vitis vinifera. Hilgardia 33 (3) :89-131.

5. Hall, F.R. and D.C. Ferree. 1975. Influence of two-spotted spider mite populations on photosynthesis of apple leaves. J. Econ. Ent. 68:517-520. 6. Hall, F.R. and D.C. Ferree. 1976. Effects of insect injury simulation on photosynthesis of apple leaves. J. Econ. Ent. 69:245-248.

7. Hanf~n, P. and J.V. Christenson. 1974. Fruit thinning. III. Translocation of C assimilates to fruit from near and distant leaves in the apple 'Golden Delicious'. Hort. Res. 14:41-45. 8. Hofacker, w. 1976. Investigations on the influence of changing soil water supply on the photosynthesis intensity and the diffusive resistance of vine leaves. Vitis 15:171-182. 9. Kriedemann, P.E. 1968. Photosynthesis in vine leaves as a function of light intensity, temperature and leaf age. Vitis 7:213-220.

10. Kriedemann, P.E., W.M. Kliewer, and J.M. Harris. 1970. Leaf age and photosynthesis in Vitis vinifera L. Vitis 9:97-104.

11. Nonnecke, G.R. 1980. The influence of cluster-thinning and shoot-tip removal on 'Seyval' grapevines. Dissertation. Depart. of Horticulture, the Ohio State Univ., Colurnlus, OH.

12. Proctor, J.T., R.L. Watson, and J.J. Landsberg. 1976. The carbon budget of a young apple tree. J. Amer. Soc. Hort. Sci. 101:579-582.

13. Shaulis, N.J., H. Amberg and D. Crowe. 1966. Response of 'Concord' grapes to light exposure and Geneva \space 1 Curtain training. Proc. Amer. Soc. Hort. Sci. 89:268-280.

14. Smart, R.E., N.J. Shaulis, and E.R. Lemon. 1982. The effect of 'Concord' vineyard microclimate on yield. I. The effects of pruning, training, and shoot positioning on radiation microclimate. Am. J. Enol. Vitic. 32(2):99-108.

50 z 3 4 5 6

Figure 1. Illustration of clusters per plant, leaves per plant, leaf position in relation to a basal cluster, and presence or absence of regrowth on 1 Seyval 1 grape grown in pot culture in the greenhouse, 1984.

51 Shl1'11; :· ,j

...... •• •

Treatment I z 3

Figure 2. Illustration of clusters per plant, leaves per plant, leaf position in relation to a basal cluster, and presence or absence of shade on 'Seyval' grape grown in pot culture in the greenhouse, 1984.

52 TABLE 1. Influence of varying leaf position and presence or absence of regrowth on yield, juice corrposition, and leaf area of 1 Seyval 1 grape grown in pot culture in the greenhouse, 1984.

Leaf Position Regrowth Variables Lower Middle Urp:r Plus Minus

Cluster Wt. (g) 153hz 175a 177a 171 166 Berries/cluster 99 100 104 101 101 Av.Berry Wt. (~) 1.4Gb 1.63a 1.60a 1.58 1.54 Leaf Area (em ) 2 756c l,097b 1,408a 1,098 1,077 Leaf A/yld. (em /g) 5.0c 6.3b 8.0a 6.4 6.4 Soluble Solids (%) 13.9b 17.7a 18.la 17. 7a 15.5b Titratable acidity (%) 1.45b 1.54ab 1.58a 1.45b 1.60a pH 3.26c 3.32b 3.38a 3.36a 3.28b

zMean separation within rows by LSD, 5% level.

TABLE 2. Influence of varying leaf position and presence or absence of regrOVJth on vegetative growth of 1 Seyval 1 grape grown in pot culture in the greenhouse, 1984.

Leaf Position Regrowth Variables Lower Middle Upper Plus Minus

Leaf fresh wt. (g) 16.2cz 28.8b 44.3a 29.4 30.1 Leaf dry wt. (g) 5.3c 9.3b 14.la 9.2 9.9 Stem fresh wt. (g) 64.1 67.3 67.1 67.6 64.8 Stem dry wt. (g) 21.6c 26.6b 29.5a 28.la 23.7b Root fresh wt. (g) 29.8 35.0 35.0 33.5 33.1 Root dry wt. (g) lO.Oc 13.4b 16.3a 14.la 12.4b

~ean separation within rows by. LSD, 5% level.

53 TABLE 3~ Influence of varying leaf position and lower leaf shading on yield, juice conposition, and leaf area of •seyval 1 grape grown in pot cul­ ture in the greenhouse, 1984.

Leaf Position ur.per Variables Lower . Upper {lower shaderl)

Cluster wte (g) 237z 251 252 Berries/cluster 145 146 139 Av. Berry Wt. 2 (g) 1.53 1.61 1.70 Leaf area (em ) 2 1,644b 1,987a 1,73lb Leaf area/yield (em /g) 6.9 8.1 7.0 Soluble Solids (%) 16.8b 19.2a 17. 7b Titratable Acids (%) 1.50b 1.55b 1. 71a pH 3.27 322 3.21

zMean separation within rows by LSD, 5% level.

TABLE 4. Influence of varying leaf position and lower leaf shading on vegeta­ tive growth of •seyval 1 grape grown in pot culture in the green­ house, 1984.

Leaf Position Upper Variables Lower Upper (lower shaderl)

Leaf fresh wt. (g) 43.9bz 57.0a 44.8b Leaf dry wt. (g) 12.9b 17.la 13.0b Stem fresh wt. (g) 47.6c 68.lb 80.5a Stem dry wt. (g) 20.9c 33.lb 39.3a Root fresh wt. (g) 51.8b 49.9b 69.2a Root dry wt. (g) 14.6b 16.6b 21.9a

~ean separation within rows by LSD, 5% level.

54 RESULTS OF PRESERVING FRESHLY PRESSED GRAPE JUICE R. R. Breen, K.L. Wilker, J.F. Gallander and J.F. Stetson Department of Horticulture The Ohio State University Ohio Agricultural Research and Development Center Wooster, OH 44691 Over the past few years, the price of Concord grapes has dropped very low. This study was initiated to find a new market for Concord grapes by producing a freshly pressed Concord juice, which is processed nuch like apple cider. The juice, called "grape cider" was targeted as a fresh-market product. It was made from cold-pressed Concord grapes and was similar in production to apple cider. Some solid matter remained in the juice so it was slightly cloudy and was full-bodied. Since it was not sterile-filtered or pasteurized, the juice was not stable. Instead, preservatives were used with refrigeration to maintain some length of shelf-life. The juice was filled into plastic containers and sold as a fresh product in supermarkets and at roadside stands. To make a fresh-market product like this, a number of factors were considered. The main factors investigated were those concerning microbiological and color stability. MICROBIOLOGICAL STABILITY Materials and Methods Juice Processing

The Concord grapes were harvested and processed at a commercial winery in Madison, Ohio. Although no special aseptic equipment was used for processing the juice, excellent sanitation was practiced at all times. ~iately after the grapes were harvested, they were destemned, crushed, and pectic enzyme was added. Clairex (!Miles Laboratories, Inc.) was added at a rate of 30 ml/150 gallons to aid in clarification and color extraction. The grapes were then cold pressed (50-55°F), and the grape cider was divided into two treatments--unfiltered and fil­ tered. Table 1 details the analysis of the initial juice before various treatments were per formed.

TABLE 1. Concord Juice Analysis

Harvest Date: 10/16/84 Harvest Location: Madison, OH <>srix: 16.8 pH: 3.24 TA: 0.85% VA: 0.019%

For the unfiltered juice, the juice was settled at 31°F for 24-48 hours. The

55 settled juice was then racked from the sediment and filled into one-half gallon plastic containers with preservatives added previously into them. The filtered juice was also settled at 31°F, but only for 12-18 hours. After settling, the juice was racked from the sediment and filtered through a coarse diatomaceous earth (DE) filter. The juice was then held at 31°F for 24 hours and then filled into one-half gallon plastic containers with the preservatives already added to them. The filled containers of juice were transported to our proc€ssing facilities at OARDC for storage and monitoring. To monitor for microbiological stability, two methods were used. The presence or start of yeast fermentation was checked using fermentation tubes. For these tests, approximately 5 ml of juice was added aseptically to a sterile 16 x 150 mm culture tube. These tubes were aseptically sealed with sterile cotton, placed at appropriate temperatures, and checked on a daily basis for gas production. When gas bubbles were first detected in the tubes, the plastic half-gallon containers were also examined for gas production to confirm the presence of fermentation. When fermentation was confirmed, viable yeasts and bacteria were determined by standard plate count methods.

The number of viable yeasts was obtain€d by plating appropriate dilutions of the juice on potato dextrose agar acidified to pH 3.5 with tartaric acid (2). Plates were incubated for five days at 20°C (4). Bacteria were enumerated by plat­ ing appropriate dilutions on TJTGFYE medium and incubating the plates for seven days. Treatments As mentioned earlier, the juice was divided into two treatments initially, un­ filtered and filtered. Diatomaceous earth filtration was investigated to determine whether this type of filtration would decrease the microbial load and increase the shelf-life of the juice at 35°F. The second treatment used two preservatives, sorbic acid and sulfur dioxide, to determine which preservative or combination of the two chemicals would be best. For this study, sorbic acid and sulfur dioxide were examined in the combinations shown in Figure 1, with and without DE filtration. Sorbic acid is an effective preservative against yeast and molds, but is not an inhibitor of most bacteria. Sulfur dioxide, on the other hand, is effective against bacteria, but only inhibits yeasts and molds (5). Sulfur dioxide is also used as an antioxidant against brown­ ing but this function will not be discussed until the second section of this article.

56 0 ppm 500 ~ 1000 ~ Sorbic Sorbic Sorbic acid acid acid

Figure 1. Amount of preservative investigated in Concord grape juice.

In addition to exandning the effects of filtration and preservatives on the shelf-life of the grape juice, the effects of storage temperature were also inves­ tigated. Juice containing the various ~unts of the preservatives described in Figure 1 was stored at either 35°F or 50~ and monitored for signs of udcrobial spoilage. Storage at 35°F sinulated refrigerator storage conc'li tions, whereas storage at 50°F simulated storage on ice. Often apple cider is displayed in super­ markets and roadside narkets at room temperature sitting in a bed of ice, and grape cider could be marketed in this way, also. COLOR STABILITY Materials and Methods Juice Processing Unfiltered juice previously described for the udcrobiological study was filled into half-gallon plastic and glass containers. These contained enough potassium sorbate to raise the juice levels to 1000 ~ sorbic acid. The antioxidants used in the treatments were also included in the half-gallon containers. To monitor the color stability of the juice, absorbance readings were taken at 420 arrl 520 nm with a Perkin-Elmer Lambda 1 spectrophotometer. These readings were obtained using juice filtered through an 0.45 m membrane filter at 1, 4, and 8 week intervals. The absorbance readings were converted into hue and brightness values. This was done to observe the changes in color (hue) and the intensity of the color (brightness) with time (1). At 1, 4, 8 and 12 week intervals the juice from each treatment was assigned a visual rating of 1-5. A 1 was given to samples that had color similar to that of the original juice and a 5 was given to samples which had brow~ and were no longer acceptable in appearance. All treatments were stored at 50-55 F. Treatments The juice was divided into six treatments, two levels of sulfur dioxide, two levels of ascorbic acid, and two controls.

Sulfur dioxide was added at 50 and 100 ~as potassium metabisulfite. Sulfur dioxide acts by inhibiting the enzyme polyphenol oxidase which is largely respon­ sible for browning in grape juice (3). Ascorbic acid was added at levels of 25 and 50 ng/100 ml of juice. Ascorbic acid improves grape juice color stability b¥ reacting with quinones formed by

57 phenolic corrpounds and oxygen in the presence of polyphenol oxidase. The quinones are reduced by the ascorbic acid before they form brown secondary products (3). Two controls without the addition of sulfur dioxide or ascorbic acid were kept. The glass containers were used for one control, while an equal number of plastic containers made up the other. The glass containers were included to deter­ mine the effect of their lower oxygen permeability on color stability.

All treatments contained 1000 ppm sorbic acid for microbial stability during the investigation. Results and Discussion

Effect of DE Filtration Diatomaceous earth filtration was effective in reducing the microbial load in the grape juice studied. The yeast counts and bacteria counts were significantly lower in the filtered juice than in the unfiltered juice (Table 2). In addition, in the juice stored at 35°F, filtration greatly extended the shelf-life of the juice (Table 3). Regardless of the preservative used, filtration greatly increased shelf-life. Apparently, tbe lower initial microbial load and a possible loss of nutrients due to the filtration helped the juice remain stable longer.

TABLE 2. Effect of DE filtration on Concord juice analysis. % Yeast Bacteria Juice Insoluble count count Sarrple solids (cfu,hnl) (cfu,hnl)

Unfiltered <0.5% 4.9 X 104 1.2x 105 Filtered <0.2 5.8 X 103 4.6 X 103

58 TABLE 3~ Shelf-life of Concord juice using different preservatives at 35°F with and without DE filtration.

Sorbic Sulfur Use of acid dioxide DE Shelf-life addition addition filtration (days)

0 PfU\ 0 PfU\ no 13 0 ppm so PfU\ no 33 owm owm yes 40 o wm so wm yes 51 All other treatments 5 months*

*Juice was still microbiologically stable when experiment was terminated after five months. Effect of Preservatives

The grape juices which had no preservatives addej Jcontrols) did not have a good shelf-life. Filtered control samples stored at 35 F lasted 40 days, whereas unfiltered control sarrples at this temperature lasted only 13 days (Table 3). Even worse results were seen at S0°F where samples stored without preservatives lasted only 4 days (Table 4). As the level of sulfur dioxide increased, the shelf-life greatly increased. Unfiltered and filtered samples with 50 ppm sulfur dioxide stored at 35°F lasted 33 and 51 days, respectively (Table 3). Both samples with 100 ppm sulfur dioxide at this temperature showed no signs of fermentation when this e~riment was ter­ minated. However, at S0°F, sanples with 100 ppm addej sulfur dioxide lasted only 40 days (Table 4). With the sorbic acid, even better shelf-life was achieved. Samples containing sorbic acid, either 500 or 1000 ppm, did not show any signs of fermentation at either storage temperature over the five month storage period. The best stability seems to result from a combination of the sulfur dioxide · and the sorbic acid. Since, in this study, sorbic acid corrpletely inhibited yeast fermentation, using it in combination with the sulfur dioxide should provide good microbial stability. ·

59 TABLE 4. Shelf-! ife of unfiltered Concord juice using different preservatives at 50°F.

Sorbic Sulfur acid dioxide Shelf-life addition addition (days)

0 Pfm 0 ppm 4 0 ppm 50 Pfm 12 0 ppn 100 ppm 40 All other trea trrents 5 months *

*Juice was still microbiologically stable when experiment was terminated after five rronths. Effect of Storage Temperature

As expected, juices stored at 35°F lasted significantly longer than those stored at 50°F (Table 5). When comparing samples whi8h received the same filtra­ tion and preservative treatrrent, samples stored at 35 F lasted almost three times as long as those stored at 50°F.

TABLE 5. Shelf-life of unfiltered Concord juice at 50°F vs. 35°F.

Sorbic Sulfur acid dioxide Storage Shelf-life addition addition temperature (days)

0 ppm 0 ppm 50°F 4 0 ppm 50 ppm 50°F 12 0 ppm 100 ppm 50°F 40 0 ppm 0 ppm 35°F 13 0 ppm 50 ppm 35°F 33 All other treatments 5 months*

*Juice was still microbiologically stable when experiment was terminated after five months.

Combination Effects of Filtration, Preservatives, and Storage Temperature

When the effects of the varying combinations of filtration, preservatives and storage temperature are examined, the best treatments become apparent. Of all the combinations examined, the best treatment would be that employing DE filtration, 500 ppm sorbic acid, minimal sulfur dioxide, and storage at 35°F.

60 Effect of Antioxidants The grape juice stored in plastic containers without the addition of sulfur dioxide or ascorbic acid rapidly deteriorated in color quality. This is demonstrated b¥ the rapid increase of the visual rating after 4 weeks (Table 8). Hue values increased (Table 6) and brightness values decreased (Table 7) at each time interval as the juice browned. The grape juice stored in glass containers had greater color stability then the plastic controls as well as equaling or bettering the other treatments. Relatively stable hue (Table 6) and brightness values (Table 7) relate to the low visual rating scores (Table 8). With the use of ascorbic acid much better color stability was achieved in the plastic containers than without it. The juice with the higher level of ascorbic acid showed a slower change in hue (Table 6) and brightness values (Table 7) than the juice with the lower concentration. After 12 weeks both ascorbic acid treat­ ments had high visual ratings (Table 8) indicating poor color.

Sulfur dioxide had a temporary bleaching effect at both the 50 and 100 ppm levels. This caused high initial hue (Table 6) and low brightness values (Table 7) and poor visual ratings (Table 8). The bleaching effect went CMay quickest in the lower sulfur dioxide treatment. Both treatments retained acceptable color after 8 and 12 weeks.

TABLE 6. Hue values (Abs. 420 nm/520 run) of Concord juice using different an­ tioxidants at three time intervals.

Treatment 1 wk 4wk 8wk Glass Control .639 .735 .851 Plastic Control .891 1.595 2.045 Vi t. C. 25 rrg/100 rnl .664 .904 .799 Vit. C. 50 mg/100 ml .621 .759 .844 so2 50 ppm .925 .699 .917 so2 100 ppm 1.221 .971 .686

61 TABLE 7. Brightness values (Abs. 420 run + 520 run) of Concord juice using dif­ ferent antioxidants at three time intervals.

Treatment 1 wk 4wk 8wk Glass Control 2.867 2.521 2.292 Plastic Control 2.384 2.069 1.864 Vi t. C. 25 ng/100 ml 2.730 2.221 2.470 Vit. C. 50 mg/100 ml 2.877 2.307 2.449 so 50 R'ffi 1. 714 2.252 2.119 so~ 100 R'ffi 1.279 1.296 2.162

TABLE 8. Visual ratings* of Concord juice using different antioxidants at four time intervals.

Treatment lwk 4 wk 8wk 12 wk Glass Control 1 1 1 1 Plastic Control 2 5 5 5 Vi t. C. 25 ng/100 ml 2 2 3 4 Vit. C. 50 mg/100 ml 2 1 2 4 002 50 R'ffi 4 1 1 2 002 100 R'ffi 5 5 1 2

*1 (good) - 5 (poor) Recormendations Microbiological Stability 1. Use high quality, clean and sound fruit. Fruit which is in good coooition will generally be lower in microbial contamination and will, therefore, have better shelf-life. 2. Keep processing equipment very clean. 3. Clarify juice irmediately after pressing. Settling the juice with a pec­ tic enzyme and DE filtration are good methods of producing a cleaner juice with lower numbers of microorganisms. 4. Store the juice at 35°F for the best shelf-life. 5. Fill juice into new containers. Never reuse old containers because they might be heavily contaminated with yeast or bacteria. 6. Add minimal amounts of sulfur dioxide to inhibit bacteria and also help prevent flavor oxidation and a brown color in the juice.

62 7~ Add 500 ppm sorbic acid to inhibit yeast.

Color Stability

Due to the rapid degradation of color in unpasteurized grape juice something is needed to increase its stability. In this experiment both the use of ascorbic acid and sulfur dioxide improved color stability. If an initial bleaching effect is tolerable the use of sulfur dioxide is recommended. The use of 50 ppm was sufficient in this experiment for acceptable color stability while bleaching the juice for a shorter time than 100 ppm. Sulfur dioxide also has the advantage of having antiseptic properties. When the avoidance of bleaching is necessary, the use of ascorbic acid is sug­ gested. At 50 mg/100 ml it grovided protection for at least 8 weeks. Storage at a temperature lower than 50-55 F would likely increase this time.

The glass containers proved to be superior to those made of plastic. Their cost, however, would likely limit their use.

LITERATURE CITED 1. Amerine, M.A. and C.S. Ough. 1980. Methods for analysis of musts and wines. John Wiley & Sons, NY. 2. Koburger, J .A., 1976. Yeasts and rolds. IN: conpendium of methods for the microbiological examination of foods. M.L. Speck, ed. Am. Public Health Assoc., Washington DC. 3. Singleton, V.L. and P. Esau. 1969. Phenolic substances in grapes and wine and their significance. Academic Press, NY. 4. Splittstoesser, D.F. and L.R. Mattick. 1981. The storage life of refrigerated grape juice containing various levels of sulfur dioxide. Am. J. Enol. Vitic. Vol. 32, No. 2. 5. Splittstoesser, D.F. 1981. Preservation of fresh grape juice. Proc. Ohio Grape-Wine Short Course. 56-60.

63 NEW APPROACHES TO aiiTE TABLE WINE PRODUCfiON Ralph Kunkee Department of Viticulture & Enology University of California Davis, CA

The title of this talk is apt, because we winemakers are definitely going to need new awroaches in the production of wine to survive. The problem is critical in California, where the expected increase in consumption of wine is not occurring, and any increase is being "eaten" up by the foreign wine imports. These wines are cheap, am often (or sorretimes) good. And thus, the problem is now to make our wines as cheaply. I have suggested that this is a California problem, rut Ohio winemakers are not imm.me. The more Ohioans get "turned on" to wine, that is, to the local wine (which they seem to be doing), the more they are going to want to enlarge their tastes. It is not unexpected that they also will turn to the cheap imports. Why are the foreign wines so cheap? One of the reasons is that it is a lot cheaper to produce wine in Europe, especially in northern Europe. All the ex­ pensive things we need here are cheaper there. The climate is cold and the harvest is late--there is little requirement in France for refrigeration and electricity is cheap. Most of the wines are made on a small scale and there is little need for a lot of professional help, and mostly nonunion labor is used. There is an abundance of water. There is also the question of subsidies. That seems to be mostly a red herring. The kinds of wine the government will buy for distilling purposes, and the amounts of money paid for it, is really out of the realm of winemaking reality. But there is another kim of subsidy that is real. That is the subsidizing of enological research in France, Germany and Italy. I can't document the exact ex­ tent of this new research money for universities, schools and research stations, rut there is enough evidence to indicate the amounts have been at least doubled of late. And why? To be able to continue the inexpensive production of wines in or­ der to continue to tap the untapped American wine market. If the Americans are not careful, we will be out of the wine business. Back to the people that are in Davis. I think I nentioned the people that had retired just recently. All viticulturists, Koch, Nelson, Lieder, and Kasamatis. The other thing, I just wanted to say one more time about the 3 new viticulturists­ -Larry Williams, Mark Matthews, and Janice Morrison--are not morphologists, Morrison is, rut they're working on the morphological aspects of the grapevine. What they are really doing is a new idea in the sense. The idea is that the grape and wine people work together to improve both aspects. It hasn't really worked ·much like that, there's the viticulturists and the enologists. But here we have these 3 new viticulturists that are really looking at the fruit quality in relation to winemaking more so than has been done in the past. Some of the graduate stu­ dents are actually in enology and I think that's a very good step forward. One of the best ways to handle the subject matter of this talk, I have found, is to let you suggest the areas of interest. This we did in the discussion times between the first talk and this one. One subject asked about has to do with the spoilage yeast, BrettanQm¥oes. It is, indeed, a spoilage yeast. It is everywhere, but one need not be overly concerned about it, if one follows good winery sanita­ tion procedures. We are not talking about sterilization of one winery, in fact, that cannot be done. However, it can certainly be sanitized. Keep the winery clean and then save the sterilization operations for when you are doing sterile

64 bottling and that sort of thing. To keep the resident population down requires attention to cleanliness, sanitizing and filtration (from time to time); and of course, judicious use of SO • Spoilage of wine by this year is characterizErl by a barnyard-like smell, or tha~ of a horse blanket. When it is not too strong, it Un­ parts a pleasant herbal, Pinot noir, bottle bouquet or tone. However, it does not take rruch to become nauseated. I am not surprised to fim it in most wineries, even in new ones. The point is if one pays attention to it, it can be kept umer control, especially because it is so2 sensitive. Another organism, though, that is not so nice is showing up in several commer­ cial wines in California. I hadn't meant to talk about this, but it is important to tell you. It is Zygosaccharomocces bailii, but you may have heard of it by its old name Saccharoym;es bailii. It is an osiOOCilic yeast, it will grow in grape juice and in grape JUice concentrate for long periods of time. It is not SO sen­ sitive, and it is not sorbic acid sensitive. So if it is in grape juice tha~ one is going to use for sweetening, one cannot stabilize the resulting wine with sorbic acid. The main problem with this is cosmetic spoilage. Sometimes it may give a little bit of a bitter taste. The only way to prevent this spoilage is by cold sterile bottling. As was mentioned, one must use heat to sterilize the filtration and bottling ~ipment. Hot water coming out of all the filter spouts for 20 minutes at 160 F is needErl. I have been asked to talk about yeast and bacterial strains. Which are the best ones to use and what are their differences. There are certainly differences in performance. If I must make a recomnendation, I would suggest the use of those which are commercially available as active dry yeast. First of all, the yeasts are grown under strong aerobic conditions so that they have a lot of the "survival fac­ tors" in their nenbranes, so that they could carry out the fermentation very well. Yeasts that are well known are Montrachet, Epernay, California Champagne, and Pasteur Champagne. The fermentation performances, while they are inherent in the genotype of the yeast, do not show up as phenotypes in exactly the sama way. Much depends on the condition of the fermentation. In other words, you can use bad winemaking techniques and get a great difference in the resulting wines due to variations in residual sugar or in acetic acid, acetaldehyde, or hydrogen sulfide produced. However, there are no differences in the flavor of the wines resulting from the particular yeast used for the fermentation. In other words, the final wine that you are going to make is going to end up with the same product, from a flavor point of view, regardless of which bona fide strain of wine yeast is used. That hurts to say because a microbiologist would have liked to be able to say that the yeast strain is of ultimate importance as far as what kind of wine you are going to make. But is is not true. That does not mean that this is the condition forever. In fact, we went to the moon, we can do other things. We could locate the gene, let's say, in the grapevine that produces the enzymes that produce the flavor components for Chardonnay (When Professor Noble finds out what the Chardonnay character is) • All it takes to do this is money. Professor Meredith could clone these genes and put them into wine yeast. We could bring is some color components, too. Thus one could be making beautiful Cabernet Sauvignon type wines, with a French oak barrel character with bottle bouquet from Thompson Seerlless grown in Bakersfield, California. The question is not if that could be done, but if it were, would winemakers want to use it. One last subject. Somebody asked about ultrafiltration. Ultrafiltration is being looked at as a new way to stabilize white wines for protein stabilization. At present, depending on the pH, same of the wine proteins are at their isoelectric

65 point and fining agents such as bentonite just will not take them out. Adding a lot more bentonite does not solve the problem. People are thinking about using proteinases, they're some people's idea of using yeast with proteinases, if you will, genetic engineering. But, another way would be to use ultrafiltration, which in a sense is not getting rid of particular materials, but getting rid of soluble materials; such as proteins. It is not a new idea; it has been around for a long tire. Hcwever, it is very expensive. The equipnent and the cost of running it should be carefully considered. In sumnary, I am going to say again, I am delighted to be asked to share ex­ periences with all of you. I do expect our paths to cross again and hopefully of­ ten. I hope I have been able to give you sore of my ideas about what we should be expecting in winemaking and viticultural science in the years to COilE. I want to look at new and more efficient, and more exciting way to do what we have already been doing and what our antecedents have been doing for us: making wonderful wine. That was exerrplified by last night's wine tasting. The product is fine. The problem is being able to get it to the consurer for a price that they will be will­ ing to pay.

66 OVERVIE.W OF VITiaJLTURE AND GRAPE uriLIZATION RESEARCH AT THE UNIVERSITY OF ARKANSAS Justin R. Morris University of Arkansas Fayetteville, AR 72701 The University of Arkansas has established an extensive research program in the areas of raw product physiology and grape processing. The majority of these research projects are designed to look at the influence of the pre-harvest complex on.both yield and quality. It is, indeed, a pleasure for me to share with the Ohio Grape Growers and Wine Makers concerning the highlights of this program. Before discussing individual projects, I want to mention the tremendous contributions of many excellent graduate students to the success of this entire program. They are co-authors of the publications shown at the end of this article. Following are individual projects that illustrate exanples of our research program: Drip Irrigation, Fruit Load, and Nitrogen Fertilization Study On •concord' Grapes

'Concord • grape response to supplemental irrigation, pruning severity, and nitrogen level was studied in a factorial experiment for 8 years. Supplemental ir­ rigation increased yields and was beneficial in attaining acceptable juice quality levels and maintaining vine size when vines were less severely pruned. Balance-pruning to a 60+10 severity increased yields for the first 2 years, after which the 60+10 severity was similar in yields to the 30+10 severity. This adjust­ ment in yield was due to the reductions in node fruitfulness and vine size b¥ the 60+10 pruning severity. Nitrogen fertilization at the levels used had little in­ fluence on yields or vine size, but tended to increase % soluble solids and pH and to reduce titratable acidity. Additional nitrogen fertilization may be necessary to mature fruit on vines receiving supplemental irrigation. Juice quality as indi­ cated b¥ % soluble solids and color tended to be related to yields, with higher yields resulting in lower quality. The results of this study has been the basis for the formation of a new irrigation district in Northwest Arkansas. Relationship of Seed Number and Maturity To Berry Development, Fruit Maturation, Horroonal Changes, and Uneven Ripening of •concord 1 Grapes Fruits were collected on weekly intervals in 1980, beginning at fruit set (ovary shatter) and continuing through harvest. Additional sanples collected at · harvest in 1980 and veraison in 1981 were sorted into preveraison green, postveraison green, and ript~ing categories. Seed number per berry was directly related to accumulation of C-photosynthate, fresh weight, and dry weight. Seed number had little relationship with berry content of indoleacetic acid (IAA), abscisic acid (ABA) or percentage of acidity. Percentage of soluble solid was not affected by seed number prior to veraison, but after veraison, percentage of soluble solids and intensity of juice color were inversely related to seed number. Nonripe fruit at the time of harvest had fewer seeds per berry, and fruit contain­ ing an immature seed did not accumulate ABA or enter veraison. IAA levels were similar in ripening and nonripening fruit. IAA declined to basal levels b¥ about 55 days after peak bloan. ABA began to increase after 65 days from ~ak bloom and berry changes associated with veraison occurred after 72 days.

67 'Concord' Training System Study Training grapevines to the shoot positioned Geneva Double Curtain system resulted in consistently larger yields than Single CUrtain or Umbrella Kniffin training. Vines of the size used in this study will benefit from GDC training un­ der Arkansas conditions. Even though yields were higher on GDC, no sacrifice of fruit quality occurred. A 70+10 pruning schedule showed definite trends of over­ cropping stress, resulting in continued quality reduction and eventually yield loss. Changing vineyard training from the conventional UK system to a shoot posi­ tioned SC training system can be accomplished with minimal effort without a reduc­ tion in productivity or fruit quality and will allow implementation of mechanized pruning. However, GDC, on the basis of productivity, as well as adaptability to mechanical pruning, would be superior to SC or the conventional UK system in Arkansas. Yield and Quality of 'Concord' Grapes as Affected by Pruning Severity, Nodes/Searing Unit, Training System, Shoot Positioning and Sampling Date Retaining roore fruiting nodes/vine increased yield, rut reduced fruit quality. Geneva Double Curtain training produced more fruit with better quality than a single wire cordon training system. Positioning the current season's growth verti­ cally toward the vineyard floor increased yields of vines pruned to short {3-node) spurs. Yield was increased by shoot positioning the season after perforrndng the operation, however, fruit quality was improved during the season that vines were shoot positioned. Pruning vines to 6- or 9-node canes increased yield without sacrifice of fruit quality as compared to 3-node spurs and reduced the yield­ increasing potential of shoot positioning. Use of longer canes, GDC training, a shoot positioning grapevines in Arkansas may allow less severe pruning than the currently recommended 30+10 pruning schedule to increase yield without a loss in fruit quality. Pruning weights were generally reduced by treatments which in­ creased yield. Work on the extent of vine size reduction by the various treatments and its effect upon future production will be continued. Soil Depth and In-Row Vine Spacing Study in 'Concord' Grapes A site was prepared with 2 distinctly different soil depths and a vineyard of 'Concord' grapes was established with in-row spacings of 1.52, 1.83, 2.13, 2.44, and 3.05 m. Wider in-row vine spacings resulted in increased vine yields on deeper soils to the point that yields per meter of cordon and per hectare were not . reduced; but yield per meter of cordon and per hectare were reduced on the shallow soi 1 when in-row vine spacings exceeded 2. 44 m. There were few effects on juice quality from either soil depth or in-row vine spacings. Mechanical Pruning Study Pruning became the largest labor demanding vineyard operation once mechanical harvesting was solved. In addition, obtaining qualified pruners in Arkansas is be­ coming increasingly difficult. OUr research indicates that mechanical trimming of 'Concord' vines on Bilateral Cordon or Geneva Double CUrtain training system can reduce the pruning labor required for cane selection and node adjustment if vines are shoot positioned. Manually limiting the number of nodes per vine to 60 following mechanical trimming maintained vine size and produced fruit yields and

68 juice quality comparable to vines balanced pruned to a 30+10 schedule. Retaining 90 or more nodes per vine following mechanical trimrndng reduced vine size and produced juice of unacceptable quality. Observations indicate that 1 year of completely mechanized pruning with no follow-up hand pruning followed by a year of balanced pruning to a 30+10 schedule (alternate year pruning cycle) may be feasible with no long term detrimental ef­ fects on production or quality. Viticultural concerns with mechanical trimning, even if followed by hand prun­ ing, at present are: 1) the impossibility of treating each vine individually (balance pruned) which could result in the overcropping or undercropping of in­ dividual vines; therefore, a vineyard of uniform vigor would be a major considera­ tion for mechanical pruning; 2) the inability to select only superior canes; it is entirely possible that some of these canes would be removed by mechanical trimning.

'Concord' Potassium Fertilization Study Excessive levels of potassium (K) fertilizer (225 to 900 kg/ha) were applied to 'Concord' grapevines for 7 years in a vineyard with adequate levels of soil K. Petiole K content increased from 1.24% (dry wt. basis) in control plots, to 6.07% in high K plots, and petiole Ca, Mg and Mn decreased with K fertilization. Juice K increased with increasing levels of K fertilization, resulting in increased pH and reduced ti tratable acidity of the raw juice. As K level in the raw juice in­ creased, there was significant acidity loss and pH increase following storage. Highly significant correlations existed between K in juice before storage and loss of acidity during storage. There was little effect of high levels of K fertiliza­ tion on % soluble solids.

In later study, three excessive rates of potassium (K) were applied throughout the growing season to 3-year-old container-grown 'Concord' (Vitis labrusca L.) vines. Excessive K fertilization increased the K content and lowered the Mg con­ tent of petioles, leaves, canes, trunks and roots when sampled at fruit harvest and, to a lesser extent, during dormancy. The K level of petioles had better cor­ relations with fresh and stored juice K and pH than did the other plant parts. Fresh and stored juice K levels and pH were increased when excessive K fer­ tilization was applied. Highly significant, positive correlations existed between juice K and juice pH. The color quality and acidity of the fresh and stored juice were lowered by excessive K fertilization. Color quality of the fresh and stored juice was significantly and negatively correlated with fresh juice pH. This demonstrated the effect of pH on the color expressed by the anthocyanins. Excessive K fertilization also resulted in a greater increase of juice pH and a greater loss in color quality during storage. Gibberellic Acid Studies on 'Concord' Grapes

Gibberellic acid (GA ) applied to 'Concord 1 vines at a rate of 100 PIX~\ reduced the percentage of green f~it and improved fruit quality (% soluble solids, color) in years when uneven ripening was a proble:n. This improvement in fruit quality through GA has occurred in both research plots and comnercial vineyards. GA has also incre~sed berry size of 'Concord' grapes, but this size increase is incodsis­ tent between years and vineyards. When berry size is increased by GA3 , slight yield increases have been observed. GA3 seems to be more effective in increasing

69 berry weight in older vineyards and when used in combination with magnesium sulfate (1 or 3%} or Cheplex (1/2 gal/acre}. Studies with GA3 in combination with plant nutrients are continuing. Effect of Ethrel on 'Concord' Juice Quality Reports have indicated that Ethrel will improve quality of same cultivars of wine grapes. Concentrations of Ethrel ranging from 0 to 1200 ppm (sufficient to cause abscission) were applied as a single application 1 week prior to harvest or in multiple applications beginning at veraison for 3 years. High concentrations caused abscission, but none of the treatments affected % soluble solids, or color of the juice. Ethrel tended to increase pH and decrease titratable acidity, both of which are undesirable for 'Concord' produced in southern growing areas. Use of Alar on 'Concord' Grapes Results of this study have substantiated reports that Alar may increase yields of 'Concord' grapes when applied between first- and peak-bloom. However, yield in­ creases were not observed in every year. Since increases in production parallel increases in berries/cluster, Alar may be of value when conditions at or prior to bloom are unfavorable for adequate fruit set. This study also confirms results reported by other researchers that Alar is capable of retarding vegetative growth of 'Concord' vines. Application of Alar appeared to adversely affect certain indicators of 'Concord' grape juice quality, but only when yields were increased. Since reduced maturity and color intensity were attributed to the greater fruit load of Alar-treated vines, use of Alar may result in unacceptable juice quality when treatments result in over-production. Primary control of production should still be achieved through regulation of pruning severity, but Alar applied between first­ and peak-bloom at the rate of 1 pound per acre may insure a good crop in years when certain environmental factors might otherwise cause yields to be low. Alar can also improve fruit set in vineyards which have a history of poor fruit set, regardless of weather conditions during bloom. Alar at 1 and 2 pounds per acre applied to a 9-year-old vineyard with a record of good fruit set did not significantly affect yield, but resulted in slightly reduced soluble solids and juice color. However, in an adjoining 19-year-old vineyard which had a history of poor fruit set, yield was increased by Alar with no effect on juice quality.

Naphthalene Acetic Acid (NAA} For Sucker Control in Vineyards

NAA has been used successfully to control sucker growth near pruning cuts in tree fruit crops. Sucker rerooval from grapevine trunks is labor consuming and chemical control would be desirable. Dilute solutions of NAA at several concentra­ tions were applied to trunks of 7-year-old 'Concord' vines with a hand sprayer in April of 1976. Excellent sucker control of treated trunks was obtained for 2 years after treatment. Intermediate control was obtained the third year after treatment and no control after the fourth year. NAA had no effect on fruit yield or quality and did not prevent underground suckers from energing for trunk renewal purposes. NAA applied to young (2-year-old} Niagara plants resulted in death of same vines. Vine age would be a factor for determining use of NAA.

70 Growth Regulators to Delay 'Concord' Budbreak Late spring frosts are always a potential problem in the Ozarks region and can result in severe losses of 'Concord' production. Delaying budbreak of 'Concord' would be beneficial to reduce chances of spring freeze damage and sufficient delay in harvest. Alar, naphthalene acetic acid, abscisic acid, dikegulac, CIPC, and Ethrel were applied for observations only at various concentrations at bud swell or 1 month prior to bud swell. When applied 1 month prior to bud swell, CIPC was the only growth regulator with any noticeable effect on delaying budbreak. When applied at bud swell, naphthalene acetic acid and dikegulac damaged foliage and produced poor­ ly filled clusters. Abscisic acid, Alar and Ethrel had no effects. The time of bloom was not delayed by any growth regulator at the concentrations used, except CIPC. Buds on vines treated with CIPC had not pushed at the time of normal bloom and many of the buds were dead. Lampblack for Frost Protection of •concord' Grapes The test began on April 4, when there was still a 50% probability of the tem­ perature falling to 28°F. Lanpblack was applied at the rate of 25 pounds per acre. Temperatures were measured at 12~inute intervals at heights at 4.5, 38 and 55 in­ ches at two locations in the treated and check plots from April 4 through April 19. Five episodes of freezing temperatures occurred during this time. Onset of 32°F averaged an hour later in the lampblack plot than in the check plot, and average duration of freezing temperatures was shorter in the lanpblacked plots than in. the check plot, averaging about 45 minutes less at both 38- and 55-inch heights.

On April 9, temperatures at the 55-inch height fell to nearly 26°F in check plots and to slightly less than 28°F in lanpblacked plots. Bud counts on April 23 showed no evidence that lampblack had reduced bud damage. This preliminary test suggests that some frost protection can be achieved by applying lampblack but temperature differences are not great. Significant protec­ tion may be noted only if freezes occur when buds are at their most susceptible stage and temperatures do not fall much below 28°F. Dormant Oil Study High concentrations of dormant oil applied 15 days prior to bud swell for grape scale control can adversely affect vegetative growth and yield of •concord' grapes. Vegetative growth is initially slowed, even at the rate of 2 gallons per 100 gallons of spray. The higher concentration treatments (4, 8, and 16 gallons/100 gallons water) continued to show reduced growth at 2 months after ap­ plication. Pruning weights also showed this trend toward reduction of vegetative growth by high concentrations (8 and 16 gallons) of oil. Seventy-one percent of the vines were killed from the highest oil concentration (16 gallons). Fruit quality was not affected by oil applications. These data are preliminary and based on only one year's results. Additional information may be needed to determine how oil can safely be used for scale control.

71 Prediction of 'Concord' Grape Maturation Early prediction of 'Concord' harvest would be helpful in scheduling harvest, transportation and plant operations. The purpose of this study was to develop a mathematical model to predict 'Concord' harvest in Arkansas, determine its reliability and characterize the sources of error encountered in predicting fruit maturation. Under conditions of this study (using data from 6 vineyards for 19 years), utilizing different combinations of base temperatures, upper temperature limits, and cardinal-temperatures in linear heat unit accumulation systems did not provide an improvement over the use of calendar days as a means of predicting 'Concord' grape maturation. The most accurate predictions of grape maturation were made from 8% soluble solids development rather than from the date of bloom. Changes in acidity or color were not as predictable as soluble solids development during maturation. Climatic variations other than temperature between years and between vineyards within a year and differences in cultural practices prevent accurate and reliable use of a forecasting system for 'Concord' grape maturation in Arkansas. However, long range estimates from a prediction model may be useful to determine the start of initial fruit sampling but continuous monitoring of fruit maturation is neces­ sary to determine actual harvest dates and scheduling of processing facilities.

Use of so2 On Mechanically Harvested 'Concord' Grapes The most important factor influencing postharvest quality deterioration of mechanically harvest 'Concord' grapes in Arkansas is the high temperature at har­ vest since this can determine the holding temperature inside a bulk pallet box for up to 72 hr under field conditions. Ambient air temperatures can reach as high as 38°C and same berry temperatures could be higher if fruit is exposed to direct sun­ light and is harvested at midday. The temperature of a large mass of grapes in a bulk pallet box will change little with normal diurnal fluctuations in ambient air temperatures. Application of potassium metabisulfite to release SO in quantities of 80 and 160 ppm will slow postharvest deterioration of 'Concord' ~rapes harvested under hot temperatures. If a delay in plant delivery for processing is inevitable, applica­ tion of SO as late as 6 hr after harvest will beneficially retard postharvest quality ch~nges for up to 24 hr. Harvesting during night hours or the cooler por­ tion of the day prior to heat build-up in fruit could be an alternate consideration if the raw product must be held for extended periods or transported for long dis­ tances prior to processing. However, the addition of 80 to 160 PPID so2 to a bulk pallet box of grapes mechanically harvested at a temperature of 35°F is as effec­ tive in retarding postharvest deterioration as is harvesting at 25°. A combination of so2 application and harvesting when grapes are cool would allow for extended holding of the raw product. Chemical Weed Control and Hazard Studies

(Cooperative work by Talbert, Lavy, and Morris) Grapehoeing adequately removes existing weeds growing in grapes. Where grapehoeing is a practice, lower initial rates of pre-emergence herbicide may be

72 used~ An additional half-rate of herbicide is required after grapehoeing to maintain weed control through fall. 'Concord • plots not grapehoed were almost completely weed free following a glyphosate treatment. No injury from glyphosate was detected on any part of the vines not sprayed. Glyphosate applied to low hang­ ing foliage and basal shoots of •concord' grapevines in August, September, and October was extremely injurious to grapevines. Injury was evident throughout the grapevine the following spring and during the full growing season. Growth on new shoots, yield, and pruning weights indicate 50% or more reduction in growth as can­ pared to the untreated check. The September treatment appeared more injurious than that of August or October. To determine the hazard to grape growers when spraying paraquat, potential dermal, respiratory and internal exposure to paraquat was monitored for 2 years. The results revealed very low levels of paraquat exposure. Respiratory exposure was minimal and there was no paraquat detected in any of the urine sanples collec­ ted. Those persons receiving the highest levels of paraquat exposure had neasure­ nents which were well below those found to be toxic to laboratory animals. Hazards from using this material by this nethod of awlication should be low when used in accordance to label directions and precautions. Niagara Study

The response of 'Niagara • grapes to various training and pruning systems in­ cluding the Geneva Double Curtain (GDC) and single wire cordon (SC) training sys­ tems, pruning severities of 30, 50 and 70+10, spur cane lengths of 3, 6, and 9 nodes, and shoot positioning are being evaluated. Preliminary results (average of 2 years data) indicate that the GDC training system is more productive than sc, while maintaining juice quality at a level comparable to the lower yielding SC training system. Less severe pruning will increase yields with a corresponding reduction in soluble solids. Little response has been obtained from the different spur or cane lengths. Shoot positioning increases yield without a sacrifice of fruit quality. Acids, which are of concern in 'Niagara• grapes, drop rapidly as the fruits mature and pH increases rapidly. Excessively high pH • s are obtained by the tine 'Niagara• grapes develop 15% soluble solids. Studies on French Hybrid Grapes A study was conducted for four years on three white and three red commercially · important French hybrid cultivars to determine their response to training systems, pruning severities and spur lengths. Chelois and Chancellor (both red) were the highest yielding and most vigorous cultivars. Verdelet and Aurore (both white) were the lowest yielding cultivars. The lower yielding white cultivars had higher % soluble solids, higher pH and lower acidity at harvest than the higher yielding red cultivars. Regression analysis showed that the Verdelet and Aurore cultivars had a higher pH at a given% soluble solids than did Seyval (white), Villard Noir (red), Chelois, and Chancellor cultivars. All cultivars except Aurore had higher yields and lower % soluble solids on the Geneva Double Curtain training system than on the single-wire, bilateral cordon system. Training system had no effect on pH or acidity. There were no differences between the 10+10 and 20+10 pruning severities on yield, pruning weight or quality parameters. There were no

73 differences between the 2-node spurs and the 4-node spurs on yield, pruning weight or quality parameters. A study has been initiated to examine the effects of shoot and cluster thin­ ning on the yield and quality of six cultivars of French hybrid grapes.

pH Imbalance Study on Wine Grapes A survey of 15 cultivars of wine grapes was conducted for 2 years to determine if a pH unbalance problem exists in Arkansas. Eight cultivars developed an exces­ sive pH (above 3.50) by harvest in a cool season, and 12 cultivars developed exces­ sive pH harvest in a very hot, dry season. Seasonal variation also was observed for % soluble solids and acidity. Acceptable % soluble solids for wine production was attained at the expense of acidity and pH. The pH of wine grapes grown in Arkansas should be used when possible to determine harvest.

A study is currently being conducted to determine the effects of cluster thin­ ning and high rates of potassium fertilization on pH and overall quality of five wine grape cultivars. Preliminary results indicate that both cluster thinning and heavy potassium fertilization increased pH and % soluble solids, and lowered acidity. These treatments had small, inconsistent effects on color, anthocyanin content of red cultivars and yield. This study is being continued with emphasis on the effects of cluster thinning and potassium fertilization on wine pH and quality.

Yield and Quality of Wine Grapes (Vitis vinifera L.)

A study was conducted to evaluate fruit maturity parameters and to determine yield and maturation rates of six major Vitis vinifera wine grape cultivars grown in the state's main wine-producing region. The cult1vars evaluated were Cabernet Sauvignon, Petite Sirah, Pinot noir, Gewurztrarniner, White Riesling, and Chardonnay. The study was conducted in an own-rooted commercial vineyard at Altus, es­ tablished in 1973 and trained to a bilateral cordon. Vines were spur pruned to 70 nodes each year. Vines were spaced 1.83 m (6 ft) in the row and 3.66 m (12 ft) be­ tween rows. The highest yielding cultivars in a cool, wet season were Petite Sirah and Cabernet Sauvignon. In 1980--a hot, dry season--Pinot noir had the highest yield. However, all cultivars had commercially acceptable yields (above 8 MT/ha) both years. Some of the cultivars were allowed to overproduce. In cases where this oc- . curred, 70 nodes were too many. Therefore, fewer nodes should be retained, and/or cluster thinning will be required for crop load control with some of these culti vars.

Examination of the interaction of cultivar X sampling date shows that the pH of Pinot noir and White Riesling did not increase as much as it did in the other cultivars between the second and third sampling dates. During a hot, dry year, White Riesling and Pinot noir did not show the expec­ ted increases in % soluble solids between the 2nd and 3rd sampling dates. It is possible that 14.6 MT/ha and 28.3 MT/ha, respectively, were excessive loads for these cultivars under hot, dry climatic conditions.

74 Also·~ the acidity of Chardonnay decreased and pH increased to a greater extent between the 1st and 2nd sampling dates compared to the other cultivars. Petite Sirah, Pinot noir and White Riesling were the best of the cultivars in maintaining a low pH between the 2nd and 3rd sampling dates. An extremely high pH and low acidity occurred with Gewurztraminer. Consistent differences in quality parameters during ripening were observed among most cultivars, and further investigation is needed to determine their in­ fluence on wine quality. The pH of the wine may be different from the pH of the raw product depending largely on the potassium level, malic acid level, and the buffering capacity of the grapes. Therefore, additional research is needed to re­ late the final wine pH to the raw product pH of these cultivars produced under Arkansas climatic conditions. However, it is important that Arkansas wineries closely monitor the fruit pH level and use this parameter as one of the major fac­ tors in determining optimum harvest time. Adequate soluble solids are attained at the expense of desired acidity and pH. Maturity Sorting of Muscadine Grapes gy Density Separation

Muscadine grapes do not ripen uniformly. The presences of imnature fruit in the once-over harvested product causes quality problems in wines and juice products. Low frequency vibrations and automatic color sorters have been evaluated for sorting muscadines, but a more rapid and inexpensive method is needed. Since most muscadine cultivars are harvested with a dry stem scar, use of salt brine for density separation was tested. 'Carlos' nuscadine grapes were sorted into 5 density grades using 4 brine solutions of 8, 9, 10 and 11% NaCl. Soluble solids and berry weight increased, color inproved, and acidity decreased with increasing grape maturity and bring con­ centration. Panelists' sensory preference increased with increasing density (maturity). Berries that floated and sank in 11% NaCl (density grades 4 and 5) had acceptable ratings for flavor, aroma, and color. Density separation was used to monitor the rates of maturation of the cultivars 'Carlos' and 'Noble'. The tech­ nique was useful in characterizing the changes in berry population during the last month of ripening. Mechanical Harvester Adaptation for Muscadines Most muscadine grape cul ti vars develop a dry stem scar and abscise when they mature. Because of poor ripening uniformity, it is necessary to delay a once-over machine harvest to allow further ripening of the less mature berries. When harvest ·is delayed, the riper fruit will detach from the vine with the slightest agitation. When harvesting commercial vineyards of muscadines in eastern Arkansas in which harvesting had been delayed to improve maturity, the benefits from delaying harvest were nullified because of ripe fruit falling to the ground in front of the harvester. The problem was corrected by installing 2 extended catching frames on an incline in front of the harvester, 1 on each side under each trellis wire of the Geneva Double Curtain training system.

75 Influence of Cultivar, Extraction and Storage Temperature, and Time on Quality of Muscadine Grape Juice A processing study was conducted on 2 cultivars, 3 extraction temperatures, 3 storage temperatures and 3 storage times to assess differences in quality of juice of muscadine grape (Vitis rotundifolia Michx.). The 2 cultivars responded dif­ ferently to all other variables in color changes. •carlos', a bronze-skinned grape was higher in acidity and lower in pH and total phenols than 'Noble', a black­ skinned cultivar. Higher extraction temperatures leached out more acids, total phenols, and color. Color and overall quality changes were rapid at 32°C storage, making the juice unacceptable at 7 months storage. Greater changes in quality oc­ curred when juice was extracted at 60°C than at 24° or 80°. Red Muscadine Wine Color Stability Study

Red muscadine grape (Vitis rotundifolia Michx.) wines were very susceptible to browning and overall loss of color quality during processing and storage. A study was designed to examine the effects of three pH levels (2.90, 3.20, 3.80}, three sulfur dioxide levels (120, 170, 220 ppm total so2}, three storage temperatures (20°C, 30°C, 40°C}, and three storage times (0, 3, 9 months}. A higher pH resulted in a loss of color intensity and redness, and increased browning during storage for 9 months. Wine with lower pH had a greater loss of free, unpolymerized an­ thocyanins, which indicated greater polymerization in lower pH wine. Sulfur dioxide severely bleached the color of red muscadine wine and lessened browning in high pH wine only. SO also lessened browning of wine stored at 20°C, but not at higher storage tempera~ures. Higher storage temperature greatly increased browning and anthocyanin loss during 9 months of storage. Wine stored at 30°C or 40°C had unacceptable color after 9 months.

A second study was designed to compare the color components and color stability of red wine from Noble and Cabernet Sauvignon at 4 pH levels (2.8, 3.0, 3.3, 3.8}. Noble browned to a much greater extent and lost more color after 10 and 16 months than did Cabernet, and Noble did not increase in chemical age (level of polymeric anthocyanins} to nearly the extent that Cabernet did. This lack of anthocyanin-tannin polymerization in Noble seems to be responsible for the color instability. A higher pH resulted in greater browning and color loss in both species, but higher pH lowered the color intensity and increased browning in Noble to a greater extent than in Cabernet. Greater anthocyanin-tannin polymerization was probably responsible for the greater color stability at lower pH.

Muscadine Juice Blending Study

A study is being conducted to determine if muscadine grape juice (cvs. Noble and carlos) can be blended with 'Concord', 'Niagara', apple or cranberry juice to create a new and improved product from muscadine grapes. Quality of the blends will be determined by sensory evaluations and by objective measurements, and stability of the products will be evaluated. Changes in Muscadine Grape Juice Quality During Storage

Muscadine grapes (Vitis rotundifolia, Michx.) of two cultivars (Noble and Carlos} were washed and extracted. The resulting juice was cold stabilized for o6 7 and 60 days at 2°C, then treated, bottled, pasteurized and stored at 2°C and 24 c for 0, 4, 8 and 12 months. Carlos juice was lower in phenols and pH and higher in

76 acidity than Noble. The high total anthocyanins and phenols in the Noble juice caused a significant loss in pigment during cold stabilization. Dilution of juice with 40% water and adjustment of the sugars was beneficial to flavor and color of Carlos, yet 40% dilution was too high for Noble juice. Treatments of either juice with caco3 increased pH and decreased acidity. During 12 IOOnths storage, the Carlos juice became darker due to browning, while the Noble juice became lighter by losing pigment, especially at 24°C.

RECENT PUBLICATIONS IN VITIOJLTURE AND ENOLOGY Some of you may have an interest in reading recent articles that have been generated from this research program. For your convenience, I am listing articles that have been published since 1970. 1. Morris, J.R., J.W. Flemdng and D.R. McCaskill. 1970. Use of Alar on 'Concord' grapes. AR Farm Res. 19(2):6. 2. Benedict, R.H., J.W. Fleming, and J.R. Morris. 1971. Postharvest changes in quality of mechanically harvested 'Concord' grapes. AR Farm Res. 20(1) :10. 3. Morris, J.R. 1971. Growth regulators on grapes under Arkansas conditons. Proc. 9th Ann. Mtg. AR Agr. Pest. Assoc. pp. 49-51. 4. McCaskill, D.R., J.W. Flemdng, and J.R. Morris. 1972. Further studies of Alar use on grapes. AR Farm Res. 21(3):9.

5. Morris, J.R., J.W. Fleming, R.H. Benedict, and D.R. McCaskill. 1972. Effects of SO~ on postharvest quality of mechanically harvested grapes. AR Farm Res. 21(2).5. 6. Morris, J.R., J.W. Fleming, R.H. Benedict, and D.R. McCaskill. 1972. Effects of sulfur dioxide on postharvest quality of mechanically harvested grapes. Proc. 93rd Ann. Mt. AR St. Hort. Soc. pp. 92-94. 7. Benedict, R.H., J.R. Morris, J.W. Flendng and D.R. McCaskill. 1973. Effects of tenperature on quality of mechanically harvested 'Concord' grapes. AR Farm. Res. 22(1):2. 8. Morris, J.R., J.W. Fleming, R.H. Benedict, and D.R. McCaskill. 1973. Maintaining juice quality of 'Concord' grapes harvested mechanically. AR Farm. Res. 22(1):9. 9. Downey, D.A. and J.R. Morris. 1974. Lanpb1ack for frost protection in a grape vineyard. AR Farm. Res. 23(5):13. 10. Morris, J.R. and D.L. Cawthon. 1975. Effect of mechanical pruning on yield and quality of 'Concord' grapes. Proc. 96 Ann. Mtg. AR St. Hort. soc. pp. 99-101. 11. Morris, J.R., D.L. Cawthon, and S.E. Spayd. 1975. Use of daminozide (Alar) on 'Concord' grapes. Proc. 97th Ann. Mtg. AR St. Hort. Soc. pp. 63-66.

77 12~ Spayd; S~E~ and J.R. Morris. 1975. Preliminary results with drip irrigation on yield and quality of 'Concord'. 96th Ann. Mtg. AR St. Hort. Soc. pp. 59-63. 13. Morris, J.R., D.L. cawthon, and J.W. Fleming. 1975. Effect of mechanical pruning on yield and quality of 'Concord' grapes. AR Farm Res. 24(3):12.

14. Spayd, S.E. and J.R. Morris. 1976. Two years results with drip irrigation on yield and quality of 'Concord' grapes. 97th Ann. Mtg. AR St. Hort. Soc. pp. 102-109,. 15. Cawthon, D.L. and J.R. Morris. 1977. Yield and quality of 'Concord' grapes as affected by pruning severity, nodes per bearing unit, training system, shoot positioning, and sanpling date in Arkansas. J. Aner. Soc. Hort. Sci. 102:760-767.

16. Cawthon, D.L. and J.R. Morris. 1977. Evaluating new training and pruning systems for increasing yield of 'Concord' grapes. AR Farm Res. 26(6):6.

17. McCaskill, D.R. and J.R. Morris. 1977. Effect of daminozide on yield and quality of 'Concord' grapes (Vitis labrusca L.) in Arkansas. J. Amer. Soc. Hort. Sci. 102:8-10. 18. Morris, J.R. and D.L. Cawthon. 1977. Quality of 'Concord' grape juice as af­ fected by cultural netl'x>ds. AR Farm Res. 26(6) :7. 19. Morris, J.R., D.L. Cawthon, and S.E. Spayd. 1977. Use of daminozide (Alar) on 'Concord' grapes. AR Farm Res. 26(2):7. 20. Rizley, N.F., W.A. Sistrunk, and J.R. Morris. 1977. Preserves from whole muscadine grapes. AR Farm Res. 26 (5) :2. 21. cawthon, D.L. and J .R. Morris. 1977. Evaluation of new training and pruning systems for increasing yield of 'Concord' grapes. Proc. 98th Ann. Mtg. AR St. Hort. Soc. pp. 58-62. 22. Lanier, M.R. and J.R. Morris. 1978. Density separation of muscadine grapes. AR Farm Res. 27(5):4.

23. Morris, J.R., D.L. Cawthon, and S.E Spayd. 1978. Evaluation of daminozide on 'Concord' grapevines of different fruit set potential. Hortsci. 13:696-697. 24. Spayd, S.E. and J.R. Morris. 1978. Influence of irrigation, pruning severity, and nitrogen on yield and quality of 'Concord' grapes in Arkansas. J. Amer. Soc. Hort. Sci. 103:211-216. 25. Spayd, S.E. and J.R. Morris. 1978. Yield and quality of 'Concord' grapes as affected by irrigation, pruning severity, and nitrogen. AR Farm Res. 27(1) :9. 26. Spayd, S.E. and J.R. Morris. 1978. Maturation and quality of 'Concord' grapes as influenced by the preharvest conplex. AR Farm Res. 27 (2) :5. 27. Lanier, M.R. and J.R. Morris. 1979. Evaluation of density separation for defining fruit maturities and maturation rates of once-over harvested muscadine grapes. J. Amer. Soc. Hort. Sci. 104:249-252. 78 28~ Morris; J.R., D.L. Cawthon, and J.W. Fleming. 1979. Effect..c:; of temperatures and potassium metabisulfite on quality and postharvest behavior of mechanical­ ly harvested 'Concord' grapes in Arkansas. J. Am?r. Soc. Hort. Sci. 104:166-169.

29. Kennedy, J.M., R.E. Talbert, and J.R. Morris. 1979. weed control in 'Concord' grapes in Arkansas. J. Amer. Soc. Hort. Sci. 104:713-716. 30. Morris, J.R. and D.L. Cawthon. 1979. Response of 'Concord' grapes to train­ ing systems and pruning severity. AR Farm Res. 28(5}:12. 31. Morris, J.R. 1979. Mechanical combing and pruning of 'Concord' grapes. Proc. lOOth Ann. Mtg. AR St. Hort. Soc. pp. 76-83. 32. Morris, J.R. and D.L. Cawthon. 1980. Yield and quality response of 'Concord' grapes to training systems and pruning severity in Arkansas. J. Amer. Soc. Hort. Sci. 105:307-310. 33. Morris, J.R. and D.L. Cawthon. 1980. Mechanical trimming of grape vines. J. Amer. Soc. Hort. Sci. 105:310-313. 34. Morris, J.R., D.L. Cawthon, S.E. Spayd, R.D. May and D.R. Bryan. 1980. Prediction of 'Concord' grape maturation and sources of error. J. Amer. Soc. Hort. Sci. 105:313-318. 35. Morris, J.R. and D.L. Cawthon. 1980. Mechanical pruning of cordon-trained 'Concord' grapevines. AR Farm Res. 29(2):12. 36. Morris, J.R., D.L. Cawthon, S.E. Spayd, R.D. May and D.R. Bryan. 1980. Prediction of 'Concord' grape harvest. AR Farm Res 29(3}:11. 37. Morris, J.R., D.L. Cawthon, and J.W. Fleming. 1980. Effects of high rates of potassium fertilization on raw product quality and changes in pH and acidity during storage of 'Concord' grape juice. Amer. J. Enol. Vitic. 30:323-328. (L.M. Ware Research Award) 38. Morris, J.R. 1980. Drip irrigation for grapes. Proc. lOlst Ann. Mtg. AR St. Hort. Soc. pp. 114-119. 39. Morris, J.R. and D.L. Cawthon. 1981. SUcker control in 'Concord' grape vineyards. AR Farm Res. 30(2):4. 40. Morris, J.R. and D.L. Cawthon. 1981. Control of trunk shoots on 'Concord' grapevines (Vitis labrusca L.} with naphthaleneacetic acid. HortSci. 16:321-322. 41. Morris, J.R. and D.L. Cawthon. 1981. Effects of vine spacing on yield and juice quality of 'Concord' grapes. AR Farm Res. 30(4}:3. 42. Morris, J.R. and D.L. Cawthon. 1981. Effects of soil depth and in-row vine spacing on yield and juice quality in a mature 'Concord' vineyard. J. Amer. Soc. Hort. Sci. 106:318-320.

79 43~ Morris; J~R. and D.L. Cawthon. 1981. Effects of ethephon on maturation and postharvest quality of 'Concord' grapes. J. Amer. Soc. Hort. Sci. 106:293-299. 44. Morris, J.R. and D.L. Cawthon. 1981. Yield and quality response of 'Concord' grapes to mechanized vine pruning. AR Farm Res. 30(6):13.

45. Capstick, D.F., A.Moshtagh, and J.R. Morris. 1981. Taste test of Venus--The new seedless table grape for Arkansas. AR Farm Res. 30 (6) :2. 46. Morris, J.R. and D.L. Cawthon. 1981. Yield and quality response of 'Concord' grapes (Vitis labrusca L.) to mechanized vine pruning. Amer. J. Enol. Vitic. 32:280-282. 47. Morris, J .R. and D.L. Cawthon. 1981. Mechanical pruning of grapes. Proc. 102nd Ann. Mtg. AR St. Hort. Soc. pp. 141-146. 48. Cawthon, D.L. and J.R. Morris. 1981. Solving the uneven ripening problems of 'Concord' grapes. Proc. 102nd Ann. Mt. AR St. Hort. Soc. pp. 147-150. 49. Morris, J.R. and D.L. Cawthon. 1982. Effects of irrigation, fruit load and potassium fertilization on yield, quality and petiole analyses of 'Concord' grapes. Amer. J. Enol. Vitic. 33:145-148. SO. Forbess, R.C., J.R. Morris, T.L. Lavy, R.E. Talbert and R.R. Flynn. 1982. Exposure measurements of applicators who mix and spray paraquat in grape vineyards. HortSci. 17:955-956. 51. Cawthon, D.L. and J.R. Morris. 1982. Relationship of seed number and maturity to berry development, fruit maturation, hormonal changes and uneven ripening of 'Concord' (Vitis labrusca L.) grapes. J. Amer. Soc. Hort. Sci. 107(6):1097-1104. (Krezdorn Award Paper Southern Region) 52. Morris, J.R. and D.L. Cawthon. 1982. Ethephon as a harvesting aid for 'Concord' grapes. AR Farm Res. 31(1):15. 53. Morris, J.R. and D.L. Cawthon. 1982. Effects of ethephon on maturation and quality of 'Concord' grapes. AR Farm Res. 31(2):6. 54. Cawthon, D.L. and J .R. Morris. 1982. Relationship of seed number, and hormone content to fruit ripening of 'Concord' grapes. AR Farm Res. 31(6):12. 55. Sistrunk, W.A. and J.R. Morris. 1982. Influence of cultivar, extraction tem­ perature, and storage temperature and time on quality of muscadine grape juice. J. Amer. Soc. Hort. Sci. 107(6):1110-1113.

56. Morris, J.R., C.A. Sims, and D.L. Cawthon. 1983. Effects of excessive potas­ sium levels on pH, acidity, and color of fresh and stored grape juice. Amer. J. Enol. Vitic. 34:35-39.

57. Cawthon, D.L. and J .R. Morris. 1983. Uneven ripening of 'Concord' grapes. AR Farm Res. 32(1):12.

80 58. Wallinder; C~J~; R~E. Talbert and J.R. Morris. 1983. Response of 'Concord' grapes to glyphosate exposure. HortSci. 18:57-59. 59. Morris, J.R., S.E. Spayd, and D.L. Cawthon. 1983. Effects of irrigation, pruning severity and nitrogen levels on yield and juice quality of 'Concord' grapes. Amer. J. Enol. Vitic. 34:229-233. 60. Morris, J.R., S.E. Spayd, and D.L. Cawthon. 1983. Influence of drip irriga­ tion, fruit loads and nitrogen on 'Concord' grapes. AR Farm Res. 32(3):5. 61. Morris, J.R. 1983. Influence of mechanical harvesting on quality of small fruits and grapes. HortSci. 18:412-417. 62. Sistrunk, W.A. and J.R. Morris. 1984. Changes in muscadine grape juice quality during cold stabilization and storage of bottled juice. J. Food Sci. 49:239-242, 245. 63. Morris, J.R., C.A. Sims, J.E. Bourque and J.L. Oakes. 1984. Influence of training system, pruning severity and spur length on yield and quality of six French hybrid cultivars. Am. J. Enol. Vitic. 35:23-27. 64. Morris, J.R., C.A. Sims, J.E. Bourque and J.L. Oakes. 1984. Effects of training and pruning systems on the yield of French-American hybrid wine grapes. AR Far.m Res. 33(1):7. 65. Morris, J.R., C.A. Sims, J.E. Bourque, and J.L. Oakes. 1984. Relationship of must pH to the level of soluble solids on six French-American hybrid. AR Farm Res. 33(3):4. 66. Sims, C.A. and J.R. Morris. 1984. Influence of pH, sulfur dioxide, storage time and temperature on the color and stability of red muscadine wine. Am. J. Enol. Vitic. 35:35-39. 67. Sims, C.A. and J.R. Morris. 1984. Variables affecting color and stability of muscadine wine. AR Farm. Res. 33(4):10. 68. Morris, J.R., D.L. Cawthon, and C.A. Sims. 1984. Long-term effects of prun­ ing severity, nodes per bearing unit, training system and shoot positioning on yield and quality of 'Concord' grapes. Amer. Soc. Hort. Sci. 109:676-683.

69. Morris, J.R. and C.A. Sims. 1984. Factors influencing pH of grape must. Presented at the 81th Ann. Mtg. Southern Assoc. Agr. Sci., Nashville, TN. 70. Sistrunk, W.A. and J.R. Morris. 1984. Quality of juices made from muscadine grapes in combination with other fruit juices. Presented at the 8lst Ann. Mtg. Southern Assoc. Agr. Sci., Nashville, NT. 71. Sistrunk, W.A. and J.R. Morris. 1984. Changes in muscadine grape juice quality during cold stabilization and storage of bottled juice. J. Food Sci. 49:239-242, 245. 72. Sims, C.A. and J.R. Morris. 1984. Effects of pH on the color components and color loss of red wine from Noble (Vitis rotundifolia) and Cabernet Sauvignon

81 (Vitis vinifera)~ Presented at the 35th Ann. Mtg. Amer. Soc. Enol., San Diego, CA (Abstr.) 73. Striegler, R.K. and J.R. Morris. 1984. Yield and quality of Vitis vinifera wine grape culti vars in Arkansas. AR Far.m Res. 33(6):3. 74. Striegler, R.K. and J.R. Morris. 1984. Yield and quality of wine grape cul­ tivars in Arkansas. Am. J. Enol. Vitic. 35:216-219.

75. Morris, J.R., C.A. Sims and D.L. cawthon. 1985. Yield and quality of Niagara grapes as affected by pruning severity, nodes/bearing unit, training system and shoot positioning. Amer. Soc. Hort. Sci. 110:186-191. 76. Morris, J.R. 1985. Approaches to more efficient vineyard management. HortSci. (in press)

77. Sims, C.A. and J.R. Morris. 1985. A conparison of the color conponents and color stability of red wine from Noble (Vitis rotundifolia Michx.) and Cabernet Sauvignon (Visit vinifera L.) at var1ous pH. Am. J. Enol. Vitic. (in press) 78. Sims, C.A. and J.R. Morris. 1985. pH effects on the color of wine from two grape species. AR Far.m Res. 34(2):

79. Morris, J.R., D.L. cawthon, and C.A. Sims. 1985. Influence of the preharvest complex on yield and quality of Concord grapes. AR Far.m Res. (in press)

PUBLICATIONS ON GRAPES: EXTENSION AND POPULAR 1. Morris, J.R. 1974. Muscadine grape production in Arkansas. Univ. AR, Coop. Ext. Ser. Leaf. No. 488. 2. Morris, J.R. 1976. Arkansas grapes inportant part of state's product produc­ tion. The Packer. May 15, p. 13A. 3. Morris, J.R. 1977. Muscadine grape production, Part I. Fruit South. 1(2):59-61. 4. Morris, J.R. 1977. Muscadine grape production, Part II. Fruit South. 1(3):92-95.

· s. Spayd, S.E. and J.R. Morris. 1979. Yield and quality of 'Concord' grapes as affected by irrigation, pruning severity and nitrogen. Fruit South 3(2):58-59. 6. Morris, J .R. 1980. Handling and marketing of muscadine grapes. Fruit South 4(2):12-14. 7. Morris, J.R. 1980. 'Concord' grapes respond to drip irrigation. Fruit South. 4(4):12-15. 8. Morris, J .R. 1981. Problems that inhibit the expansion of the comnercial muscadine grape industry. Fruit South 5(2):28-29.

82 9~ Morris~ J~R. and D.L. Cawthon. 1981. Chemical control of suckers in grape vineyards examined. Fruit South 6(1):27. 10. Morris, J.R. 1983. Drip irrigation of grapes. Eastern Grape Grower and Winery News 9(2):38-39.

11. Morris, J .R. I S.E. Spayd, and D.L. cawthon. 1984. Concords benefit from drip irrigation. Wines and Vines. 65(4):42-44.

12. Morris, J .R., C.A. Sims and D.L. Cawthon. 1984. Excessive potassium in­ creases pH. Wines and Vines 65(6):56.

83 AN OVERVIEW OF WINERY SANITATION Susan Read Canandaigua Wine Company Canaooaigua, NY Basis for Sanitation Program State and Federal laws require good sanitation based on souoo raw materials, clean processing equipment, good housekeeping and manufacturing practices. Management is legally obligated to operate the winery in a sanitary manner in ac­ cordance with the Federal Food, Drug and Cosmetic Act and the State Department of Agriculture.

We as winemakers, quality control, and winery personnel, by practicing good winemaking techniques, can make compliance with these regulations less of a duty and more of a way of life. Winery Sanitation The responsibility of monitoring a sanitation program can vary due to the size aoo requirements of each plant. In large wineries, a single person mdght be ap­ pointed winery sanitarian or they mdght fit into the duties of the quality control department, or even the winemaker.

Monitoring Probably the most important factor, and one which will determine the effec­ tiveness of your program, is the training of each employee to form good working and housekeeping habits. It takes far less energy and time to keep things clean as you work than having to speoo the time to scrub and sanitize before starting. By in­ cluding sanitation as part of standard operating procedures, you can guard against clean-up procedures. Weekly inspection of the premises, more often for larger plants, and either reporting or instituting action on those areas that require immediate attention should also be part of a working program. Mechanical Control - Plant Design Mechanical control of sanitation begins with good design and construction of buildings and equipment. Whether building new or renovating old premises, the fol­ lowing points should be considered.

1. Simple function and design -- walls, floors, storage areas and processing equipment should be readily cleanable and suited to the proposed used.

2. Allow for enough space for easy operation and possible expansion, if practical. 3. Visit other wineries or processing plants to compare ideas and the effects they have had.

84 4. Have your plan reviewed by a qualif1ed contractor or sanitarian, or both.

Construction Building materials should be of concrete, brtck, tile and metal, as tney require less maintenance. Avoid wood when poss1ble, as it is attached by molds and insects, harbors rodents and increases fire hazards. Floors should be dense, readily cleanable, acid resistant and slope towards drains. The gutters also should pitch toward the drains and have perforated or grated covers. Walls should be sealed tightly, avoiding hollow or double off-walled areas, as they provide excellent nesting areas for rodents. Overhead structures such as walkways should be constructed so they are below top level of the tanks, rather than across the top, this prevents impurities from sifting into the air or tank. Avoid unnecessary recesses and ledges where dirt, debris, insects and rodents may harbor. Equiprrent Equipment, no matter how sophisticated, should be designed and set up so as to facilitate cleaning, prevent corrosion, be easily maintained, and stored properly when not in use. CLOSED TRANSFER SYSTEMS of stainless steel or plastic should be installed to avoid low spots, dead ends and pockets at joints, elbows and outlet valves. These systems are best cleaned by recirculation, us1ng a suction pump so as to achieve an agitation action by the introduction of air. OPEN TRANSFER SYSTEMS such as surge tanks should be covered if possible, drained properly and be at least rinsed if not washed immediately after use. TANKS should be designed and installed so that they slop toward the drain. A regular monthly inspection and maintenance program is necessary to prevent leaks, more often if older wooden cooperage. Top open1ngs should be constructed so that liquids or dirt will not fall into the wine.

WOOD TANKS should be cleaned and san1t1zed before and after use. If they are to be empty for several days, the use of so2 gas should be employed to prevent mold growth. Should they be empty for a week or longer, sprinkling with a garden hose or lawn sprinkler can help prevent drying out. Exterior monthly cleaning is a must. Coatings do not always prevent mold growth. STAINLESS STEEL, steel, glass or epoxy lined tanks should be sanitized regularly. They should be equipped with pressure vents and gauges and regular in­ spection for chips on linings and corrosion is necessary for proper maintenance. Stainless steel tank interiors require exposure to a1r and oxidizing conditions so as to build up a corrosive resistant film. On all tanks, the manhole covers or bungs should fit tightly and seal when in place. FILTERING EQUIPMENT should be constructed and 1nstalled for ease of cleaning. A regular inspection of gaskets and screens with replacement of such when neces­ sary. Reverse flushing to reroove solids has been successful in cleaning up after a heavy load filtration. Provisions for prompt disposal of waste materials is mandatory in order to avoid creating possible breeding areas for drosophila, flies

85 and other wine contaminants. Disposal with respect to local, state and federal regulations. The BOTTLING should be carried out in an area away from the processing and heavily trafficked areas. Again, the equipment should be designed for ease of cleaning. And hot water of 75°F mdnimum or clean steam should be readily avail­ able. Spills should be cleaned up immediately. Care should be taken when using chain lubricants to avoid puddles on and around the lines. A regular sanitizing program should be established and monitored by swabings to indicate any problem areas. PASTEURIZING and REFRIGERATION equipment become more efficient if coils and pipes are cleaned and sanitized regularly. When cleaning refrigeration equipment, it may be necessary to remove coolant; check with the manufacturer for recommended procedures before proceeding. HIGHWAY and RAIL TANK CARS, like storage or processing tanks, require cleaning and regular inspection for corrosion. Special attention should be given to the un­ derside of vent pipes, manhole well housings and valve opening steam housings. In most cases, scrubbing with a long-handled, stiff bristled brush and standard clean­ ing solution is sufficient, allowing approximately 20 to 30 minutes to drain before closing {do not seal). Care should be taken not to use flowing steam or hot water above 140°F, as it could damage the tank lining. Environmental Controls Controlling the winery environment is sometimes taken for granted. Clean air, water and facilities are not just for our own comfort, but help eliminate areas of possible contamination.

Vents/holes of more than 1/4" should be covered with screen to prevent entrance of rodents, insects and birds. In sophisticated systems, air curtains or pressure systems, are used for microbe and insect control. Proper cleaning and sanitizing requires water as a medium for carrying out the operation. There should be sufficient water connections in all parts of the winery, and hot water of 75°F mdnimum is recommended in those areas where sanitiz­ ing is critical. Controlled use of water is necessary not only from an economdcal point of view, but also in respect to the effectiveness of your program. Standing puddles ·of water serve as ideal breeding areas for mold, fruit flies, and mosquitoes. In tanks sulphured for storage, hydrogen sulfide contamination of the wine is possible if allowed to dissolve in puddles. Work areas should be well lighted. This not only provides for good working conditions, but helps to eliminate propagation areas for fruit flies.

Facilities for employees should be in accordance with regulations. This in­ cludes toilet and washing facilities, lunch room/break area and first aid room. Each should be sufficient for the number of employees at the peak of the season. Trash cans should be emptied daily or more often if the need demands.

Winery grounds should be properly maintained. Remove any areas that could

86 harbor insects or rodents. A regular 'policing' of the grouoos to point out any problem areas. Chemical Controls Thorough cleaning is important to an effective sanitation program. Unless soil/dirt is thoroughly removed, the deposits can serve as nutrient centers for the growth of microorganisms. When organisms are imbedded in such deposits, they be­ come more difficult to kill with heat or chemicals, and become centers for con­ tamination later on. Detergents are used to reduce the workload of the sterilizing and sanitizing agents. Each detergent is usually a little different in as much as they are 'built' to fit the different cleaning requirements. The 'building blocks' of a detergent consist of the following considerations:

1. Water condition properties. Simple phosphates and alkalis react with cal­ cium and magnesium to produce insoluble precipitates. By including cer­ tain water conditioning chemicals that decrease the availability of cal­ cium and magnesium, even with the use of hard water, these precipitates can be avoided. 2. Wetting properties aid in penetration of cracks and between soil par­ ticles. The addition of wetting agents to a detergent insure rapid and complete wetting of the surface to be cleaned by the cleaning solution. 3. Dissolving properties--When choosing a detergent, consideration should be given to the application and dissolving properties of specific detergent. Where cold water is used, liquids may be preferred for their mixing properties, but may prove costly. Powders are activated when mixed with water; therefore, they retain their activity better than liquids. 4. Rinsing properties-If appreciable residues remain, we have exchanged one type of soil for another so additives are selected to promote rinsing.

5. In some cases it is desirable that the detergent have anti~icrobial properties. These can be added when building a detergent sanitizing for use.

6. Type of soil rust be considered. Oily, fatty, tartrates, pigments. Based on this, an acid or alkaline cleaner is considered. 7. Corrosive properties: a. Chlorides (used as builders in sone detergents) are qui:te corrosive to stainless (reducing compounds also lower the corrosion resistance of stainless steel.) b. Alkaline cleaner--corrode glass, glass enamel, aluminum, zinc, including galvanized iron. To reduce corrosiveness on glass, addition of phosphates have been chosen.

87 8~ Methods of application (scrubbing) -determined by amount of dirt and "filth". CIP - Allow stronger detergent mixtures. Foam - spray. 9. Method of disposal of rinse water--with growing concern for the environ­ nent, effect on waste water treatment plants, etc. The appropriate type of detergent/sanitizer should be chosen. There are four detergent classifications: alkalis, mild alkalines, wetting agents and acids. 1. Alkalis--Usually pertain to those materials which in a 1% solution yield pH excess of 12. Include lyes, caustics (NaOH), sodium metasilicates, sodium orthosilicates and ammonia. They dissolve fairly good and are reasonable deflocculating agents. However, they differ in wetting and rinsing properties and are not good water conditioners. These types of cleaners are effective against organic deposits (including fats, oils and proteinaceous materials). Strong alkalis have poor rinsing qualitities; eye splash is a severe hazard. All will react with magnesium and/or calcium to cause cloudy, insoluble precipitates to be deposited on the equipment. 2. Mildly Alkaline--Sodium carbonate (soda ash) and the sodium phosphates tri-sodium ortho polyphosphates are good water conditioners, have excel­ lent rinsing properties, and suppress the magnesium or calcium reaction mentioned before, but due to their effect on the environnent are restric­ ted in use and no substitute has been found. 3. Wetting agents are most valuable for their emulsification, suspension, penetration, surface tension, reducing and rinsing properties by making cleaning possible by application and rinsing (CIP). 4. Acids--two groups: Organic and Inorganic a. Inorganic such as nitric are not popular; however, are widely used in Europe for recirculatory cleaning of high temperature short-time pasteurizing. b. Organic acids are the 'building blocks' of detergents used in CIP systems. They combine well with wetting agents and other ingredients to provide detergents and detergent sanitizers that are: non-volatile, non-corrosive; stable at elevated temperatures; relatively harmless to hands, skin and clothing, but strong enough to be used in day-to-day applications.

Sterilizing & Sanitizing Agents

Some applications require additional treatment to reduce the microbial population. We sometines inaccurately refer to this additional treatment as sterilization. It is neither practical nor economically feasible to sterilize, but more

88 appropriately to sanitize--that is, to reduce the microbial population to a level consistent with the demarrls of public health and product "stabilization". Several methods are available for sanitizing--heat and chemical are the most widely recognized.

HEAT--Generally applied as hot water or steam at temper itures of 75-95°C (160/180°F) for a duration of two to 20 minutes, depending on ~he degree of sanitizing required, the product, and the type of equipment. CHEMICAL SANITIZERS--Are effective only on clean surfaces and tlte eff 1ciency increases or decreases depending on temperature, concentration and pH. Standard temperature is approximately 25 C (77°F), and the exposure time must be doubled for each 10°C (20°F) decrease in solution temperature. High concentrations of chlorine are extremely corrosive and are best monitored by pH. "Normal strength" is under acidic conditions. It is the free chlorine that determines germicidal effect and should be monitored for eff1c1ency and proper usage. Generally used as a hypochlorite (powder or l1quid). Calcium is more stable than sodium salt, but both are effected by heat, light and moisture. To reduce this decomposition, the use of alkaline filler is employed, but produce a solution of higher pH arrl lower anti-microbial activity (200 ppm recommended concentratton) and can be monitored with test kit usually available from your supplier.

IODINE--In itself has long been recognized as an anti-microbial agent. However, due to its low solubility in water, its use has been restricted in food processing operations. With the addition of wetting agents to produce a product known as a iodophore, iodine becomes more soluble, has increased germicidal activity, and reduced the corrosive properties. There is no universal cleaning or sanitizing gent. Each application should be reviewed and the appropriate detergents and sanitizer chosen (see soap dealers).

Insects and Pests Insects can become pests, create unsanitary conditions and subject the wine or grape products to possible contamination. To prevent regulatory action and produce quality products, it is necessary to control the infestation from vineyard to plant. Only by the controls applied by the grower in the vineyard and the wineries using good sound fruit can control be expected.

Drosop~ila Melanogasts (Vinegar or Fruit Fly)

The life span of the adult is 30 days (summer) to five months in cooler climate. Females live longer than males. They lay approximately 25 eggs per day, 400 to 2000 during their 1 i fe span. They have the ab1 l i ty to hoLd the eggs unti 1 nearly ready to hatch, allowing them to locate a suitable "nursery".

The larva feed on fruit juices and for this reason the female lays her eggs 1n exposed areas; i.e., broken fruit, open tanks, puddles. The pupa is the dormant

89 stage and for effective control, it requires that this part of the life cycle be disrupted. This can be accomplished by having well-lighted areas, keeping areas clean and dry, Unnediate disposal of waste mate5ials; i.e., filter pads. For problem areas, regular cleaning with 140 to 160 F water and chlorinated detergent and smearing of a paste of the detergent over the cleaned area will help to prevent re-infestation. Muscidae (House and Stable Flies) House and stable flies comprise a large group of flies and are identified as carriers of disease. They are associated with decaying animals and animal excrenent.

Like the Drosophila, control is accomplished by eliminating their breeding place. Proper rodent control arrl waste removal is a nust. Air current and accept­ able knockdown pesticides have proven useful for severe cases of infestation. Rodents Rats, mice and other rodents are probably the most destructive forms of life fourrl in or near populated areas. They nultiply rapidly, are carriers of disease and difficult to eliminate. Mice mature in 42 days, live for about one year, and average five to six per litter, eight to ten times per year. Rats mature in three to four months, average eight to nine per litter, four to five times per year. The Norway or Sewer Rat may enter the plant through main or sewer lines; the Black rat is a clunber and may enter through low or high openings. They prefer to nest in ceiling locations. Their detection is usually via droppings and gnawed paper or wood, as they are seldan seen in open places. They need food, shelter and nesting material. By elnninating access to these you can discourage their presence. SOME SUGGESTIONS: Store any edible raw products or food in closed storerooms, preferably metal or concrete. Keep areas well lighted, use screening to prevent entry. Rodents can get through openings of 1/4 inch. Should control be necessary, consult with a commercial exterminator who can suggest bait stations and trapping. In conclusion, the success of a sanitation program, no matter what the scale, depends on the attitude of those performing the tasks on a daily basis. Unless good habits are formed by new personnel and this is reinforced by all concerned, even the best of programs will fail.

90 A Sanitation Seminar Wine Institute Sanitation Guide The American Sanitation Inst. Wine Institute 884-86 Hodiamont Ave. 165 Post Street St. Louis, r-D San Francisco, CA (415-986-0878) $10.00 Institute of Food Technologists 221 North LaSalle St. Chicago, IL 60601

Table Wines, M.A. Amerine and M.A. Josyln; Univ. CA Press, Berkeley and Los Angeles, CA.

Technology of Winema.ki~, M.A. Amerine, H.W. Berg, R.E. Kunkee, c.s. OUgh, v.L. Singleton, and A.D. we ; AVI Pub. Co. 1 Inc. Westport, CT. Comrerci al Winemak ing-Processing arrl Controls; AVI Publ. Co. , Inc. Westport, CT. Selected References and Suppliers Diversey, Sandotte Corp. Klenzade Division 1532 Biddle Ave. Eoonorrdcs Laboratory Inc. Wojandotte, MI 48192 Osborn Building (800) 521-8120 St. Paul, 1\ti 55102 Oakite Products, Inc. 50 Valley Rd. Berkeley Heights, NJ 07922

91 THE DEVELOPMENT OF AN INTEGRATED PFST MANAGEMENT PROGRAM FOR OHIO VINEYARDS Daniel M. Pavuk and Roger N. Williams Department of Entomology Ohio Agricultural Research & Development Center, The Ohio State University Wooster, OH 44691

The control of crop arthropod pests is currently a very complex and ever­ changing field. In the early part of this century, insect and mite enemies of crops were fought with chemicals such as lead arsenate, sulfur, and with cultural and sanitary methods. During the 1940's, the chlorinated hydrocarbons came into widespread usage. Later, organophosphate and carbamate insecticides were formu­ lated and addErl to the arsenal of pest management personnel. At the present time, integration of chemical, biological, and cultural control methods to regulate pest populations is the state of the art. Hence, the phrase integrated pest management has become familiar to all those involved in the control of arthropod pests. The application of integrated pest management principles to the regulation of economically important grape arthropods is not new. The use of phylloxera­ resistant rootstocks and cultural control of the grape berry moth are two examples of management methods which have been combined with chemical control schemes to ef­ fectively reduce the harmful impact of grape pests. Recently, researchers in California found that a small, parasitic wasp is capable of effectively controlling grape leafhoppers under certain conditions. In most cases, however, those in­ dividuals who grow grapes rely heavily on the applications of chemicals to prevent insects and mites from seriously damaging the vines and the potential crop. With the increasing prices for chemicals, equipment, and labor, it is in the best interests of the Ohio grape growers to find the approach to pest management which provides the best possible control at the lowest cost. A good integrated pest management (IPM) program achieves this objective. As entomologists, we are interested in studying the arthropod pest complex attacking Ohio grapes in order to determine what control options are the most effective, economically advantageous, and environmentally sound. One step in developing an IPM program is to obtain a thorough knowledge of the biology of' the pests and how these pests affect the grape plants. CUrrently, we are surveying insect and mite populations at 13 vineyards locatErl throughout the state. The occurrence of each major injurious grape arthropod is checked for in these vineyards on a weekly basis. If any of the pests are found in damaging num­ bers or if it is believed that these pests may be potentially damaging, the cooperating grower is notified. Thus, the survey program has two major goals: to provide data on the biology and population characteristics of the pests, and to supply the grower with information useful to him in making pest management deci­ sions. The monitoring aspect of IPM is a critical one, for in many cases it allows for the elimination of unneedErl spray applications. If a vineyard is found to be free from a particular pest after a careful examination, a spray which normally would have been applied for that pest could be put off to a later date or left out completely. In addition, if the pest management scout finds a pest in only one area of the vineyard, the infestErl place could be selectively treated. In either

92 case; unnecessary spraying would not be done, and this situation would save the grower substantial outlay for insecticides. Another principle of IPM is grower education. Knowledge of the pests, includ­ ing their biology, damage, and options available for their control, is essential if the grower is to effectively regulate insect and mite populations in his vineyard. Mailing bulletins and newsletters to individuals on a regular basis is of enormous benefit in the education process. Frequent contacts with growers and having per­ sonnel available for advice on problems also provide means of dispensing useful information. Probably the most crucial factor in the successful development of an IPM program is the acceptance of the fact that such an approach is superior to a spray schedule. There is a need to demonstrate that spraying is not always necessary or even desirable. It is our place, as pest management specialists, to provide con­ vincing evidence for non-chemical control options and reducing spraying. Of course, it is unrealistic to believe that the grape industry could survive without the use of insecticides. However, the possibility of reducing pest management costs is real. With effort and concentration on the integration of all viable con­ trol schemes, it is possible to lower expenses and attain excellent pest regula­ tion.

93 GRAPE CUL·riVAR RESEARCH

G.A. Cahoon Department of Horticulture The Ohio State University Ohio Agricultural Research & Development Center Wooster, OH 44691

During tl1e past 20 year period many experiments involving the suitability of various grape cultivars and selections to survive and produce in Ohio have been conducted at the Ohio Agricultural Research and Development Center and its Branches. This information has been summarized annually, but never compiled into one publication. However, since the information takes up more space than is regularly allotted in the Proceedings, it has been published as a separate but companion publication; Horticulture Department Series #554. Only a partial list­ ing is presented here. It is the authors intention that the information be presented so that the reader can determine: (1) where the experiment was conduc­ ted (OARDC, Wooster; Southern Branch, Ripley; Overlook Branch, Carroll; or OSU, Columbus), (2) under what training or trellising systems (Umbrella Kniffin, Single Curtain Cordon, or Geneva Double Curtain), and (3) the span of years covered by an experimental trial. Examination of the data will show that breeding programs from several state and federal experimental facilities outside Ohio have been the principal source of material for evaluation. Selections from some private breeding programs and nurseries have also been made available. State and federal programs include: Agricultural Experiment Stations in New York, Geneva, NY; University of Arkansas, Fayetteville, AR; Virginia Polytechnic Institute and State University, Blacksburg, VA; State Fruit Experiment Station, Mountain Grove, M:>; Oklahoma State University, Stillwater, OK; and University of California, Davis, CA; the Horticultural Fruit Research Institute, Vineland, Ontario, Canada;· the Plant Introduction Station, Glen Dale, MD; and the Plant Quarantine Station, Sydney, British Columbia, canada. Private breeding programs include those of E.J. Reeves and others. During the course of the study numerous selections have been named. Examples of these include: Q~-3 (Cayuga White); Ark. 1163 (Reliance); N.Y. 21572 (Suffolk Red); N.Y. 35814 (Glenora); v. 51061 (Ventura); V. 53033 (Festivee); v. 65164 (Vanessa); VPI 26 (Moored); VPI 30 (Price); VPI 32 (Century I); Minnesota 40 (SWenson Red) and 439 (Edelweise). Many of the ?rench-Arnerican hybrids that were identified only by breeder identification number were also named and include .such varieties as Vidal and Seyval blanc (Vidal 256 and Seyve Villard 5276), Chancellor (Seibel 7053) and others. Several cultivars have been under evaluation at more than one location but not necessarily during the same time period. Similarly cultivars may have been grown during the same time period and at the s~~ or a separate location but un­ der a different training or trellising system. Overall, however, what the reader should look for are those cultivars or selections that show good vigor and productivity, cold hardiness and quality under a variety of cultural and climatic conditions.

94 GRAPE CULTIVAR SUMMARY CULTIVAR CLASS CODE/ YEAR TRAIN HARVEST COLOR/ FRUIT CLUSTER S.SOL ACID PRUNE NODES YEARS LOCAT PLT SYSTI1 DATE SEEDLS YIELD NO. IH " " !.IT RETND FRT AGADAI v 1-R 1970 UK 09/07/73 2/4 AGADAI v 1-R 1970 UK 09/17/74 "' 3.9 3.9 . 15 15.0 .90 28.0 2/41 AGADA I v 1-R 1970 UK 08/27/75 "' 1 0 . 1 1 0 . 1 . 12 16.5 .46 2.20 42.0 2/4 AGADAI v 1-R 1970 UK 76 "' _... u ~I.. I 2/4 "' 7.0 -----7.0 ----.14 -----15.8 .46 1. 30 32.3

AHI1UER A 2-R 1970 UK 09/06/72 B 4.4 28.0 . 16 15.5 .58 4/4 AH11UER A 2-R 1970 UK 09/14/73 B 6.2 48.0 . 13 15. 1 .53 5.60 60.0 4/4 AHI1UER A 2-R 1970 UK 09/12/74 B 11 . 6 90.0 .13 13.7 .37 4.50 60.0 4/4 AHI1UER A 2-R 1970 UK 09/02/75 B H: ... i H:.!L..!! _... !! _1! ... § _... :2J ! ... :2.!! U ... .!! 4/4 7.8 62.8 . 14 15.5 .52 4.87 60.0

ALDEN A 3-R 1961 Ul< 64 B 14.6 .80 28.0 9/9 ALDEN A 3-R 1961 Ul< O'J/03/65 B 20. 1 62.0 .32 14.5 .41 1. 20 36.0 9/9 ALDEN A 3-R 1961 Ul< 08/31/66 B 6.7 23.0 .28 15.2 .78 1.10 32.0 9/9 ALDEN A 3-R 1961 Ul< 08/30/67 B 26.1 77.0 .34 10.2 .54 1 . I 0 31 . 0 9/9 ALDEN A 3-R 1961 Ul< 08/28/68 B 7.8 22.0 .35 12.4 .85 .30 13.0 9/9 ALDEN A 3-R 1961 UK 08/30/69 B 28.1 52.0 .54 14.6 .52 1 . 40 25.0 9/'J ALDEN A 3-R 1961 UK O'J/09/70 B 35.1 65.0 .54 15.0 1. 30 27.0 9/9 ALDEN A 3-R 1961 UK 09/21/71 B 22.9 48.0 .48 16.5 .60 26.0 9/9 ALDEN A 3-R 1961 UK 08/30172 B u ... r: _... !.!! n ... .!! 9/9 19.5 -----49.9 ----.41 -----14.1 .62 .90 27.5

ALDEN A 3-IJ 1973 sc 08/29175 8 22.5 53.0 .43 12.6 .56 8/8 ALDEN A 3-IJ 1973 sc 09/26/76 B 4.9 21 . 0 .22 17.7 .96 1 .• 1 0 32.0 8/8 ALDEN A 3-IJ 1973 sc 09/06/77 8 18.8 54.0 .34 16.5 2.30 44 0 8/8 ALDEN A 3-IJ 1973 sc 10/04/78 B 41.6 82.0 .so 15.5 . 63 2.00 40.0 8/8 ALDEN A 3-IJ 1973 sc 09/26179 8 26.2 60.0 .44 15.5 .86 1. 80 36.0 8/8 ALDEN A 3-IJ 1973 sc 10/02/80 B 30.9 91 . 0 .34 1 . 90 40.0 8/8 ALDEN A 3-IJ 1973 sc 09/16/81 B 2.5 7.0 .36 3.50 50.0 8/8 ALDEN A 3-W 1973 sc 09121182 B H .•JI _H ... .!! _... u _H ... :i _ ... §.!! iL.U !JLJ! 8/8 20.4 50.6 .39 15.0 .73 2.09 40.3

ALDEN A 3-IJ 1973 Ul< 08/29175 B 27.5 52.0 .46 12.6 70 8/8 ALDEN A 3-W 1973 UK 09130/76 B 3.9 20.0 .20 16.0 .97 .90 30 0 8/8 ALDEN A 3-IJ 1973 UK 09106177 B 5.5 20.0 .27 17.3 3.60 57.0 8/8 ALDEN A 3•1.1 1973 UK 10/04/78 B 20.5 54.0 .38 17.8 .63 5 so 57 0 8/8 ALDEN A 3-W 1973 UK 09/26179 B 47.0 121 . 0 .39 14.5 .86 3.90 55.0 8/8 ALDEN A 3-IJ 1973 UK 10/07/80 B 42.6 114.0 .37 3.30 53.0 8/8 ALDEN A 3-W 1973 UK 09116/81 B 1 . 5 8.0 .19 1 . 90 38.0 8/8 ALDEN A 3-IJ 1973 Ul< 09/21/82 B ;}:;! ... § _§§ ... .!! _ ... :is: _n ... e _... u S: ... !l !2... 1 8/8 23.5 56.6 .36 15.4 .74 3.07 47.9

ALDEN A 3-IJ 1973 GDC 08/29175 B 40 7 80 0 .51 10.3 59 8/8 ALDEN A 3-lol 1973 GDC 09128/76 B 9.0 38.0 24 17 7 96 1 50 35.0 8/8 ALDEN A 3-IJ 1973 GDC 09/06177 B 62.5 119. 0 52 16 5 4 so 60.0 8/8 This page intentionally blank. This page intentionally blank.

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