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In This IssueCrop ConditionsPhysiological DisordersStrawberry Fruit Bud DevelopmentGrape Harvest – 2018Purdue Fruit and Vegetable Grower MailListsAnnual Strawberry Production in SouthernIndianaUpcoming Events

Crop Conditions(Peter M Hirst, hirst@purdue.edu, (765) 494-1323) & (BruceBordelon, bordelon@purdue.edu, (765) 494-8212)

Apple harvest has begun with early varieties stillbeing harvested. A lack of cool nights hasdelayed red color development but manyvarieties are still developing acceptable redcolor. Quality generally looks good.

Blackberry (primocane): fruit developing welldespite severe Japanese beetle damage

Apple: Pixie Crunch are developing good color

Grape: Full veraison on most varieties

Physiological Disorders(Janna L Beckerman, jbeckerm@purdue.edu, (765)494-4628)

With weird weather often comes weirdphysiological disorders (on top of our summerfruit rots). Often confused with hail injury,disease or insect damage, these physiologicaldisorders are marring the appearance of manyapples.Symptoms of bitter pit include circular or evenirregular sunken spots on the fruit surface,beneath brownish or streaked dead regions (Fig.1). Note that the damage can be separated fromthe skin surface. Symptoms may be mistaken for

Issue: 18-10August 10, 2018

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hail damage, or any of the below problems. A keydiagnostic feature is that hail usually affects onlyone side of the fruit, whereas bitter pit is moresevere on blossom end of the fruit. Somevarieties, like Honeycrisp, are more prone to thisdisorder, whereas hail will impact (literally) allvarieties of fruit. Bitter pit can show upthroughout the orchard, not just the edges.

Fig. 1. Bitter pit and lenticel rot often appear at the calyxend of the fruit. Photo by Janna Beckerman

Cork spot is another physiological disorderaffecting outer portion of the fruit, and symptomsbegin on the fruit flesh as small dimples ordepressions. This disorder begins developing inJune, and continues throughout the growth andenlargement of the apple. Lesions enlarge anddevelop 1/4 to 1/2 inch corky, discolored areasinto the flesh of the apple. Unlike bitter pit, thecorky spots may occur anywhere on the fruitflesh. It is important to note that all of theseproblems are only surface blemishes.Unfortunately, their unattractive appearanceoften reduces the marketability of the fruit.Both disorders can be mistaken for brownmarmorated stink bug injury (BMSB) (Fig. 2).BMSB usually appears around the edges of theorchard, although I do question their literacyskills and their ability to follow directions. BMSB

can occur all over the apple, and more aroundthe shoulder than the calyx. There should be a‘sting’ in the center of the depression—this is akey diagnostic feature. Cornell has a really niceblog post by Peter Jentsch here:http://blogs.cornell.edu/jentsch/2014/09/18/bmsb-update-assessing-fruit-damage-at-harvest-is-it-hail-bitter-pit-apple-maggot-or-stink-bug/

Fig. 2. Comparison between bitter pit and BMSB. Photo byPeter Jentsch

You can perform preharvest sampling for bitterpit: Two weeks prior to harvest select large fruitand dip the fruit in a solution of 2,000 ppmethephon in water (about 1 ½ teaspoons ofethephon to one gallon of water) to hasten theripening. Hold the fruit for two weeks at roomtemperature. Should bitter pit develop, delayharvest for as long as possible, being sure to coolharvested fruit immediately, and delayingpacking for as long as possible (preferably fourweeks). During the delay, bitter pit will develop inthe affected fruit, which can then be removedduring the packing process.For those that have had problems with thesedisorders: Bitter pit, cork spot and Jonathan spotare complex problem that require an integratedmanagement scheme to reduce the problem toacceptable levels. It is very simple to say “justadd more calcium” but the reality is morecomplex. Calcium isn’t as soluble as potassium ormagnesium, making it less readily available tothe plant. High levels of nitrogen, potassium, and

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magnesium compete with and reduce the fruituptake of calcium. Furthermore, applications ofnitrogen preferentially drive shoot growth overfruit growth, also reducing available calcium.Finally, high levels of available water canincrease fruit calcium if shoot growth is notexcessive, and drought prevents nutrient uptakethat is needed to assure proper fruitdevelopment. That said, one study found, at leastfor ‘Honeycrisp’, the addition of calcium alonewas beneficial (Rosenberger et al. 2004). Anothernutrient issue on postharvest rots is excessivenitrogen use. Not only is judicious N use prudentto minimizing the risk of fire blight, but excessiveN results in fruit that are predisposed topostharvest problems, compared to the lower Ncounterparts. Finally, in addition to ‘Honeycrisp,’other susceptible varieties include ‘Baldwin,’‘Gravenstein,’ ‘Grimes Golden,’ and ‘NorthernSpy.’ ‘Golden Delicious’ is considered moderatelysusceptible, while ‘Delicious’ and ‘Winesap’ arefairly resistant.At this point, other than delayed harvest, all youcan do is plan for next year. Bitter pit, cork spotand Jonathan spot can be remedied with calciumchloride at 2 pounds per 100 gallons of water (or1.5 tablespoons per 1 gal. water) applied in foursprays beginning two weeks after full bloom andcontinuing at 10 to 14-day intervals thereafter toreduce cork spot. At this rate, calcium chloridemay be added to pesticide sprays normally usedin controlling post-bloom diseases (or insects)affecting fruit. Do NOT apply calcium chloridesprays when temperatures are above 85 degreesF. Calcium chloride is highly corrosive—be sure torinse sprayer thoroughly after use. As nitrogenmanagement is also implicated in this disease,reduce excessive shoot growth by not applying(or greatly minimizing) nitrogen to the soil ofapple trees for at least one year. Evaluate resultsat the end of that season; in the second year, use½ the recommended amount of N, and evaluate

harvest again.References and additional information:Bitter pit control in apples. Available online at:http://www.omafra.gov.on.ca/english/crops/facts/00-009.htmRosenberger, D.A., J.R. Schupp , S.A. Hoying , L.Cheng, and C.B. Watkins. 2004. Controlling BitterPit in ‘Honeycrisp’ Apples. HortTechnology 14(3)342-9.http://horttech.ashspublications.org/content/14/3/342.full.pdf

Strawberry Fruit BudDevelopment(Bruce Bordelon, bordelon@purdue.edu, (765) 494-8212)

June bearing strawberries are “short day” plantsthat initiate flower buds in response to short days(less than 14 hours day length). Day length forIndianapolis drops below 14 hours about August10. As we get into late summer, strawberryplants respond to shorter days by setting theflower buds that will result in the crop nextspring. It is important to maintain appropriatenutrition and soil water status during this time.General recommendations are to fertilizestrawberry fields with 20 to 50 pounds of actualnitrogen per acre per during late summer. Nitrogen rates depend upon amount supplied atrenovation and plant vigor. New fields with highvigor may not need additional nitrogen now, butolder fields should benefit. Irrigation during thistime is also extremely important if rainfall hasnot been sufficient in your area. We suggestabout 1 inch per week. Continue to irrigatestrawberries through fall to assure a good cropnext year.

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Grape Harvest – 2018(Bruce Bordelon, bordelon@purdue.edu, (765) 494-8212)

Grape harvest is just about to get started in thesouthern part of the state. Growers will startharvesting early varieties next week. Mostvarieties are slightly ahead of normal this year. InLafayette, early varieties are at full veraison andshould be ready to harvest in the next couple ofweeks. We generally harvest early varieties suchas Brianna, Edelweiss and Prairie Star about thethird week of August and many other earlyvarieties starting the first week of September.Depending the weather for the next couple ofweeks, we might be a bit early this year. Fruitquality overall is very good. The cooler conditionslately have favored fruit quality.With wine grapes, all fruit of a given cultivar istypically harvested from the vineyard or block ata single time to coordinate winery activity and toreduce costs. It is important to plan carefully sothat the harvest date coincides with the optimumfruit quality.Fruit quality is comprised of several factors, mostimportantly sugars, organic acids, and pH. Otherfactors such as phenolics, anthocyanins, aromaand flavor compounds are also very important towine quality. And of course, freedom from rots isan important consideration. Unlike some otherfruits, grapes do not continue to ripen afterharvest. Consequently, it is important to harvestgrapes at the peak of quality and with thedesired parameters for the intended use.Most vineyards have some degree of variability insoil type and drainage, sunlight exposure, wind,insect and disease pest, nutritional status, etc.Fruit from different parts of the block, fromadjacent vines, as well as from different parts ofthe same vine can vary. Much of the variability isreduced with proper vineyard management, e.g.cluster thinning, shoot thinning, canopymanagement, etc.

As harvest nears, it is very important to monitorgrape chemistry. Growers should sample weeklyleading up harvest with a protocol to collect arepresentative sample of fruit from the entirevineyard. This can be a sample of 200 berries perblock collected from vines randomly, but withemphasis on collecting berries from top, middleand bottom of clusters, and from exposed andshaded clusters. Some growers prefer to collect asample of 5 to 10 whole clusters per block ratherthan individual berries to capture the variabilitywithin clusters. Often sampling occurs from a fewselect “cardinal” vines in a block, chosen for theiraverage performance overall. Whateverapproach is used, be sure to compare yoursampling results to the actual final harvest juiceparameters at the press to determine theaccuracy of your sampling. Most of the time pre-harvest samples tend to over estimate the levelof fruit maturity, but not always.Wine grape growers should have the ability ofmeasure sugar content (with a refractometer),titratable acidity and pH (with a pH meter andburette). Equipment and supplies to measurethese parameters can be purchased for about$500. Each of these factors is important fordetermining proper harvest time, but none alonecan accurately estimate overall fruit quality. It isthe balance of sugars, acids and juice pH that isimportant to the wine maker. And of course,there are the subjective qualities of seed andskin maturity, tannins, anthocyanins, flavors,aromas, etc. The Berry Sensory Analysis methodaddresses evaluation of these more subjectivefactors such as skin, pulp and seed maturity.More needs to be done to adapt the method foruse with our Midwest varieties, but as adescriptive tool, it can be an excellent way forgrowers to go beyond the basics of sugar, acidand pH. Work with your winemaker/buyer onharvest decisions as much as possible.

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As harvest nears every grower begins to worryabout what can go wrong. Birds, raccoons, deer,etc can all take a toll. More importantly, berryskin cracking from rain, bird pecks and beedamage can lead to sour rot caused by yeastsand vinegar spoilage bacteria. The vinegar(acetic acid) leads to high volatile acidity levels inthe wine. We experience major problems withsour rot in wet years. So far, we have not hadmajor problems this year. Let’s hope the weathercontinues to cooperate. Growers need to closelymonitor for development of sour rot, especially ifrains occur near harvest, and take measures toreduce the spread by managing fruit flies andmicrobial organisms. We discussed sour rotmanagement at the summer IWVA meeting.Contact me if you want a refresher. Ultimately itmay be necessary to develop a strategy tominimize harvest of rotted clusters. A pre-harvestwalk through the vineyard block should identifyany clusters with sour rot and those lagging inripeness. In most cases, late clusters will nevercatch up to the rest, and will only reduce theoverall quality of the crop at harvest. Now is agood time to drop any undesirable fruit. Don’texpect your harvest crew to sort as they pick. Gothrough beforehand and eliminate theguesswork.

Purdue Fruit and VegetableGrower Mail Lists(Bruce Bordelon, bordelon@purdue.edu, (765) 494-8212)

With harvest around the corner for many fruitcrops, I thought this would be a good time toremind readers about our email lists. Variousforms of social media is used by just abouteveryone in today’s society. While Facebook andTwitter are much more commonly used thanemail, there is still a place for email lists. Mail

lists continue to be a successful communicationtool for groups of people.The way a mail list works is that people subscribeand then have the authority to post messages tothe list. All other subscribers on the list receivethe messages. One message can be sent tohundreds of readers at once. Replies tomessages on a mail list can either go only to thesender of the message or to the entire list.Purdue HLA Extension maintains two mail lists forusers. The “Fruitveg” list is for all fruit andvegetable growers, farm marketers, etc. inIndiana and surrounding states. The “Winegrape”mail list is primarily for the Indiana wine industry.Anyone can subscribe to either list. Oncesubscribed users can post messages to the list. Our lists are are set so that replies go only to thesender. If you prefer to reply to everyone on thelist, hit “reply all” and check to see that the listaddress is in the send box.The mail lists were established to allow Indianafruit and vegetable growers, wine grape growersand wineries, and farm marketers to interact witheach other electronically. Growers and marketershave been using this forum for free and openexchange of information and ideas. The list areused to coordinate group purchases ofequipment and supplies, and as a forum to buyand sell produce and used equipment andsupplies. Each year grape growers post grapesavailable and many wineries have used the siteto sell used equipment. We encourage allgrowers to subscribe to the lists.To subscribe to the lists, click on the links below.Commercial Fruit and Vegetable – TheFruitveg mail list is for Indiana fruit andvegetable growers, and farm marketers tocommunicate electronically.Wine and Grape Production – The Winegrapemail list is for Indiana and regional grape growers

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and winemakers to communicate electronically.While we do not moderate the lists, we watchactivity. We do not allow personal vendettas,inflammatory comments or other inappropriateuse of the list. Any statements made do notrepresent “official” opinions, and PurdueUniversity takes no responsibility for content.

Annual Strawberry Productionin Southern Indiana(Wenjing Guan, guan40@purdue.edu)

Strawberries are primarily grown in the mattedrow system in Indiana, in which bare-rootstrawberry plants are set in the spring, fruit isfirst harvested in the second year and plantingsare renovated each year for a few seasons.Growers in Southern Indiana have expressedinterest in growing strawberries in the annualplasticultural system. With this annual system,plants are set in the fall and harvested in thespring of the following year. Plantings are notnormally carried over a second year. Althoughthe annual plasticultural system is very popularin the southern states, its usage is limited inIndiana mainly because our short fall weatherconditions pose a challenge for strawberry plantsto develop enough branch crowns, which allowsthem to achieve the optimal yield in the followingspring.In the past two years, we have been testing theannual strawberry production system withadditional protection from high tunnels and lowtunnels at the Southwest Purdue Ag Center inVincennes, IN. Although we are far from comingto a conclusion about the production system inSouthern Indiana, I would like to share with yousome of the facts we have learned in thisjourney.Plant materialsThe most commonly used strawberry plant

materials are bare-root strawberry plants andstrawberry plugs. Strawberry plugs are moreexpensive than bare-root plants. However, plugssurvive better, grow faster, and establish earlier.They are suitable for mechanical transplantingwith a water-wheel. This is particularly beneficialfor large-scale planting. Easy transplanting is alsoan advantage for less experienced growers.Strawberry plugs are normally not available untilthe end of August. Sometimes, it is a dilemmawhether to plant them in late summer. It is truethat any of the warm days in the end summerand fall are very good for plant growth. But onthe other hand, extremely high temperatures(above 95 °F) can cause plant leaf burn (Figure1) and eventually kill the plants. This couldparticularly be a problem in high tunnels.

Figure 1. A severe case of plant leaf burn under hightemperatures.

To attain the same plant growth in the fall, bare-root strawberry plants should be planted 1-2months earlier than the plugs. It is important tonote that bare-root plants do not have an activelygrowing root system, in addition, they areplanted in the middle of summer. Continuousoverhead watering in the first week followingtransplanting is essential to ensure plantsurvival.

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Day-neutral and June bearersMost strawberries grown in Indiana are Junebearing, or short-day plants. Interest exist amonggrowers in day-neutral strawberries for extendedseason production. However, in the experimentaltrials we have done in Southern Indiana, we didnot see a dramatic benefit in terms of seasonextension with day-neutral strawberries. Day-neutral cultivars could produce some fruit in thefall, but the yield is normally too low to justify thelabor cost. It is also true that day-neutralstrawberries can be continuously harvested inthe summer, but the temperature is usually toohigh to allow the plants to produce high qualityberries. Using shade cloth may help to solve theissue. This is an idea that we would like to test inour future trials. So far, growing a combination ofvarieties with the different flowering habit, andthe use of season extension tools, such as highand low tunnels, row covers, etc. isrecommended to extend the harvest period.Winter cold and Spring frost protectionIn general, we recommend use floating rowcovers for the annual strawberry productionsystem (Figure 2). Although row covers are muchmore expensive than straw mulch, benefitsgained from using row covers can normally justifythe cost. First, row covers can be easily removedand recovered. If strawberries were grown insidehigh tunnels, the plants would benefit fromadditional growth in late winter if row coverswere removed in sunny days and covered back atnight. In the open field, it is not recommended toremove row covers in the winter, but temporarilyremoving and recovering the plants is needed toprotect blooms from late frost in the spring.Secondly, compared with straw mulch,strawberry plants covered with row coversnormally develop faster in the spring which leadsto early yields.

Figure 2. Strawberry plants were covered with strawmulch and row covers in the winter

It should be noted that straw mulch is moreeffective at retaining heat compared with rowcovers when temperature is extremely low in thewinter. A detailed comparison of wintertemperatures under straw mulch and row coverscan be found in this articlehttps://vegcropshotline.org/article/strawberry-winter-protection-straw-mulch-vs-row-covers/

Upcoming Events(Lori K Jolly-Brown, ljollybr@purdue.edu)

August 30, 2018 Small Farm Education FieldDay Purdue Daniel Turf CenterContact Lori Jolly-Brown, ljollybr@purdue.eduor 765-494-1296Register here: http://www.cvent.com/d/hgqx6gSeptember 5, 2018 Greenhouse & IndoorHydroponics WorkshopPurdue University, PFEN 1159 & PurdueHorticulture GreenhouseContact Lori Jolly-Brown ljollybr@purdue.eduRegister here: https://tinyurl.com/yaxd4k2zSeptember 24, 2018 Purdue FallWinegrape WorkshopFrom Vineyard to Winery. Registration info and

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itinerary coming soon! Save the date!Contact Jill Blume blume@purdue.eduOctober 17, 2018 Indiana Flower GrowersConferenceDaniel Turf CenterContact Lori Jolly-Brown ljollybr@purdue.eduJanuary 8, 2019 Illiana Vegetable GrowersSymposiumTeibel’s Family Restaurant, Schererville, IN

Contact Liz Maynard emaynard@purdue.eduhttps://ag.purdue.edu/hla/Extension/Pages/IVGS.aspxFebruary 12-14, 2019 Indiana HortCongressIndianapolis Marriott East Indianapolis, INContact Lori Jolly-Brown, ljollybr@purdue.eduor 765-494-1296http://www.inhortcongress.org

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Facts for Fancy Fruit © Purdue University - fff.hort.purdue.eduEditor: Peter M Hirst | Department of Horticulture and Landscape Architecture, 625 Agriculture Mall

Dr., West Lafayette, IN 47907 | (765) 494-1323